Acute and chronic graft-versus-host disease (GVHD) continue to present a significant challenge to physicians, accounting for considerable haematopoietic stem cell transplant (HSCT)-related morbidity and mortality, particularly those patients with steroid-refractory disease.In this review, we discuss recent advances in understanding the underlying pathophysiology, prevention and management of acute and chronic GVHD. Barriers to progress include the difficulty in obtaining high-quality evidence with sufficient patient numbers to identify optimal preventative and treatment strategies, with the heterogeneity of multiple patient, donor, graft and transplant-related factors, in addition to limited availability of human tissue to study the underlying pathophysiology, particularly in steroid-refractory disease. Continued collaborative efforts to improve our understanding of the pathophysiology involved, particularly in steroid-refractory disease, identification of biomarkers to permit risk stratification, and further well-designed randomised clinical trials are essential to help physicians determine optimal GVHD preventative and treatment strategies for each individual patient. An overlap syndrome between the two is well recognised, as is late presentation of aGVHD. In this review, we discuss recent advances in understanding the underlying pathophysiology, prevention and management of aGVHD and cGVHD.Despite significant advances in many areas of haematopoietic stem cell transplant (HSCT) over the last few decades, graft-versus-host disease (GVHD) continues to account for considerable morbidity and mortality. Acute (aGVHD) and chronic (cGVHD) GVHD encompass two different entities with distinct underlying pathophysiologies. However, strategies to prevent and treat aGVHD and cGVHD often overlap. aGVHD typically manifests in the first 3 months post-HSCT as a characteristic rash, secretory diarrhoea, cholestatic liver dysfunction or a combination of these. In addition to the skin, gastrointestinal tract and liver, targets in aGVHD include the thymus gland and endothelium; however, how to clinically stage/grade their involvement has not yet been established3. T-lymphocyte interaction with APCs and subsequent TCR stimulation triggers the activation of tyrosine kinases and a series of intra-cytoplasmic events culminating in the activation of transcription factors, including NF-kB, NFAT and JNK, leading to T-lymphocyte activation and proliferation. This generates an effector T-lymphocyte response leading to tissue damage directly by cellular cytotoxicity and indirectly via the release of further pro-inflammatory mediators, including tumour necrosis factor-alpha (TNF-α), interferon-gamma (IFN-γ) and interleukin 1 (IL-1). Recent studies have investigated intrinsic players that attempt to counteract this inflammatory response, including the role of regulatory T-lymphocytes (Tregs), innate lymphoid cells and invariant natural killer T-lymphocytes (iNKTs)6, as well as identifying new areas involved in promoting the inflammatory response, including the NOTCH pathway, Janus kinase (JAK) signalling and Th17 cells9. Advances in understanding the role of these cell populations and pathways offer potential for clinical translation. The metabolomics employed in this dysregulated immune process has been the subject of recent investigation. Pathways shown to contribute to aGVHD include aerobic glycolysis, oxidative phosphorylation, glutaminolysis and fatty acid oxidation, and understanding these pathways may provide new therapeutic targets10. Involvement of the gut microbiome in the pathogenesis of aGVHD has also been the subject of recent investigation. Gut dysbiosis is associated with an increased risk of aGVHD due to disruption of normal gut immune cells and reduction in bacteria which produce short-chain fatty acids, an important nutritional source for intestinal epithelial cells11. In addition, microbial metabolites play an important role in maintaining the integrity of the epithelial barrier, and their deficiency contributes to epithelial leakiness, pathogen translocation and immune system activation12.Multiple clinical risk factors for aGVHD, including donor-recipient human leukocyte antigen (HLA) disparity, older patient age, conditioning with total body irradiation or high-intensity chemotherapy, and female donor-to-male recipient, have been identified. The pathophysiology underlying aGVHD involves a sequential inflammatory cascade precipitated by initial inflammatory stimuli, including pre-transplant infection and chemo- and/or radio-therapy conditioning with subsequent activation of the immune system by damage-associated molecular patterns (DAMPs) and pathogen-associated molecular patterns (PAMPs) causing a ‘cytokine storm’ and providing an environment that promotes T-lymphocyte migration to sites of tissue damage, activation and proliferation. Alloreactive T-lymphocyte interaction with antigen-presenting cells (APCs) expressing host peptides leads to the initial activation of the T-lymphocyte (cell) receptor (TCR). In addition to cytokine stimulation and APC interaction, TCR co-stimulation is required; positive and negative co-stimulatory mediators studied in aGVHD models include CD28, ICOS, CD40L, CTLA4 and PD1/PD-L114. Elevated endothelial stress markers observed in SR-aGVHD include angiopoietin-2, IL-8, soluble thrombomodulin and hepatocyte growth factor16. Novel transcriptomic findings include increased CHI3L1 and decreased AQP8 gene expression in the gut mucosa of patients with gastrointestinal SR-aGVHD13, and further studies are needed to understand the role of these genes.Previously, steroid-refractory aGVHD (SR-aGVHD) has been assumed to reflect continued T-lymphocyte alloreactivity unrestrained by corticosteroids, but more recent studies suggest that specific pathophysiological mechanisms, including endothelial dysfunction, impaired recipient tissue repair and immune tolerance responses, are at playThe pathophysiology of cGVHD is less well understood. Contributing factors thought to be involved include thymic damage with disruption to central tolerance causing dysregulated T-lymphocyte development, along with dysregulated peripheral tolerance mechanisms, including dysregulated B-lymphocyte immunity, and chronic inflammation and tissue damage with aberrant tissue repair mechanisms .18. Sirolimus, a mammalian target of rapamycin (mTOR) inhibitor, is thought to target effector T-lymphocytes whilst sparing Tregs. A recent single-centre randomised control trial demonstrated that the addition of sirolimus to standard GVHD prophylaxis of CSA and MMF led to significantly reduced rates of grade 2 to 4 aGVHD, associated with improved overall survival and non-relapse mortality but no difference in rates of cGVHD in non-myeloablative matched unrelated donor HSCT19. The absence of nephrotoxicity in comparison with CNIs makes it an attractive option in patients with renal dysfunction, but there are concerns that sirolimus may increase the risk of endothelial injury and associated thrombotic microangiopathy and veno-occlusive disease20. Abatacept, a recombinant CTLA4 fusion protein which interferes with T-lymphocyte co-stimulatory signalling, in addition to standard CNI/MTX-based GVHD prophylaxis, has been shown to be safe and improve rates of aGVHD without increasing the risk of infection or relapse21. Similar success with adding abatacept to standard GVHD prophylaxis has been demonstrated in other studies involving patients with non-malignant conditions23.Calcineurin inhibitor (CNI)-based GVHD prophylaxis has been the longstanding standard of care in matched sibling and unrelated donor HSCT, in combination with either methotrexate (MTX) or mycophenolate mofetil (MMF) . Previou24, and myeloablative conditioning26, and more recent studies have demonstrated its effectiveness in matched donor HSCT28. The mechanisms underlying PTCy continue to be investigated but are thought to involve suppression of proliferating alloreactive T-lymphocytes and deletion of intrathymic clonal alloreactive T-lymphocyte precursors whilst sparing Tregs29.Prophylaxis with post-transplant cyclophosphamide (PTCy) has revolutionised the use of haploidentical HSCT in recent years. This strategy has demonstrated low rates of severe aGVHD and cGVHD in haploidentical HSCT with both reduced intensityIn vivo T-lymphocyte (cell) depletion (TCD) is another method of reducing GVHD risk, most commonly with anti-thymocyte globulin (ATG), a purified polyclonal immunoglobulin G fraction harvested from sera collected from horses or rabbits immunised with human thymocytes or T-lymphocyte lines. ATG has been shown in several prospective randomised trials to particularly reduce the incidence of cGVHD, although it does not confer improved survival in most studies and is associated with viral reactivation33. A better understanding of pharmacokinetics and utilisation of therapeutic drug monitoring to allow individualised dosing regimens, particularly for paediatric patients, presents a potential strategy to reduce GVHD risk whilst optimising immune reconstitution34. Alemtuzumab, an anti-CD52 monoclonal antibody, is a newer approach to in vivo TCD compared with ATG, and comparatively less evidence is available from prospective randomised trials. Its effectiveness in reducing GVHD has been demonstrated, but at the expense of increased infection and relapse risk35.ex vivo methods of TCD has evolved significantly in recent years. Previous methods include CD34+-positive selection and CD3+/CD19+-negative selection. More recent advances include the successful use of HLA-mismatched grafts in which CD3+ T-lymphocytes bearing the TCRαβ receptor and CD19+ cells have been selectively removed, and TCRγδ receptor-bearing T-lymphocytes and natural killer (NK) cells have been preserved39. Other ex vivo TCD methods include removal of naïve T-lymphocytes from the graft whilst keeping memory T-lymphocytes, which was shown to reduce cGVHD (though not aGVHD) without impairing engraftment or increasing infection risk40, and CD34+ selection with an infusion of Tregs and conventional T-lymphocytes on day -4 and D0 of transplant respectively41. Another approach under investigation to exploit the potential benefit of Tregs in reducing GVHD is the use of iNKT cells, a population which expresses both T and NK cell markers and possesses immunomodulatory effects via the production of IL-4 and IL-10 and promotes Treg activation and expansion. A 2017 trial using a synthetic derivative of alpha-galactosylceramide, which binds to CD1 leading to iNKT cell activation and expansion, infused on day 0 was well tolerated and was associated with Treg expansion in a subset of patients who had a lower incidence of aGVHD42.Graft engineering with different 43. The group with non-responsive, progressive or corticosteroid-dependent disease is particularly associated with a poor prognosis45. The underlying pathophysiology of steroid-refractory GVHD (SR-GVHD) is complex and incompletely understood but may involve a less important ongoing role of donor alloreactive T-lymphocytes than in the initiation of aGVHD14. Interference of corticosteroids with Treg-mediated peripheral tolerance, especially when used in combination with agents that disrupt IL-2 pathways47 and the negative impact of corticosteroids on tissue repair and regeneration leading to ongoing mucosal barrier dysfunction and alterations in the intestinal microbiome11, may be more critical. Corticosteroids, along with aGVHD-related thymic damage, impair thymopoiesis, disrupting normal thymic function and delaying the restoration of adaptive T-lymphocyte immunity48.Corticosteroids remain the first-line treatment option for aGVHD, but only about 50% of patients will respond49; therefore, ECP does not increase infection or disease relapse risk. The mechanisms behind ECP have not yet been fully elucidated; it is thought that the ECP procedure induces preferential apoptosis of alloreactive T-lymphocytes, and uptake of apoptotic antigen by APCs precedes multiple processes leading to increased immune tolerance involving dendritic cells, Tregs and changes in cytokine profiles. A small number of ECP-responding patients were shown to display a distinct T-lymphocyte transcriptomic signature with decreased expression of genes important in T-lymphocyte activation, including ERRα and GαS signalling pathways50. Recent studies have also reported the possible contribution of immunomodulatory NK cells to the mechanisms behind ECP52. Confirmation of these findings in additional patients is needed. ECP has repeatedly demonstrated safety and efficacy in SR-aGVHD/cGVHD54 but has often been utilised late in the disease course, and data are limited mainly to small non-randomised studies55. A multi-centre phase 3 trial involving paediatric patients with SR-aGVHD demonstrated an overall response rate of 55% at day 28, increasing to 79% by week 1256. Previous studies suggested better outcomes with earlier adoption of ECP54, and this was observed in a recent phase 2 randomised trial where aGVHD patients who received upfront ECP alongside corticosteroids were more likely to respond compared with those receiving corticosteroids alone, particularly for skin-only aGVHD57. However, use of ECP as part of GVHD prophylaxis did not show a benefit in another randomised trial58.An increasing number of therapeutic options have been investigated for patients with SR-GVHD, although no clear frontrunner has emerged. Extracorporeal photopheresis (ECP) is an apheresis-based therapy involving exposure of mononuclear blood cells to 8-methoxypsoralen and ultraviolet-A radiation, followed by re-infusion of photoactivated cells into the patient. There are no systemic immunosuppressive effects, and ECP facilitates weaning of immunosuppressive medications59. Recent meta-analyses evaluating both prevention and treatment of GVHD with MSCs suggest that they may reduce the incidence of cGVHD but not aGVHD. Some studies have shown that MSCs are effective in aGVHD treatment, but the quality of available evidence is low61. Studies do indicate that MSCs are safe and well tolerated. There are ongoing questions regarding the optimal timing of MSC infusion, and more robust data in the form of well-designed clinical trials are required to confirm their efficacy.Mesenchymal stem cells (MSCs) are another type of cellular therapy with immunomodulatory effects through a diverse range of actions used in both the prevention and treatment of GVHD62. Side effects include cytopaenias and increased infection risk, but there does not appear to be a negative impact on the graft-versus-leukaemia effect9. In the REACH3 randomised trial evaluating ruxolitinib compared with best available therapy for SR-cGVHD, the 6-month overall response rate was superior in the ruxolitinib group (49.7% vs. 25.6%), although complete response rates were low in both groups (6.7% vs. 3.0% respectively), highlighting the difficulty in successfully treating these conditions63. Other early promising data are emerging on selective targeting of JAK1 with itacitinib64 and inhibition of spleen tyrosine kinase65.JAK signalling plays an integral role in the pathogenesis of aGVHD, including the production of inflammatory cytokines leading to activation of APCs and subsequent activation and migration of alloreactive T-lymphocytes. The use of ruxolitinib, a JAK1/2 inhibitor, demonstrated an overall response rate of 62% in patients with SR-aGVHD in the REACH2 trial, a multi-centre randomised trial comparing ruxolitinib with the best available therapy66 and as first-line therapy67. Tyrosine kinase inhibitors (TKIs) are another group of emerging therapies in cGVHD. Ibrutinib is a TKI with inhibitory effects on Bruton’s tyrosine kinase and interleukin-2 inducible T-cell kinase (ITK), consequently blocking B- and T-lymphocyte signalling and activation, respectively, and significant promise has been observed in preclinical studies69. Initial clinical data include a study in which 71% of patients demonstrated a sustained response at a median follow-up of 13.9 months70. Further clinical studies include the iNTEGRATE phase 3 clinical trial investigating upfront ibrutinib in combination with corticosteroids in moderate to severe cGVHD  and an ongoing clinical trial investigating ibrutinib as a first-line solo therapy in cGVHD .Evidence implicating the role of dysregulated B-lymphocyte immunity in cGVHD has prompted the development of B-lymphocyte-directed therapies such as the anti-CD20 monoclonal antibody rituximab, which has shown efficacy in corticosteroid-refractory disease71. In a phase 2 clinical trial, belumosudil, an oral ROCK2 inhibitor, demonstrated an overall response rate of 62% to 69% depending on the dose used, was associated with improved quality of life and weaning of corticosteroids and was well tolerated72. Another randomised multi-centre trial demonstrated an overall response rate of 77%, a sustained (median of 54 weeks) response, and improvement in all organ systems affected73.Other new strategies for cGVHD include targeting the ROCK2 (rho-associated coiled-coil–containing protein kinase-2) signalling pathway, which regulates Th17/regulatory T-lymphocytes. Inhibition of ROCK2 signalling reduces Th17 lymphocytes, promotes Tregs and has an anti-fibrotic effectin vivo T- and NK cell depletion and suppresses T-lymphocyte receptor activation. A phase 1/2 trial involving 20 patients with SR-aGVHD demonstrated a day 28 overall response rate of 60% and a complete response rate of 50%74, and further investigation in a phase 3 trial is in progress (CTN 1802). Other new T-lymphocyte-directed therapies include brentuximab vedotin (targeting CD30 expression on activated CD8+ T-lymphocytes in aGVHD)75 and vedolizumab (anti-α4β7 integrin that inhibits T-lymphocyte migration)76. CD6 is predominantly expressed on T-lymphocytes and binds to activated leukocyte cell adhesion molecule (ALCAM) expressed on APCs and various host tissues and plays an integral role in T-lymphocyte activation, proliferation, differentiation and migration. A phase 1/2 clinical trial  is evaluating itolizumab, a humanized anti-CD6 monoclonal antibody, as first-line treatment for aGVHD alongside corticosteroids. Finally, another novel intervention for GVHD undergoing investigation is faecal transplantation. Disruption of the intestinal microbiome is associated with an increased risk of aGVHD, and restoration of the gut with normal diverse gut flora has been shown to be safe and effective in gastrointestinal SR-aGVHD in some early studies79.Novel approaches on the horizon for managing SR-GVHD include a combination of anti-CD3 and anti-CD7 antibodies conjugated to recombinant ricin A, which induces 80. Other tissue-supportive strategies include epidermal growth factor derived from urinary-derived human chorionic gonadotropin81, lithium82, glucagon-like-peptide-283 and interleukin-2284.Based on recent studies suggesting impaired tissue repair mechanisms in SR-aGVHD, alternative approaches in development target tissue protection and promote recovery following insult. Alpha-1 antitrypsin is a protease inhibitor that protects tissues from proteolytic degradation but, in aGVHD murine models, has also been shown to reduce pro-inflammatory cytokines and increase Tregs and, in a clinical trial, was demonstrated to be safe and effective in SR-aGVHD  and have low rates of infection85 and the Hematopoietic Cell Transplantation-specific Comorbidity Index (HCT-CI)86 or blood biomarkers. Identification of reliable biomarkers in aGVHD and cGVHD would be instrumental in allowing risk stratification. Many candidate biomarkers have been investigated to date, but at present, none is widely used in clinical practice, and this is due mainly to a lack of validation in large prospective clinical trials87. Promising biomarkers evaluated in recent studies include suppressor of tumorigenicity-2 (ST2) and regenerating islet-derived protein 3-α (REG3α) in aGVHD89. The Mount Sinai Acute GVHD International Consortium (MAGIC) algorithm uses these two biomarkers to predict mortality in aGVHD and has the potential to implement early risk-stratified therapies90. Readily available markers indicating endothelial injury  have shown promise in predicting GVHD outcomes 91. Serum albumin at GVHD onset has been shown to identify those with severe disease as well as correlate with prognosis in those with SR-aGVHD93. Amphiregulin, an epidermal growth factor receptor ligand, has also been used to stratify patients into high-risk subgroups in aGVHD94. Promising biomarkers in cGVHD include CXCL9, CXCL10, sBAFF, ST2 MMP3, osteopontin, CD163, IL-17A and IL-2195. Significant morbidity and mortality are associated with long-term high-dose corticosteroids, and future biomarker-guided clinical trials must aim to substitute or reduce corticosteroids by, for example, identifying those who would benefit from alternative upfront therapies or patients who would tolerate a rapid corticosteroid tapering approach.A challenge to physicians is predicting the trajectory of the GVHD course to allow a risk-stratified management approach and pre-emptive therapy for individual patients to improve outcomes. This would allow the reduction of treatment in those with mild disease to lessen the risk of treatment-associated adverse effects and early intensification of treatment in patients projected to have high-risk disease. A risk-adapted approach can utilise clinical factors such as the Minnesota Risk Score for aGVHDDespite significant advances, aGVHD and cGVHD continue to be significant challenges and causes of HSCT-related morbidity and mortality, particularly for patients with corticosteroid-refractory disease. Even when GVHD is controlled by corticosteroids, many patients have adverse side effects and die from infections related to immunosuppression. Barriers to progression in managing patients with SR-GVHD include the inability to accurately risk-stratify, an incomplete understanding of the pathophysiology behind corticosteroid resistance, a deficiency of high-quality evidence to determine optimal treatment strategies, and the difficulties in comparing strategies because of heterogeneity in many factors, including patients, donors and conditioning regimens. Ongoing efforts to improve our understanding of GVHD pathophysiology, development of targeted therapies, further prospective randomised trials to provide more robust data and validated biomarkers, and collaboration between centres will help to inform physicians of optimal GVHD prophylactic and therapeutic strategies and ultimately allow an individualised precision-prevention and treatment approach.


The coronavirus disease 2019 (COVID-19) pandemic began at the end of 2019 in Wuhan, the capital of Hubei Province, China. This novel coronavirus is classified as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Neurological manifestations are commonly associated with moderate to severe COVID-19 infection. Guillain-Barré syndrome (GBS) is a rare immune-mediated postinfectious neuropathy but there has been an increase in the number of cases of GBS associated with COVID-19, supporting the present body of global evidence of the notable association between the 2 conditions. We present the first proven case of GBS and pulmonary embolism associated with COVID-19 infection in Ghana, West Africa.A 60-year-old apparently healthy female presented in August 2020 to the COVID-19 treatment center of the Korle-Bu Teaching Hospital in Accra, Ghana from a referral facility following a week’s history of low-grade fever, chills, rhinorrhoea, and generalized flaccid limb weakness. A positive SARS-CoV-2 test result was recorded 3 days after the onset of symptoms and the patient had no known chronic medical condition. Following cerebrospinal fluid analysis, neurophysiological studies and a chest computed tomography pulmonary angiogram, Guillain-Barre syndrome and pulmonary embolism were confirmed. The patient was however managed supportively and then discharged after 12 days on admission, as he made mild improvement in muscular power and function.This case report adds to the body of evidence of the association between GBS and SARS-CoV-2 infection, particularly from West Africa. It further highlights the need to anticipate potential neurological complications of SARS-CoV-2, particularly GBS even in mild respiratory symptoms for prompt diagnosis and initiation of appropriate therapy to improve outcomes and avert long-term deficits. The classic manifestation is an immune-mediated acute onset demyelinating polyradiculoneuropathy (acute inflammatory demyelinating polyneuropathy) typically presenting with ascending weakness, loss of deep tendon reflexes, and sensory deficits. Well-known causative pathogens include bacteria . Viruses such as cytomegalovirus, Epstein–Barr virus, influenza virus, hepatitis E virus, and recently Zika virus have been also reported.,2 Following the first reported case of coronavirus disease 2019 (COVID-19)-associated GBS in Wuhan, China, there has been extensive case reportageof this new entity further supporting the evidence of the association. This case adds to the reportage as the first proven case of COVID-19-related GBS with pulmonary embolism in Ghana since the confirmation of the first 2 cases in March 2020. The paper will discuss the major clinical and laboratory findings and elucidate possible underlying pathophysiology for the case features therein.Guillain-Barre syndrome (GBS) represents the most common cause of acute flaccid paralysis.A retired, 60-year-old female who was apparently healthy, presented in August 2020 to the COVID-19 treatment center of the Korle-Bu Teaching Hospital in Accra from a referral facility. She had a week’s history of low-grade fever, chills, rhinorrhoea, and generalized limb weakness. The patient had tested positive for COVID-19 infection 3 days following the onset of symptoms. There was no history of cough, pleuritic chest pain, exertional dyspnea or dyspnea at rest, recent calf pain/swelling, prolonged bedrest, long-distance travel and cancer diagnosis in the last 6 months. The generalized weakness was of sudden-onset and progressive, initially involving the lower limbs and extending to the upper limbs. There was no associated bowel or bladder incontinence and no sensory deficit. Her past medical history was negative for hypertension, diabetes or asthma.The patient on presentation was not acutely ill-looking but febrile: 38.2 C, not clinically pale, anicteric, acyanosed, and well-hydrated. There was no palpable lymphadenopathy. A neurological exam revealed a conscious and alert woman with no cranial nerve deficits. She had hypotonia, areflexia and zero power in all limbs . The plantar response was absent bilaterally. No sensory level was elicited. The pulse rate was 96 beats per minute with a regular rhythm, normal precordial findings and the blood pressure reading was 164/94 mm Hg. The respiratory rate was 20 cycles per minute with oxygen saturation of 98% on room air and normal chest findings. The abdominal exam was essentially normal whiles fasting blood glucose reading was 9.1 mmol/L.Lumbar puncture for cerebrospinal fluid (CSF) analysis, neurophysiological studies, chest computed tomography pulmonary angiogram confirmed Guillain-Barre syndrome and pulmonary embolism Tables –3.The nerve conduction study shows electrodiagnostic evidence suggestive of absent motor responses in all the motor nerves evaluated in the upper and lower limbs. The median sensory nerve shows prolonged onset latency, reduced  SNAP amplitude and slowed conduction velocity on the Right. All F-Wave latencies were absent. There was evidence of muscle electrical instability in the muscles evaluated in the upper limbs.Both lung fields are well aerated and showed normal computed tomogram features. No masses or pleural effusion seen bilaterally. Bilateral segmental pulmonary emboli with small wedge-shaped right pulmonary opacity.Linear hypodensity in the anterior limb of the left internal capsule likely a small chronic infarct.Patient’s condition over the period of admission remained relatively stable. She however had labile blood pressure readings ranging between 164/94 mm Hg and 233/123 mm Hg but no respiratory distress or swallowing difficulty and as such intensive care was not initiated. Her quadriplegia improved slightly about 6 days into admission with power in the upper limbs increasing to 2 (MRC 2/5) with regular intensive physiotherapy sessions. Her blood pressures were managed with oral amlodipine 10 mg od, lisinopril 10 mg od and methyldopa 250 mg bid. The newly diagnosed diabetes was managed with oral metformin 1 g bid and gliclazide 30 mg od with resultant controlled blood glucose profile over the period of admission. She was also put on oral Rivaroxaban (Xarelto) 15 mg bd for the pulmonary embolism. Patient’s repeat nasopharyngeal swab for SARS-CoV 2 PCR test 10 days post admission recorded negative and as such discharged to continue physiotherapy and rehabilitation on out-patient basis. Upper and lower limb muscle power was MRC 2/5 upon discharge.Patient was pleased with the prompt manner of diagnostic investigations and efficient nature of treatment offered to ensure the best possible outcome. She remained elated for the degree of recovery achieved with her overall management. The time of specific clinical events, diagnosis and outcomes are available at Figure Guillain-Barre Syndrome; Acute motor sensory axonal variantPulmonary Embolism.Parainfectious myositis.The clinical assessment saw significant improvement in motor and sensory function after day 6 on admission. Patient-assessed outcomes saw gradual improvement after day 6 on admission until she was discharged. No follow-up diagnostic tests were conducted. No major intervention was performed as such, no tolerability had to be assessed. No adverse and unanticipated events were also recorded.The first reported case of COVID-19-associated GBS was reported from China as a suspected parainfectious disease, as the patient developed COVID-19 symptoms 7 days after the onset of GBS symptoms. was mainly characterized by myalgia, fever, and other systemic symptoms from which patients usually recovered after a few days. Neurological manifestations were observed in 30% of the patients during the outbreak.The notable epidemic of severe acute respiratory syndrome that arose from SARS-COV in Asia in February 2003 but none from Sub-Saharan region. GBS is an acute onset demyelinating polyneuropathy with ascending paralysis. The major subtypes of GBS include acute inflammatory demyelinating polyneuropathy, acute motor axonal neuropathy, acute motor sensory axonal neuropathy, and Miller Fisher syndrome. Diagnosis of GBS relies on the results of clinical, electrophysiological, and CSF examinations .,2,7SARS-COV 2 related GBS spectrum disorder has seen increasing reportage globally since the onset of the pandemic and several case reports have already been published thus far, These antibodies portray the strongest association with certain forms of GBS.,10 A likely mechanism is an autoimmune reaction in which the antibodies on the pathogen, which are similar to the protein structures of the peripheral nerve components, cause damage to the nervous system. This similarity has been termed “molecular mimicry” which is defined as the theoretical likelihood that sequence similarities between foreign and self-peptides are enough to lead to the cross-activation of autoreactive B cell or T cell by pathogen-derived peptides.The mechanism of the GBS occurrence is based on molecular mimicry and anti-ganglioside antibodies during or following a susceptible infection in genetically predisposed patients. The onset of ascending weakness with mild respiratory symptoms and the confirmation of RT-PCR SARS - CoV-2 3 days thereafter in our patient is quite atypical. This however shows similarity with 2 reported cases of GBS diagnosed with or before the confirmation of SARS-CoV 2 by RT-PCR.,12Our case is the first patient in Ghana during this COVID-19 pandemic with GBS in SARS-CoV2 infection also likely as a parainfectious process and presented with mild respiratory symptoms and ascending paralysis. This patient tested negative for nasopharyngeal swab reverse transcriptase polymerase chain reaction (RT-PCR) SARS-CoV2 14 days after the first positive test. Neurological presentations of COVID-19 are often associated with severe acute respiratory distress syndrome but our patient presented with a neurological complication following mild COVID-19 symptoms. The timeline of GBS development is usually 1 to 2 weeks after an underlying infection and most cases of COVID-19 related GBS have been reported between 1- and 4-weeks post infection. Cerebrospinal fluid RT-PCR for severe acute respiratory syndrome coronavirus (SARS-CoV-2) RNA was however not performed in our patient and as such difficult to rule out a possible direct central nervous viral invasion or involvement. The other supportive laboratory results are shown in (Table Of diagnostic significance, the CSF examination showed normal cell counts, increased albumin and elevated CSF/serum albumin ratio. These results give an albumin cytologic dissociation profile, the characteristic finding in GBS as shown in Table in Table  and nota,14 In addition, the finding of absent motor responses in this case may be suggestive of presumed distal demyelination with unexcitable nerves. This type of pathology has been reported in GBS with anti GM1 antibodies which ideally should have been tested for in this index case but regrettably not done due to time and resource constraints. This test would have further highlighted the systemic inflammatory nature of SARS-CoV-2 infection with prognostic implications to the development of chronic inflammatory demyelinating polyneuropathy.Neurophysiological studies were successfully performed in this index case and the findings were consistent with acute motor sensory axonal variant GBS Table . RegardiAn interesting and important finding in our patient was the presence of pulmonary emboli with relatively normal lung parenchyma as indicated above. The absence of any history of pulmonary emboli or predisposition to venous thromboembolism makes this pathological finding a part of the COVID-19 sequelae. Thromboembolism due to vasculopathy and coagulopathy induced by SARS-CoV2 infection has been well described and reported.It is also worth highlighting that, dysautonomia, a well-recognized feature of GBS, characterized our patient’s clinical course and was evidenced mainly by new onset elevated labile blood pressure readings for which intensive antihypertensive regimen had to be employed to attain control. New onset moderate hyperglycemia was also observed, which responded well to oral antidiabetic agents as stated above.This case report adds to the body of evidence of the association between GBS and SARS-CoV-2 infection particularly from West Africa. It also supports the increasing global reportage of COVID-19 associated neuropathies and related sequelae. It is imperative to anticipate potential neurological complications of SARS-CoV-2 particularly GBS even in mild respiratory symptoms for prompt diagnosis and initiation of appropriate therapy to improve outcomes and avert long-term deficits.Conceptualization: Eugene Tetteh-Wayoe, Fiifi Duodu, Nana Boakye Agyeman Badu, Patrick Adjei.Data curation: Eugene Tetteh-Wayoe, Fiifi Duodu, Albert Akpalu.Formal analysis: Eugene Tetteh-Wayoe, Fiifi Duodu, Patrick Adjei.Investigation: Eugene Tetteh-Wayoe, Nana Boakye Agyeman Badu, Albert Akpalu, Patrick Adjei.Methodology: Fiifi Duodu, Prince Kwabla Pekyi-Boateng.Resources: Eugene Tetteh-Wayoe.Software: Albert Akpalu.Supervision: Nana Boakye Agyeman Badu.Validation: Fiifi Duodu, Albert Akpalu, Patrick Adjei.Writing – original draft: Eugene Tetteh-Wayoe.Writing – review & editing: Eugene Tetteh-Wayoe, Fiifi Duodu, Prince Kwabla Pekyi-Boateng, Nana Boakye Agyeman Badu, Albert Akpalu, Patrick Adjei.


This report contemplates a unique case of clinically amyopathic dermatomyositis (CADM) that presented as interstitial lung disease. The patient was a 55-year-old woman who showed up with progressive exercise intolerance and a dry cough without muscular or dermatological clinical manifestations. Diagnostic workup and imaging revealed the presence of interstitial lung disease, and further evaluation led to a positive autoimmune panel for anti-nuclear matrix protein 2 (anti-NXP2) and anti-Ro52 antibodies, establishing the diagnosis of anti-NXP2 plus anti-Ro52 antibodies-positive amyopathic idiopathic inflammatory dermatomyositis. The patient was started on intravenous corticosteroids. She showed improvement on her chest X-ray (CXR) and was then switched to oral corticosteroids. After six months of steroid treatment, corticosteroids were stopped, and the patient was re-evaluated one month later disease relapse. Dermatomyositis/polymyositis is a rare immune-mediated disorder belonging to the idiopathic inflammatory myopathies (IIMs) that present with a skin rash and weakness of the proximal limb and neck muscles. Heliotrope rash and Gottron sign/papules are the pathognomonic cutaneous manifestations . SeveralOur report discusses a specific subtype of the disease, anti-Ro52/anti-nuclear matrix protein 2 (anti-NXP2) dermatomyositis, based on the autoantibody profile of the patient ,5, with A 55-year-old female teacher, an ex-smoker (45 pack years), was referred to the emergency department of our hospital after reporting a significant decrease in exercise tolerance starting two months ago, from running 5 km to only 1 km. Her main symptoms were mild shoulder discomfort and a dry, non-productive cough without hemoptysis or dyspnea. Additionally, she mentioned recovery from a mild COVID-19 infection that had been managed conservatively at home three months ago. Her past medical history includes thyroxine replacement therapy for nine years following a thyroidectomy. The patient was admitted to the Department of Respiratory Medicine for further evaluation.Upon admission, the patient was afebrile and normopnoic. Psoriatic-like rashes were observed on the extensor surfaces of the elbows. The cardiac examination did not reveal any pathological findings. On auscultation, velcro-like crackles were heard over the bases of both lungs. Peripheral lymph nodes were normal. No evidence of muscular weakness was noted. The rest of the physical examination was unremarkable.A hypoxemic respiratory failure with an elevated alveolar-arterial gradient was noted Table  accordinA chest X-ray (CXR) was performed Figure , which sBronchoscopy demonstrated no endobronchial abnormalities. Bronchoalveolar lavage (BAL) from the right lower lobe revealed no alveolar hemorrhage and was sent for further evaluation. The polymerase chain reaction for acid-resistant bacteria and acid-fast stains was negative. Additionally, the BAL differential cell count showed lymphocytic predominance Table .A complete immunological panel was conducted Tables -4.Based on the clinical presentation and diagnostic evaluation, several possible diagnoses were considered at first: (i) organizing pneumonia-like post-COVID-19 reaction; (ii) anti-Ro52 interstitial pneumonia with autoimmune features; (iii) COVID-19-related anti-NXP2 dermatomyositis-polymyositis (DM-PM); (iv) anti-NXP2 amyopathic idiopathic inflammatory myopathy (amyopathic DM-PM) presenting as interstitial lung disease with anti-Ro52 progressive phenotype; (v) anti-Ro52/Anti-NXP2 amyopathic idiopathic inflammatory myopathy (amyopathic DM-PM) with connective tissue disease overlap presenting as interstitial lung disease.After a multidisciplinary team meeting including rheumatologists, radiologists, and immunologists, based on the clinical features  of our patient, the specific positive immunological panel results, the prolonged time between the COVID-19 positive test and the appearance of the symptoms, the HRCT scan findings, and the negative PET-CT for malignancy or inflammatory muscle tissue, the anti-NXP2 amyopathic idiopathic inflammatory myopathy (amyopathic DM-PM) presenting as interstitial lung disease with anti-Ro52 progressive phenotype was considered the most appropriate diagnosis.SARS-CoV-2 may cause postinfectious myositis, which may range from direct virus-induced myositis to virus-triggered autoimmunity-related myositis. Patients who have both DM and COVID-19  present Even though hypoxemia indicated a severe presentation of the disease, the patient was initially only treated with steroids  with additional prophylaxis for osteoporosis and pneumocystis jirovecii pneumonia. Because of a remarkable improvement in CXR Figure  and pulmThe patient was reevaluated in our outpatient clinic after one month with a marked improvement both in lung function Table  and in HThe disease remained well controlled Figures -6 after Currently, anti-NXP2 dermatomyositis is a recognized subtype, as the anti-NXP2 antibody, a myositis-specific autoantibody (MSA) . The antAnti-Ro52 antibodies belong to the anti-Ro/SSA family, a group of antibodies that has historically been used as markers of Sjögren syndrome and systemic lupus erythematosus. Ro-52 was described in 1988 as one of the proteins that Ro/SSA antibodies targeted. Ro-52 functions in cell cycle regulation, apoptotic processes, and cellular oxidative stress at the cellular level. The anti-Ro52 antibody is also part of the myositis-associated antibodies group, found in dermatomyositis. However, their low specificity in patients with non-autoimmune disorders makes anti-Ro52 diagnostic value debatable [Over the past years, several researchers have tried to find associations between the anti-Ro52 antibodies and particular clinical features, mostly interstitial lung disease. Studies have shown that patients with positive anti-Ro52 antibodies have a higher frequency of rapidly progressing interstitial lung disease and mortality than those without anti-Ro52 antibodies. Hence, seropositivity for that autoantibody is of negative prognostic value.Interstitial lung disease is a clinical entity that has been observed as one of the most frequent extramuscular manifestations of inflammatory dermatomyositis and is generally associated with poor outcomes . The hisIt is paramount to screen interstitial lung disease (ILD) patients for dermatomyositis , given tTo this end, hospitalized patients presenting with bilateral pneumonia refractory to antibiotics should be meticulously evaluated for myositis-associated ILD, as timely intervention is of vital importance . It has The management of these patients depends on the disease severity at the presentation regarding pulmonary function test status, hypoxemia, and extent of CT involvement, as well as on disease progression, either with an insidious buildup or with an acute exacerbation . In clinDermatomyositis, a rare immune-mediated disorder manifesting with a skin rash and muscle weakness, might also present without any clinical manifestations or laboratory evidence of muscle involvement as an amyopathic variant with interstitial lung disease. A high clinical suspicion is required in order to include clinically amyopathic dermatomyositis in the differential diagnosis of progressive dyspnea in a young woman. We hope our work will help raise further awareness about the unusual presentation of autoimmune disorders through pulmonary manifestation and will be of great interest to physicians who may deal with cases like our own. Myositis-specific autoantibodies such as anti-NXP2 antibodies or myositis-associated antibodies such as anti-Ro52 play a key role in the identification of amyopathic variants, so whenever a physician is dealing with a patient with interstitial lung disease, a complete autoimmunity panel should be ordered. As for the radiological patterns in HRCT, the most prominent are peribronchovascular patchy consolidations and ground-glass opacities with irregular thickening of interlobular septa. Regarding therapeutic options, a relatively stable patient can be treated only with corticosteroids without a second immunosuppressive agent when a very close follow-up for disease progress can be secured.


T-wave inversions on electrocardiograms (ECGs) can present a diagnostic challenge due to their association with various underlying causes. One less-explored cause is memory T-waves, a phenomenon characterized by T-wave inversions, often seen in chest and inferior leads, following a period of abnormal ventricular conduction. In this case report, we discuss the intriguing case of an 80-year-old woman who recently underwent percutaneous coronary intervention (PCI) for a myocardial infarction and subsequently developed memory T-waves. We are also discussing how important it can be to understand and recognize memory T-waves, as it will avoid further unnecessary tests and longer hospital stays. Memory T-waves represent a unique ECG pattern that emerges once normal ventricular conduction is restored after a period of abnormal conduction . This unAn 80-year-old retired woman, who had previously enjoyed good health, presented to the emergency department (ED) two months after undergoing PCI for a myocardial infarction (MI) involving the left anterior descending artery (LAD). Her chief complaints were a general sense of unwellness and mild, non-radiating chest pain rated at 3/10 on the chest pain scale. The pain was different in character when compared with the pain of MI a couple of months ago. It also did not respond to glyceryl trinitrate (GTN) spray Initial blood tests, including a comprehensive metabolic panel (CMP), thyroid function tests (TFTs), and serial troponin measurements, returned unremarkable results. The patient's chest pain resolved with an analgesic (paracetamol).Upon admission, her ECG displayed intermittent left bundle branch block (LBBB) Figure . The bedGiven the patient's previous myocardial infarction and her current medication regimen  inhibitor), she received reassurance and was discharged after ruling out other potential causes of T-wave inversions.Memory T-waves is a term used to describe a phenomenon in electrocardiography (ECG) where the T-wave pattern on an ECG reflects the previous cardiac cycle’s events rather than the current cycle. This phenomenon is important to understand to avoid misdiagnosis and unnecessary investigations .T-wave inversions on ECGs can be attributed to multiple factors, including electrolyte imbalances, medication side effects, pulmonary embolism, ventricular tachycardias, and hypothyroidism. However, in the acute setting, ischemia remains a primary concern . One of The ECG criteria for diagnosing memory T waves include T-wave inversions in precordial and inferior leads with positive or isoelectric T waves in leads I and AVL. These criteria have demonstrated a sensitivity of 100% and specificity of 96% when distinguishing memory T-waves from acute coronary syndrome (ACS) .Identifying memory T-waves can be facilitated by recognizing ECGs with wide QRS complexes before the appearance of T-wave inversions in the same leads .Memory T-waves represent an underreported and often overlooked phenomenon in electrocardiography (ECG). While they have been recognized and studied to some extent, they remain less explored than more common ECG abnormalities like ST-segment changes.Memory T-waves pose a unique diagnostic challenge. Their resemblance to other ECG abnormalities, such as T-wave inversions due to ischemia or other cardiac disorders, can lead to confusion and misinterpretation. Recognizing memory T-waves is critical to avoid unnecessary investigations and treatments . IdentifDespite their clinical relevance, memory T-waves remain an area of limited research. More comprehensive studies are needed to establish diagnostic criteria, prevalence rates, and long-term clinical outcomes associated with memory T-waves.The presentation of memory T-waves can vary among individuals and can be influenced by factors such as underlying cardiac conditions, medication use, and electrolyte imbalances. This variability makes it challenging to establish universal diagnostic guidelines .Mimicry of other ECG abnormalitiesMemory T-waves can mimic other ECG abnormalities, such as Wolff-Parkinson-White syndrome (WPW). This similarity underscores the importance of careful interpretation and the need for additional diagnostic tests to confirm the presence of memory T-waves .The treatment of memory T-waves involves addressing the underlying cause, which can be complex and multifactorial. This may require adjustments in medications, correction of electrolyte imbalances, or optimization of pacemaker settings, depending on the individual patient's circumstances.In a normal cardiac cycle, the ECG waveform consists of the P-wave , QRS complex (ventricular depolarization), and T-wave (ventricular repolarization . The T-wThis phenomenon occurs when there is a delay in the repolarization process of the ventricles, causing the T-wave in one cardiac cycle to reflect the electrical changes from the previous cycle .Important causes of memory T-wavesBradyarrhythmiasSlow heart rhythms, such as bradycardia or heart block, can lead to memory T-waves. In these cases, the prolonged duration of the cardiac cycle allows the T-wave to be influenced by the previous cycle’s events .Pacemaker DysfunctionPatients with malfunctioning pacemakers or pacemaker-induced rhythms can also exhibit memory T-waves .Certain MedicationsDrugs that affect cardiac repolarization, such as antiarrhythmics, may contribute to this phenomenon.Electrolyte ImbalancesAbnormal potassium, calcium, or magnesium levels can disrupt the normal repolarization process and lead to memory T-waves.Identifying memory T-waves on an ECG can provide valuable information about the patient’s cardiac status and rhythm abnormalities . It may Memory T-waves remain a poorly understood aspect of cardiology, often leading to unnecessary investigations and treatments. Enhanced awareness of this phenomenon can help reduce unwarranted hospital admissions and alleviate patient anxiety. While distinguishing memory T-waves from T-wave inversions due to ischemia can be challenging, any doubts should be managed with a cautious approach, treating T-wave inversions as potentially ischemic until ruled out. Greater recognition of memory T waves can enhance patient care, reduce healthcare costs, and prevent undue patient distress.


Evaluating the Crystal Cam handheld gamma-camera for preoperative and intraoperative sentinel lymph node (SLN) localization in early-stage oral cancer.57Co-penpoint marker was evaluated in 15 patients.The handheld gamma-camera was used complementary to conventional gamma-probe guidance for intraoperative SLN localization in 53 early-stage oral cancer patients undergoing SLN biopsy. In 36 of these patients, a blinded comparison was made between preoperative handheld gamma-camera and lymphoscintigraphy outcomes. Of those, the reliability for marking the SLN’s location using both handheld gamma-camera and a n = 36), 71/77 (92%) SLNs were correctly identified by handheld gamma-camera. Overlooked SLNs by handheld gamma-camera were mainly located near the injection site. The SLN’s marked location by handheld gamma-camera and 57Co-penpoint marker was considered accurate in 42/43 (98%) SLNs. The intraoperative use of the handheld gamma-camera led to the extirpation of 16 additional ‘hot’ lymph nodes in 14 patients, 4 of which harbored metastases, and prevented 2 patients (4%) from being erroneously staged negative for nodal metastasis. In those with follow-up ≥ 24 months or false-negative outcomes < 24 months following SLNB, a sensitivity of 82% and negative predictive value of 93% was obtained.In the entire cohort, the handheld gamma-camera preoperatively detected 116/122 (95%) of SLNs identified by lymphoscintigraphy. In those patients where the observer was blinded for lymphoscintigraphy (The Crystal Cam handheld gamma-camera offers reliable preoperative and intraoperative SLN localization and might reduce the risk of missing a malignant SLN during surgery. Detecting SLNs near the injection site by handheld gamma-camera remains challenging. Over the last decade, sentinel lymph node biopsy (SLNB) is being increasingly advocated for staging the clinically negative neck (cN0) in early-stage oral squamous cell carcinoma (OSCC) , 2.Recent trials have confirmed the less-invasive character of SLNB in OSCC, with lower functional morbidity and similar oncological outcomes when compared to elective neck dissection (END) –5.However, as the rate of false-negative SLNB still varies between 5 and 15%, with its accompanying oncological implications , efforts are made to further improve the accuracy of SLNB, especially in floor-of-mouth cancers .Several novel lymphographic techniques have been proposed to improve preoperative identification of sentinel lymph nodes (SLN) . HoweverConventionally, SLNs identified by lymphoscintigraphy (including SPECT/CT) are localized intraoperatively through gamma-tracing using a handheld gamma-probe . Handhel99mTc-nanocolloid), on the other hand, has shown promising results for intraoperative SLN localization  and one patient was upstaged from pN1(sn) to pN2b(sn), which had no therapeutic consequences since the patient chose to undergo complementary radiotherapy instead of a complementary neck dissection followed by adjuvant neck irradiation. The remaining patient was upstaged from pN1(sn) to pN3b(sn), yet opted for complementary radiotherapy only and declined a complementary neck dissection or concurrent chemotherapy.n = 24), the performance of the handheld gamma-camera was considered reliable, but did not provide additional helpful information (45%). None regarded the information provided by the handheld gamma-camera as “confusing”.In 29 patients (55%), the surgeon deemed the complementary use of the handheld gamma-camera as “helpful” for localizing SLNs intraoperatively. In the remaining patients (p = 0.482). In these 10 patients, 2 additional ‘hot’ lymph nodes were harvested on account of information provided by the handheld gamma-camera, none of which harbored metastasis.For the 10 patients in whom also fluorescence guidance was available, the handheld gamma-camera was still considered to be of added value in 4 patients , which did not differ significantly when compared to the rate of patients in whom no fluorescence guidance was available and the handheld gamma-camera was regarded as helpful , a sensitivity of 82% and a NPV of 93% was obtained. The false-negative rate of SLNB in this cohort without the use of the handheld gamma-camera would have been 7.6% (4/53), corresponding with a sensitivity of 64% and a NPV of 87%.In this cohort, two patients developed an isolated nodal recurrence in the side of the neck staged negative by SLNB at 5- and 6-month follow-up, corresponding with a false-negative rate of 3.8%. Accordingly, in those with follow-up ≥ 24 months or false-negative SLNB within 24-month follow-up . The surgeon deemed the complementary use of the handheld gamma-camera helpful for intraoperatively localizing SLNs in 55% of patients.This study evaluated the use of the Crystal Cam handheld gamma-camera in 53 early-stage OSCC (cT1-3N0) patients undergoing SLNB. Overall, this handheld gamma-camera was able to preoperatively detect 95% of SLNs (116/122) as identified by conventional lymphoscintigraphy. When blinded for lymphoscintigraphy, 92% of SLNs were correctly identified by handheld gamma-camera. The marked location of SLNs by handheld gamma-camera and When considering its accuracy in detecting and localizing SLNs, both preoperatively and intraoperatively, the clinical utility of the Crystal Cam handheld gamma-camera in early-stage OSCC appears similar to several other gamma-detecting imaging devices –21, 32. 57Co-penpoint marker. Owing to the close proximity of the handheld gamma-camera to the skin, the majority of SLNs can easily be localized and marked by the nuclear physician using this dual-isotope feature. Since the location of SLNs in definite surgical position may slightly differ from the preoperatively marked location, the handheld gamma-camera can also be used to adjust skin marks intraoperatively [57Co-penpoint marker is small and can easily be incorporated in a sterile setting using a surgical glove, the dual-isotope feature can even be used after the incision is made to further narrow down the exact location of SLNs. Accordingly, this handheld gamma-camera has been introduced within the clinical care of this institution.In addition, the dual-isotope capability of this handheld gamma-camera has shown to enable accurate preoperative localization of designated SLNs by ratively , 13. MorThere are a few shortcomings of the handheld gamma-camera used in this study. First, since it only provides a two-dimensional view, no real-time information on the depth of SLNs can be obtained. Second, as demonstrated by the overlooked and undetected SLNs using the handheld gamma-camera in this study, (handheld) gamma-cameras remain susceptible to the shine-through phenomenon and may, therefore, experience difficulties in detecting SLNs located near the injection site , 10, 12.Certain limitations of this study have to be acknowledged. Most importantly, since the handheld gamma-camera was used in all patients, several of its potential benefits  cannot be assessed. Obviously, the surgical procedure cannot be performed twice in each patient and considerable interpatient variability renders randomization an unrealistic option. Therefore, determining its additional value on these matters is unfeasible. Second, due to the number of surgeons (n = 7) having used the handheld gamma-camera intraoperatively, examination bias is inevitable, even though handling this handheld gamma-camera is intuitive and interpretation of its images fairly straightforward . FinallyIn conclusion, the results of this study demonstrate that the relatively inexpensive and portable Crystal Cam handheld gamma-camera offers reliable preoperative and intraoperative SLN localization in early-stage OSCC patients, which facilitates SLNB and might even reduce the risk of missing a malignant SLN during surgery. Still, detecting SLNs close to the injection site or with low radioactive uptake by handheld gamma-camera can be challenging. In those situations, complementary near-infrared fluorescence imaging may be of additional value.


ACS Central Science, Thoreau et al. report a bioorthogonal chemical ligation techniqueto construct synthetic antibodies, dubbed SynAbs.1 The overall structure of SynAbs mimics the naturally occurringIgG, but they differ in one key aspect: unlike IgGs that specificallyrecognize only one epitope per antibody, SynAbs can be made to containtwo distinct antigen-binding sites, enabling them to bind two biologicaltargets at a time. In other words, they are bispecific.Antibodies, also known as immunoglobulins,are proteins secreted by immune cells to specifically bind foreignantigens, often from invading species. Immunoglobulin G (IgG), oneof the major classes of antibodies, is composed of two heavy chainsand two light chains that are interlinked via disulfide bonds, resultingin two identical fragment antigen-binding (Fab) domains for recognizingbiological targets, and one fragment crystallizable (Fc) domain thatmediates immune reaction and improves stability. In recent years,chemically producing and/or modifying antibodies for improved therapeuticfunctions have attracted attention across the fields of chemistryand medicine. In this issue of 2 However, many of these synthetic strategies areincapable of incorporating the Fc domain that could confer bsAbs withhigher stability, better solubility, longer half-life,3 and enhancement of tumor killing capacity due to Fc-mediatedantibody-dependent cell-mediated cytotoxicity (ADCC) and complementdependent cytotoxicity (CDC) effects.4 Existingmethods for producing Fc-containing IgG-like bsAbs are almost exclusivelyprotein bioengineering, including quadroma cell line technology,5 “knobs-into-holes”,6 CrossMab,7 etc. Despite greatprogress made by these strategies, bioengineering methods are oftenhampered by low yield, complicated purification processes, and lowmodularity.Bispecificantibodies (bsAbs) are attractive as they are capable of recruitingimmune cells to attack tumors or increasing binding specificity. Owingto recent advances in antibody conjugation methodologies, more than200 types of bsAbs have been made for clinical and preclinical trials.9 To construct IgG-like bsAbs, the authors started by producing HER2/HER2bivalent monospecific antibodies. After the site-selective disulfiderebridging reaction of CD20 Fc and HER2 Fab fragments, the duallyclickable-Fc and mono clickable-Fab could be generated to assembleFcCD20-(FabHER2)2 antibodies througha tetrazine-bicyclononyne (BCN) click reaction. The strategies describedby the authors achieved first-in-class purely chemical constructionof full IgG-like bivalent antibodies -FabCD3 construct. Incubatingthe resulting bispecific SynAb with T cells and epithelial carcinomaHCC1954 cells led to T cell activation and HCC1954 cell death, whichdemonstrates its capacity to recruit T cells to attack the targetcells.As a proof-of-concept demonstration, the HER2/CD3bispecific SynAb was used as a bispecific T cell engager (BiTE). TheFc domain of CD20 was functionalized using disulfide rebridging reagentswith two equivalent tetrazine handles, so the FabThe reported strategy is highly modular and easy to industrialize:both Fc and Fab fragments were obtained from commercial mAbs, andthe production of one SynAb was accomplished within 5 days with highyield. It is anticipated that this novel approach could be furtherapplied to generate an array of IgG-like antibodies for biomedicaland clinical investigations. Future improvement of the method couldbenefit from a greater choice of bioorthogonal chemical ligations.For example, if the disulfide rebridging reagents contained two distinctclick handles, antibody assembly processes could be well controlledin a more orthogonal manner. Additionally, the Fc domains could becarefully chosen and further modified to fully unlock the potentialof SynAbs, for example: (1) SynAbs containing an Fc domain are expectedto have a longer half-life, so introducing a suitable Fc domain tocurrently developed non-IgG bsAbs promises to increase their serumhalf-life. (2) Tumor killing capacity could be enhanced through Fc-mediatedADCC and CDC effects; this property could be utilized to improve therapeuticpotency. (3) The Fc domain could be further modified to generate antibody-drugconjugates for cancer treatment. (4) The click handle bearing theFc domain could be used as a platform to attach multiple molecules,such as cytokines or metabolites, for extended functionality. We expectthe functions of Fc-containing SynAbs will be fully exploited, andbioorthogonal chemical conjugation methods will drive technologicalprogress in immune therapy.


Prostate cancer is the second most frequent malignancy in men worldwide and the fifth leading cause of death by cancer. Although most patients initially benefit from therapy, many of them will progress to metastatic castration-resistant prostate cancer, which still remains incurable. The significant mortality and morbidity rate associated with the progression of the disease results mainly from a lack of specific and sensitive prostate cancer screening systems, identification of the disease at mature stages, and failure of anticancer therapy. To overcome the limitations of conventional imaging and therapeutic strategies for prostate cancer, various types of nanoparticles have been designed and synthesized to selectively target prostate cancer cells without causing toxic side effects to healthy organs. The purpose of this review is to briefly discuss the selection criteria of suitable nanoparticles, ligands, radionuclides, and radiolabelling strategies for the development of nanoparticle-based radioconjugates for targeted imaging and therapy of prostate cancer and to evaluate progress in the field, focusing attention on their design, specificity, and potential for detection and/or therapy. Prostate cancer (PCa) is the second most frequent malignancy in men worldwide and the fifth leading cause of death by cancer, with a near estimate of 1.4 million new cases and 375,000 deaths worldwide . Accordi99mTc-labelled bisphosphonate bone scintigraphy (BS) Ga-PSMA-11 or [18F]F-DCFPyL is approved by the US Food and Drug Administration (FDA) and recommended in the Guidelines of the European Association of Urology as an imaging technique of choice for the majority of patients with biochemically recurrent PCa after curative treatment and for assessment of metastases Tc-PSMA agents have been explored for PCa imaging and radio-guided surgery. Although clinical studies have shown that these molecular probes possess high sensitivity and specificity in the initial diagnosis of PCa, monitoring of disease progression and response to therapeutic treatment, none of them exceeds the accuracy and sensitivity of the PSMA PET radiopharmaceuticals Lu-PSMA-617 (PluvictoTM) was approved by the FDA for the treatment of patients with PSMA-positive mCRPC who have previously failed other therapy options [177Lu]Lu-PSMA-617 [177Lu]Lu-PSMA-617 is not efficient for the treatment of micrometastatic disease and circulating tumour cells because β− particles emitted from 177Lu have a relatively long range in the soft tissue (1–10 mm), well beyond a diameter of micrometastases CuS) (64Cu]CuS radioconjugate and untargeted PEG-[64Cu]CuS) radioconjugate, and determined their specific binding and cellular uptake in vitro into aggressive prostate cancer cells PC-3-KD1. The ability of these radioconjugates to accumulate in orthotopic prostate tumours was further evaluated via PET imaging in nu/nu mice bearing PC-3-KD1 tumours. The in vitro results showed that bombesin-targeted showed a much faster cellular binding rate and far better uptake efficiency compared with untargeted NPs.In 2018, Cai et al.  presente4Cu]CuS) . The aut64Cu]CuS NPs had the potential to reduce a nonspecific uptake of NPs by the mononuclear phagocytic system.The PET/CT imaging revealed that in vivo uptake of untargeted NPs by tumour tissue was very low and ranged from 1.2 and 1.4% (ID/g) after 1 and 6 h, respectively. In contrast, the bombesin-targeted radioconjugate gradually accumulated in the tumour tissue, displaying enhanced tumour-to-surrounding tissue contrast and significantly higher tumour accumulation levels . Analysis of biodistribution confirmed the PET/CT data and showed that both bombesin-targeted and -untargeted NPs were highly uptaken by liver. Moreover, untargeted NPs displayed significantly higher uptake than bombesin-targeted NPs in the spleen, suggesting the active targeting capability of the Bom-PEG-PEG-(DFB)3, [89Zr]PEG-(DFB)3(ACUPA)1 and [89Zr]PEG-(DFB)1(ACUPA)3 were tested in PSMA-positive PC3-Pip and PSMA-negative PC3-Flu cells. In vivo PET imaging of the 89Zr-labelled nanocarriers and organ biodistribution studies were performed in the nu/nu athymic mice bearing subcutaneous dual xenografts of PC3-Pip and PC3-Flu tumours. In vitro results revealed that the use of multivalent PSMA binder [89Zr]PEG-(DFB)1(ACUPA)3 with three copies of ACUPA ligands increased PSMA binding affinity and cellular internalization compared with the conjugate containing the single ACUPA ligand.In 2022, Meher et al.  designedchelator . In vitr89Zr]PEG-(DFB)1(ACUPA)3 bearing three ACUPA ligands showed a remarkably higher PC3-Pip/blood ratio and background clearance.In vivo and ex vivo studies revealed that both conjugates demonstrated remarkably higher tumour retention and background clearance in PSMA-positive PC3-Pip tumours compared to nontargeted conjugates. Although targeting significantly improved tumour retention and tissue penetration of both nanocarriers in PSMA-positive PC3-Pip xenografts, the multivalent nanocarrier -AuNP-Lys3-bombesin conjugate in tumour, liver, and spleen. The results revealed a 1.5 times higher uptake by the tumour tissue and tumour-to-blood ratio for the targeted NP-based conjugate than for targeted NP-free [99mTc]-HYNIC-Lys3-bombesin conjugate.In vitro binding studies revealed that the NPs are able to specifically recognise the GRP receptors overexpressed in prostate cancer PC-3 cells. Cellular uptake of the targeted NPs ] in nude mice bearing PC-3 tumour showed ~six-fold higher tumour uptake after 24 h post-injection compared with non-targeted AuNP-DTDTPA-67Ga.Biodistribution studies of this radioconjugate -PSMA-PLGA-CUR accumulated specifically in the tumour tissue in a dose-dependent manner in the LNCaP C4-2 xenograft mice model. The whole-body and ex vivo imaging of multiple organs proved that the NP-based radioconjugate retained within the tumour tissue at a much higher level than the NP-free [131I]-PSMA targeting antibody. In contrast to the tumour, other organs exhibited minimal 131I radioactivity from the NP-based radioconjugate.The results indicated that these NPs efficiently inhibited the growth of PCa cells both in vitro and in vivo. The NP-based radioconjugate [111In by DOTA chelation. The hydrophobic antiangiogenic drug sorafenib was loaded onto these nanoparticles for chemotherapeutic applications  and radiolabelled with 64Cu [64Cu]DOTA-cys-DB-PEG-LNP, and NP-free doxorubicin radiolabelled with 64Cu [64Cu]DOTA-Dox  compared to the NP-based untargeted [64Cu]DOTA-Dox-PEG-LNP radioconjugate (10% ID/g) and NP-free untargeted [64Cu]DOTA-Dox radioconjugate (3% ID/g). Moreover, a four-fold increase in tumour uptake was observed for NP-based untargeted radioconjugate containing doxorubicin [64Cu]Dox-DOTA-PEG-LNP (10% ID/g) compared to NP-free untargeted doxorubicin [64Cu]-DOTA-Dox (3% ID/g).A pharmacokinetic study revealed that blood clearance of a covalent mixture of NP-based [3), comprising a small molecule Lys–urea–Glu-based PSMA inhibitor (PSMAL), PEG2000, and palmitate linker, and radiolabelled with 99mTc radionuclide or loaded with doxorubicin . The purpose of this study entitled, “Molecular Phenotyping and Image-Guided Surgical Treatment of Prostate Cancer Using Ultrasmall Silica Nanoparticles”, is to determine the usefulness of [225Ac and 223Ra). This prevents daughter radionuclides from escaping from the target site and reduces toxic side effects. In addition, nanoparticles allow overcoming difficulty in the stable attachment of some radionuclides  to the targeting ligands. Moreover, they allow encapsulation and delivery of drugs , sorafenib, and curcumin) into the tumour. The in vivo results confirmed the controlled release of the drug over a long period of time, increasing therapeutic index, accumulation into the tumour tissues, and inhibition of the tumour growth. Furthermore, the most important advantage of some NP-based radioconjugates is the possibility to deliver the drug and imaging agent(s) at the targeted site to diagnose and treat the PCa. Despite these many advantages of the NP-based radioconjugates, there are still some disadvantages/challenges hampering their translation to the clinic. One of the biggest problems in the use of NP-based radioconjugates is their entrapment in mononuclear phagocytic systems. Surface modification of NPs with polyethylene glycol (PEG) prevents their agglomeration and results in prolonged presence in circulation due to hindered recognition and phagocytosis, but this strategy is not efficient against accumulation in non-tumour tissues. The next important disadvantage of these radioconjugates is the lack of adequate knowledge about their long-term impact on cellular signalling pathways and biochemical processes of the human body. Another disadvantage is poor control of degradation, pharmacokinetics, and biodistribution in vivo. Therefore, for each promising NP-based radioconjugate evaluated in preclinical studies in vitro, the risk-to-benefit ratio should be determined in vivo before introducing them to the clinic.Recent developments in the field of NP-based radioconjugates for targeted imaging and therapy of PCa have revealed a wide diversity of design approaches and methods of preparation. The most important advantage of these radioconjugates is highly specific targeting . This pr


Bile leakage (BL) is a challenging complication after hepatobiliary surgery and liver trauma. Gadolinium ethoxybenzyl (Gd-EOB-DTPA)–enhanced magnetic resonance cholangiopancreatography (MRCP) is used to diagnose BL non-invasively. We assessed the value of Gd-EOB-DTPA-MRCP in the detection of postoperative and post-traumatic BL hypothesizing that exact identification of the leakage site is pivotal for treatment planning and outcome.We retrospectively enrolled 39 trauma and postoperative patients who underwent Gd-EOB-DTPA-MRCP for suspected BL. Three readers rated the presence of BL and leakage site . Imaging findings were compared to subsequent interventional procedures and their complexity and outcome.p < 0.001). Aberrant or disconnected ducts were diagnosed in 8%/26% of cases in the postoperative subgroup. Inter-rater agreement for the detection and localization of BL was almost perfect . Intraparenchymal BL required significantly less complex interventional procedures (p = 0.002), whereas hospitalization and mortality did not differ between the subgroups (p > 0.05).BL was detected in Gd-EOB-DTPA-MRCP in 25 of patients and was subsequently confirmed. Sites of BL differed significantly between postoperative  and trauma patients (intraparenchymal [100%]; Gd-EOB-DTPA-MRCP reliably detects and exactly locates BL in postoperative and trauma patients. Exact localization of biliary injuries enables specific treatment planning, as intraparenchymal leakages, which occur more frequently after trauma, require less complex interventions than central or peripheral leaks in the postoperative setting. As a result of specific treatment based on exact BL localization, there was no difference in the duration of hospitalization or mortality.Gd-EOB-DTPA-MRCP is a reliable diagnostic tool for exactly localizing iatrogenic and post-traumatic biliary leakage. Its precise localization helps tailor local therapies for different injury patterns, resulting in comparable clinical outcomes despite varying treatments.• Gd-EOB-DTPA-MRCP enables adequate detection and localization of bile leakages in both postoperative and post-traumatic patients.• The site of bile leakage significantly impacts the complexity of required additional interventions.• Intraparenchymal bile leakage is commonly seen in patients with a history of liver trauma and requires less complex interventions than postoperative central or peripheral bile leakages, while hospitalization and mortality are similar. Bile leakage (BL) following hepatobiliary surgery is a complication with growing importance due to a rising number of complex hepatic and biliary surgical procedures and can impact duration of hospitalization or cause liver failure , 2. The Initially, BL is often suspected when there is bile in abdominal drainages. Ultrasound, computed tomography (CT), and magnetic resonance imaging (MRI) with magnetic resonance cholangiopancreatography (MRCP) detect intra-abdominal fluid collections and assess their relationship to biliary structures. These primary imaging findings often trigger further investigations of the underlying cause, but are insufficient in providing evidence of active biliary leakage .In routine clinical practice, the question of whether BL is present is often already answered by bile in the drains while various methods have been established to confirm and treat BL , 8. HoweEndoscopically, BL can be classified into low grade (identified only after intrahepatic opacification) or high grade (visible before intrahepatic opacification) . SeveralWith gadolinium ethoxybenzyl-diethylenetriaminepentaacetic (Gd-EOB-DTPA), approximately 50% of the contrast agent is taken up by hepatocytes and excreted by the biliary system . ContrasThe purpose of this study was to assess the clinical relevance of Gd-EOB-DTPA-MRCP in the detection and exact localization of postoperative and post-traumatic BL. The two subgroups were compared retrospectively regarding the site of BL , duration of hospitalization, liver laboratory parameters, mortality, and complexity of required interventional procedures after imaging.This retrospective study was approved by the regional committee for research ethics . Our database search revealed 47 patients who were scheduled for Gd-EOB-DTPA-MRCP after hepatobiliary surgery or hospital admission due to abdominal trauma with liver injury between October 2016 and April 2021. Eight patients had to be excluded from the final analysis due to missing data after Gd-EOB-DTPA-MRCP. We thus included a total of 39 patients.In postoperative patients, BL is clinically defined as fluid with an elevated bilirubin concentration in the abdominal drain (three times the serum bilirubin concentration measured at the same time) . In the In the post-traumatic subgroup, patients presented with a history of abdominal trauma and underwent whole-body trauma CT using the local standard trauma protocol. BL was suspected when liver injury and adjacent fluid collections were visible on CT in conjunction with suggestive clinical findings or altered liver function on laboratory parameters. All patients in both subgroups then underwent Gd-EOB-DTPA-MRCP.®, Bayer AG) followed by a 20-mL saline infusion at a rate of 2 mL/s through a peripheral venous catheter with a minimum size of 20G; (5) 3D GRE axial T1-weighted imaging with fat suppression 15, 50, 90, and 120 s after contrast administration; (6) axial T2-weighted fast spin-echo imaging; (7) 3D GRE axial T1-weighted imaging with fat suppression 4 min after contrast administration; (8) axial T2-weighted fast spin-echo sequence with fat suppression; (9) axial diffusion-weighted imaging; (10) sagittal T1-weighted fast low-angle shot imaging with a flip angle of 70°; (11) hepatobiliary phase imaging with a slice thickness of 3 mm or less: 3D GRE axial T1-weighted imaging with fat suppression 20 min (n = 20 patients), 30 min (n = 1 patients), or at both of these timepoints (n = 26 patients) after contrast administration; and (12) additional late-phase (> 240 min) 3D GRE axial T1-weighted images with fat suppression in patients with borderline biliary excretion and/or a dilated biliary tree (n = 7).MRI was performed on a 1.5-Tesla scanner  using a phased-array body coil with the patient in supine position using the following clinical imaging protocol: (1) in- and out-of-phase non-enhanced T1-weighted axial 3D gradient-echo (GRE) sequences; (2) coronal T2-weighted non-enhanced MRCP sequences; (3) non-enhanced fat-suppressed 3D GRE axial T1-weighted imaging; (4) intravenous administration of 9 mL Gd-EOB-DTPA  in abdominal MR imaging who were blinded to clinical data. Adequate biliary excretion was defined as visible contrast excretion into the biliary tree. BL was defined as contrast agent extravasation outside the biliary system during the hepatobiliary or late phase. BL was assigned to one of three sites: (1) intraparenchymal BL confined by surrounding liver tissue, (2) peripheral BL extending to or beyond the liver capsule including the hepatic resection margin, and (3) central BL due to injury of perihilar bile duct or the biliary confluence as well as leakage from a biliodigestive anastomosis. The presence of aberrant or postoperatively disconnected bile ducts was documented accordingly in a binary fashion (yes/no). In case of discrepancies between the readers after the initial blinded evaluation, a consensus reading was performed for further statistical evaluation. Findings were compared to subsequent ERCP, percutaneous transhepatic cholangiography (PTC), or surgical therapies.Regarding the complexity of interventional procedures after MR imaging, we allocated patients with ERCP ± papillotomy or drainage change only to the “standard” group and patients with a history of ERCP and stent implantation, PTBD, radiofrequency ablation (RFA) of leakage site, biliary embolization, or percutaneous biloma drainage to the “complex” group.Patient and laboratory data were retrieved from the local Radiology Information System .t-test was performed to identify possible differences between two groups. The Wilcoxon rank-sum test was performed for non-parametric variables. Inter-rater variability was evaluated by kappa statistics. Statistical significance was defined as p ≤ 0.05.Statistical analysis was performed using Stata/MP . Patient characteristics are expressed as mean and range. Normal distribution was analyzed with the Kolmogorov-Smirnov test. The paired-sample p = 0.007). The most frequent initial indication for surgery in the postoperative subgroup was right hepatectomy in twelve patients, followed by atypical liver resection in seven patients and cholecystectomy in six patients. In the post-traumatic subgroup, five patients were admitted for blunt and two patients for penetrating liver trauma.Table Κ = 0.85; p < 0.001) and localization of BL . Eighteen (72%) of the BL detected by Gd-EOB-DTPA-MRCP were interventionally confirmed by ERCP or PTC. When aberrant bile ducts or disconnected ducts are present, leakage cannot be detected by ERCP/PTC; in all of these cases (n = 7), ERCP/PTC ruled out leakage from ducts that were connected to the biliary tree. The diagnosis in these cases was also confirmed by persistent bile leakage via the indwelling drains. BL was visible in 100% of MRIs in the hepatobiliary phase (either 20 or 30 min after contrast agent administration) in patients with adequate biliary excretion. Seven patients had inadequate hepatic contrast agent excretion in hepatobiliary phase imaging after 30 min (three patients with poor or borderline biliary excretion and four patients with dilated bile ducts). Three of these seven patients showed BL detected exclusively in very late-phase images (> 240 min). Mean time from hospital admission (post-traumatic subgroup) or surgery (postoperative subgroup) to Gd-EOB-DTPA-MRCP was 17.6 days. In the trauma subgroup, Gd-EOB-DTPA-MRCP was performed significantly earlier . Elevated liver function parameters (either liver enzymes or bilirubin) were detected in eight patients prior to the MRI examination (< 48 h). There was no significant correlation between elevated liver laboratory parameters and the presence of BL (p = 0.916). Sites of BL differed significantly between the two subgroups: all post-traumatic patients were diagnosed with intraparenchymal BL (100%), while central (58% of postoperative subgroup) and peripheral (42% of postoperative subgroup) BL were observed in postoperative patients only (p < 0.001). In five patients of our cohort with confirmed peripheral BL, Gd-EOB-DTPA-MRCP detected the presence of leakage from disconnected bile ducts after surgery. Three of these patients were successfully treated with RFA, the other two patients underwent a percutaneous biliary embolization, which led to subsidence of the perihepatic biloma. An aberrant bile duct responsible for the leakage was identified in two patients, treated by percutaneous embolization in one case and percutaneous biloma drainage in the other.Results of retrospective Gd-EOB-DTPA-MRCP readings as well as data on subsequent interventions and outcome are summarized in Table p = 0.002). Of six patients with confirmed BL in the trauma subgroup, two patients did not need further interventions, two patients underwent ERCP and papillotomy and another two patients received a simple change of drainages (inserted during emergency surgery performed before MRI). No patient with traumatic intraparenchymal BL required complex local treatment. Conversely, 14 of 19 patients (74%) with confirmed BL in the postoperative subgroup underwent complex interventional procedures including biliary stenting (43%), ablation of disconnected biliary ducts (21%), PTBD (14%), percutaneous biloma drainage (14%), biliary embolization of aberrant/disconnected ducts (14%), and one patient needed surgical revision due to the size and central location of the biliary defect. There were no significant differences in duration of hospitalization and mortality between the two subgroups (p = 0.390).Patients in the postoperative subgroup underwent significantly more complex interventional procedures after Gd-EOB-DTPA-MRCP-based diagnosis of BL compared to trauma patients  Gd-EOB-DTPA-MRCP enables the detection and precise localization of BL, in both postoperative and trauma patients; (2) Gd-EOB-DTPA-MRCP-based detection and localization show high agreement between readers with different levels of experience; (3) intraparenchymal BL is typical for a history of liver trauma whereas central or peripheral BL is more common after hepatobiliary surgery; (4) patients with intraparenchymal BL require fewer complex interventional procedures than patients with central or peripheral BL following hepatobiliary surgery; (5) although treatment differs significantly for different sites of BL, Gd-EOB-DTPA-MRCP allows adequate treatment planning, so that there are no significant differences in hospitalization duration and mortality.In our study, Gd-EOB-DTPA-MRCP detected all cases of ultimately proven BL in hepatobiliary and late-phase imaging and accurately identified leakage sites in a relatively large population. Similar findings were reported by Castellanos et al, who detected 100% of bile leaks in postoperative patients by Gd-EOB-DTPA-MRCP 20 min after contrast agent administration . MoreoveOn the other hand, central and peripheral BL is more frequently seen in postoperative patients, who required more complex interventions than intraparenchymal BL. This could be attributable to the unconstrained excretion of bile into the adjacent peritoneal cavity with a higher risk of biliary peritonitis. Central and peripheral leaks are typically treated with endoscopic stents or, in the case of biliodigestive anastomosis, with PTBD. In rare cases, however, the bile duct defect is so large that surgical revision is necessary Fig. . PeripheA major challenge in hepatobiliary surgery, both diagnostically and therapeutically, is leakage from disconnected or aberrant bile ducts as these leaks usually cannot be treated by an endoscopically placed stent or PTBD. In our study, Gd-EOB-DTPA-MRCP could identified such ducts in seven patients with peripheral BL. In these cases, imaging findings led to the decision to perform RFA/embolization instead of standard internal or external drainage  Figs. 55 and 6.FOur study has some limitations. The two groups we investigated differed significantly in age and preexisting conditions, which might have confounded the results, specifically clinical outcome. Interventional confirmation of the imaging diagnosis was only evaluated when BL was suspected in Gd-EOB-DTPA-MRCP, so that the sensitivity of the method could not be determined, nor was this our intention as several studies on this topic have already confirmed the high sensitivity of Gd-EOB-DTPA-MRCP . MoreoveIn conclusion, Gd-EOB-DTPA-MRCP is a reliable noninvasive method to detect and to exactly localize iatrogenic and post-traumatic BL, which typically differ in the site of biliary injury. Intraparenchymal leakages, which occur more frequently after trauma, require less complex interventions compared to central or peripheral postoperative BL. The exact localization of the leakage by Gd-EOB-DTPA-MRCP makes it possible to plan a tailored local therapy for specific injuries, so that comparable clinical outcomes can be achieved despite different treatments.


The SARS-CoV-2 virus, causing the devastating COVID-19 pandemic, has been reported to affect platelets and cause increased thrombotic events, hinting at the possible bidirectional interactions between platelets and the virus. In this review, we discuss the potential mechanisms underlying the increased thrombotic events as well as altered platelet count and activity in COVID-19. Inspired by existing knowledge on platelet–pathogen interactions, we propose several potential antiviral strategies that platelets might undertake to combat SARS-CoV-2, including their abilities to internalize the virus, release bioactive molecules to interfere with viral infection, and modulate the functions of immune cells. Moreover, we discuss current and potential platelet-targeted therapeutic strategies in controlling COVID-19, including antiplatelet drugs, anticoagulants, and inflammation-targeting treatments. These strategies have shown promise in clinical settings to alleviate the severity of thrombo-inflammatory complications and reduce the mortality rate among COVID-19 patients. In conclusion, an in-depth understanding of platelet–SARS-CoV-2 interactions may uncover novel mechanisms underlying severe COVID-19 complications and could provide new therapeutic avenues for managing this disease. The economic burden caused by COVID-19 is also tremendous. Most COVID-19 patients exhibit mild to moderate symptoms; however, at the beginning of pandemic, around 15% of patients developed severe pneumonia, and approximately 5% progress to acute respiratory distress syndrome or/and multiple organ failure . P. P163]. receptor . Serotonreceptor . Comparereceptor . Howeverreceptor . Platelereceptor . ConsideConsidering the extraordinary thrombotic effects platelets exert during the development of inflammatory conditions, it is promising to utilize antiplatelet drugs or develop novel antiplatelet therapies in controlling or treating COVID-19 ,169. A sIn addition to antiplatelet strategies, anticoagulants have been used to ameliorate thrombotic events in COVID-19 . FurtherThroughout the course of the COVID-19 pandemic over the past three years, a multitude of studies had reported increased thrombotic events and platelet alterations, notably in terms of platelet count and volume. The escalated platelet activation and aggregation induced by inflammation and endothelial dysfunction in COVID-19 indicate that SARS-CoV-2 coronavirus may affect the function of platelets by either directly invading them or indirectly altering their transcriptome. In accordance with the previous literature, platelet–microbial pathogen interactions are bidirectional and are involved in the pathology of many diseases, which provides insights into about the mechanisms of anti-SARS-CoV-2 activity of platelets. Inspired by the knowledge of interactions between platelets and known pathogens and the anti-microbial activity of activated platelets, we proposed possible mechanisms by which platelets antagonize SARS-CoV-2 coronavirus, including directly killing viruses and recruiting immune cells to eliminate viruses. We also cast eyes on well-developed therapies or ongoing clinical trial of novel drugs targeting platelets and platelet-mediated thrombo-inflammatory complications, which have been reported to exhibit promising therapeutic effects in COVID-19 patients. Overall, we maintain that understanding platelet–SARS-CoV-2 interactions could shed light on how severe COVID-19 complications arise and that modulation of this interaction could lead to new therapeutic possibilities.