Fungal infections may occur within tattoos. These include not only dermatophyte infections (tattoo-associated tinea) but also systemic mycoses . The PubMed search engine, accessing the MEDLINE database, was used to search for all papers with the terms: (1) tinea and tattoo, and (2) systemic fungal infection and tattoo. Tattoo-associated tinea corporis has been observed in 12 individuals with 13 tattoos; this includes the 18-year-old man who developed a dermatophyte infection, restricted to the black ink, less than one-month after tattoo inoculation on his left arm described in this report.Trichophyton rubrum, Epidermophyton floccosum, Microsporum canis, Microsporum gypseum, and Trichophyton tonsurans. Several sources for the tinea were documented: autoinfection (two patients), anthrophilic (tinea capitis from the patient’s son), and zoophilic (either the patient’s cat or dog). Three patients presented with tinea incognito resulting from prior corticosteroid treatment. Tinea appeared either early  in six patients or later  in six patients.Tattoo-associated tinea typically occurred on an extremity in the black ink. The diagnosis was established either by skin biopsy, fungal culture, and/or potassium hydroxide preparation. The cultured dermatophytes included Injury to the skin from the tattoo needle, or use of non-sterile instruments, or contaminated ink, and/or contact with a human or animal dermatophyte source are possible causes of early tinea infection. Tattoo ink-related phenomenon  and/or the creation of an immunocompromised cutaneous district are potential causes of late tinea infection. Treatment with topical and/or oral antifungal agents provided complete resolution of the dermatophyte for all the patients with tattoo-associated tinea.Acremonium species, Aspergillus fumigatus, Purpureocillium lilacinum, Saksenaea vasiformis, and Sporothrix schenckii. Contaminated tattoo ink was a confirmed cause of the systemic fungal infection in one patient; other postulated sources included non-professional tattoo inoculation, infected tattooing tool and/or ink in an immunosuppression host, and contaminated ritual tattooing instruments and dye. Complete resolution of the tattoo-associated systemic fungal infection occurred following systemic antifungal drug therapy.Tattoo-associated systemic fungal infection has been reported in six patients: five men and one patient whose age, sex, immune status, and some tattoo features  were not reported. The onset of infection after tattoo inoculation was either within less than one month (two men), three months (two men), or 69 months (one man). The tattoo was dark (either black or blue) and often presented as papules (three men) or nodules (two men) that were either individual or multiple and intact or ulcerated. The lesion was asymptomatic (one man), non-tender (one man), or painful (one man). The systemic fungal organisms included In conclusion, several researchers favor that tattoo inoculation can be implicated as a causative factor in the development of tattoo-associated tinea; however, in some of the men, tattoo-associated systemic fungal infection may have merely been coincidental. Epidermophyton, Microsporum, and Trichophyton organisms. They can affect the hair, nails, and skin. Tinea corporis is a dermatophyte infection of the skin [Dermatophyte infections can be caused by the skin -8.Tattoos are a form of body adornment. They can be associated with cutaneous complications such as hypersensitivity reactions to the tattoo ink and skin cancer. In addition, albeit less commonly, either tinea or a systemic fungal infection has developed within a tattoo ,9.A man who developed tinea corporis that was located within a black tattoo on his forearm and presented with tinea incognito is described. The purpose of this paper is to review the features of individuals with dermatophyte infection that has been observed to occur within a tattoo. In addition, the rationale for this report is to summarize the characteristics of persons with tattoo-associated systemic fungal infections. These issues are of importance since they provide evidence of a potential role of tattooing as a contributing etiology for dermatophyte and systemic fungal infection within a tattoo -15.A healthy 18-year-old Caucasian man presented for evaluation of a new asymptomatic red rash that he noticed on his left upper extremity. Four months earlier, a green and red tattoo had been inoculated on his left forearm. Within a month of receiving the tattoo, the skin lesion appeared only on an area of green ink.He was evaluated by a physician. A bacterial culture was performed, and he was prescribed double-strength trimethoprim-sulfamethoxazole twice daily for ten days and topical 0.1 percent triamcinolone cream twice daily. The culture was negative for bacteria, and he continued to use the corticosteroid cream.Three months later, the rash was still present and had enlarged; he was seen by a dermatologist. Cutaneous examination showed a non-tender, 1.0 x 1.0 centimeter erythematous plaque with superficial scaling on his left forearm. The plaque, which had originated in the green tattoo ink, had extended to the adjacent skin  with focal mounds of retained epithelial cell nuclei within the thickened stratum corneum (parakeratosis) overlying the mildly thickened (acanthotic) epidermis. There were focal areas showing widening of the intercellular spaces (spongiosis) in the epidermis. There was a sparse, predominantly perivascular, infiltrate of lymphocytes in the upper dermis. Both hematoxylin and eosin and periodic acid-Schiff (PAS) stains demonstrated fungal hyphae in the stratum corneum Figures , 3.Correlation of the clinical presentation and pathologic findings established the diagnosis of tinea corporis originating within a tattoo; the persistent use of the topical corticosteroid cream had resulted in an atypical presentation of his dermatophyte infection: tinea incognito. The 0.1 percent triamcinolone cream was discontinued. He was treated with two percent ketoconazole cream twice daily to the affected area on his forearm.Follow-up examination, four weeks later, showed complete resolution of his tattoo-associated tinea infection.An atypical presentation of tinea corporis (tinea incognito) occurred within a recently inoculated tattoo on the forearm of a healthy young man. The infection was initially misinterpreted as a bacterial infection and dermatitis. When the lesion failed to resolve after treatment with oral antibiotics and a mid-potency topical corticosteroid cream, the microscopic evaluation of a skin biopsy from the lesion established the diagnosis of a dermatophyte infection. It is important for clinicians evaluating patients who have tattoos to be aware of the possibility of tinea corporis or a systemic fungal infection originating within the tattoo. This paper discusses tattoo-associated tinea, tattoo-associated systemic fungal infections, and whether the relationship between tattoos and tinea or systemic fungal infections is bona fide or coincidental.Several infections have been observed to occur within a tattoo ,9. TheseThe history of published reports of tattoo-associated tinea is summarized in Table Trichophyton tonsurans was cultured from both the tattoo-related tinea lesions on her leg and the tinea capitis site on her five-year-old son’s scalp [It was more than 20 years later before Ammirati reported the next patient with tattoo-associated tinea in 2004. The investigator described a woman who developed pruritic, peripherally expanding concentric lesions which had a vesiculopustular border that developed within the black tattoo that had been inoculated 18 days earlier. Microsporum gypseum-related dermatophyte skin lesions in the black cosmetic eyebrow tattoos that had been performed four weeks earlier. They were initially mistaken for an allergic reaction to the tattoo pigment, treated topical and systemic corticosteroids for a month, and spread to involve her forehead and cheeks prior to the actual diagnosis of tinea faciei being established [Tattoo-associated tinea incognito was subsequently described in 2012. A 63-year-old woman developed In addition to the man in this report, another patient with tattoo-associated tinea incognito was also reported in 2018. The other patient was a 52-year-old man with evidence of tinea pedis and toenail onychomycosis whose right calf tattoo of four years had received 18 consecutive months of topical treatment  for an allergic reaction to the red tattoo pigment. Three months earlier, the tattoo reaction had enlarged and became more pruritic; a potassium hydroxide preparation of the current erythematous and scaling patch revealed septate fungal hyphae [Microsporum canis on her left calf was described. The dermatophyte skin lesions appeared within the tattoo 18 days after inoculation. Her pet dog also had Microsporum canis mycosis [In 2016, a 29-year-old woman with tattoo-associated  mycosis .Trichophyton rubrum (three patients) or Epidermophyton floccosum were cultured [Four patients were reported by investigators in 2019. All the individuals had a black tattoo of more than two months duration. Either cultured .Microsporum canis was described; tinea lesions developed on her right forearm 12 days after inoculation and on her left thigh six days after inoculation. Her sister, who lived with the patient, had similar lesions on her tattoo-free abdomen. In addition, the patient’s pet cat had ringworm-related hair loss that was begin treated by the veterinarian [Recently, another woman with black tattoo-associated rinarian .The epidemiologic features and clinical characteristics of tattoo-associated tinea are summarized in Table Four men and four women with tattoo-associated tinea have been described; the sex was not provided for four patients. All the patients ranged in age from 18 years to 63 years . The men ranged in age from 18 years to 52 years  and the women ranged in age from 27 years to 63 years .The duration of the tattoo--from inoculation until the patient became aware of the dermatophyte lesion within the tattoo--varied from six days to nearly six years. Indeed, the tattoo duration prior to the discovery of tinea is likely to be influenced by the pathogenesis of tattoo-associated tinea in that individual. Six of the patients (with seven tattoos) developed tinea within one or less months after tattoo inoculation: six days to one month . In contrast, six individuals experienced a later occurrence of dermatophyte infection ranging from more than two months (four patients) to either 45 months or 71.25 months after they received their tattoo.Trichophyton rubrum (four patients), Epidermophyton floccosum (two patients), Microsporum canis (two patients), Microsporum gypseum (one patient), and Trichophyton tonsurans (one patient). The organism was not cultured in two of the patients.The diagnosis of tinea was based only on the presence of hyphae observed on the potassium hydroxide preparation (one patient), demonstration of hyphae on the tissue specimen from a skin biopsy (one patient), or both observation of hyphae on the potassium hydroxide preparation and culture of the dermatophyte organism (ten patients). The identification of the dermatophyte included Trichopyton rubrum) and tinea cruris (potassium hydroxide preparation-positive) and the 52-year-old man had clinical findings of tinea pedis and toenail onychomycosis. One patient had an anthrophilic source of infection--her five-year old son. The woman with tattoo-associated Trichophyton tonsurans of her leg tattoo had a five-year-old son whose tinea capitis cultured the same dermatophyte organism; the researchers postulated that she had scratched her tattoo during the initial days after its inoculation with fingers that had contacted her son’s tinea-infected scalp.Tinea can be transmitted as an anthrophilic infection (from person to person), or a zoophilic infection  or a geophilic infection (from soil to person). A source for the tinea that developed in the tattoo was described for five of the patients and speculated--yet unconfirmed--for an additional individual; no source was provided for six of the patients. Autoinfection of tinea from another body area was suggested for two patients; the 35-year-old man had tinea pedis  of the dermatophyte-infected tattoos were on an extremity; these included either the upper extremity (with two on the arm and two on the forearm) or the lower extremity . The specific extremity was not specified for four patients. The last patient, a 63-year-old woman, had tinea that infected her eyebrows after cosmetic tattooing.The color of the tattoo was described for 12 of the tattoos. Nine of the tattoos only had affected areas that were black. One tattoo was multicolored (including black) and the tinea-infected areas of one tattoo were both black and green. Only one patient did not have a tinea-infected portion of the tattoo that was black--the 52-year-old man with a red tattoo, that was infected by a dermatophyte, on his right calf.The most common presenting feature was a new lesion or a progressively enlarging lesion within a tattoo. Six of the dermatophyte lesions were pruritic. The patient was either asymptomatic (one patient) or no symptoms were described (five patients) for the other tinea lesions.The morphology of tattoo-associated tinea is variable. Tinea incognito refers to the non-classical presentation of superficial tinea infection which can occur in the setting of immune suppression when the patient is receiving either topical or systemic corticosteroids. Three patients presented with atypical appearing lesions secondary to tinea incognito; the lesions were pruritic erythematous patches in two patients--the 52-year-old man and the 63-year-old woman--and an asymptomatic red scaly plaque in the 18-year-old man.Four patients had red plaques. Two patients had concentric, peripherally expanding plaques with central resolution and vesiculopustular borders. The other three patients had red, scaly or non-scaly, annular or non-annular, patches; one of the patients also had erosive and oozing lesions.Treatment of tattoo-associated tinea--described in 11 of the patients--involved only topical agents (in two patients) or both topical and oral antifungal drugs (in nine patients). The topical antimycotic therapy included amorolfine cream (four patients), ketoconazole two percent cream (two patients), miconazole cream (two patients), terbinafine one percent cream (two patients), or luliconazole . Oral antifungal drugs--used in nine of the patients--included itraconazole (five patients) terbinafine (three patients), or griseofulvin (one patient).Trichophyton tonsurans whose son had tinea capitis.The response to therapy was described in 11 patients. There was complete resolution of the tattoo-associated tinea in all 11 individuals. Neither treatment nor follow-up was provided for the woman with leg tattoo-associated The epidemiologic features and clinical characteristics of tattoo-associated systemic fungal infections are summarized in Table Candida albicans infection developed in his right eye instead of occurring within the tattoo [Tattoo-associated Candida endophthalmitis has also been described in a 40-year-old immunosuppressed man (caused by a trauma-associated splenectomy during childhood). The development of his systemic fungal eye infection occurred within less than one week after he received a tattoo. However, in contrast to the other patients with tattoo-associated systemic fungal infections, his e tattoo .The man had a black tattoo inoculated onto the deltoid area of his left proximal arm; three days later he developed a red right eye and reduced vision. One week after tattoo acquisition, he was evaluated by an ophthalmologist; the visual acuity of his right eye was 20/40 and the visual acuity of his left eye was 20/20. Additional evaluation of his right eye showed disc hyperemia; the anterior chamber had one plus cells and the vitreous body not only had two plus cells but also debris. Also, along the inferotemporal vascular arcade, a white fluffy chorio-retinal lesion was noted .Candida albicans. He was initially treated with intravenous amphotericin B (at a dose of two milligrams per kilogram) followed by daily oral fluconazole (at a dose of 200 milligrams per day). His visual acuity in both eyes was 20/20 and his right eye was normal at his four-month follow-up visit [A diagnostic vitrectomy from his right eye was performed; the sample from the vitreous body grew up visit .Five men with tattoo-associated systemic fungal infection within the tattoo have been described; the sex was not provided for the sixth patient. The patients ranged in age from 24 years to 36 years . The immunologic status was provided for five of the six individuals: four patients were immunocompetent and one patient (the 33-year-old man) was immunosuppressed since he was a kidney transplant recipient.The duration of the tattoo--from inoculation until the patient became aware of the systemic fungal lesion within the tattoo--varied from several days to 69 months . Four of the patients (80 percent) noticed their systemic fungal infection lesion in three months (two patients) or less: either a couple of weeks or several days. Although the 36-year-old man was aware of this tattoo-associated fungal lesion after three months, he did not seek medical evaluation until four years later.The diagnosis of tinea was based only on tissue biopsy for at least five of the patients. Microscopic examination of the tissue specimen demonstrated the fungal organism in three patients; however, biopsy-negative, culture-positive specimens were obtained in two patients. Fungal organisms were also observed on the potassium hydroxide preparation of a teased tissue mount in a 25-year-old man. In addition, 18s ribosomal ribonuclear protein (RNA) polymerase chain reaction confirmed the diagnosis of the fungal organism in the 33-year-old man.Sporothrix schenckii (two patients), Acremonium species (one patient), Aspergillus fumigatus (one patient), Purpureocillium lilacinum (one patient), and Saksenaea vasiformis (one patient). The 36-year-old man with tattoo-associated Sporothrix schenckii also had concurrent bacterial infection of the nodular fungal lesions. In addition to the fungus, the initial cultures revealed Staphylococcus aureus, group A Streptococcus and an atypical (pigmented rapid growing) mycobacteria; repeat cultures also grew the fungus but also demonstrated Staphylococcus aureus and Enterobacter aerugenes [The identification of the systemic fungal organism included erugenes .Systemic fungal infections can be acquired by inhalation of spores. However, primary systemic fungal infections of the skin can be acquired percutaneously. Indeed, this is the proposed mechanism of pathogenesis for cutaneous infection in patients with tattoo-associated systemic fungal infections.Acremonium fungi. A patient, who had been reported in the Czech Republic, developed a mycetoma on the tattooed arm. Subsequently, additional investigation during the summer of 2004 revealed that several batches of tattoo ink were analyzed and withdrawn from the French market due to contamination by several germs including not only Acremonium species, but also bacteria of the genus Aeromonas, Pseudomonas aeruginosa, and Pseudomonas putida [The infectious source of the tattoo-associated systemic fungal infection has only been definitively established for one of the individuals--contamination of the tattoo ink. Several batches of ink, that had been made in the United States, were discovered to be contaminated with s putida .Aspergillus fumigatus within his back tattoo had a homemade tattoo performed by a non-professional tattooist; the person who inoculated his tattoo was a friend. An increased risk of adverse cutaneous events has been observed when tattoos are performed by amateurs, who are also referred to as backyard tattooists or scratchers. In addition, the investigators speculated several other possibilities for acquiring tattoo-associated Aspergillus fumigatus: contaminated instruments or tattoo ink, lack of appropriate aftercare, and/or aerosolization of fungal organisms from building renovation either at his home or at his work [The infectious source of the tattoo-associated systemic fungal infection has been postulated to be the method of inoculation by either an amateur tattooist or by the patient themselves. The 24-year-old man with his work ,11.Sporothrix schenckii infection within his dorsal left foot tattoo. When the researchers discovered that he had performed self-tattooing, they considered the possibility that he may have used non-sterile instruments or tattoo pigment. In addition, the researchers hypothesized that he may have percutaneously acquired a fungal organism from the soil when he exposed the tattoo site to grass, on the same day after he inoculated his own tattoo, by mowing the lawn while wearing only sandals on his feet [The second patient was the 32-year-old man with lymphocutaneous his feet .Purpureocillium lilacinum [The investigators did not have a source of infection for the other three men with tattoo-associated systemic fungal infection ,14,15. TAspergillus fumigatus that infected his back a couple of weeks after tattooing.Over 93 percent (five of six) of the systemic fungal-infected tattoos were on an extremity. These included either the upper extremity (with two on the forearm and one on the arm) or the lower extremity (with two on the foot and one on the thigh). The last patient, a 24-year-old man, had The color of the tattoo was described for five of the tattoos. All the tattoos were dark colored. Three of the tattoos only affected areas that were black. Two of the tattoos were blue.Sporothrix schenckii and the 33-year-old man with Purpureocillium lilacinum--had asymptomatic or non-tender skin lesions. The 24-year-old man with Aspergillus fumigatus had painful tattoo-associated systemic fungal skin lesions. The presence or absence of symptoms was not described in the other patients.Two patients--the 32-year-old man with The morphology of tattoo-associated systemic fungal lesions was variable. Some of the lesions were pink or erythematous and firm. They appeared as individual (one patient) or multiple (five patients), intact (three patients) or ulcerated (two patients), papules (three patients) or nodules (two patients); in some of the individuals, multiple satellite lesions (one patient) or pustules (two patients) were also present. The lesion was only described as a mycetoma in one patient.Aspergillus fumigatus was successfully treated with topical antimycotic therapy (terbinafine) and one month of voriconazole. The 33-year-old man kidney transplant recipient with Purpureocillium lilacinum was also successfully treated with three months of voriconazole.Treatment of tattoo-associated systemic fungal infections tinea--described in five of the patients--included both a topical agent and an oral antifungal drug (in one patient) or only oral therapy (in four patients). The 24-year-old man with Sporothrix schenckii could not tolerate the medication because of drowsiness (one man) and/or nausea (both men); both were subsequently successfully treated with itraconazole. The third man was being treated with potassium iodide for 20 months but experienced a recurrence of Saksenaea vasiformis secondary to decreased compliance; his systemic fungal infection was subsequently successfully treated with intravenous amphotericin.Three men were initially treated with potassium iodide. The two men with In summary, including this patient, tattoo-associated tinea corporis has been observed in 12 individuals with 13 tattoos. The tattoo-related superficial fungal infection most commonly occurred on an extremity in black tattoo ink. The dermatophyte infection usually appeared as a red, scaly or non-scaly, annular or non-annular, patch or plaque, with or without central resolution and vesiculopustular borders; however, prior corticosteroid treatment resulted in tinea incognito in three patients. Half of the patients developed tinea within one month or less after tattoo inoculation; the development of tattoo-associated dermatophyte during tattoo healing suggests several potential mechanisms of pathogenesis for the occurrence of the tinea infection: injury to the skin from the tattoo needle, or use of non-sterile instruments, or contaminated ink, and/or contact with a human or animal dermatophyte source. The other six patients developed the tinea infection more than two months after receiving their tattoo; the development of tattoo-associated tinea after tattoo healing raises the possibility of a tattoo ink-associated phenomenon such as the presence of nanoparticles, polycyclic aromatic hydrocarbons, or cytokine-enhancement, and/or immunocompromised cutaneous district creation. All patients had complete resolution of tattoo-associated tinea after treatment with topical and/or oral antifungal agents .Acremonium species, Aspergillus fumigatus, Purpureocillium lilacinum, Saksenaea vasiformis, and Sporothrix schenckii were the diagnosed systemic fungal organisms. The cause of the systemic fungal infection was only confirmed for one patient: contaminated ink. Non-professional tattoo inoculation, infected tattooing tool and/or ink in an immunosuppression host, and contaminated ritual tattooing instruments (boar tusk or bone) and dye (soot and crushed candlenut tree seeds) were postulated as the source of the infection in some of the other men. Systemic antifungal drug therapy resulted in complete resolution of the tattoo-associated systemic fungal infection [Tattoo-associated systemic fungal infection has been reported in six patients; however, several features were not described in one patient. The onset of infection after tattoo inoculation was either within less than one month (two men), three months (two men), or 69 months (one man). All the tattoos had dark ink: black (three men) or blue (two men). The lesions were non-painful (two men) or tender (one man). The lesions were described as papules or nodules that were either individual or multiple and intact or ulcerated; one man had a mycetoma. nfection -15.It remains to be determined whether the relationship between tattoos and the development of either dermatophyte infection or systemic fungal infection is causative or coincidental. The increasing number of reported individuals with tumor-associated dermatophyte infections introduces the possibility that the tattoo may elicit this cutaneous response. This could result from a direct or an indirect effect of tattooing -7. Tattoo-associated tinea has been observed in two clinical settings based on the duration of time between the inoculation of the tattoo and the appearance of the dermatophyte infection within the tattoo: early tinea infection on a recent  tattoo--reflecting a direct effect of the tattooing process on the development of the dermatophyte infection--in six patients or late dermatophyte infection on an older  tattoo--reflecting an indirect effect of the tattooing process--in six patients. Tattoo needle-related injury to the skin, or instruments that were not sterile, or ink that was contaminated, and/or contact with a human or animal dermatophyte source may have promoted the development of tattoo-associated tinea in healing tattoos -4,7. In Aspergillus fumigatus or Sporothrix schenckii--during or shortly after the creation of their tattoo and with the time associated with the healing process [The paucity of tattoo-associated systemic fungal infections raises the possibility that the infection that occurred within the tattoo of some of the patients may have merely been a coincidence. However, the tattoo duration was less than one month prior to the onset of the associated systemic fungal infection for two of the men. Both received non-professional tattoos (that were either home-made and performed by a friend or self-inoculated) and may have had exposure to the fungal organisms--either  process ,11,13.Purpureocillium lilacinum infection. Hence, it might be speculated that both men acquired the systemic fungal infection during either the inoculation or healing of their tattoo but experienced a delay in the development of the clinical manifestations; indeed, an immunocompromised district may have been created associated with the tattooing process or the tattoo ink or both that allowed the systemic fungal infection to eventually manifest [Also, although the systemic fungal infection was initially noticed three months after tattooing for two of the men, their investigators favored--but could not document--exposure to the organisms during tattooing. The patients included the man who experienced ritual Samoan body tattooing and developed sporotrichosis and the immunocompromised kidney transplant recipient who acquired a manifest ,15.Saksenaea vasiformis that appeared six years and nine months after tattooing in the otherwise healthy 25-year-old man. Human zygomycosis rarely has been observed in association with this fungal organism; indeed, the affected individual is typically either immunosuppressed or has experienced severe trauma. Hence, in this patient, the tattoo-associated systemic fungal infection may have merely been coincidental [The researchers were unable to provide a mechanism for pathogenesis for the cidental .Acremonium species-related mycetoma on his arm tattoo developed the systemic fungal infection secondary to contaminated tattoo ink [The patient with an ttoo ink ,9. An olttoo ink . Howeverttoo ink . Hence, Tattoo-associated infections include not only bacteria, mycobacteria, and viruses, but also fungal infections. The features of a man who developed tattoo-associated dermatophyte infection in the black inked portion of a tattoo on his left arm less than one-month after its inoculation was described. The relationship between tattoos and the development of either dermatophyte infection or systemic fungal infection remains to be determined. In patients with tumor-associated tinea, several researchers favor that the tattoo inoculation can be implicated as a causative factor in the development of the subsequent dermatophyte infection. However, in some of the men with a tattoo-associated systemic fungal infection, the occurrence of the systemic fungal infection within the tattoo may have merely been coincidental.


High visibility (0.56) neutron-based multi-modal imaging with a Talbot–Lau interferometer at a wavelength of  Computed tomography (CT) is a versatile and non-destructive imaging method used with different kinds of radiation to yield three-dimensional (3D) representations of complex objects which are often not accessible with other methods. It usually uses projectional images or signals which are created by physical interactions inside the object to reconstruct a 3D distribution of some physical property. Different types of CT can be combined for special applications to study different physical interactions in correlation to their spatial distribution. Many applications have been developed to exploit complementary tomographic methods, such as X-ray CT and positron emission tomography, where radioactive tracers are used to mark certain molecular processes in the human body and create overlays of, e.g., metabolic tumor activity in an X-ray CT image. Another example is the combination of conventional CT with X-ray fluorescence analysis in scanning mode, enabling one to detect spatial distributions of sub-parts-per-million trace elements in transmission tomograms which would never be possible by the absorption mechanism only.V is the visibility calculated from the maximum  in Grenoble, France , the Paung (SAS) . The darng (SAS) :(1)D=V/Vay tubes  or neutray tubes .This method has certain limitations—especially with strongly absorbing objects. If a high fraction of the radiation is absorbed along a certain beam path through the object, the scattering and phase signals are affected by strong noise. Further, such interferometers are chromatic in nature and therefore create an energy-dependent visibility. When polychromatic radiation sources are used, the energy-dependent interaction will introduce artifacts in the DPC and the DFI ,20. The Hence, the usability of the method strongly depends on the geometrical shape, the chemical composition and particularly the ratio of the absorption to small-angle scattering cross-sections of the involved materials and microstructures in the sample. Studying scattering structures in strongly attenuating objects becomes difficult and often requires higher-energy radiation. The energy, and therefore the penetrative power of such imaging systems, are limited by the absorptive properties of the gratings. X-ray-based Talbot–Lau imaging systems typically do not exceed 50 keV design energy, since the absorptive gratings become transparent to high energy X-rays; the propagation distances to induce the intensity modulation via the Talbot effect become longer; and the refractive and scattering interactions become weaker with shorter wavelengths. All those factors require gratings with smaller periods and greater heights of the absorbing material and become extremely difficult to fabricate. Neutron-based Talbot–Lau imaging so far has used wavelengths of about 3 Å and above due to similar grating-related limitations. We have recently reported on a grating fabrication method  which alt FRM II . A quartThe neutron grating interferometer at ANTARES/FRM II was designed in an asymmetric Talbot–Lau geometry finding a trade-off between sensitivity and achievable resolution while using relatively large n detail . Here, tma spots ,29. A phThe X-ray scans were performed with a symmetric Talbot–Lau interferometer illustrated in On top of the grating-based multimodal data, the sample was scanned with a conventional X-ray micro–computed tomography (micro-CT) system (GE phoenix v|tome|x S) with a high resolution at 130 kVp tube voltage and In the case of neutron data, the acquired images were corrected for dark current with averaged dark frames, and defective pixels were interpolated by a median with a kernel size of 3. Afterwards, artificial bright structures (gamma spots) characteristic for neutron scintillator-based CCD detectors were removed by a slightly adapted algorithm compared to the standard procedure ,29 descrThe X-ray data were processed with the same algorithm after the dark current correction and bad pixel masking without any further image filtration. The projections and flat fields were normalized using a sample-free background to correct for flux fluctuation of the X-ray source. B (outside the sample); and ROIA (inside the sample) where only absorbing material is present. The contrast-to-noise-ratio (CNR) was retrieved from the peak signal of the scattering structure B) and the standard deviation B with the formula:The tomographic reconstruction consisted of a filtered back-projection (FBP) of cient) ϵ ,32 for tne plots e, the baThe mean values and standard deviations of the ROIs and the CNRs are given in When evaluating the projections shown in The tomographic reconstruction of the different imaging modalities reveals further differences that were not obvious from projectional data. The dark-field CT data emphasizes the findings that could be already vaguely concluded from single projections. A comparison of the slices from A) and outside the sample (ROIB) were calculated and given in A was chosen inside the sample where the X-ray micro-CT data do not show any structures that could potentially create SAS signals. While there is a strong signal increase  in the case of X-rays, the neutron DFI signal hardly increases and the beam hardening-related artifacts do not deteriorate the image. Note that even the strongly absorbing structure depicted by the arrow in To quantify the artificial, absorption-induced dark-field signal in both DFI CT reconstructions, the FBP values (mean and standard deviation) of some ROIs inside of absorbing material (ROINeutron-based imaging with a Talbot–Lau interferometer has been successfully translated to sub- 2 Å wavelengths and can be extended to a larger variety of strongly absorbing samples. Compared to other recent works, the setup reached high visibility, high neutron flux and a relatively large FoV. The method was also demonstrated in CT, with the attenuation and the dark-field signal reaching a resolution of about 300 The scans in this work have been performed with two different setups. To simplify alignment issues and be able to study processes in situ without temporal separation using both neutrons and X-rays conducting simultaneous scans would be of great benefit. Hence, the ANTARES beamline will be extended with a micro-focus X-ray source and a high resolution detector to acquire micro-CT and neutron data at the same time. Additionally, this can be combined with different sample environments that are usually not available in conventional micro-CT laboratories. This complementary CT approach with X-rays and multi-modal nGI will deliver further detailed insights for a wider variety of especially strongly absorbing samples with additional sensitivity to many different elements or chemical compounds. Complex geometries with unique micromorphologies, such as porous structures or magnetic domains, will be better accessible non-destructively in 3D.


Background: The European Working Group on Sarcopenia has recently proposed revised cut-off values for the definition of low grip strength (EWGSOP2). We therefore compared performance of the EWGSOP2 cut-off definition of low grip strength with other internationally used cut-off points in a sample of older patients. Methods: We analyzed geriatric assessment data in a cross-sectional sample of 98 older patients admitted to a post-acute care hospital. First, we compared prevalence of sarcopenia and frailty phenotype in our sample using low grip strength cut-points from the EWGSOP2 and seven other internationally used consensus statements. Second, we calculated correlations between low grip strength and two independent surrogate outcomes  for the EWGSOP2 and the other seven cut-point definitions. Results: Prevalence of sarcopenia based on the EWGSOP2 grip strength cut-off values was significantly lower (10.2%) than five of the seven other cut-point definitions  criteria). Similarly, frailty phenotype prevalence was significantly lower based on EWGSOP2 cut-points (57.1%) as compared to SDOC (70.4%). The correlation coefficient of gait speed with low grip strength based on EWGSOP2 cut-points was lower (0.145) as compared to other criteria . Conclusions: Sarcopenia and frailty phenotype were identified considerably less using the EWGSOP2 cut-points for low grip strength, potentially underestimating prevalence of sarcopenia and frailty phenotype in post-acute hospital patients. Sarcopenia and physical frailty are clinical syndromes occurring in older patients associated with adverse outcomes such as mobility impairment, fracture, functional impairment, and mortality ,2. PriorIn the diagnostic work-up of sarcopenia, frailty grip strength is a core determinant as a proxy measurement for overall muscle strength. In the latest guidelines of the European Working Group on Sarcopenia in Older People (EWGSOP2), low grip strength is the primary parameter together with low muscle mass to diagnose sarcopenia . SimilarThe EWGSOP2 consensus statement proposes new cut-points for defining low grip strength . These cThe wide range of different published cut-points is confusing, given the importance of grip strength in the diagnosis of sarcopenia and identification of physical frailty. Therefore, using the EWGSOP2 cut-points of low grip strength instead of using other cut-points could have an impact on the prevalence of patients identified with sarcopenia and frailty. However, we were unable to find any studies that have systematically compared detection rates for sarcopenia and frailty between published grip strength cut-points. It is unclear, how many patients with sarcopenia and frailty would be overlooked depending on what cut-point of low grip strength is used.The purpose of this study was to determine how the EWGSOP2 cut-points for low grip strength compared to other internationally used cut-points perform for identifying sarcopenia and frailty phenotype in a sample of older patients in a post-acute care hospital.We conducted a retrospective analysis of cross-sectional anonymized assessment data of patients admitted to a Geriatric Rehabilitation Hospital in Bern, Switzerland, between November and December 2019. Standard geriatric assessments were conducted for all patients upon admission. The assessments were performed by clinically trained assessors  using standardized assessment forms. We excluded 9 patients who had a contraindication for muscle mass measurement by bioelectrical impedance analyses (implantable cardioverter defibrillator or pacemaker), leaving a total sample of 98 patients ) included in the analysis.Our study project was approved by the Ethics Committee in Bern, Switzerland (Req-2020-00125). In accordance to regulations on research projects of health-related data of human beings in Switzerland we analyzed anonymized data. While researchers do work with health-related data of human beings, the data can no longer be assigned to the specific individual.2, men < 7 kg/m2) [On admission, patients were assessed for sarcopenia and frailty. The assessment of sarcopenia was based on the EWGSOP2 consensus guidelines  and incl7 kg/m2) .Grip strength was assessed in an upright sitting position using the Martin vigorimeter. The test was performed 3 times using the dominant hand, with a 30 s interval between each measurement. Patients were instructed to firmly squeeze the balloon for three seconds. The maximum score of the 3 measures was used for analysis. Scores were converted from kPa to kg using the conversion table by Neumann et al. .Gait speed was measured using a standardized protocol of a 4m walk test ,17. PatiFrailty was assessed using Fried’s frailty phenotype . The fra(1)Asia Working Group for Sarcopenia (AWGS1) .(2)Asia Working Group for Sarcopenia (AWGS2) .(3)European Working Group on Sarcopenia in Older People 1 (EWGSOP1) .(4)The Foundation for the National Institutes of Health Biomarkers Consortium Sarcopenia Project 1 (FNIH 1) .(5)The Foundation for the National Institutes of Health Biomarkers Consortium Sarcopenia Project 2 (FNIH 2) .(6)Fried frailty phenotype (Fried) .(7)Sarcopenia Definitions and Outcomes Consortium, (SDOC) .In addition to the EWGSOP2, we identified low grip strength cut-points from seven other consensus definitions of sarcopenia and frailty phenotype. These included :p-values  of McNemar tests using the Hochberg method were calculated to account for multiple pairwise comparisons. The decision to not perform statistical comparisons among subgroups of patients to avoid type I and II error inflation was made a priori. To assess convergent validity, we investigated correlations between different low grip strength cut-point with independent outcomes of sarcopenia (gait speed) and frailty ). The point biserial correlation coefficient was calculated to analyze correlation of prevalence of low grip strength based on cut-off definitions (binary variables) with gait speed (continuous variable) and CFS . All analyzes were computed using Stata Version 16.0 . An adjusted p-value of <0.05 was considered statistically significant.Study population characteristics from admission data are presented by absolute and relative frequencies or by mean with standard deviation (sd) for categorical and continuous variables, respectively. Power analysis was based on prior evidence expecting prevalence of sarcopenia of 20% in older patients in a post-acute care setting . At a twThe overall and gender-specific clinical characteristics of the sample are summarized in The prevalence of low grip strength, sarcopenia, and frailty phenotype calculated using the EWGSOP2 cut-off and for each of the other seven cut-off definitions of low grip strength is compared in p < 0.01).Overall, the EWGSOP2 cut-off value yielded the lowest prevalence of low grip strength (27.6%), while the SDOC cut-off definition yielded the highest prevalence (56.1%). All cut-off definitions, except for those used by the AWGS1 and FNIH1, showed statistically significant higher prevalence of low grip strength compared with the EWGSOP2 cut-off definition  and methods for determination of cut-points. EWGSOP2 used a similar approach for derivation of cut-off that is known for the definition of osteoporosis, setting the cut-off at −2.5 SD below the gender-specific mean. In contrast, the SDOC and FNIH based their cut-off for low grip strength on a model best predicting slow walking speed in an older population. This was also the approach used for the EWGSOP1 cut-off definition. EWGSOP2 proposed the lowest cut-off points of low grip strength for both men and women, resulting in low prevalence of sarcopenia and frailty. Similarly, van Ancum et al. concluded that setting the cut-off of low grip strength at −2.5 SD may account for lower prevalence of sarcopenia based on EWGSOP2 . NeverthSubgroup analyses in our study suggest that men demonstrate higher prevalence rates of both frailty and sarcopenia. In our study population, male patients tended to show higher degrees of multimoribidity and polypharmacy, suggesting a generally greater disease burden compared to female patients. Thus, general health status may account for the higher prevalence of sarcopenia and frailty that we observed among men .Our study has several limitations. First, our study focused only on how variability in grip strength cut-points impacted the prevalence of sarcopenia and frailty phenotype in one sample of post-acute hospital patients. Other methodological issues associated with measurement of grip strength measurement  could also affect prevalence . Second,Our results have both clinical and research implications. Our results demonstrate that the selection of a cut-off point for defining low grip strength has a clinically relevant impact on identification of sarcopenia and frailty phenotype. The EWGSOP2 recommended cut-off for low grip strength results in lower prevalence of sarcopenia and frailty compared with various other internationally used cut-off definitions of low grip strength. Correlation analyses of our data suggest limited validity of EWGSOP2 cut-off definition of low grip strength for identifying sarcopenia and frailty phenotype. Therefore, clinicians should be aware of the fact that patients with an actual sarcopenia or frailty phenotype are potentially overlooked by applying the EWGSOP2 cut-points of low grip strength.Further research is needed to clarify which cut-off values of low grip strength are adequate for identifying cases of sarcopenia and frailty phenotype in older patients. Ideally for practical use, cut-off values of low grip strength would be the same for the diagnostic work-up of both sarcopenia and frailty phenotypes. Since concepts of sarcopenia as an ICD relevant diagnosis and frailty phenotype as a clinical syndrome are different, it is possible that different cut-off values are preferable for sarcopenia and frailty phenotype. Therefore, interventional and longitudinal studies are needed to identify and agree on a valid cut-off of low grip strength in the context of sarcopenia and frailty phenotype.The selection of a cut-point of low grip strength has a clinically relevant impact on the prevalence of sarcopenia and frailty phenotypes. Applying the EWGSOP2 cut-points potentially results in underestimation of actual sarcopenia and frailty phenotype compared with various other cut-off values of low grip strength.


Apostolidis et al. identify genes linked to vascular injury in SSc by scRNA-seq. Among several genes, they found Apelin Receptor (APLNR) and Heparan Sulfate Proteoglycan 2 (HSPG2), not yet associated to SSc pathogenesis but of great interest as they have been reported to sustain vascular dysfunction and fibrosis in different settings  autoantibodies in vascular injury. The authors analyze the expression of distinct functional markers of smooth muscle cells (SMC) from human pulmonary arteries (HPASMC) exposed in vitro to anti-PDGFR autoantibodies from SSc patients. They show that PDGFR autoantibodies activate SMC and may contribute to the development of SSc vascular lesions, therefore suggesting that a downregulation of B cell response could modify disease development  can induce Reactive Oxygen Species (ROS) generation in fibroblasts through the interaction with the urokinase-type plasminogen activator/uPA receptor (uPA/uPAR) system, activation of the nicotinamide adenine dinucleotide phosphate (NADPH) oxidase and alteration of the redox state observed in SSc. Napolitano’s data indicate novel therapeutic strategies in SSc, through the use of small molecules to impair FPRs functional interaction with uPAR and their signal , daily stretching produced a measurable beneficial on reducing skin thickness and improved mobility during the fibrotic phase of the model. Of note, stretching reduced mRNA expression of C-C Motif Chemokine Ligand-2 (CCL2) and a disintegrin and metalloproteinase domain-8 (ADAM8) which are important inflammatory mediators associated with the sclGvHD model and upregulated in SSc skin. B cells appear to have an important role in SSc pathophysiology beyond the classical production of autoantibodies. Data on B cells subsets distribution and functional properties in animal models of SSc are scarce. Moreover, no study has ever considered a possible variation in B cell involvement during the course of SSc. This is of peculiar importance since several works have suggested that B cell-targeted therapeutic strategies may have different effects whether they are started at an early or late stage of the disease. To address these issues  induce a systemic fibrosis. The authors study the modifications in B cell homeostasis. Phenotypic analyses show an early expansion of the mature naïve subset, decrease in plasmablasts, and memory B cells. Functional analyses reveal B-cell overproduction of pro-inflammatory cytokines (Interleukin 6 and CCL3) and an impairment of their anti-inflammatory capacities (decreased production of IL-10 and Transforming growth factor-β and reduced levels of B-regs) at the early inflammatory stage, followed by an overproduction of pro-fibrotic cytokines (TGF-β and IL-6) at the late fibrotic stage. This work reports, for the first time in an SSc animal model, the existence of B cell dysfunctions similar to those observed in SSc patients. It is of note that these anomalies vary over the course of the disease and may contribute to the inflammatory and fibrotic events observed in SSc. This makes the HOCl mouse a relevant experimental model for the study of B cells, and especially B cell- targeted therapies, in SSc  subsets display functional defects in SSc patients  or Scleroderma is a complex and puzzling disease having an incidence of 1–2 cases per 100,000. In SSc, inflammation leads to organ failure due to severe fibrosis of the skin and internal organs. At late stages, this disease is characterized by a profound decline in the quality of life and premature death (elopment . Napolitr signal . Dolcinotibodies . Xiong ee issues , Sanges , in SSc . SSc is e in SSc . The autThe two authors share the supervision of the papers included in the Research Topics and the expressed view. All authors contributed to the article and approved the submitted version.The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.


Acute lower respiratory infection (ALRI) due to RSV is a common cause of global infant mortality, with most cases occurring in developing countries. Using data aggregated from priority countries as designated by the United States Agency for International Development's (USAID) Maternal Child Health and Nutrition (MCHN) program, we created an adjustable algorithmic tool for visualizing the effectiveness of candidate maternal RSV vaccination on infant mortality. Country-specific estimates for disease burden and case fatality rates were computed based on established data. Country-specific RSV-ALRI incidence rates for infants 0-5 months were scaled based on the reported incidence rates for children 0-59 months. Using in-hospital mortality rates and predetermined “inflation factor,” we estimated the mortality of infants aged 0-5 months. Given implementation of a candidate maternal vaccination program, estimated reduction in infant RSV-ALRI incidence and mortality rates were calculated. User input is used to determine the coverage of the program and the efficacy of the vaccine. Using the generated algorithm, the overall reduction in infant mortality varied considerably depending on vaccine efficacy and distribution. Given a potential efficacy of 70% and a maternal distribution rate of 50% in every USAID MCHN priority country, annual RSV-ALRI-related infant mortality is estimated to be reduced by 14,862 cases. The absolute country-specific reduction is dependent on the number of live births; countries with the highest birth rates had the greatest impact on annual mortality reduction. The adjustable algorithm provides a standardized analytical tool in the evaluation of candidate maternal RSV vaccines. Ultimately, it can be used to guide public health initiatives, research funding, and policy implementation concerning the effectiveness of potential maternal RSV vaccination on reducing infant mortality. Globally, acute lower respiratory infection (ALRI) is a major contributor to infant morbidity and mortality. Respiratory syncytial virus (RSV) is one of the most commonly identified etiologic viral pathogens leading to ALRI –3. AccorThe prevention and treatment of RSV poses a great financial burden; an estimated 50-70% of infants become infected with RSV during their first winter season . CurrentAn analysis of cost-effectiveness published by Cromer et al. compares the various strategies for preventing and treating RSV-related illness. The most economic strategies were single dose protection that could be given to specifically protect infants born just prior the start of RSV season . MaternaSome ambiguity remains in identifying the immune response and target most effective in providing immunity to RSV . The RSVThough the need for an approved and effective RSV vaccination is currently unmet, we created an adjustable algorithmic tool for visualizing the effectiveness of candidate maternal RSV vaccination on reducing disease incidence and infant mortality. We used data specific to priority countries as designated by the United States Agency for International Development (USAID) Maternal Child Health and Nutrition (MCHN) program as depicted in Based on data from Shi et al. , USAID MAbsolute value of RSV incidence by country was calculated for infants age 0-5 months using the following scale. Regional RSV incidence rates were obtained from the literature for infants age 0-5 months (RI:0-5) and children age 0-59 months (RI:0-59). Using these rates as a scale along with the reported country-specific RSV incidence rates for children 0-59 months (CI:0-59), we estimated the country-specific RSV incidence rates for infants age 0-5 months (CI:0-5) by equating the regional and country-specific ratios using Equation . (1)RI:0Then, the country-specific incidence rate for infants 0-5 months old was multiplied by the number of live births in each country to obtain the absolute incidence of RSV for each country . Using tAI:Absolute incidenceE:EfficacyD:Distribution to pregnant womenDBV:Estimated RSV disease burden postmaternal vaccine implementation.Infant RSV incidence was also calculated using region-wide incidence rate estimates. The regional RSV incidence rate for infants 0-5 months was multiplied by country-specific live birth rates yielding the absolute incidence of RSV in each country based on region wide estimates. Using this value, and user determined values for efficacy and distribution of a candidate vaccine, we estimate the reduction in incidence of RSV given implementation of a vaccination program.http://data.unicef.org, using 2016 midyear estimates throughout [Next, infant RSV mortality rate given implementation of a candidate maternal vaccination program was calculated. RSV hospitalization rates were reported by age bands: 0-1 month, 1-2 months, and 2-5 months. Using the country-specific number of live births and mortality rate, we first calculated the absolute number of infants age 0-1 month-old, 1-2 months old, and 2-5 months old . Neonataroughout , 19. TheWe then multiplied the absolute number of infants in each age group by reported age-specific hospitalization rates and in-hospital mortality rates. Additionally, we multiplied by a predetermined inflation factor to account for infant RSV mortalities that occurred outside of the hospital setting . The sumAM:Absolute RSV-ALRI infant mortalityE:EfficacyD:Distribution to pregnant womenIMV:Estimated RSV-ALRI infant mortality postmaternal vaccine implementation.Infant RSV-ALRI mortality rate given implementation of a candidate maternal vaccination program was also calculated using region-wide estimates for hospitalization rates and in-hospital mortality rates.We assumed that vaccination success was binary, in that the vaccine only prevents RSV and does not reduce virulence or severity of disease. Programing was carried out in R, and the interactive visualizations were produced with the R Package Shiny.We have developed a web-based interactive tool that can be used to assess the efficacy of candidate maternal RSV vaccination implementation at reducing infant disease incidence and mortality in developing countries. Using the control panel , the useAn example of the visualization of the interactive tool is shown in The absolute reduction in incidence and infant mortality are most dramatic in countries with higher birth rates such as India, Nigeria, and Pakistan.This tool is unique in that the user can determine the variables to best fit their purpose. It can give perspective and account for a highly effective vaccine that has decreased distribution due to cost or need for refrigeration or a vaccine with lower efficacy but a greater ability to be distributed.The treatment and prevention of RSV-related ALRI is multifaceted; maternal vaccination provides only one approach for reducing disease burden and mortality. Extensive effort has gone into developing childhood vaccines and pharmaceutical treatments. Conducting experimental RSV treatments on children and infants has proved difficult due to the sensitivity of the population and disease acuteness . We chosAnticipation of maternal RSV vaccine availability has led to a number of mathematical tools to estimate effectiveness of vaccine implementation. A model created by Hogan et al., based on data from Western Australia, reports that an RSV vaccine with a distribution of 50% and an efficacy of 80% could reduce hospital admissions by 26% for infants <3 months of age and 40% for infants age 3-5 months . Data frRainisch et al. also utilized the Shi et al.  data setOther infectious diseases that cause significant infant mortality, such as Group B Strep, could be assessed in a similar manner. Group B Strep (GBS) is detected in the vaginal flora of 10-40% of reproductive age women . Fetal aA major limitation of this project was the manipulation of data to fit the target population of infants age 0-5 months in USAID MCHN countries. Due to the subjectivity of the calculations and mathematical assumptions made, there is possibility of error in our estimates. For this reason, we have given the user opportunities to adjust the algorithm as necessary, including adjusting calculations to fit low or high ends of published estimates of disease incidence. In the future, if new data become available, we can make direct comparisons to our model and adjust accordingly to provide the most accurate and up-to-date estimates.The adjustable algorithm provides a standardized analytical tool in assessing the effectiveness of candidate maternal RSV vaccination on reducing infant disease and mortality in developing countries. As vaccines continue through clinical trials and become widely available, this algorithm can provide foresight into vaccine application. Ultimately, it can be used to guide public health initiatives, research funding, and policy implementation concerning the impact of RSV on developing countries.


Over the past decade, tremendous progress has been made in systems biology-based approaches to studying immunity to viral infections and responses to vaccines. These approaches that integrate multiple facets of the immune response, including transcriptomics, serology and immune functions, are now being applied to understand correlates of protective immunity against hepatitis C virus (HCV) infection and to inform vaccine development. This review focuses on recent progress in understanding immunity to HCV using systems biology, specifically transcriptomic and epigenetic studies. It also examines proposed strategies moving forward towards an integrated systems immunology approach for predicting and evaluating the efficacy of the next generation of HCV vaccines. Acute hepatitis C virus (HCV) infection resolves spontaneously in approximately 30% 15–45%) of infected individuals, whereas the remaining 70% (55–85%) of persons develop persistent infection and progressive chronic liver disease and are at risk of developing liver cancer 5–45% of . EliminaSystems immunology approaches that employ integrated interdisciplinary methods to define the interactions between the different cellular and molecular components of the immune system have become powerful tools for profiling immune responses to vaccines and viral infections ,15,16,17Over the past two decades, different methods have been developed and used to measure gene expression by quantifying mRNA levels in transcriptomic analysis, as well as gene expression modifications through epigenetic analysis. Each method has its own advantages and limitations. The most common methods that were used or are likely to be used in the context of HCV and their limitations are summarized in this section.Microarrays are the earliest form of high-throughput technology used in transcriptomic analysis. This approach is based on the use of many probes  of specific single-strand DNA fragments, corresponding to genes of interest that are loaded on a chip . These pThe development of next-generation sequencing (NGS) led to its application to RNA-sequencing (RNA-seq), in which the entire transcriptome can be examined. This method is based on the direct sequencing of fragmented cDNA libraries reverse transcribed from the mRNA of the sample of interest. Sequence reads are then mapped to the genome and the data are further transformed and processed to obtain read counts that reflect expression levels within the sample. RNA-seq has completely replaced microarrays due to several key advantages. First, it provides a significantly superior dynamic range for measuring expression across a wide range of transcript levels with less input RNA, making it more suitable for rare patient samples and for the detection of transcripts of low abundance . Second,The advent of scRNA-seq has provided unprecedented opportunities for examining transcripts at the single-cell level and for defining the heterogeneity of cellular populations within a tissue or specific cellular subsets . This process is based on partitioning individual cells into plates or droplets, where they are lysed and labeled with a unique identifier and then processed using procedures similar to those used for bulk RNA-seq. This method can also be coupled with analysis of the T or B cell receptors, thus providing the capacity to analyze the T or B cell repertoire and to track the expansion of specific T or B cell clones during the course of infection or in different tissue compartments. This technology is highly useful in understanding the interaction of individual cells with their microenvironment and has been successfully used to characterize the heterogeneity of macrophage populations in the liver and their evolution during different stages of fibrosis ,34,35. HTranscriptomic data requires validation at the protein level. Advances in high-dimensional flow cytometry and mass cytometry (cytometry by time-of-flight mass spectrometry (CyToF)) and the capacity to run high-resolution panels have provided additional dimensions for data validation but are still limited in terms of the different antibody combinations that can be used  . Recent Changes in gene expression may be partially due to epigenetic changes that limit chromatin accessibility for gene transcription. One method that was used to assess genome-wide chromatin accessibility in HCV studies is the assay for transposase-accessible chromatin with high-throughput sequencing (ATAC-seq) . This asIt is becoming increasingly important to examine cells in the context of their tissue microenvironment to understand their spatial interactions ,44. AlthMultiple studies in humans and chimpanzees have used systems biology approaches to characterize the immune response during acute HCV infection progressing to either spontaneous resolution or persistent infection. Early microarray studies in the chimpanzee model observed the rapid induction of intrahepatic interferon signals, as demonstrated by an increase in the expression of interferon-stimulated genes (ISGs) in the liver shortly after experimental infection, irrespective of the outcome ,50. TranStudies performed on liver biopsies and/or PBMCs obtained during chronic HCV infection demonstrated that ISGs remain upregulated but that their level was variable among different patients ,54,55,56These studies performed on whole liver tissue or unfractionated PBMCs provided snapshots of the overall immune response during acute HCV infection and demonstrated that innate immune responses are induced early, irrespective of infection outcome, and remain upregulated during chronic infection. However, signals associated with adaptive immunity, although detectable in some studies, were diluted and it was not possible to identify signatures that can predict infectious outcomes, suggesting that protective immune functions are limited to a small cellular subset.T cell responses during acute HCV infection have been extensively studied and are reviewed elsewhere ,61,62. TThe immune response during the early phase of acute infections that become chronic is not substantially different, as relatively broad HCV-specific CD4+ and CD8+ T cell responses are generated early and may contribute to the transient control of viremia, but this response is short-lived. Specifically, HCV persistence is associated with the sudden failure and disappearance of HCV-specific CD4+ helper T cell responses. The lack of CD4+ T cell help compromises CD8+ T cell function(s) and facilitates the emergence of viral escape mutants in targeted CD8+ T cell epitopes ,69,70 reTo decipher the mechanisms underlying T cell failure during acute HCV infection and to identify predictors of the infectious outcomes, Woloski et al.  performe+CD127+PD1+T-betlo HCV-specific CD8+ T cells expressing both exhaustion and memory markers were described in chronically infected subjects and termed ‘memory-like’ or ‘stem-like’ T cells because of their ability to retain proliferative capacity [CD8+ T cell exhaustion during chronic HCV is not an all-or-none phenomenon but rather a spectrum of different degrees of impairment of antiviral functions associated with the expression of different levels of T cell exhaustion and memory markers ,84. TCF1capacity ,86. DAA-capacity . This iscapacity ,87,88.hi, CD127int and CD127lo [hi cells and CD127lo cells had the molecular and phenotypic signatures of memory-like and exhausted CD8+ T cells, respectively [hi memory-like and CD127lo exhausted CD8+ T cells via a CD127int intermediate stage [To understand the molecular mechanisms and pathways underlying CD8+ T cell dysfunction during chronic HCV and whether these pathways are reconstituted following DAA therapy and clearance, a series of recent elegant studies examined this question in different cohorts using multiple systems biology approaches ,90,91. T CD127lo . CD127hiectively . These mectively ,90,92. ste stage .HCV-specific CD8+ T cells targeting escaped epitopes were also examined. Given that immune escape occurs early in most cases, the premise was that CD8+ T cells targeting escaped epitopes would have been subjected to a shorter period of antigenic stimulation and exhaustion. This approach would also allow the distinction between antigen-mediated exhaustion versus exhaustion mediated by the inflammatory environment due to ongoing HCV infection and replication. Indeed, the core exhaustion signature identified in exhausted CD8+ T cells was less pronounced in CD8+ T cells targeting escaped epitopes, suggesting that this signature was antigen-dependent ,90. By eIn a companion study, Yates et al. used ATAC-seq to examine the epigenetic state and chromatin-accessible regions (ChARs) in the same type of samples . They idThese results suggest that CD8+ T cells that are maintained post-DAA-mediated HCV clearance will not be protective upon reinfection and may not respond to vaccination. Interestingly, one study in a chimpanzee treated with DAA then experimentally rechallenged demonstrated that pre-existing intrahepatic HCV-specific CD8+ T cells were narrowly focused and failed to prevent viral persistence . Both thAltogether, these studies clearly demonstrate the development of a permanent/locked antigen-dependent exhaustion scar in HCV-specific CD8+ T cells with the establishment of chronic infection. This scar impairs the antiviral capacity of virus-specific CD8+ T cells long after virus clearance. The reversibility of this scar is likely dependant upon the period of antigen exposure, and early antigen removal (as in the case of escaped epitopes) may facilitate the unlocking and reversal of this exhaustion scar and functional restoration . FurtherMechanisms underlying the dysfunction of HCV-specific CD4+ T cells and their failure to help CD8+ T cells are understudied, mainly due to the difficulty in detecting antigen-specific CD4+ T cells. Studies using a limited number of MHC class II tetramers demonstrated that HCV-specific CD4+ T cells express a narrower range of T cell inhibitory receptors compared with CD8+ T cells, with high expression levels of PD-1 and CTLA-4 . HCV-speEarly studies of the antibody response against HCV suggested that anti-HCV antibodies are delayed, short-lived in resolvers and do not always correlate with spontaneous resolution ,101. AdvAs reviewed in the previous sections, there has been tremendous progress in the use of systems transcriptomic approaches to understand protective immunity against HCV. The data collected so far have revealed mechanisms of CD8+ T cell functionality and exhaustion that are shared with other viral infections and cancer. Such studies can inform and be informed by studies in other models. They are also crucial to establishing benchmark signatures and parameters that should be achieved by the next generation of vaccines. However, most studies are still performed independently, and an integrative approach should be applied to future cohort studies and vaccine clinical trials through a systematic and standardized process in order to enhance the data that can be extracted and their comparisons among different studies. This can be guided by recent collaborative studies and approaches applied to understanding immunity against SARS-CoV2, the development of predictors of disease outcomes and the evaluation of the efficacy and durability of vaccine-induced responses ,107,108.Blood samples are the easiest to collect and can be used directly to obtain clinical data and to examine the metabolome. However, the amount of blood that can be drawn at a regular visit is limited and the ability to perform leukapheresis at key timepoints during infection and vaccine clinical trials should be considered. Peripheral blood can be processed to separate plasma and PBMCs. Plasma can be used for multianalyte testing of inflammatory mediators and serum markers, antibody profiling via both ELISA and neutralization assays using standardized protocols, reagents and HCVpp panels. Plasma can also be used to perform virus sequencing using full-length NGS approaches to understand the interaction between different viral variants and the adaptive immune response . Indeed,Total PBMCs can be used to monitor the overall immune response using standardized assays and peptide sets, as well as MHC class I and II tetramers. HCV-specific T cells can be identified and sorted using MHC class I and II tetramers or activation surface markers. Similarly, HCV-specific B cells can be identified and sorted using E2 tetramers. These sorted cells can be used to perform bulk RNA-seq to understand the overall transcriptomic signature in these different populations and scRNA-seq combined with B cell or T cell repertoire analysis to monitor the evolution of different T or B cell clones during various stages of infection. Sorted B cells can also be used to clone and express HCV-specific antibodies and assess their neutralization profile using standardized HCVpp panels. Systems serology approaches and algorithms can be applied using various assays  to assess the B cell response and to evaluate the efficacy of next-generation vaccines, as has been proposed for HIV .The peripheral blood only reflects part of the immune response. As discussed above, it has become increasingly important to study the immune cell interactions in tissues of interest, whether it is the liver as the site of infection or the lymph nodes, where key interactions in the germinal centers drive the antibody response. To examine the immune response in the liver, it is still possible to obtain fine-needle aspirates during clinical trials and compare the HCV-specific T and B cells in the blood and liver compartments at the single-cell level. Fine-needle aspirates of draining lymph nodes are also well integrated in clinical trials for various vaccines and would provide key information about the interaction between CD4 helper T cells and B cells. Archived liver biopsy samples can be used for spatial transcriptomics and tissue imaging in order to understand the interactions of HCV-specific T cells within the liver microenvironment.Animal models represent a valuable model for the preclinical testing of new vaccines. They also represent a unique complementary tool, in which both systems and classical immunological approaches can be employed to understand the intrahepatic immune response and changes in the liver microenvironment during and post-infection and to assess factors associated with the continued risk of developing liver fibrosis and cancer.Moving forward towards an integrated systems immunology approach for future HCV immunological studies and vaccine clinical trials, there are several key steps to consider, each with its own challenges. First, a team-based approach is essential for the standardization of protocols for sample collection and processing to reduce batch effects and to ensure the reproducibility of results generated in different cohorts. Second, access to sufficient samples for analysis by systematically integrating leukapheresis at key immunological time points is needed. Third, there is a need to build the bioinformatic capacity to filter the huge amount of data that will be generated with the understanding of both the biological processes and the bioinformatic algorithms and to develop novel analysis algorithms that integrate the different types of data into predictive models. Furthermore, as described above, many limitations exist for high-throughput analysis and customized bioinformatics analysis approaches are often needed. Fourth, the validation of the biological mechanisms inferred from the bioinformatics data is critical, using the proper analysis tools and using novel cutting-edge technologies such as high-resolution flow cytometry and tissue imaging with validated sets of antibodies and bioinformatic support for analysis. Finally, the biggest challenge is securing continued funding for the ongoing and new cohorts, as well as vaccine clinical trials and support for the bioinformatic and immunological infrastructures required.Systems transcriptomic studies have unravelled important facets of the immune response against HCV. Specifically, innate immune responses are induced early and are maintained during chronic infection. Recent analysis of HCV-specific CD8+ T cells demonstrated the existence of a relatively permanent exhaustion scar in HCV-specific CD8+ cells that is antigen-dependent and that may not be easy to reverse following DAA treatment and thus represents an obstacle to the generation of long-term protective immunity. The role of CD4+ helper T cells and B cells in immunity against HCV and the underlying molecular mechanisms remain virtually unknown. New studies will need to focus on understanding these two subsets, their interaction with CD8+ T cells and their exact contribution to HCV clearance during primary infection and reinfection. A collaborative and integrated systems immunology approach to new cohort studies and vaccine clinical trials is urgently needed. The knowledge gained and infrastructures established to examine immunity against SARS-CoV2 ,108,111


Cellular therapies, deemed live medicine, have brought a wave of new generation biological therapies to treat previously untreatable diseases such as cancers and degenerative diseases like osteoarthritis. These cellular therapies have gained significant recognition in clinical research. The area has been further strengthened with the approval of Chimeric Antigen Receptor added on T cells (CAR-T) therapies by the regulatory authorities USA's Food and Drugs Administration (FDA), European Medical Agency (EMA), the Australian Therapeutic Goods Administration (TGA), and in many countries in 2017 to treat hematological cancers. Another milestone was achieved when allogeneic Mesenchymal Stem Cell- (MSC-) based therapy was approved by the EMA to treat Chrohn's disease in 2018. Allogeneic donor-derived MSC therapies in particular hold great promise and real hope because of their ‘off-the shelf' availability and accessibility for patients in need of urgent treatment. So far, thousands of clinical trials have explored the safety and efficacy of both autologous and allogeneic cell therapies, deeming them safe, however with varying degrees of efficacy. In the current pandemic, clinical trials have begun in many parts of the world to treat severe cases of COVID with MSCs. However, the risk of tissue rejection and the development of undesirable effects due to alloreactivity of allogeneic cells are currently not adequately addressed. Therefore, this warrants careful investigation and detailed reporting of such events by clinical researchers. This review aims at discussing the current landscape of approved allogeneic MSCs along with a few other cellular therapies. We explore any possible reactivity reported to inform the readers of any safety concern and on the efficacy of such therapies. These studies are investigating 25 conditions under category for over recruiting . There are over 530 clinical trials focusing on the allogeneic stem cell therapy and have several different types of stem cells being used, e.g., hematopoietic stem cells (HSCs: CD34/NK), MSCs, and CAR-T cells and 629 clinical trials with autologous cell sources. In the current pandemic, both autologous and allogeneic MSCs have been explored in several registered clinical trials around the world to treat the severe cases of COVID-19, e.g., pneumonia and acute respiratory distress syndrome (ARDS). In such a dynamic and evolving situation dealing with a novel virus globally, a recent review describes the swift and precise targeting the COVID-19-related illness with auto/allogeneic MSC trials which demonstrates the huge therapeutic potential of MSCs in the treatment of viral infection, inflammation, and immune diseases [In recent times, cell therapies have had unprecedented progress, exploring a wide range of adult stem cells other than hematopoietic stem cell transplantation (HSCT) for treatment of a number of disease through the use of MSCs, Natural Killer Cells (NK Cells), skin cells, T cells, and more. With this enormous progress, a milestone was achieved with the approval of one of the first cell therapies to treat Graft Versus Host Disease (GvHD) in Canada and New Zealand in 2015 followed by EMA and a recent approval of CAR-T therapy, Kymriah by FDA in 2018 . The regOver five decades ago, a ground-breaking bone marrow transplant in a sibling with a close histocompatible match was performed and heralded a new era of treating complex medical conditions. Thus, a brand-new field of therapy was uncovered and termed stem cell therapy. To date, allogeneic bone marrow transplantation (BMT) is a treatment option for a range of hematologic diseases including acute myeloid leukaemia. HSCT derived from donor bone marrow has been an established therapeutic method for over 5 decades. The curative action of HSCT is due to immune-mediated graft-versus-leukaemia effects of the donor T cells contained in the graft. However, donor T cells are also the cause of Graft-vs-Host disease (GVHD). As GVHD is a major complication arising from allogeneic HSCT, research into the prevention of GVHD has provided a unique opportunity to understand the mechanisms of alloreactivity. One such mechanism that causes severe GVHD is the production of antirecipient helper (Inerleukin-2-producing) T lymphocyte precursors (HTLp). These precursors amplify the immune response as shown by a positive correlation between patients with high HTLp and the development of GVHD . These fThere are number of advantages of using autologous (self-derived) cellular treatment including the following: (i) the autologous cell therapy poses a low risk of tissue rejection, (ii) less chance of getting foreign infections, and (iii) lower risk of acquiring an unwanted immune response. However, this modality is costly, time consuming, and in some cases may not be efficacious, especially in chronically ill patients with potentially compromised cell quality or inability to donate tissue due to potential surgery risk. Furthermore, the self-derived tissue may also contain underlying genetic factors that are the cause of the disease. Allogeneic (donor-derived) cell therapy also has some issues including (i) the suitability for a diverse population, (ii) chance of carrying foreign antigens that could illicit unwanted immune response, and (iii) tissue rejection. However, if these limitations are overcome with careful health screening of donors; then, allogeneic cell therapy presents many added advantages over the autologous therapy. These include the following: it is less expensive, ‘off the shelf' and therefore immediately available, and well-characterised allogeneic donor cell lines with potentially increased efficacy. However, the issue with developing allogeneic reactivity in the long term remains the main concern for the allogeneic cell therapy and warrants better long-term follow-up and reporting in clinical trials.In this review, given the perceived risks discussed above with allogeneic antigens in the recipients and possible tissue rejection, we reviewed the scientific literature for evidence of alloreactivity and rejection and summarise the current status of alloreactivity and allogenic MSC cell therapies.The MHC group of genes determines and regulates the unique molecular constituents of specific antigens and their interaction with the various immune cells. Therefore, the molecular recognition of foreign cells originates at the genetic level and the peptides on the MHC molecules contribute to allorecognition. Of the three types of MHC gene family subgroups, classes I and II are directly involved in the antigen presentation process. Class MHC class III are structurally and functionally less well defined and the gene cluster contains signalling molecules such as TNF-alpha and heat shock protein. Classes I and II therefore orchestrate the allogeneic reactivity in the recipients' immune cells . In cellMany other immune cells, e.g., macrophages, B-cells, and Natural Killer (NK) cells are primed to illicit strong reactive immune responses when nonself cells or tissues are introduced. This can then trigger undesirable tissue rejection and cause severe morbidity in the recipient. These cells express high levels of class I and II MHC complexes. For this reason, several preventative measures are employed before allogeneic cell or tissue transplantation. One of many measures is cytotoxic cross-match, and together with Allomap Molecular Expression testing and ABO-compatibility, to help predict the success of transplantation . With moMSCs are one of the most studied therapeutic cell types; they are adult stem cells and derived from a number of connective tissues such as the bone marrow, adipose tissue, umbilical cord, placenta, and dental pulp. With the regulatory approval of the use of allogeneic MSCs for acute GvHD, the field has gained a renewed confidence in the therapeutical benefits of these multipotent cells . These cLe Blanc and coworkers first used allogeneic MSCs clinically to treat acute GVHD . This laCAR-T cell therapy is one the most novel immunotherapies of the 21st century, it is used for cancer treatment and has been explored in many clinical trials globally. The process of Chimeric Antigen Receptor (CAR) is an engineered T cell receptor with the ability to recognise a predefined target antigen. It is genetically introduce to the patients' T cells which helps to activate cytotoxicity against the target cells, i.e., malignant cells. It has been described as an antitumour weapon, which acts directly in the immune system . A milesFurthermore, Adoptive Cell Transfer (ACT) therapy is an immunotherapy that separates immunocompetent cells in cancer patients and transfers them back in the patients after expansion or functional identification in vitro. The adoptive cells kill tumour cells directly or stimulate the body's own immune response. There are ‘four-generations' of CAR-T cells that have been used in ACT therapy . The firAs discussed above, autologous therapies are more expensive and time-consuming, allogeneic donor-derived CAR-T provides an advantage over the autologous approach. Healthy donors with distinct HLA types generate ‘off-the-shelf' CAR-T cell banks that can and be matched with the recipient HLA alleles for precision medicine and therefore avoid the risk or incidence of allograft rejection . In our The ability to select CD34+ cells from mobilized peripheral blood makes it feasible to expand these purified cells in cytokine-supported cultures for clinical use. The transplantation of allogeneic Peripheral Blood Progenitor Cells (PBPC) provides complete and sustained hematopoietic and lymphopoietic engraftment . The posγ exposure [Cell therapy has been a breakthrough for major burn victims for permanent skin replacement using cultured autologous epidermal grafts . Rheinwaexposure , 44.Keratinocytes, like all epidermal cells, have MHC class I antigens displayed on their cell surface but the human leukocyte antigen type DR (HLA-DR), a MHC class II antigen strongly associated with immune rejection, is not constitutively expressed . In an eγ. Castillo et al. examined the immunogenicity of cultured allogenic keratinocytes by coincubating them with peripheral blood mononuclear cells and IFN-γ [γ was able to induce HLA-DR activation in keratinocytes [γ exposure in the coculture experiment. These results suggest that HLA-DR is not actively expressed on keratinocytes and these cells have been described as being nonprofessional antigen presenting cells with their limited immunogenicity [However, other studies have shown that these MHC class II antigens on keratinocytes can be activated by stimulation with the proinflammatory cytokine IFN-nd IFN-γ . They fond IFN-γ , 45. Siminocytes . Howevergenicity .https://www.fda.gov/vaccines-blood-biologics/cellular-gene-therapy-products/approved-cellular-and-gene-therapy-products).The first cell therapy product to get regulatory approval for therapeutic use was in August of 2017 for relapsed or refractory (r/r) paediatric and young-adult B-cell acute lymphoblastic leukaemia and then in May 2018 for adult r/r diffuse large B-cell lymphoma [With extensive clinical research in cellular therapies, there currently is a number of products that have been approved by various regulatory authorities. Currently the FDA has 19 cell therapy products approved for use in patients  . In a 20Allogeneic cell therapies are “off-the-shelf” options that provide innovative, efficacious, and safe treatment solutions for many of the untreatable diseases. Allogenic cell therapies are currently in use in many clinical trials and have also been approved for clinical use in several jurisdictions. Our review provides evidence that the alloreactivity risks of the implanted allogenic cells to the recipients are minimal and do not cause severe adverse reactions in patients. With several approved cell therapies, this heralds a new era of cell therapies for previously untreatable diseases such as Chrohn's disease and GvHD. However, many new cellular therapies that are in various stages of clinical trials and currently underway for the treatment of cancers and other degenerative medicine need close monitoring and stringent reporting of any unexpected adverse reactions along with the efficacy data. Cell therapy is an exciting emerging field and the continued reporting of the clinical outcome data is vital to help strengthen the future of this very promising modern live medicine.