Antinuclear antibodies (ANAs) detected by indirect immunofluorescence (IIF) method in acute COVID-19 infection; future roadmap for laboratory diagnosis.
INTRODUCTION
As in other viral infections, anti-nuclear antibodies (ANAs) are observed in SARS-CoV-2 infection. We investigated the presence of autoantibodies in acute COVID-19 and the association with early laboratory findings.


MATERIALS AND METHODS
We examined 50 sera (>18 years, 25 Female) from patients with acute COVID-19. ANAs (HEp-20-10 liver biochip), anti-neutrophil cytoplasmic antibody (ANCA, Europlus Granulocyte Mosaic 32) and anti-double stranded DNA were investigated with product of Euroimmune AG (Luebeck, Germany) by indirect immunofluorescence (IIF) method. Also, antibody against cyclic citrullinated peptide (anti-CCP) was examined by a chemiluminisens assay (Euroimmun AG, Luebeck, Germany). Samples from 50 blood bank donors collected before the COVID-19 pandemic were used as controls.


RESULTS
The IIF-ANA test was positive in 18% (N = 9/50) of the patients. The median time of sample collection was 7 days (range: 1-28 days) after diagnosis. ANA was positive in only one (2%) control sample. Five (55.5%) patients were ANA positive with a strong titer (3+). There was no relationship between antibody titration and time of sample collection (p = 0,55). Anti-CCP was detected in a nucleolar (3+) positive patient (2%). ANA was detected in 14.28% (N = 1/7, rods-rings (±), p = 0,78) of patients in the intensive care unit(ICU). Patients treated in the clinic have more and higher titers of ANA, mostly in nucleolar patterns, than ICU patients.


CONCLUSIONS
The variety of antibodies detected in acute COVID-19 and the uncertainty of how long they persist can lead to confusion, especially in the diagnosis of systemic autoimmune rheumatic diseases for IIF-ANA testing in immunology laboratories. Improvements in cell lines and methods will facilitate the diagnostic process.
['Peker|Bilal Olcay|BO|', 'Şener|Aslı Gamze|AG|', 'Kaptan Aydoğmuş|Figen|F|']
D000208:Acute Disease D000328:Adult D000368:Aged D000369:Aged, 80 and over D000974:Antibodies, Antinuclear D000086382:COVID-19 D019411:Clinical Laboratory Techniques D005260:Female D019084:Fluorescent Antibody Technique, Indirect D006801:Humans D008297:Male D008875:Middle Aged D058873:Pandemics D055815:Young Adult
Laboratory diagnosis Anti-nuclear antibody Anti-neutrophil cytoplasmic antibodies Coronavirus disease 2019 Indirect immunofluorescence test