Clinical significance of antinuclear antibody positivity in patients with severe coronavirus disease 2019

Background/Aims This study aimed to investigate the clinical characteristics and outcomes of fluorescent antinuclear antibody (FANA)-positive patients admitted for coronavirus disease 2019 (COVID-19) and identify FANA as a prognostic factor of mortality. Methods This retrospective study was conducted at a university-affiliated hospital with 1,048 beds from September 2020 to March 2022. The participants were consecutive patients who required oxygenation through a high-flow nasal cannula, non-invasive or mechanical ventilation, or extracorporeal membrane oxygenation, and conducted the FANA test within 48 hours of admission. Results A total of 132 patients with severe COVID-19 were included in this study, of which 77 (58.3%) had FANA-positive findings (≥ 1:80). FANA-positive patients were older and had higher inflammatory markers and 28-day mortality than FANA-negative patients. In the multivariate Cox proportional hazard regression analysis, FANA-positive findings (hazard ratio [HR], 2.65; 95% confidence interval [CI], 1.04–6.74), age (per 1-year; HR, 1.05; 95% CI, 1.01–1.10), underlying pulmonary disease (HR, 3.16; 95% CI, 0.97–10.26), underlying hypertension (HR, 2.97; 95% CI, 1.28–6.87), and blood urea nitrogen > 20 mg/dL (HR, 3.72; 95% CI, 1.09–12.64) were independent predictors of 28-day mortality. Remdesivir (HR, 0.34; 95% CI, 0.15–0.74) was found to be an independent predictor that reduced mortality. Conclusions Our findings revealed an autoimmune phenomenon in patients with severe COVID-19, which provides an ancillary rationale for strategies to optimize immunosuppressive therapy. In particular, this study suggests the potential of FANA to predict the outcomes of COVID-19.