Latent Rheumatic, Thyroid and Phospholipid Autoimmunity in Hospitalized Patients with COVID-19.

Abstract Autoimmune responses mediated by autoantibodies have been previously observed in SARS-CoV-2 infection. Herein, we evaluated the presence of rheumatic, thyroid and phospholipid autoantibodies in sera samples from 120 hospitalized patients with COVID-19 in comparison to pre-pandemic samples from 100 healthy individuals. In addition, to estimate the frequency of these autoantibodies in COVID-19, a meta-analysis of selected articles was conducted. Hospitalized patients with COVID-19 displayed latent autoimmunity mainly mediated by a high frequency of anti-thyroid peroxidase antibodies, rheumatoid factor (RF), anti-cyclic citrullinated peptide third generation antibodies, antinuclear antibodies (ANAs), IgM β2-glycoprotein I (β2GP1) and IgM anti-cardiolipin antibodies. The meta-analysis confirmed our results, being RF and ANAs the most common autoantibodies. In addition, cluster analysis revealed that those patients with high positivity for RF, IgM β2GP1 antibodies and ANAs had a longer hospital stay, required more vasopressors during hospitalization, and were more likely to develop critical disease. These data suggest that latent autoimmunity influences the severity of COVID-19, and support further post-COVID studies in order to evaluate the development of overt autoimmunity.