Immunoserologic detection and diagnostic relevance of cross-reactive auto-antibodies in COVID-19 patients.

During the COVID-19 pandemic, we detected a new immunofluorescence (IF) pattern in serum autoantibody (autoAb) screening of laboratory-confirmed COVID-19 patients. The IF pattern was composed of liver and gastric mucosa staining on rat kidney/liver/stomach sections. We describe 12 patients positive for the cross-reactive Ab, compared to a negative group of 43 hospitalized COVID-19 patients, finding association with either neurologic or thrombotic complications. In sequential pre- and post-COVID-19 serum samples, we confirmed autoAb seroconversion. Our data indicate that autoAb screening in COVID-19 patients may be easily performed by IF and alert for auto-reactive mediated complications such as thrombotic or neurologic events.