Antinuclear antibodies in individuals with COVID-19 reflect underlying disease: Identification of new autoantibodies in systemic sclerosis (CDK9) and malignancy (RNF20, RCC1, TRIP13)

A high prevalence of antinuclear antibodies (ANA) in COVID-19 has been insinuated, but the nature of the target antigens is poorly understood. We studied ANA by indirect immunofluorescence in 229 individuals with COVID-19. The target antigens of high titer ANA (>= 1:320) were determined by immunoprecipitation (IP) combined with liquid-chromatography-mass spectrometry (MS). High titer ANA (=1:320) were found in 14 (6%) of the individuals with COVID-19. Of the 14 COVID-19 cases with high titer ANA, 6 had an underlying autoimmune disease and 5 a malignancy. IP-MS revealed known target antigens associated with autoimmune disease as well as novel autoantigens, including CDK9 (in systemic sclerosis) and RNF20, RCC1 and TRIP13 (in malignancy). The novel autoantigens were confirmed by IP-Western blotting. In conclusion, in depth analysis of the targets of high titer ANA revealed novel autoantigens in systemic sclerosis and in malignant disease.

Automated summary

A high prevalence of antinuclear antibodies (ANA) was found in COVID-19 patients, with the target antigens poorly understood. Through immunoprecipitation combined with liquid-chromatography-mass spectrometry, novel autoimmune antigens were identified in systemic sclerosis and malignant disease. This in-depth analysis of high titer ANA targets provides valuable insights into the autoimmune response in COVID-19.