Autoantibodies

No significant between-group differences were observed for IgM autoantibodies at any timepoint. Overall, antimodified peptide/protein antibody titer evolution did not differ relevantly between abatacept and hydroxychloroquine. COVID-19 patient serum reacted with 25 of 80 tissue antigens involved in autoimmune disorders. The PALABA trial measured IgG, IgA, and IgM autoantibody isotypes for each antigen specificity at baseline and follow-up timepoints. Autoantibodies may appear years to decades before clinical autoimmune disease manifests. Rheumatoid factor and anticitrullinated protein antibodies are among the strongest predictors of rheumatoid arthritis development in at-risk individuals. Higher cardiolipin and platelet glycoprotein antibody levels were associated with more severe COVID-19 clinical presentation. Many people with palindromic rheumatism have rheumatoid factor or anticitrullinated protein antibody positivity. Older individuals had higher antibody levels in the COVID-19 systems biology analysis. Autoantibodies can identify at-risk individuals, support disease sub-phenotyping, inform prognosis, and guide individualized treatment.