Multi‐Autoantibody Testing Identifies Expansion of Reactivity to Targeted Antigens Before a Diagnosis of Rheumatoid Arthritis

Rheumatoid arthritis (RA) has a "pre-RA" period in which multiple autoantibodies, including antibodies to citrullinated (cit) proteins (ACPA), rheumatoid factor (RF), anti-peptidyl arginine deiminase (anti-PAD), among others, have been described; however, few studies have tested all autoantibodies in a single pre-RA cohort. This study aims to evaluate the prevalence of multiple autoantibodies in pre-RA and potentially identify an autoantibody profile in pre-RA that indicates imminent onset of clinical RA.