TRIM21 and systemic sclerosis: In this study of 307 Japanese patients with SSc, we identified “isolated” anti‐SSA seropositivity—defined by the absence of other major SSc‐related autoantibodies detectable through clinical laboratory testing covered by health insurance in Japan (ATA, ACA, ARA, and anti‐U1‐RNP)—as an independent predictor of both poor OS and shorter PFS (Figure 2; Tables 2 and 3).