TRIM21 and polymyositis: Anti-Ro52/TRIM21 antibodies (anti-Ro52) are commonly detected in the sera of patients diagnosed with different types of SARD, including Sjögren's syndrome12, polymyositis/dermatomyositis (PM/DM)13,14, systemic sclerosis (SSc)15,16, and systemic lupus erythematosus (SLE)17.