TRIM21 and systemic lupus erythematosus: In the SLE patients, 44% were positive for anti-U1-A RNP activity, 34% for anti-Sm-B, 44% for anti-SSA (32% for TRIM21 and 46% for Ro 60), 32% for anti-SSB/La, and 11% for anti-Ku reactivities.