TRIM21 and systemic sclerosis: Among the ATA- and ACA-negative patients, in the first cohort, we identified 2 patients positive for anti-fibrillarin (U3 RNP), 1 for anti NOR-90, 1 for anti-RNA polymerase III, and 1 for anti-Ro52 antibodies; 1 patient was negative for all SSc-related antibodies measured.