TRIM21 and systemic lupus erythematosus: Anti-Ro (also called anti-SSa) and anti-La (also called anti-SSb) AAbs are often associated with SS but can also occur in SLE with a prevalence between 36 and 64% and between 8 and 33.6% for anti-Ro AAb and anti-La AAb, respectively (37, 38, 61, 75, 76).