RNPC3 and mixed connective tissue disease: Autoantibody targets commonly associated with autoimmune connective tissue diseases (SLE, MCTD, SjS, systemic sclerosis, and drug-induced lupus) such as anti-dsDNA, anti-Smith, anti-U1 RNP, anti-Smith/RNP common motif, anti-SS-A (60 kD), anti-SS-B, anti-centromere, anti-Scl-70 (topoisomerase I), anti-RNA polymerase III, and anti-histone antibodies were then compared between ANA+SAID+ and ANA+SAID− subgroups (Table 2).