RNPC3 and systemic sclerosis: Specific SSc antibodies include anti-topoisomerase I (anti-topo I)/anti-Scl-70, anti-centromere antibodies (ACAs), anti-U3 ribonucleoprotein (RNP)/anti-fibrillarin, anti-U1 RNP, anti-U11/12 RNP, RNA polymerase III, and nucleolar antigens, such as anti-Th/To, anti-NOR 90, anti-Ku, and anti-RuvBL1/2, as well as anti-PM/Scl antibodies [2].