PRTN3 and rheumatoid arthritis: In contrast, a small cross-sectional study found no differences between patients with RA with SS (n = 11) and those with RA alone (n = 296) regarding age, sex, RA disease duration, disease activity score, and ACPA seropositivity; however, it showed that patients with RA and secondary SS had a tendency for higher numbers of tender and swollen joints and pain [17].