In addition, the proportion of peripheral B cell subsets, such as CD27+IgM+IgD+ and CD27+IgM−IgD− memory B cells, are reduced in pSS compared to healthy controls (HC) and patients with rheumatoid arthritis and systemic lupus erythematosus [3, 4], suggesting that these memory B cell subsets may be recruited to glandular tissues, where they differentiate into plasmablasts and plasma cells and produce IgG [5]. This evidence concerns the gene CD27 and rheumatoid arthritis.