TLR9 and rheumatoid arthritis: CD39 expression was increased in CpG and IL-2 stimulated B cells within untreated rheumatoid arthritis patients and healthy controls. This also led to suppressed CD4+ and CD8+ T cell proliferation [27]. CD35 is an inhibitor of BCR-mediated human B cell activation and differentially regulates TLR7, and TLR9 induced responses [28].