CD4 and rheumatoid arthritis: Our lab recently showed that monocytes, activated in vitro with LPS or with cytokines known to be present in the RA joint, can induce expression of proinflammatory cytokines (IL-17 and IFNγ) in CD4+CD25+CD127low Tregs in an IL-6-, TNFα-, and IL-1β-dependent manner (18).