CD4 and rheumatoid arthritis: Though the exact pathogenesis of RA has not been thoroughly explicated,1 cluster of differentiation positive 4 (CD4+) T cells are thought to play a crucial role, as it stimulates proliferation and differentiation of B‐lymphocytes2 and participate in the induction and propagation of inflammatory responses by secreting pro‐inflammatory cytokines, growth factors, and interferons.3, 4