CD200R1 and rheumatoid arthritis: M1 macrophage indicators HLA‐DR, CD86, CD64 and CCR5 are highly expressed in mononuclear macrophages in the peripheral blood of patients with RA, while M2 macrophage indicator CD163 shows low expression, and CD200R and CD16 show no difference,38 indicating that the mononuclear macrophages in the peripheral blood of patients with RA tend to be M1 macrophages (Figure 2).