CD200Fc increased CD200R1 expression in lymphocytes, and CD200 expression in neurons also increased; at the same time, the anti‐inflammatory cytokine Arg‐1 was increasingly expressed, and the expression of iNOS, a marker of proinflammatory cytokines, was inhibited in the ischemic penumbra of the ischemic brain 7 days after stroke. The gene discussed is ARG1; the disease is stroke disorder.