Naturally occurring CD49b⁺CD200R3⁺ DC_regs protect mice from the incidence and severity of cutaneous cGVHD. (A,B) The irradiated recipient BALB/c mice (10 per group) were transplanted with T cell–depleted BM cells and CD4⁺CD25⁻ T cells obtained from B10.D2 mice and then treated with or without the recipient-type BM-DC_regs, CD11c⁺ DCs, CD49b⁺CD200R3⁺ cells, huIgFc, or CD200R3ext-huIgFc after the transplantation. The incidence (A) and severity (B) of cutaneous cGVHD were monitored for 45 days after the transplantation. *P < .01 compared with the untreated recipient mice. (C,D) The irradiated recipient BALB/c mice that had received anti-CD200R3 mAb or control Ig (10 per group) were transplanted with T cell–depleted BM cells and CD4⁺CD25⁻ T cells obtained from B10.D2 mice. The incidence (C) and severity (D) of cutaneous cGVHD were monitored for 45 days after the transplantation. *P < .01 compared with the untreated recipient mice. Data are mean ± SEM, and the results are combined from 3 replicate experiments (A-D).