To gauge the effect of LEN on the production of several cytokines from donor‐derived T cells during GVHD, we examined the percentage of T cells expressing IFN‐γ, IL‐17, IL‐4, IL‐13, IL‐2, IL‐10, and TNF‐α in host mice treated with a high dose of LEN and host mice treated with vehicle, as these cytokines are important for aGVHD pathogenesis and Treg proliferation.28, 29. Here, IL4 is linked to graft versus host disease.