IL13 and graft versus host disease: 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