IL17A and graft versus host disease: However, it was shown for the first time that, in MR1-/- and IL-17A-/- mouse transplant models, MAIT cells from the recipient but not the donor after bone marrow (BM) transplantation produced a large amount of IL-17A to promote gastrointestinal integrity, modulate microbial communities, and inhibit alloantigen presentation and effector T cell expansion, inhibiting the occurrence of GVHD (51).