Host Basophils Are Dispensable for Induction of Donor T Helper 2 Cell Differentiation and Severity of Experimental Graft-versus-Host Disease

Host hematopoietic-derived antigen-presenting cells are important for induction of graft-versus-host disease (GVHD). The relative importance of various subsets of hematopoietic-derived antigen-presenting cells is not well understood. Recent data suggest that basophils can function as antigen-presenting cells and induce T helper 2 (Th2) lymphocyte responses. We investigated the role of host basophils in the induction of donor T cell responses and GVHD after allogeneic bone marrow transplantation. Elimination of host basophils did not alter the severity of GVHD-induced mortality across multiple clinically relevant models of allogeneic bone marrow transplantation. Furthermore, induction of donor T cell proliferation and Th2 polarization was not altered significantly after depletion of host basophils. Our results demonstrate that, in contrast to their role in inducing Th2 responses in certain contexts, basophils are dispensable for the induction of donor Th2 responses and for the severity of GVHD.