Recipient nonhematopoietic antigen-presenting cells are sufficient to induce lethal acute graft-versus-host disease

Graft-versus-host disease (GVHD) can be a life-threatening complication of bone marrow transplantation (BMT). Understanding the mechanisms causing GVHD is important to developing treatments or preventive therapies. In this issue, Koyama et al . report the surprising finding that recipient nonhematopoietic antigen-presenting cells, rather than dendritic cells, are the crucial factor in inducing CD4 + T cell–dependent GVHD and death in mice.