Graft-versus-host disease.

Combinations of drugs such as methotrexate, cyclosporin A, and prednisone have reduced the incidence of graft-versus-host disease (GVHD) to 20% to 30%. However, GVDH remains a major complication (up to 90%) following allogeneic bone marrow transplantation from unrelated or mismatched donors. GVHD is now understood as a two-step phenomenon: first, the activation of specific cytotoxic T cells and second, the release of several cytokines. Recent treatment modalities, including new immunosuppressors, T-cell depletion, and anticytokine monoclonal antibodies are discussed.