Prevention of lethal graft-versus-host disease by monoclonal antibody treatment in vivo.

Graft-versus-host disease (GVHD) is a major complication of allogeneic bone marrow transplantation (BMT). The disease is caused by mature T cells in the graft that recognize foreign antigens of the host and subsequently elicit an immune response to host tissues. Although T-cell depletion of the graft strongly reduced the incidence and severity of GVHD, the overall survival of allogeneic BMT did not increase because of the increased rate of graft rejection and leukemic relapses. New prophylactic and therapeutic approaches have to be developed to improve the outcome of allogeneic BMT. T-cell-specific monoclonal antibodies (mAb) administered in vivo to the allograft recipients seem to be promising in the prevention and treatment of lethal GVHD. In this study we especially addressed the effect of in vivo treatment of recipients with anti-T-cell subset mAb in a murine model for acute GVHD. We also determined the long-term effects.