Chronic graft-versus-host disease.

Chronic graft-versus-host disease (GVHD) continues to be the major problem in the long-term survivors of allogeneic hematopoietic stem cell transplants. Because of its similarities to autoimmune disease, the pathogenesis of chronic GVHD has been thought to differ from acute GVHD. Autoreactive T lymphocytes are an important effector mechanism with interferon gamma playing a central role in the increased collagen deposition that is the central histopathologic feature of chronic GVHD. Therapies that prevent the development of acute GVHD have been unsuccessful in the prevention of chronic GVHD. None of the present therapies for established chronic GVHD are successful in the majority of patients.