Acute graft versus host disease: pathophysiology, risk factors, and prevention strategies.

Acute graft versus host disease (GVHD) remains the greatest complication of allogeneic bone marrow transplantation and a major cause of morbidity and mortality. This article summarizes the risk factors and prevention strategies for acute GVHD by considering them within the context of disease pathophysiology. Acute GVHD can be considered a 3-step process: 1) damage from chemotherapy/radiotherapy; 2) host antigen-presenting cell activation and amplification of donor T cells; and 3) target cell apoptosis via cellular and inflammatory mediators. This conceptual framework helps to explain the effectiveness of current prevention strategies and points to areas where new drugs and approaches may be of clinical benefit.