Acute Graft-Versus-Host Disease

Acute graft-versus-host disease (GvHD) remains a major course of short term (100 days and 1 yr) mortality and morbidity after allogeneic stem cell transplantation. The pathophysiology of GvHD is described as a 3 step process starting with initial tissue damage by conditioning followed by host antigen presenting cell activation by damage and pathogen associated molecular patterns and finally resulting in activation of alloreactive T cells and proinflmmatory cytokines inducing target cell apoptosis. This activating cycle elicits multiple regulatory mechanisms and cells such as regulatory T cells and myeloid derived suppressor cells. Besides the disturbed balance between immune activation and immune tolerance, a disturbed capacity of tissue repair contributes to clincal damage.