Acute graft-versus-host disease

Despite advances in HLA typing, acute GvHD remains a leading cause of morbidity and mortality among allogeneic transplant recipients. It is estimated that 30-50% of patients who receive stem cell products from HLA-identical siblings will develop grades 2-4 GvHD, while rates of GvHD in matched unrelated donor transplants are estimated to be between 50 and 70%. Acute GvHD has historically been defined as occurring prior to day +100 and chronic GvHD as occurring after day +100. However, recently there has been a move to define GvHD based on the clinical symptoms and pathologic findings rather than by an arbitrary timeline. The outcome of acute GvHD is dependent on the overall grade of GvHD and the patient's response to initial treatment.