Allogeneic haematopoietic stem cell transplantation (HSCT) following myeloablative conventional conditioning regimen is associated with a higher incidence of transplant-related morbidity and mortality, limiting its applicability to younger patients without significant co-morbidities. The morbidity and mortality of HSCT are related closely to relapse of malignancy, conditioning-related toxicities, infection, and donor–recipient human leucocyte antigen (HLA) disparity. Disparities at minor histocompatibility antigens are thought to be responsible for acute graft-versus-host disease in patients receiving HSCT from a HLA-matched donor.
Serious complications tend to erupt within specified periods of immunologic reconstitution after bone marrow grafting. Because their innate and acquired immune systems are especially vulnerable, HSCT recipients often have infectious and noninfectious complications. This article reviews the major complications of HSCT.