Graft versus Host Disease

Definition Graft-versus-host disease (GVHD) is the most common complication of allogeneic hematopoietic stem cell transplantation (HSCT). In HSCT, the patient’s bone marrow is destroyed with chemotherapy and/or radiation and replaced by donor hematopoietic stem cells. In allogeneic HSCT the donor is usually a close family member or occasionally someone outside the family who has been found to be a “match”. GVHD occurs when transplanted donor’s immune cells (graft) react to patient’s tissues (host) and tries to destroy them. As a consequence of this action, the patient's organs impair their ability to function, and increase the patient's susceptibility to infection. GVHD is generally divided into two syndromes acute and chronic. Acute GVHD (aGVHD), is that occurring within three months after transplantation, and chronic GVHD (cGVHD), usually develops after the third month post-HSCT. Patients may develop one, both or neither reaction. Acute and chronic GVHD differ in their symptoms, clinical signs and time of onset. Acute GVHD primarily involves the skin, liver, oral mucosa, and gastrointestinal tract. In contrast, cGVHD presents a far more varied clinical picture including liver dysfunction, pulmonary fibrosis, sclerodermatous skin changes, oral and gastrointestinal mucosa changes, and a reduced production of tears and saliva.