Graft-versus-host disease.

Graft-versus-host disease (GVHD) is the most frequent and potentially fatal complication of an allogeneic hematopoietic progenitor cell transplantation. It appears when immunocompetent T cells from donor origin recognise antigens from recipient origin as foreign. The immune response activates donor T cells and destroys recipient tissues. The clinical picture of this immune response is called acute and chronic GVHD. Acute GVHD is the main fatal complication during the first months after allogeneic hematopoietic progenitor cell transplantation, while chronic GVHD accounts for a significant long-term fraction of the mortality, morbidity and reduced quality of life of patients. Our goal is to review the frequency, clinical manifestations, diagnosis, treatment and prevention of GVHD.