[Acute and chronic graft-versus-host disease after allogeneic hematopoietic stem cell transplantation].

Acute and/or chronic graft-versus-host disease (GVHD) is a serious complication after allogeneic hematopoietic stem cell transplantation (alloHSCT). It is a multisystemic inflammatory and/or fibrotic disease that occurs when the immune cells derived from the graft (and therefore originating from the donor) recognize recipient's healthy tissues as foreign and react against them. Acute GVHD is one of the main causes of non-relapse mortality after alloHSCT. Chronic GVHD can be very disabling in its severe form and can also be responsible for late mortality, mainly due to long-term immune deficiency and opportunistic infections. In contrast, GVHD can be associated with certain beneficial effects in patients transplanted for hematological malignancies, through simultaneous «graft versus tumour» positive effects. Therefore, one of the challenges of alloHSCT is the prevention and treatment of severe forms of GVHD without losing the beneficial anti-tumour effects of the graft.