Transforming growth factor-β1 polymorphisms and the outcome of hematopoietic stem cell transplantation

Hematopoietic stem cell transplantation (HSCT) is a medical procedure used to treat malignant and nonmalignant haematological diseases, congenital immunodeficiency syndromes, solid tumours and metabolic diseases. Despite its usefulness, several major complications, such as graft-versus-host disease, can negatively affect patients treated with HSCT. Apart from clinical factors well known to affect the outcome of HSCT, patient and donor genetics have been shown to play an important role in the susceptibility to post-transplant complications. Histocompatibility as determined by the human leucocyte antigen (HLA) system has been a major genetic determinant of the success of HSCT. Non-HLA immunogenetics are increasingly recognized to play a part in the events related to transplantation. Cytokine genes, and their receptors, bear a considerable amount of polymorphism. One of the genes that may play an important role on the outcome of allogeneic HSCT is TGFB1, which encodes transforming growth factor, βeta 1 (TGF-β1). TGF-β1 is a pleiotropic cytokine, which plays a central role in the development, homeostasis and responses of the immune system. Several functional polymorphisms in TGFB1 have been identified, and these are known to cause alterations in cytokine secretion in several settings. The present review will focus on the current knowledge surrounding the effect of polymorphisms within TGFB1 on the outcome of HSCT.