Human leukocyte antigen graft rejection

Contamination of blood products with lymphocytes can lead to transfusion-induced reactions ranging from a mild fever to severe reactions such as alloimmunization and graft versus host disease (GvHD), in which the transfused lymphocytes (graft) survive the defensive immune reaction of the patient (host) and start a reaction which destroys the cells of the host. The patient also may develop an immune response to the human leukocyte antigen (HLA) type of the graft s cells and reject all platelet transfusions that do not match their own HLA system. The HLA system, found on blood platelets and lymphocytes, is more compHcated than, but similar to, the ABO blood group system of red cells. 

Allogeneic hematopoietic stem cell transplantation is the only therapy that is curative. The best candidates are younger than 16 years of age, have severe complications, and have human leukocyte antigen-matched donors. Risks must be carefully considered and include mortality, graft rejection, and secondary malignancies. 

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