Human Leucocyte Antigens in blood transfusion

Abstract

Human Leucocyte Antigen (HLA) genes and molecules have an important role in transplantation, aetiology of many autoimmune, non‐autoimmune and infection diseases. Due to the extremely high polymorphism of HLA genes and their different frequency distributions in various populations, an increasing probability of HLA non‐compatible blood products, tissues or organs usage exists. For that reason, the aim of this paper was to give a concise overview of the role of HLA antigens and antibodies in adverse reactions caused by administration of transfusion products. The HLA system can cause detrimental immune reactions in transfusion therapy (platelet immune refractoriness, febrile transfusion reaction, transfusion‐related acute lung injury and transfusion‐associated graft versus host disease). Anti‐HLA antibodies present in the patient are responsible for some of these reactions, while anti‐HLA antibodies or HLA reactive cells present in the transfused product are accountable for immune‐reactivity in other cases. In order to avoid or reduce the development of these transfusion‐related events, anti‐HLA antibody‐negative or compatible products should be used. This is increasingly facilitated by introduction of more sensitive and specific techniques to determine anti‐HLA antibodies and gene polymorphisms. In conclusion, the most common adverse reactions related to administration of incompatible HLA transfusion products are discussed. Basic information about HLA genes and antibodies as well as methods for their detection is also provided in order to give sufficient data for safe and efficient administration of transfusion products.