Relevance of RH variants in transfusion of sickle cell patients

Transfusion is a life sustaining therapy in sickle cell disease. Allo-immunization against red blood cells remains an important side effect responsible for post transfusion hemolysis. Numerous RH variant antigens are encountered in these patients of African descent. These RH variants can be associated with allo-immunization when the variant belongs to the partial type and when the carrier of this partial variant is exposed to the normal antigen through transfusion or pregnancy. Variants can be characterized by molecular typing, and many commercial tools have been developed. In this review, we will discuss the involvement of RH variants in sickle cell disease transfusion, with regards to their clinical significance in term of allo-immunization and haemolytic transfusion reaction.