Clinical and molecular aspects of antigens and antibodies of blood cells

Abstract

Red cell alloantibodies may cause hemolytic disease of the newborn and hemolytic transfusion reactions, while red cell autoantibodies participate in the immune destruction of red cells seen in autoimmune hemolytic anemia. Neutrophil alloantibodies may produce neonatal alloimune neutropenia and transfusion related acute lung injuri (TRALI), on the other hand granulocyte autoantibodies provoke neutrophil immune destruction observed in patients with autoimmune neutropenia. Platelet alloantibodies may induce neonatal alloimmune thrombocytopenia, post-transfusion purpura, and platelet transfusion refractoriness, conversely platelet autoantibodies induce primary or secondary immune thrombocytopenia purpura. The aim pf the present immunohematological project is to examine not only the molecular basis of the blood cells alloantigen systems, but also calculate the risk associated to the exposition to allogenic blood cells by blood component transfusion, transplantation, or pregnancy. The major project consists of 5 subprojects designed to study blood group systems: 1 subproject connected to platelet alloantigen systems; and 6 subprojects associated with granulocyte alloantigen systems. We propose to study immune mechanisms which take place in autoimmune hemolytic anemia, in homolysis post-kidney transplant, and in vaso-oclusive crisis seen in patients with sickle cell disease. We will also investigate molecular aspects of the Rh blood group system in brazilian individuals, the gene frequency of some platelet alloantigen systems, and the platelet alloimmunization risk in Brazilian ethnic groups. Finally, we will determine the phenotypic and genotypic distribution of the granulocyte alloantigen systems in different brazilian ethnic groups, the relevance of some polimorphisms in the expression of such antigens, and the role of granulocyte specific alloantibodies in some transfusion reactions. (AU)