Frequency Of Alloantibody In Multiple-Transfused Thalassemia Major Patients And Factors Influencing On Alloimmunization.

Background & Objective: The recommended treatment for beta thalassemia major involves regular blood transfusions, whichstimulate the patient’s immune system and results in the formation of antierytrocyte antibodies usually IgG class. They can result in clinical hemolysis and complication of blood cross matching. The purpose of this study was to determine the frequency of RBC alloantibodies, the type of these antibodies, factors influencing on alloimmunization among multiple- transfused thalassemia major patients. Methodology: ABO blood grouping,Rh (D) typesand Phenotyping done by the electromagnetic technology using Qwalys 3 Diagast. Antibody screening was done by using 3-cell panel followed by11- cell panel of Biorad Corporation. Results: 10 patients developed alloantibodies against RBC Antigen. Among total alloimmunizedpatients, 7.35%were female and 4.27% were male. Majority of alloantibodies were directed against antigen in the Rh and Kell system. i. e. Anti c, Anti E and Anti K. Frequency of Alloantibody positivism is maximum in AB positive patients. From extended Antigen typing of voluntary donors, we can see the frequency of D, C and e Antigens are more than frequency of c, E and K Antigens. Conclusion: Frequency of red cell alloimmunizationwas 5.40% in this study. Alloantibodies found were mainly against Rh blood group systemand Kell system. Red cell alloantibody formation was not influenced by age at first transfusion, number of blood transfusion, splenectomy and leuckodepleted blood transfusion. In our study alloimmunized patients did not revealed any evidence of haemolytic transfusion reaction. The frequency of Antibody positivity depends on immunogenicity of Antigen. Females and group AB patients are showing more frequency of alloimmunization. Routine pretransfusion matching of blood, other than ABO and RhD antigen is not recommended because of low rate of red cell alloimmunization and high cost associated with such testing.