Clinically significant red blood cell antibodies in multitransfused Egyptian thalassemic patients

Background Red blood cell (RBC) alloimmunization is a major challenge to repeated transfusions in β-thalassemia-major patients. The aim of this study was to evaluate the magnitude of RBC alloimmunization and autoimmunization in regularly transfused Egyptian patients with β-thalassemia major and analyze factors that may be responsible for the development of antibodies. Patients and methods This study was conducted on 200 Egyptian β-thalassemia-major patients with age less than 16 years, who routinely visited the Pediatric Hematology Clinic of Ain Shams University Hospital for regular transfusions. All the patients underwent antibody screening. Patients with a positive antibody screen were further tested for antibody identification. The data were analyzed to find out the frequency of alloimmunization, and the patients records were revised to analyze the factors influencing it. In case of pan-positivity of the antibody-screening cells and the autocontrol, adsorption by autogenic RBCs was performed to uncover the presence of alloantibodies. Results RBC alloantibodies were found in 21 (10.5%) patients. The most frequent alloantibodies encountered were anti-Kell (52.4%) and anti-E (19%). Autoantibodies were encountered in only one patient. They were the warm autoantibody type, and adsorbtion using autogenic RBCs was succesful in eliminating them. The frequency of blood transfusion, the transfusion index, serum ferritin, and the age at first transfusion showed a statistically significant correlation with alloimmunization ( P 0.05). In contrast, there was no statistically significant association between the patients sex, age, the ABO, Rh blood groups, and the spleen state and alloimmunization (P 0.05). Conclusion We conclude that alloimmunization to RBC antigens is a relatively frequent finding among Egyptian transfusion-dependent thalassemic patients. The most frequent antibodies detected were against the Kell and Rh blood groups, mainly anti-Kell and anti-E. The majority of alloantibodies detected in this study were clinically significant.