Prevalence of Alloantibodies in Transfusion-dependent Thalassemia Patients

BACKGROUND: The aim of this study was to determine the prevalence of alloantibodies among transfusion-dependent thalassemia patients at our hospital. MATERIALS AND METHODS: The present study is a retrospective study done at a tertiary care hospital in North India. All 92 patients with thalassemia, receiving blood transfusions during the study period were included in the study. The blood samples of these patients were collected immediately prior to transfusion. These samples were subjected to antibody screening by the indirect antiglobulin test utilizing a commercial three cell panel. Plasma samples that showed a positive result with antibody screening underwent antibody identification using an extended commercial eleven-cell panel. The secondary data were obtained from the records of these 92 patients. RESULTS: Four of the 92 patients developed alloantibodies. Among these four patients, one patient showed alloantibodies against E antigen, another against K antigen, while two patients had alloantibodies which did not show clear specificity using the eleven-cell panel. Alloantibodies were noted in two of the six patients having an Rh (D)-negative phenotype. A significant association was noted between Rh-negative blood group and alloimmunization ( P = 0.0202). No significant association was observed between alloimmunization and patient age, age at first transfusion, pretransfusion hemoglobin, splenectomy status, serum ferritin level or annual red cell consumption. CONCLUSION: The prevalence (95% confidence interval) of alloantibodies in transfusion-dependent thalassemia patients in the present study was noted to be 4.3% (1.7%-10.6%). Patients with an Rh (D)-negative phenotype had a significantly higher prevalence of alloimmunization as compared to patients with an Rh (D)-positive phenotype.