Frequency and Risk Factors of Red Blood Cell Alloimmunization in Thalassemia Major Patients in Markazi province

Background: Thalassemia is one of the most common genetic disorders throughout the world. Blood transfusion plays an important role in the treatment of thalassemia but it leads to numerous complications such as iron overload and alloimmunization. This study evaluated the frequency and risk factors associated with alloimmunization in thalassemia major patients living in Markazi province, Iran. Materials and Methods: In this descriptive study, 48 thalassemia major patients who underwent blood transfusion at Amirkabir hospital were included. Patients' demographic data were recorded using a questionnaire. In order to perform alloimmunization screening and autoantibody assessment, patients were referred to Tehran Blood Transfusion Organization Laboratory. Results: The current study was performed on 48 patients with thalassemia major,. The mean age of patients was 12.5 ± 8.3 years. Among patients 26 (54.16%) were male and 22 (45.83%) were female, 13 patients (27.08%) had alloantibodies. Among 48 patients, 19 (39.58%) had undergone splenectomy. The patients' age of the first blood transfusion ranged from 1 month to 14 months      and the mean age of the first blood transfusion was 9.5 ± 7.08 months. The blood transfusion intervals in patients were from 21 days to 40 days and the blood volume received at each transfusion session was 10-15 cc/kg of the body weight. In the current study, the data analysis indicated no significant correlation between alloantibodies and RH phenotype (P=0.43), patients' gender (P=0.9), or blood groups (P=0.4); whereas, a significant correlation was found between alloantibodies and splenectomy (P=0.02) as an increase in the prevalence of alloantibodies was reported in splenectomised patients. Conclusion: No significant difference was found between the patients with and without alloantibodies in terms of the prevalence of Rh phenotype, gender, and blood groups. However, there was a significant difference between the patients with and without alloantibodies in terms of splenectomy. Key words: Allo-immunization, Risk factors, Thalassemia major