Prevalence of Rh and K phenotypes among blood donors from different ethnicities in Samtah (Southwestern Region) Saudi Arabia.

INTRODUCTION: Rh and Kell blood group systems are amongst the most important blood group systems; being highly immunogenic after ABO system. The aim of this study was to evaluate the frequencies of Rh antigens, haplotypes and K antigen among blood donors belonging to various ethnicities in Samtah, Jazan, Saudi Arabia. METHODS: This study was conducted during January 2019 and August 2020 at Samtah General Hospital, Samtah. Records of all blood donors recruited during this period were included for data acquisition. A total of 4977 blood donors' records were reviewed and data were analysed. A total of 3863 donors' results were considered in the final analysis. RESULTS: In comparison to Saudi blood donors, C antigen was less frequent in Sudanese donors (69.7% and 34.0%), the c antigen was less frequent in Indian (79.2% and 59.3%) and Philippine (79.2% and 40.0%) donors and more frequent in Sudanese (79.2% and 97.9%) donors, the E antigen was less frequent in Yemini (27.0% and 19.5%) and the e antigen was more frequent in Yemini (96.7% and 99.2%) donors. The DcE haplotype was less frequent (3.1% and 0.7%) and the ce haplotype was more frequent (4.3% and 7.6%) in Yemini donors. The K antigen was less frequent in Pakistani (11.9% and 4.1%; p = .041) and Indian (11.9% and 1.9%; p = .023) donors. CONCLUSION: Rh and K antigens showed marked variations in their frequencies among blood donors of different ethnicities. Utilization of blood from various ethnicities warrant extended phenotyping of Rh and K antigens to avoid the risk of alloimmunization in multiply transfused patients.

Red Cell Alloimmunisation Among Sickle Cell Disease and Thalassemia Patients Following Rh- and K-Matched Red Cell Transfusion in Southwestern Saudi Arabia: A Multicenter Study.

Background: Alloimmunisation remains a major consequence of blood transfusion among sickle cell disease (SCD) and thalassemia patients due to the exposure to non-self-red blood cell (RBC) antigen. The complication is associated with transfusion reactions and delayed transfusion procedure because of the difficulty of finding compatible blood. This study aims to determine the prevalence of alloimmunisation to RBC and alloantibody specificities among SCD and thalassemia patients in, an endemic area of SCD and thalassemia, Jazan province of Saudi Arabia, from three major hospitals. Methods: This is a retrospective, multicenter cross-sectional study conducted on 1027 patients with SCD and thalassemia, which received Rh/K matched transfusions in 2019 in the three centers. Demographic data and medical records of participants from three transfusion institutions were collected and analysed. Results: A total of 1027 were enrolled in the cohort; 906 (88.2%) and 121 (11.8%) patients with SCD and thalassemia, respectively. There were 483 (47%) males and 544 (53%) females with median age of 15 (range 1-48). Among the studied population, 78 were alloimmunised with an overall alloimmunisation rate of 7.6%. These patients developed a total of 108 alloantibodies, and anti-E was the most detected antibody (25.9%) followed by anti-K (24.1%). Conclusion: The overall rate of alloimmunisation to RBC antigen among the studied population in Jazan was low compared to other areas in the country. Most alloantibodies detected were against E and K antigens. The knowledge of most encountered alloantibodies in our population will aid in selecting the most appropriate antigen-negative red cells. Further research, however, is needed to explore factors associated with residual risk of alloimmunisation in these patients.