Prevalence Of Rh Antigens, Its Phenotype And Most Probable Genotype Among The Regular Blood Donors In Sarawak
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Date
2015-08
Authors
Kong, Hung Chuo
Journal Title
Journal ISSN
Volume Title
Publisher
Universiti Sains Malaysia
Abstract
Since the initial discovery of the D antigen in 1939, 50 related antigens have been assigned to the Rh blood group system by the International Society of Blood Transfusion (ISBT), among which the antigens D, C, c, E and e are the most essential. RhD antigen testing was made compulsory before issuing a compatible blood in transfusion medicine due to its potent immunogenicity along with ABO grouping. Uniquely Sarawak with multi-racial and intermarriage have substantial effect towards the distribution of Rh phenotype and most probable genotype among the regular blood donors in Sarawak. Until now, there is no study presented in major Rh antigens, its phenotype and most probable genotype in the Sarawak's population. This study was carried out at Blood Bank, Department of Pathology, Sarawak General Hospital from January to February 2015 involving 155 Iban, 128 Chinese, 123 Malay, 43 Bidayuh, 32 Orang Ulu and 27 Melanau. Blood samples collected from 508 subjects were tested for ABO blood group by using the tube agglutination method and five major Rh antigens via gel technology. For the ABO system, blood group O (37.80%) and B (32.28%) are the most common blood group found among the Sarawak's population. Incidence of RhD was 99.80% and only 0.2% samples negative for D antigen. The incidence of other Rh antigens such as C, E, c and e was 95.87%, 31.89%, 35.43% and 97.05% correspondingly. Antigen D was the most frequent antigen amongst five major antigens and the least common was antigen E. Most common phenotype in D-positive samples was DCCee (60.24%) and in D-negative was dccee (0.20%). Most probable genotype in order of frequency was CDe/CDe (R1R1) ˗ 60.24%, CDe/cDE (R1R2) ˗ 23.23% and CDe/cde (R1r) ˗ 7.28%. Meanwhile, the most frequent probable genotype was cde/cde (rr) in Rh negative samples. Less common phenotypes found in this study were CDE/CDE (RzRz) and cDe/cde (R0r) ˗ 0.20% each, which was predominant in Iban subjects. Unusual rare phenotype –D-/-D- (Rh17) was revealed in one of the Bidayuh subject (0.20%). This present study concluded that Rh genes and phenotypes vary widely across races and geographical boundaries. In conclusion, this study has managed to establish the database and compare the distribution of Rh antigens, its phenotype and most probable genotype among six major ethnic groups in Sarawak. The established database will be of great benefit and importance in the future local blood transfusion service.
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Keywords
D antigen