ABSTRACT
Introduction: Rhesus (Rh) antigen was discovered in 1940 by Karl Landsteiner and Wiener. In later years, because of its immunogenecity along with ABO grouping, RhD antigen testing was made mandatory before issuing a compatible blood. Presently there are five major antigens i.e. D, C, E, c and e in Rh blood group system. Aims: To know the distribution of major Rh antigens, its phenotype and most probable genotype in the population of Gwalior region i.e. Central India. Place and Duration of Study: This study was carried out at Blood Bank, Department of Pathology, Gajra Raja Medical College, Gwalior, India from 1st October 2008 to 30th September 2010. Methodology: The distribution of Rh antigens, its phenotype and most probable genotype was studied in 1000 samples collected from blood donors, blood recipients and other patients. Samples were tested for ABO blood group and five major antigens of Rh system by tube agglutination method /or by gel technology. Results: Out of 1000 samples studied, the incidence of RhD was 91.6% and only 8.4% samples were negative for D antigen (p=.000005). The Incidence of other Rh antigens i.e. C, E, c and e was 84%, 25.6%, 58.3% & 78.5% respectively (p=.000005) Most common phenotype in RhD positive samples were DCCee (41%) and in RhD negative it was dccee (5.6%) (p= .000005). Eleven samples (1.1%) were negative for antithetical antigens E & e. Most probable genotype in order of frequency was DCe/DCe (R1R1)-41%, DCe/Dce (R1R0)-25.5% & dce/dce (rr)-5.6% (p= .000005). Conclusion: Like previous studies, our study also concluded that there is a wide range of racial and geographical variation in the distribution of Rh phenotype and genotype. The Rh blood group system has vital role in population genetic study, in resolving medico legal issues and more importantly in transfusion practice.