Rare Rh E/e Negative Antithetical Antigens Found Only among Women with at Least One History of Pregnancy – A Maternal Phenotype (Novel)

Background: Rh blood group antigens are hereditary characters inherited by Mendelian principle, and are useful in the population genetics study, in resolving medico-legal issues, in disease aetiology and more importantly in compatibility issues in transfusion medicine. This study was a descriptive cross-sectional study to determine the prevalence of rare Rh phenotype among patients requiring a red cell transfusion in a specialist hospital Sokoto.

Materials and Methods: Three millilitres of whole blood was collected from each of the patients and the red cells were screened for the presence of Rh antigens by Ortho Biovue system cassettes (AHG/Coombs) technique.

Results: In this study, the percentages of Rh D, C, c, E and e obtained were 97.3%, 24.3%, 92.2% 18.9%, and 93.6% respectively. We found no Rh null and no D deletion, however, rare Rh phenotypes were encountered among which were Rh Cc deletion and Rh E/e deletion. The Rh E/e Negative antithetical antigens encountered was 4.7% (DCc 1.0%, DC, 1.0% and Dc was 2.7%). And Cc deletion was also 4.7% (Dee, 1.3% and De, 3.4%). The Rh E/e negative phenotypes showed a statistically significant relationship with gender (p = 0.007), marital status (p = 0.002), history of pregnancy (p < 0.001) and ethnicity (p = 0.028). There was. However, no statistical significant difference found with Rh C/c negative phenotype. We also encountered no Rh e negative and Rh E/e negative among male patients, unmarried patients, Igbo patients and also Yoruba patients.

Conclusion: We conclude from this study that rare Rh E/e negative antithetical antigens are high in the study area and found only among women with at least one previous pregnancy, possibly caused by low levels of maternal hormones, suggesting a role of maternal hormones on rare Rh Ee negative antithetical phenotype.