Rh antigen and phenotype frequencies and probable genotypes for the four main ethnic groups in Port Harcourt, Nigeria.

Rh is the most complex and polymorphic of the RBC group systems and is of major importance in transfusion medicine. Data are not available on the frequency of Rh antigens D, C, E, c, and e in Port Harcourt, Nigeria. Two mL of venous blood was collected into an EDTA tube from each of 400 persons of mixed ethnic groups recruited for the study. The study population comprised 167 Ijaws (41.8%), 141 Ikwerres (35.2%), 50 Ekpeyes (12.5%), and 42 Ogonis (10.5%). The RBCs were phenotyped for D, C, E, c, and e antigens according to standard serologic methods. The most frequently occurring antigen was found to be c (99.8%),followed by e (98.7%), then D (95.0%), E (20.5%), and finally C (17.7%). The antigens occurred independently of the ethnic groups (p > 0.05) except the antithetical antigens Ee, which were found to be statistically significant in the Ijaw ethnic group when subjected to Pearson chi-square test (chi(2) = 9.890, p < 0.02). One (0.2%) of the study population was found to be c- while 20 (5.0%) were D-.