Rh antigens and phenotype frequencies of the Ibibio, Efik, and Ibo ethnic nationalities in Calabar, Nigeria

This report forms part of the study on the Rh phenotypes within the various ethnic nationalities in the south-south region of Nigeria. The aim is to demonstrate the Rh polymorphisms among the people of African descent. The frequencies of Rh blood group antigens and phenotypes of the Ibibio, Efik, and Ibo ethnic nationalities in Calabar municipality, Nigeria, were determined using standard serologic techniques. Of the 720 Calabar individuals tested, the frequencies of the Rh antigens within the nationalities were c (100%), e (96.38%), D (96.38%), E (15.22%), and C (3.62%) for the Ibibios; c (100%), e (95.60%), D (96.70%), E (21.98%), and C (0%) for the Efiks; and c (100%), e (94.29%), D (91.43%), E (28.57%), and C (2.86%) for the Ibos. The overall frequencies of the Rh antigens in these 720 individuals were c (100%), e (95.56%), D (94.44%), E (18.89%), and C (2.78%). Forty (5.56%) were found to be D–, while all were found to possess the c antigen. The most frequently occurring Rh phenotype was Dccee, with a frequency of 73.61 percent. The alternative allele, C, did not appear in homozygous form (CC) in the population tested. This study further demonstrates the variability of Rh blood group phenotypes in Nigeria and Africa. Immunohematology 2005;21:21–24.