Diversity is demonstrated in class IHLA-A and HLA-B alleles in Cameroon, Africa: description of HLA-A*03012, *2612, *3006 and HLA-B*1403, *4016, *4703

To examine the genetic diversity in west Africa, class I HLA-A and HLA-B al leles of 92 unrelated individuals from two areas in the Cameroon, the capit al Yaounde and the village of Etoa, were identified by direct automated DNA sequencing of exons 2 and 3 of the HLA-B locus alleles and sequence-specif ic oligonucleotide probe (SSOP) and/or sequencing of the HLA-A locus allele s. HLA-A*2301 (18.7%), A*2902 (10.4%), B*5301 (10.9%), and B*5802 (10.9%) w ere the most frequently detected alleles, present in at least 10% of the po pulation. A total of 30 HLA-A locus and 33 HLA-B locus alleles, including s ix novel alleles, were detected. The novel alleles were HLA-A*03012, A*2612 , A*3006 and HLA-B*1403, B*4016, and B*4703. HLA-B*4703 contains a novel am ino acid sequence that is a combination of the first 5 amino acids of the B w6 epitope and the last 2 residues of the Bw4 epitope. The addition of 6 al leles to the ever-expanding number of known class I HLA alleles supports ou r hypothesis that extensive genetic diversity, including previously undescr ibed alleles, would be observed in this African population. In the Yaounde population, the allele frequency distribution at the HLA-A locus is consist ent with distributions indicative of balancing selection. Extensive HLA-A-B haplotypes were observed in this population suggesting that only a fractio n of the Cameroon HLA-A-B haplotype diversity has been observed.