EVOLUTIONARY IMPLICATIONS OF CURRENT HIV EPIDEMIC ON THE POPULATION OF KENYA, EAST AFRICA : STUDY OF POPULATION GENETICS BY SEQUENCE-BASED DRB TYPING.

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EVOLUTIONARY IMPLICATIONS OF CURRENT HIV EPIDEMIC ON THE POPULATION OF KENYA, EAST AFRICA : STUDY OF POPULATION GENETICS BY SEQUENCE-BASED DRB TYPING.
Ma Luo , Joshua Kimani , Keith Fowke , Blake Ball , Kelly MacDonnald , Suzie Ramdahin , Jeckoniah Ndinya-Achola , Simon Njenga , Job B. Bwayo , Joanne Embree and Francis A. Plummer . Winnipeg Canada, University of Manitoba, Medical Microbiology ; Nairobi Kenya, University of Nairobi, Medical Microbiology ; Canada University of Toronto, Medicine and Winnipeg Canada, National Microbiology Laboratory, HIV/Human Genetics .

To study temporal changes in the frequency of DRB genes in two open cohorts of Kenyan women, established through two decades of STD research in Kenya and the effect of current HIV epidemics in Sub-Sahara Africa on the population genetic compositions. The frequencies of DRB genotypes were determined among 899 women enrolled in the Pumwani-Sex-Worker cohort, who have a very high HIV infection rate. Among them, 584 enrolled before 1993 and 315 enrolled after 1993. As a comparison, 454 women enrolled in the Nairobi Mother-to-Child HIV transmission study before 1993 were also typed. The DRB genes were amplified, sequenced, and assigned with a taxonomy-based-sequence-analysis method (TBSA). DRB1*01 allele, specifically, DRB1*01021 has been previously shown to have a strong protective effect against HIV seroconversion. Our results show that DRB1*01 allele frequency in the population of women enrolled in the Pumwani-Sex-Worker Cohort increased overtime. The frequency of DRB1*01 alleles was 18.7 % in the population of women enrolled after 1993 compared with 11.8 % in the population enrolled before 1993 (OR=1.72, CI95% 1.2-2.5, p<0.005). The frequency of DRB1*01 allele in the population of lower risk women was 8.6%. The increase in DRB1*01021 allele is accounted for the increase. This suggests that the HIV epidemic is already having selective effects on the genetic make-up of the population of women who become sex workers. Ultimately HLA alleles that protect or enhance the risk of HIV infection will be selected for or against in the larger population.