Int Conf AIDS. 1998;12:152 (abstract no. 13331). Unique Identifier :

INTRODUCTION: The chemokine receptor CKR5 was recently demonstrated to be a co-receptor for macrophage-tropic HIV-1 strains. In caucasian population, an allelic mutation of the CKR-5 gene, consisting of a 32-bp deletion, has been found, with a frequency of 13% as heterozygous and 1% as homozygous. This mutation has been considered genetically dominant. The incomplete expression of the receptor is associated with partial resistance to HIV-1 infection in vitro and with long term non-progression and exposed HIV-1 antibody negative individuals. It has been shown that in Latin American populations, despite the racial mixture with Caucasians, the frequency of the CKR5 mutation is lower than in Caucasians-Americans. OBJECTIVE: To establish the frequency of the CKR5 deletion in a general population from Mexico, and to correlate it with the presence of Caucasian ascendants. METHODS: We sampled 100 Mexican individuals, who were questioned for the existance of European ascendants in three generations. CKR5 genothype was determined in PBMCs through a PCR that amplified the CKR5 coding region (735-bp). The product was vizualized in a 2% agarose gel and purified using Gene-Clean, the purified fragment was digested with Eco-R1 and classified as wild homozygous, heterozygous and pure deletion according to the digestion pattern. RESULTS: From the 100 Mexican individuals chosen for the study, we found 97 wild homozygous and 3 (3%) (95% IC 0.6-8.5%) heterozygous for the CKR5 deletion. Twenty six (26.8%) of the wild homozygous had direct European heritage and only 1 (33.3%) from the heterozygous (p = 0.81). CONCLUSIONS: In this study, the frequency of CKR5 heterozygous deletion in Mexican general population was lower than the reported for Caucasians, the presence of this mutation was not related with Caucasian heritage. Moreover, we did not find the homozygous form of the deletion, which can be related to a selection against the mutation in the European-Indian descendants. This selection would decrease the chances of partial resistance to HIV-1 infection. Our findings would argue against the genetic dominance of the CKR5 deletion in the Caucasian-Indian mixture in Mexico.

MEETING ABSTRACTS *Alleles Caucasoid Race/*GENETICS Gene Frequency Genotype Heterozygote Human HIV Infections/*GENETICS *HIV-1 Indians, Central American/GENETICS Mexico Mutation Receptors, CCR5/*GENETICS Sequence Deletion