Frequency of a mutated CCR-5 allele in HIV-1 positive and negative individuals in the Province of Chaco.

The importance of chemokine receptors in the pathophysiology of HIV infecti on became apparent when it was demonstrated that persons at high risk for H IV-1 infection remain uninfected when they carry a polymorphic variant of C CR5. In individuals who are homozygous for the 32 base-pair deletion in the CCR5 gene, a functional protein cannot be synthesized and such persons are not found in HIV-1 positive cohorts. Furthermore, in individuals heterozyg ous for that mutation, there is an association with slow disease progressio n. The mutant allele of CCR-5 is present at high frequency in the Caucasian population, but is absent in the Japanese and black populations. The aim o f this study was to assess the frequency of the truncated allele of CCR-5 g ene in the cohort of HIV infected and non-infected subjects in the Province of Chaco, Argentina (with guarani and hispanic genetic background). A tota l of 118 unrelated seronegative healthy blood donors and 80 seropositive HI V-1 subjects were studied. A portion of CCR-5 gene from genomic DNA was amp lified by PCR and analyzed on a 3% agarose gel. The frequency of the delta CCR-5 allele was 2.5% for homozygous and 15.3% for heterozygous seronegativ e subjects, similar to that reported in the Caucasian population; the homoz ygous CCR-5 allele was absent in HIV-1 positive patients and the frequency of heterozygous was 2.5%, significantly lower than reported in the Caucasia n population.