Distribution of CCR5- Delta32, CCR5 promoter 59029 A/ G, CCR2- 64I and SDF1- 3’ A genetic polymorphisms in HIV-1 infected and uninfected patients in the West Region of Cameroon

Abstract

Background

Genetic variants of the genes encoding Human Immunodeficiency Virus-1 (HIV-1) co-receptors and their ligands, like CC-Chemokine Receptor 5 delta 32 mutation ( CCR5- Delta32), CCR5 promoter A/ G (Adenine/Guanine), CC-Chemokine Receptor 2 mutation 64 isoleucine ( CCR2- 64I) and the Stromal cell-derived Factor 3’A mutation ( SDF1- 3’ A), are involved in the susceptibility to HIV-1 infection and progression. The prevalence of these mutations varies by Region. However, little is known about their distribution in the population of Dschang, located in the West Region of Cameroon. The prevalence of HIV in the West Region of Cameroon is lower than elsewhere in Cameroon. The objectives of this study were to determine the distribution of four AIDS Related Gene (ARG) variants in HIV-infected and non-infected population of Cameroon especially in the West Region and to estimate the contribution of these variants to the susceptibility or resistance to HIV infection. We also aimed to evaluate the effectiveness of genotyping using dried blood spot (DBS) samples.

Methods

A total of 179 participants were recruited from two hospitals in Dschang in the West Region of Cameroon. Their genotypes for CCR5- Delta32, CCR5 promoter 59029A/ G, CCR2- 64I and SDF1- 3’ A were analyzed using polymerase chain reaction (PCR) and restriction fragment length polymorphisms.

Results

A total of 179 participants were enrolled in the study. Among them, 32 (17.9%) were HIV positive and 147 (82.1%) were HIV negative. The allelic frequencies of these genes were: 0%, 49.72%, 17.6% and 100% respectively for CCR5- Delta32, CCR5 promoter 59029A/ G, CCR2- 64I and SDF1- 3’ A. No individual was found to carry the CCR5- Delta 32 mutation. All participants recruited were heterozygous for the SDF1- 3’ A allele.

Conclusion

Our data suggest that the CCR5- Delta32 cannot account for the protection as it was completely absent in our population. SDF1- 3’ A variants, may be in association with other polymorphisms, may account for the overall protection from HIV-1 infection in participants recruited as everyone carries this allele. The CCR5 promoter 59029 G/ G genotype may be associated with the risk for HIV-1 infection in this population, while the CCR2- 64I (A/A genotype) may account for the protection against HIV infection. The results of genotyping from fresh blood and DBS were comparable.