Host Molecular Factors and Viral Genotypes in the Mother-to-Child HIV-1 Transmission in Sub-Saharan Africa

CCR2 Genetic Polymorphism And Its Potential Effect On HIV Acquisition In A Population Of Children Living In The Northern Region Of Cameroon

Background and objectives

The association of chemokine receptor-2 (CCR2) polymorphism with HIV transmission or disease progression remains highly controversial. The role of CCR2-64I allele in HIV infection may differ from one population to another because of their genetic background. The objectives of this study were to characterize the CCR2 genetic polymorphism and to determine its potential effect in HIV acquisition in children living in the Northern Region of Cameroon.

Materials and methods

A cross-sectional study was carried out in five health facilities in the Northern region of Cameroon. DNA was extracted from the Buffy coat of each participant using the QIAamp^®DNA mini kit. The DNA extract was then subjected to polymorphic analyses. CCR2 genotypes were analyzed by polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP). The Chi-Squared test was used for the assessment of the Hardy-Weinberg equilibrium.

Results

A total of 134 children under 15 years comprised of 38 HIV-exposed infected (28.36%) and 96 HIV-exposed un-infected (71.64%) participants were recruited. Prevalences of 44.78% wild type homozygous, 48.52% heterozygous and 6.7% mutant homozygous alleles were found in the overall population. An allelic frequency of 29.69% for the mutant allele CCR2-64I was found in HIV-exposed un-infected individuals as compared to 34.21% in HIV-infected children (p=0.47).

Conclusion

The CCR2-64I allele is relatively common in the Northern Region of Cameroon, with a similar distribution among HIV-exposed un-infected and infected children. As this allele alone does not seem to confer protection against HIV-1 infection, further studies using genotype-combination of CCR2 polymorphism and other single nucleotide polymorphisms would be of great relevance in both HIV prevention and novel therapeutic strategies.

IMPLICATION OF FIVE AIDS RELATED GENES IN MOTHER-TO-CHILD TRANSMISSION AND ACQUISITION OF HUMAN IMMUNODEFICIENCY VIRUS 1 IN CAMEROON

BACKGROUND

Genetic variants in the mother and/or infant have been described with evidence to be associated with mother-to-child transmission of HIV, but somehow with contradictory results depending on ethnic or geographic populations. We aimed at looking at the association between the allelic frequency of some genes with vertical transmission or acquisition of HIV in Cameroon.

METHODOLOGY

A total of 262 mothers (212 HIV-infected and 50 HIV non-infected) with their babies (270 in total, 42 HIV exposed-infected, 178 HIV exposed non-infected and 50 HIV non-exposed) were recruited in Yaounde-Cameroon. Their genotypes for CCR5-Delta32, CCR5 promoter59029A/G, CCR2-64I, SDF1-3'A and TRIM5α-136Q were analyzed using polymerase chain reaction and restriction fragment length polymorphisms.

RESULTS

Allelic frequencies were 14.7%, 41.9%, 9.5% and 14.7% for CCR2-64I, CCR5-59029-A/G, TRIM5α-136Q, SDF1-3'A respectively in the mothers and 18.8%, 35.9%, 11.3% and 20.5% in the babies. No delta 32 mutation in the CCR5 gene was found. The mutant genotype was most significantly frequent in the non-transmitter than in the transmitter (p= 0.005) for the SDF-1 3'A. SDF1-3'A [Odd ratio = 1.69; 95% confidence interval: 0.1158 to 0.7277); was associated to MTCT, P = 0.008.The homozygote mutants for the CCR5-59029-G were significantly higher in the infected than in the exposed uninfected babies (p=0.04). The mutations in the other genes were neither implicated in the acquisition nor in the transmission.

CONCLUSION

SDF1-3'A was associated to the reduction of MTCT. The CCR5-59029-A/G favored acquisition of HIV by babies. Our study showed that polymorphisms in chemokine ligand may be involved in MTCT.

Role of SDF-1 3'A polymorphism in HIV-1 disease progression: A systematic review and meta-analysis

BACKGROUND

Chemokine stromal cell-derived factor 1(SDF-1) 3'A polymorphism has been reported to influence HIV-1 disease pathogenesis and progression, but the results remain controversial.

OBJECTIVES

A meta-analysis was carried out to evaluate their association.

METHODS

Comprehensive literature search of Pubmed, Web of Science and China National Knowledge Infrastructure was conducted. The strength of association between SDF-1 3'A polymorphism and HIV-1 progression was evaluated using the pooled ORs and 95%CIs calculated under different comparison models. Subgroup analyses, heterogeneity, Galbraith plot analyses and test for publication bias were also carried out.

RESULTS

Our result showed that when compared with the typical progressors, the GA + AA and GA genotype of SDF-1 3'A polymorphism was found positively associated with the long-term non-progressors (LTNP) in the Caucasian HIV-1 infectors (GA + AA vs. GG, OR = 1.49, 95% CI: 1.02-2.18, p = 0.040; GA vs. GG, OR = 1.58, 95% CI: 1.06-2.35, p = 0.024), while AA genotype was found significantly higher in Asian LTNPs (AA vs. GG + GA, OR = 3.32, 95% CI: 1.25-8.85, p = 0.016).

CONCLUSIONS

Our result suggested that HIV-1 infectors with SDF-1 3'A polymorphism have a higher chance of developing late AIDS than infectors with the SDF-1 GG genotype.