Investigation of CCR5-Δ32 (rs333) genetic polymorphism frequency and its relationship with HIV-1 susceptibility and disease progression: A Moroccan case-control study

Background: Host genetic factors are involved in resistance/susceptibility to HIV-1 infection and progression. The most relevant genetic variant of the gene encoding HIV-1 major co- receptor, CCR5-Δ32, has a protective effect against HIV-1 infection, and the prevalence of this mutation varies by ethnicity. In Morocco, only limited information is available concerning this protective allele. Objectives: The aim of this case-control study was to investigate the frequency of CCR5-Δ32 among HIV-1 infected and uninfected individuals in Morocco and to assess the association between this protective allele and HIV-1 susceptibility and disease progression. Patients and methods: A total of 148 HIV-1 seropositive (cases) and 342 healthy Moroccan individuals (controls) were recruited from Mohammed V Military Training Hospital in Rabat. The CCR5-Δ32 variant was analysed by Polymerase Chain Reaction (PCR) assay. Comparison of Genotype and allele frequencies between cases and controls was performed using the χ 2 test and the Fisher exact test. Association between CCR5-Δ32 polymorphism and HIV-1 disease progression was assessed using ANOVA test. Results: 7 of 148 (4.73%) HIV-1 seropositive (cases group) were heterozygous for the CCR5-Δ32 allele compared to 6 of 342 (1.75%) HIV-1 seronegative individuals (controls group). None of the analysed individuals had CCR5-Δ32 homozygous genotype. No statistical significant association was found in the genotype distribution between cases and controls. Also, we didn't observe any significant association between CCR5-Δ32 polymorphism and the markers of HIV-1 disease progression (HIV-1 viral load or CD4 cell counts) (p > 0.05). Conclusion: The present results are the first findings on the association of CCR5-Δ32 variant allele with HIV-1 susceptibility and the markers of HIV-1 disease progression among Moroccan HIV-1 seropositive patients. These results suggest that CCR5-Δ32 mutation may not affect HIV-1 susceptibility in heterozygous individuals. Given the low frequency of the Δ32 mutated allele in our population, further studies are needed to confirm our results and evaluate the relationship between CCR5-Δ32 polymorphism and HIV-1 disease progression in Morocco.