Background: The importance of the C-C chemokine receptor type 5 (CCR5) in HIV infection and disease progression was recognized with the discovery of the ∆32 allele. Individuals homozygous for this mutation lack functional CCR5, and are almost completely resistant to HIV infection while heterozygous individuals display decreased cell surface CCR5, which slows disease progression. However, this mutation is rare in Africa. Genetic variations within the CCR5 promoter region have been associated with regulation of CCR5 gene expression and could attempt to explain the different disease progression statues seen within Uganda. However, the distribution and impact of these variations are not known within this setting where this population exists. A study done in Rakai, reported a prevalence of LTNPs as 9.1% and another study done by Alex Kayondo in 2018, reported a prevalence of 0.26% of HIV controllers in an Urban HIV ambulatory center in Kampala, Uganda. Reasons for their intrinsic resistance to HIV are not fully understood. We hypothesized that variations in the CCR5 promoter gene could affect CCR5 expression thus impacting on the clinical course of HIV. In this study, we determined the median CCR5 expression by CD4 + T cells and the CCR5 promoter genetic variations that could be associated with delayed progression to HIV/AIDS seen among this study group.Results: There was significant reduction in CCR5 densities on CD4 + T cells among elite and viremic controllers compared to non-controllers. CCR5 Promoter polymorphism − 2459 G/G was highly prevalent among Elite and Viremic Controllers and it is associated with delayed progression to AIDS while − 2459 A/A and − 2132C/T were high prevalent among NCs and they are associated with rapid progression to AIDS.Conclusion: The reduction in CCR5 densities and percentage CCR5 + CD4 + T cells could explain the delayed progression to AIDS among these individuals. The reduction could be accounted for by the mutation 2459 G/G reported in the CCR5 promoter region.

IntroductionBy Sept 2018, only 59.3% of all HIV positive children on cART under 5 years were achieving virological suppression compared to 88.4% in the general population in Uganda. CCR5 promoter genotype specifically single nucleotide polymorphisms have been linked to modulate patient virological status. However, the few studies that have studied the association in infants have utilized allele-specific PCR a genotypic method limited to detecting already known SNPs. By using Sanger sequencing, we explored the association taking into account novel mutations. Methods Following ethical approvals, a cross sectional study was conducted using archived buffy coat samples from a pediatric HIV drug resistance study between May 2019 and January 2022 at the Joint Clinical Research Centre in Kampala, Uganda. 100 HIV seropositive infant buffy coat samples were sequenced for CCR5 SNP genotype following nucleic acid extraction, polymerase chain reaction and sanger sequencing. Odds ratios were used to determine the association between CCR5 SNPs and infant HIV plasma loads. Results 10 SNPs were identified with frequencies as follows; 58227G/A (21.8%), 58636A/G (28.7%), 58934T/G (74.7%), 59029G/A (48.3%), 59353T/C (55.2%), 59356C/T (23.0%), 59402G/A (94.2%) 59653C/T (66.7%), 59802A/C (34.5%), and 60024A/G (34.5%). Notably, 58227G/A, 58636A/G, 59802A/C, and 60024A/G are novel SNPs. However, none of these SNPs was significantly associated with infant virological failure but SNPs 59029G/A and 59353T/C showed higher odds of occurring in non-suppressors whereas 59356C/T and 59402G/A appeared to correlate with reduced plasma HIV loads. Infant virological suppression remained at 59% and in agreement with the national data. Conclusion Our study augments previous studies that CCR5 promoter SNPs play a role in modulating patient virological status however, strong conclusions could be drawn from either utilizing in-vitro studies or large epidemiological studies.

Background Mechanisms for HIV control among HIV-1 elite and viremic-controllers are not fully understood. In Uganda, Studies have reported individuals who without Antiretroviral therapy have the inherent ability to control HIV progression to AIDS for a period of greater than 5 years. However, reasons for this phenotype are not understood. The study objective was to determine the distribution of CCR5 co-receptor on CD4+ T-cells and its associated promoter variants among HIV-1 elite and viremic-controllers. Methods We isolated CD4+T-cells from PBMCs using EasySep CD4+ T-cell negative selection kit, and stimulated them with anti-CD3 and anti-CD28 for 48 hours. To quantify CCR5 expression, we performed immune-phenotyping using flow cytometry. CCR5 promoter polymorphisms were determined through sanger sequencing. The Kruskal–Wallis and the Mann-Whitney test were used to compare differences in the percentages of CCR5+ CD4+ T-cells and the differences in CCR5 densities on CD4+ T-cells respectively. p values < 0.05 were considered significant. Results The percentage of CCR5+CD4+ T-cells was higher among the non-controllers compared to the controllers although, the difference was not statistically significant; elite and viremic-controllers (p=0.9173), viremic and non-controllers (0.0702), elite and non-controllers (0.6010). Of significance was the CCR5 densities on CD4+ T-cells, which were significantly higher among non-controllers relative to the controllers; elite and viremic-controllers (p=3048), viremic and non-controllers (P=0.0312), elite and non-controllers (P=0.0210) From the sequence analysis, the rs1799987A>G mutation was found among elite (71%) and viremic-controllers (61%), while the -2459A/A and rs41469351C>T mutation were among the non-controllers (57%). This study also identified two novel mutations 1070T>G and 785A>G among the elite controllers (14.3%). Conclusion Rs1799987 SNP highly detected among the elite and viremic controllers may be associated with reduced CCR5 densities on CD4+ T-cells while higher frequency of -2459 A/A and rs41469351 SNP among non-controllers may be associated with increased CCR5 densities on CD4+ T-cells. Thus Rs1799987 SNP may be responsible for the delayed HIV progression among elite and viremic controllers, while -2459A/A and rs41469351 SNP may be responsible for the rapid progression of HIV among non-controllers. In vitro studies are needed to study the effect of the two novel mutations 1070T>G and 785A>G among elite-controllers.