2. Department of Pediatrics and Child Health, University of Zimbabwe.
3. Department of Microbiology, University of Oslo and Oslo University Hospital, Rikshospitalet, Oslo, Norway.
4. Letten Foundation Research Centre, Harare, Zimbabwe.
5. Department of Community Medicine, University of Zimbabwe.
6. Division of Women and Children, Oslo University Hospital, Rikshospitalet and Institute of Clinical Medicine, University of Oslo, Oslo, Norway.
Background: HIV-1 gp120 envelope variable regions potential N-glycosylation sites (PNGs) and amino acid length polymorphisms have been shown to play pivotal roles in disease progression in spite of other studies demonstrating contradictory results.
Methods: Regression analysis was used to assess the association between changes in PNGs or amino acid sequence lengths of C2V5 region/sub-regions and disease progression as a function of HIV-1 RNA load or CD4% among antiretroviral therapy naïve subtype C infected but slowly disease progressing children.
Results: Unit increases in amino acid sequence lengths within the V3 region was associated with a 5 unit increase in CD4%, p=0.010. Unit increases in PNGs within the C2V5 region, V3 and V5 sub-regions were associated with 3, 9 and 8 unit increases in CD4%; p=0.041, 0.040 and 0.02, respectively. Interestingly, a unit PNGs increase within the C4 sub-region correlated with a 1.2 million copies/ml decrease in viral load, p=0.009.
Conclusion: C4 sub-region PNGs may be influential in viral replications whilst amino acid length polymorphism within the V3 regions could be key in host immunological surveillance. However, bigger studies with more clones per sample are warranted to substantiate these preliminary findings and whether such observations are also true for the adult the population.
Keywords: HIV subtype C, C2V5 sequence lengths, potential N glycosylation sites, children