Th1 cytokine gene polymorphism and the corresponding plasma cytokine levels: A comparative study in HIV-1 positive and exposed uninfected infants

The pro-inflammatory (Th1) cytokines namely interleukin (IL)-2, IL-6, IL-12, interferon (IFN)-gamma, tumor necrosis factor-alpha (TNF-alpha) are vital in the clearance of HIV infection. This prospective cohort study aimed to evaluate the polymorphisms of Th1 cytokine genes and their corresponding plasma cytokine levels in HIV-1 positive and exposed uninfected (EU) infants born to HIV-1 positive mothers. CD4 count, viral load of HIV-1 positive mothers was done using commercially available reagents. Cytokine genotyping analysis and levels were done in 20 HIV-1 positive and 54 EU infants. The polymorphisms of Th1 cytokines were done using the PCR-SSP method. Plasma cytokine levels were estimated using Bio-Plex-Pro cytokine assay (BIO-RAD; USA). Results revealed treatment status of the mothers and viral load were the two confounding factors having a significant effect on HIV status of the infant. TNF-alpha GG genotype is significantly higher in EU infants as compared with HIV-1 positive infants. GG genotype was associated with high TNF- alpha levels in HIV-1 positive infants but the difference was not statistically significant. HIV-1 positive infants with -IFN-gamma (+874) TT genotype was significantly associated with high IFN-gamma levels. To the best of our knowledge, this is the first study reporting the role of Th1 cytokine gene polymorphisms and their corresponding plasma cytokine levels in HIV-1 positive and EU infants from India.