Haplotype diversity in the interleukin-4 gene is not associated with HIV-1 -transmission and aids progression

Interleukin-4 (IL-4) is a pleiotropic cytokine produced primarily by activated CD4⁺ T lymphocytes, mast cells, and basophils. It modulates the functions of a variety of cell types involved with the immune response. This cytokine differentially regulates two major HIV-1 coreceptors and activates viral expression, and is thus a reasonable candidate gene for analyses in HIV-1/AIDS cohort studies. Population genetic variation in five single nucleotide polymorphisms (SNPs) in the 5′ region of the IL-4 gene was assessed in five racial groups. Neutrality tests reveal that the populations are evolving in accord with the infinite-sites model. However, coalescent simulations suggest greater haplotype diversity among African Americans than expected. This increased variation is presumably attributable to recombination or gene conversion. Genetic epidemiological analyses were conducted among European American and African American participants enrolled in five USA-based HIV-1/AIDS cohorts. One SNP, -589T, known to influence IL-4 transcription was previously shown to be associated with HIV-1/AIDS in both Japanese and French populations. Present analyses failed to identify any significant associations with HIV-1 infection or progression to AIDS.