Genotyping for cytokine polymorphisms in a Northern Ivory Coast population reveals a high frequency of the heterozygote genotypes for the TNF-alpha-308G⁄A SNP

Cytokine polymorphisms influence the outcomes of parasitic diseases and vary among populations because of their different evolutionary histories and selective pressures imposed by host–pathogen interactions. In this frame, we investigated the frequencies of TNF-a (-308G ⁄A), TGF-b1 (codon 10C⁄T, codon 25C⁄G) and IL-10 (-1082A ⁄G) SNPs in 133 individuals from Ouangolodougou, a rural village in Northern Ivory Coast, where malaria and other parasitic diseases are endemic. The SNPs alleles were determined by ARMS-PCR methodology. Allele frequencies of the SNPs investigated were as follows: IL 10 -1082G = 0.741 and - 1082A = 0.259; TGF-b1 Codon 10 C = 0.835 and T = 0.165; TGF-b1 Codon 25 G = 0.782 and C = 0.218. For the TNF-a gene, we found high frequencies of the -308A allele (0.305) and heterozygote genotypes (0.594), with a consequent deviation from the Hardy–Weinberg equilibrium. The high heterozygosity at the TNF-a locus suggests a possible selective advantage of the heterozygote genomes, associated with intermediate levels of TNF-a expression, against the infectious agents endemic in Western Africa.