Combined promoter haplotypes of the IL10R genes are associated with protection against severe malaria in Gabonese children

Abstract

The critical barrier in control of infections remains the failure of the immune system to clear parasites despite antigen recognition. We examined and validated possible association of regulatory immune gene polymorphisms in a cohort of children with mild and severe malaria. We focussed on two precursors of the Interleukin 10 Receptor (IL10R) gene namely the IL10R alpha and IL10R beta that play a fundamental role in initiation of signal transduction. Initial screening across 40 Gabonese adult individuals revealed two promoter variants for the IL10R alpha and three for the IL10R beta precursor, respectively. Validation of these variants for their allelic gene expression by transient transfection assays exhibited an altered expression in rs56356146 and rs7925112 of the IL10R alpha (P < 0.5); rs8178435 and rs999788 in the IL10R beta constructs (P < 0.0001), respectively. We further investigated the functional role of those SNP variants exhibiting altered expression in a cohort of children with mild and severe malaria. We genotyped 145 children with mild and 185 children with severe malaria for IL10R alpha; for IL10R beta, 102 children with mild and 101 children with severe malaria. We found that none of the SNP variants had any significant association neither in children with mild or severe malaria. The haplotype -185/-116 of IL10R alpha (TT) in combination with the haplotype -754/-750 of IL10R beta (AC) contributed towards mild malaria in comparison to severe malaria [TT + AC odds ratio of 0.73 (95% CI 0.56-0.94) P = 0.01]. This study may provide a better understanding on the role of IL10R promoter allelic variants contribution to a protective effect on the development of severe malaria. © 2011 Springer-Verlag.