Abstract

The promoter region of human interleukin-10 (IL-10) gene is highly polymorphic while the first intronic region of interferon gamma (IFN-) gene is also highly polymorphic. These polymorphisms are associated with susceptibility or resistance to Schistosoma haematobium infection. Schistosomiasis is known to be a highly inflammatory disease that requires the delicate balance of pro- and anti-inflammatory cytokines. The polymorphisms are associated with low, moderate or high cytokine production resulting in exacerbation of the infection leading to pathological severity. Urine filtration technique was used for diagnosis the S. haematobium. Whole blood samples were collected from 400 children aged between 6 to 13 years. Molecular determination of polymorphism related to resistance or susceptibility to infection was performed using the allele-specific polymerase chain reaction. SNPs in the IL-10 and IFN- cytokine genes were examined in blood samples from 400 school-aged children. Schistosomiasis was detected in 49.8% (199). For IFN- +874A/T, the distribution of TT, TA and AA was 7, 41 and 51% respectively. An analysis of the polymorphisms on IL-10 -1082G/A showed that most of the samples were heterozygous (47% GA) whereas AA (32%) and GG (21%) were monozygous. SNPs within the promoter region of IL-10 gene and in the intronic region of IFN- have been associated with altered profiles of circulating IL-10 and IFN-. Our findings suggest that IL-10 and IFN- polymorphisms participate in the progression of schistosomiasis rather than in its initial development in school aged children. It is recommended to study more polymorphisms in the other cytokines implicated in schistosomiasis.

Key words: Polymorphism, cytokine, Schistosoma haematobium, interleukin-10, interferon gamma.