Effects Of Tnf-Alpha And Il-10-819 T > C Single Nucleotide Polymorphisms On Urogenital Schistosomiasis In Preschool Children In Zimbabwe

Background: Knowledge gaps exist between host genetic factors and susceptibility to schistosomiasis.Objective: This study determined cytokine levels and single nucleotide polymorphisms of tumour necrosis factor (TNF)-alpha (rs1800629) and interleukin (IL)-10 (rs1800871) and their possible impact on susceptibility to schistosomiasis in preschool-age children in the Madziva area of Shamva district, Mashonaland Central province, Zimbabwe.Methods: Urogenital schistosomiasis was diagnosed using the urine filtration method, while a sandwich enzyme-linked immunosorbent assay was used for cytokine level determination. The survey was done in August 2015 and reinfection levels post treatment were assessed at 3, 6 and 12 months. Amplification refractory mutation system polymerase chain reaction with visualisation on 2% agarose gel electrophoresis was used for genotyping.Results: Schistosomiasis prevalence was found to be 10.5% (59/563). Reinfections were detected in only six children at 3 months and only one was reinfected at 12 months. There were no significant differences in TNF-alpha-308 G/A allele or genotype frequencies between the Schistosoma haematobium infected participants (p = 0.360) and uninfected participants (p = 0.279). However, no children with the IL-10-819 TT genotype had schistosomiasis. The TNF-alpha GG genotype corresponded with significantly lower TNF-alpha levels when compared with the GA or AA genotypes (p < 0.001), and TNF-alpha levels were significantly lower in infected children compared to uninfected children (p < 0.001).Conclusion: Higher TNF-alpha levels and lower IL-10 levels are potentially protective against schistosomiasis infection. The IL-10-819 TT genotype is potentially protective against infection through its association with lower IL-10 levels.