School-age children residing in schistosomiasis high-prevalence regions in Egypt displayed higher baseline levels of plasma IL-10 than children in low-prevalence regions (mean ≥ 80 versus 20 pg/mL, respectively), perhaps because of more intensive exposure to worm excretory–secretory products,42 whereas the differences in circulating IFN-γ baseline levels were less striking. This evidence concerns the gene IFNG and schistosomiasis.