Schistosomiasis co-infection in humans influences inflammatory markers in uncomplicated Plasmodium falciparum malaria

SUMMARY Malaria and schistosomiasis are the two major parasite diseases present in developing countries. The epidemiological coinfection with schistosomiasis could influence the development of the physiological reaction associated with Plasmodium falciparum infection in human. Most studies have demonstrated the association of circulating levels of interferon- γ (IFN- γ ), tumour necrosis factor-a (TNF- α ), interleukin-10 (IL-10), transforming growth factor (TGF- β ) and soluble Tumour Necrosis Factor Receptors (sTNF-RI and sTNF-RII) with the morbidity of malaria. In the present study, we showed that Schistosoma haematobium co-infection influences, in an age-dependent manner, the unbalance between pro- and anti-inflammatory circulating cytokines that play a key role during malaria infection. Indeed, children co-infected by S. haematobium have higher levels of IFN- γ and sTNF-RII than children infected only by P. falciparum . In contrast, coinfected adults presented a significant increase of IFN- γ , IL10, TGF- β , sTNF-RI and sTNF-RII rates and IL-10/TNF- α ratio. Taken together, this study indicates that schistosomiasis co-infection can unbalance the regulation of inflammatory factors in uncomplicated P. falciparum malaria. The possible consequences of the schistosomiasis co-infection for agedependent malaria morbidity are discussed.