Altered generation of interleukin 1 in chronic human schistosomiasis mansoni

Chronic schistosomiasis mansoni is associated with impaired cell-mediated immune responsiveness (CMI). To assess co-stimulatory factors essential in the induction phase of CMI, interleukin 1 (IL-1) concentration was determined in the sera and cell culture supernatants of Schistosoma mansoni-infected patients, and circulating monocytes were phenotyped, labelling membrane IL-1 and HLA-DP. In addition, adherent cell oxidative-burst capacity was investigated. Since involvement of IL-1 beta in the pathogenesis of severe granulomatous lesions could not be ruled out, 17 patients with intestinal schistosomiasis and 17 patients with hepatosplenic schistosomiasis were matched for intensity of infection and monitored 3-6 months after praziquantel therapy. Seventeen age- and sex-matched uninfected residents of the study area in Alagoas, Brazil, acted as controls. Whereas schistosomiasis patients and controls did not differ in the expression of monocyte surface antigens and the capacity of adherent cells to generate H2O2, IL-1 beta release by monocytes in vitro was significantly reduced in both intestinal and hepatosplenic patients. Low concentrations of circulating IL-1 beta were detected in comparable frequencies in untreated patients and controls. Three months after therapy, IL-1 beta was detectable in serum in an increased proportion of intestinal schistosomiasis patients. IL-1 release in vitro gradually increased in all patients and reached control values 6 months after therapy.