The effect of the intensity of infection (eggs per gram faeces, epg) on the production of interferon-gamma (INF-gamma), interleukin (IL)-10 and IL-13 by peripheral blood mononuclear cells (PBMCs) from individuals living in a Schistosoma mansoni-endemic area was evaluated. In vitro stimulation of PBMCs with soluble egg antigen (SEA) resulted in significantly higher secretion levels of IFN-gamma in egg-negative individuals compared with those with an intensity of infection of more than 100 epg. In contrast, the egg-positive group produced significantly higher amounts of IL-10. Levels of IL-13 did not differ significantly between egg-positive and egg-negative groups. These findings suggest that IL-10 is an important cytokine in the control of the T helper cell (Th) type 1 responses during human S. mansoni infection, shifting the immune response from Th0 in egg-negative individuals from an endemic area to a Th2 polarization in chronic infected individuals.

Acute schistosomiasis is associated with a primary exposure and is more commonly seen in nonimmune individuals traveling through endemic regions. In this study, we have focused on the cytokine profile of T lymphocytes evaluated in circulating leukocytes of acute Schistosomiasis mansoni-infected patients (ACT group) before and after praziquantel treatment (ACT-TR group). Our data demonstrated increased values of total leukocytes, eosinophils, and monocytes in both groups. Interestingly, we have observed that patients treated with praziquantel showed increased values of lymphocytes as compared with noninfected group (NI) or ACT groups. Furthermore, a decrease of neutrophils in ACT-TR was observed when compared to ACT group. Analyses of short-term in vitro whole blood stimulation demonstrated that, regardless of the presence of soluble Schistosoma mansoni eggs antigen (SEA), increased synthesis of IFN-γ and IL-4 by T-cells was observed in the ACT group. Analyses of cytokine profile in CD8 T cells demonstrated higher percentage of IFN-γ and IL-4 cells in both ACT and ACT-TR groups apart from increased percentage of IL-10 cells only in the ACT group. This study is the first one to point out the relevance of CD8 T lymphocytes in the immune response induced during the acute phase of schistosomiasis.

Estudo clínico comparativo e ultra-sonografia entre indivíduos negativos e positivos para Schistosoma mansoni em áreas endêmicas de baixa morbidade e pacientes hospitalizados com doença hepatosplênica G2 and G3, respectively, in 11.1, 12.1 and 26.3%. In G1, G2 and G3, periportal with periportal echogenicity (3-6mm); and G4 -9 hepatosplenic patients with periportal echogenicity (> 6mm). Hepatomegaly detected by physical examination of the abdomen evaluated in the midclavicular line was verified in G1,