IMMUNOLOGICAL PROFILES OF PATIENTS FROM ENDEMIC AREAS INFECTED WITH SCHISTOSOMA-MANSONI

Crude extracts of eggs (SEA) adult worms (SWAP) or cercariae (Cerc) ha ve been used to stimulate Peripheral Blood Mononuclear cells (PBMC) an d have provided rather distinct profiles of responses in different typ es of patients. In general it is clear that patients with early infect ions respond strongly to SEA while response to SWAP are develop more s lowly. As infection progresses into the more chronic phases, a general pattern is seen which leads to lower anti-SEA proliferative responses in the face of higher responses to SWAP and variable anti-cerc respon siveness. Cured not re-exposed patients express very high levels of an ti-SEA proliferation. It has recently been seen that those individuals who live in endemic areas and have continued water contact, but are r eapeatedly stool-negative (who are presumed to have self-cured or be p utatively resistant; endemic normals) are strongly responsive to antig enic extracts, particularly to SEA. Furthermore, our results show that endemic normal individuals have significantly higher IFN gamma produc tion upon PBMC stimulation with schistosome antigens than infected ind ividuals. With the emergence of more studies it is becoming apparent t hat both the intensity and the prevalence of a given area may influenc e or shape the general responsiveness of the population under study.