INCREASED INTERLEUKIN-4 AND INTERLEUKIN-5 PRODUCTION IN RESPONSE TO SCHISTOSOMA-HAEMATOBIUM ADULT WORM ANTIGENS CORRELATES WITH LACK OF REINFECTION AFTER TREATMENT

Acquired immunity to human schistosomiasis correlates with increased s erum levels of schistosome antigen-specific IgE. Since interleukin (IL )-4 stimulates IgE production, the hypothesis that Th2-associated cell -mediated immunity participates in protection to reinfection was studi ed in a cohort of adolescent boys 12-18 months after chemotherapeutic cure in Upper Egypt. Initial Schistosoma haematobium prevalence was 51 % and posttreatment incidence was 44%. Water contact was similar betwe en putatively resistant and susceptible patients. Resistant persons ha d a 3.5- to 14-fold greater frequency of schistosome adult worm antige n (SWAP)-specific lymphocytes secreting IL-5 or IL-4 (by ELISPOT) and IL-5 or IL-4 production in peripheral blood lymphocyte culture superna tants (P < .05 to < .001, n = 48) versus susceptible subjects (n = 38) . In contrast, SWAP-induced interferon-gamma and IL-10 production and lymphocyte proliferation were similar between the 2 groups. Schistosom e egg antigen and streptolysin O each stimulated similar cytokine prod uction in susceptible and resistant persons. Thus, enhanced SWAP-drive n IL-4 and IL-5 production correlates with immunity to reinfection in adolescents exposed to urinary schistosomiasis.