RESISTANCE TO SCHISTOSOMA-MANSONI IN HUMANS - INFLUENCE OF THE IGE IGG4 BALANCE AND IGG2 IN IMMUNITY TO REINFECTION AFTER CHEMOTHERAPY/

The hypothesis of an association between human resistance to reinfecti on by the parasite Schistosoma mansoni and anti-larval immunoglobulin isotypes was tested by logistic regression in the presence of the expl icative variables water contact, age, and sex. Of the seven isotypes t ested (IgM, IgG1, IgG2, IgG3, IgG4, IgA, and IgE), only IgE, IgG4, and IgG2 showed an association (positive for IgE and negative for IgG2 an d IgG4) with resistance to reinfection after chemotherapy. The opposit e effects of IgE and IgG4 were undissociable in the analysis, indicati ng that these isotypes probably antagonize each other in protection. T he negative association of IgG2 with resistance is consistent with the view that anti-carbohydrate antibodies may facilitate reinfection. Fi nally, epidemiologic and immunologic studies support the view that the re is progressive but slow development of acquired immunity in childre n and adolescents.