Humoral immune responses in acute schistosomiasis mansoni: relation to morbidity.

An analysis of 25 individuals simultaneously exposed to cercariae of Schistosoma mansoni showed that morbidity (measured by the clinical/sonographic index) was more severe in patients with high-level egg output, irrespective of age or intensity of water contact. High levels of IgM and IgG antibodies to keyhole limpet hemocyanin and of IgA antibody to soluble egg antigen were documented predominantly during the acute phase of illness. Increased levels of these antibodies and of IgM antibody to soluble egg antigen correlated positively with morbidity after adjustment for age and intensity of water contact.