IgE responses in human schistosomiasis. I. Quantitation of specific IgE by radioimmunoassay and correlation of results with skin test and basophil histamine release.

We have developed a non-competitive solid-phase radioimmunoassay (SPRIA) to quantitate human IgE antibodies to Schistosoma mansoni antigens that was capable of accurately measuring IgE antibodies in both high and low titer sera. Ninety sera from "early" or "chronic" schistosomiasis patients were studied. Both levels of parasite-specific IgE antibodies and the proportion of the total IgE response that was parasite-specific were significantly lower in "early infection" sera than in sera of patients with chronic infections. The SPRIA to adult worm antigen was compared with basophil histamine release and direct intradermal skin testing also performed with the adult antigen. Both tests showed significant correlations with the SPRIA in detecting specific anti-parasite antibody.