Value of isotypic characterization of antibodies to Echinococcus granulosus by enzyme-linked immuno-filtration assay.

In order to establish prognostic criteria for patients with hydatid cysts and to identify functional antigenic components of Echinococcus granulosus 87 sera from 36 patients were studied by enzyme-linked immuno-filtration assay (ELIFA) to characterize the four main classes of specific immunoglobulins and to determine compared immunological profiles (CIP) between samples or subjects. This method uses filtration with labelled antibodies to reveal precipitating systems preformed by immuno-electro-diffusion on cellulose acetate strips. IgG antibodies were demonstrated in the arc 5 and in 11 others bands. Specific IgA, IgE and IgM to Echinococcus granulosus was found in 19%, 53% and 69% respectively of patients with hydatids. The presence of IgM and/or IgE antibodies one year after treatment always correlated with disease. Specific IgA was detected more often in patients with pulmonary cysts. Pre- and post-operative monitoring by CIP-ELIFA proved simple and rapid to perform and of decided prognostic value. Two antigens, corresponding to arc 5 and arc X, were frequently associated with the poly-isotypic immune response.