SUBCLASS-SPECIFIC SEROLOGICAL REACTIVITY AND IGG(4)-SPECIFIC ANTIGEN RECOGNITION IN HUMAN ECHINOCOCCOSIS

Immunglobulin (Ig) subclass-specific antibody responses and isotype-sp ecific recognition of E. multilocularis (Em) and E. granulosus (Eg) an tigens (Ag) were evaluated in both alveolar echinococcosis (AE) and cy stic echinococcosis (CE). AE patients were divided into 3 groups by cl inical and therapeutic criteria according to their actual state of inf ection, i.e. elimination of parasite, and regression or progression of disease. CE patients were either before or after surgery, or in conti nuous chemotherapy due to parasite persistence. Total IgE was highly e levated in progressive AE cases (7/11), hut not in the cases with elim inated infection or regression. In AE patients with active disease, Em Ag-specific IgE, coral IgG, IgG(1), IgG(2) and IgG(4) were particularl y high. Similarly, in 9 of 30 CE patients, total IgE was raised above reference values, indicating progressive disease. CE patients' sera an tibody cross-reacted with crude EmAg, and detectable Ig levels of the same isotype were also measured by ELISA. In both AE and CE, parasite- specific antigen recognition was dominated by IgG(1) and IgG(4). In AE patients with progressive disease, IgG(4) distinctively recognized lo w molecular weight EmAg of Mr 26 kD, 18 kD, 16 kD and 12 kD. As promin ent IgG(4) and IgE responses develop with chronic helminth infections only, these serological parameters may indicate successful parasite in festation and severe outcome of disease. In summary, analyses of immun oglobulin isotype responses in AE patients by ELISA in combination wit h immunoblotting are a useful approach for post-treatment follow-up of patients at risk of developing recrudescent disease.