Specific IgE antibodies and IgE containing circulating immune complexes in human schistosomiasis

IgE antibodies (IgE-AB) have been investigated in patients infected with S. mansoni, S. haematobium, S. mansoni and S. haematobium or S. intercalatum using an enzyme immuno assay based on the RAST principle. Antigens applied were crude extracts from S. mansoni, S. haematobium and S. japonicum adult worms. IgE containing immune complexe (IgE-CIC) were determined by precipitation with PEG and subsequent identification with I125 labelled antihuman IgE. In the patients with schistosomiasis IgE-AB to the homologous antigen were demonstrated in 84% of monoinfected and in 100% of the mixed-infected individuals. Within the mixed-infected patient group IgE-AB to S. mansoni antigen were significantly higher than to S. haematobium. Cross-reactivity of IgE-antibodies was proved by use of S. haematobium and S. japonicum antigen in S. mansoni monoinfection . Specifity of the test was 94%. The amount of IgE-CIC correlated significantly with the concentration of the homologous IgE-AB, indicating that these CIC were composed of specific antibodies linked to parasite antigen.