HUMAN IGE, IGG4 AND RESISTANCE TO REINFECTION WITH SCHISTOSOMA-HAEMATOBIUM

A WELL recognized feature of the immune response to parasitic helminth infections, including schistosomiasis, is the production of large amounts of specific and nonspecific IgE 1,2. Immunological pathways involving IgE can lead to damage to the developing schistosomulum 3-9 and it has been suggested that responses involving IgE could have evolved as protection against helminth infections 10,11. There has been no epidemiological evidence to support this idea and the only significant IgE responses known in man are those involved in the pathogenesis of allergic disease 12. Here we measure serological response during reinfection with S. haematobium and demonstrate that IgE antibodies in man can be beneficial. Our results support the hypothesis that the slow build-up of IgE to high levels and the early production of IgG4 antibodies, which may block IgE pathways 13,14, are responsible for delaying the development of protective immunity to S. haematobium.