Human IgE, IgG4 and resistance to reinfection with Schistosoma haematobium

Abstract

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 disease¹². 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.