Immunoepidemiology of Dracunculus medinensis infections I. Antibody responses in relation to infection status

The specific serum IgG1, IgG4, and IgE responses to Dracunculus medinensis and the level of total IgE of individuals living in a highly endemic area o f northern Ghana were measured by ELISA. Sera were obtained in the high tra nsmission season from individuals with prepatent, patent, or postpatent inf ection as well as hom individuals from the same endemic area who claimed to have never had a patent infection (i.e., endemic normal individuals). Indi viduals with prepatent or postpatent infections responded with a significan tly lower mean level of specific IgG1 and IgG4 compared with individuals wi th a patent infection, and with a significantly higher mean level of specif ic IgG1 and IgG4 compared with endemic normal individuals. For specific IgE , no differences were found in the mean antibody level between the infectio n status categories. Individuals with a patent infection had a significantl y lower mean serum level of total IgE compared with prepatent, postpatent, and endemic normal individuals. Endemic normal individuals had the highest mean level of total IgE. Furthermore, in all clinical categories, high resp onders for specific IgG1 and IgG4 generally had low levels of total IgE, wh ereas low responders for specific IgG1 and IgG4 generally had high levels o f total IgE. A similar dichotomy, although less distinct, was observed betw een specific IgG1 and IgG4 on the one hand and specific IgE on the other. T hus, similar to what has been suggested for schistosomiasis and lymphatic f ilariasis, the relationship between the IgG subclasses and IgE appears to p lay a role in, or at least to reflect, a mechanism for protective immunity in dracunculiasis.