HUMAN IGE, IGG SUBCLASS, AND IGM RESPONSES TO WORM AND EGG ANTIGENS IN SCHISTOSOMIASIS-HAEMATOBIUM - A 12-MONTH STUDY OF REINFECTION IN CAMEROONIAN CHILDREN

Levels of IgE, IgM, and IgG subclasses against Schistosoma haematobium adult worm antigen (AWA) and soluble egg antigen (SEA) in a cohort of 148 S. haematobium-infected schoolchildren were determined before and up to 12 months after chemotherapy. Infection intensities were determ ined as concentrations of circulating anodic antigen (CAA) in serum. O ne month posttreatment, the antibody levels of all isotypes against AW A were increased, but 1 year after treatment they returned to pretreat ment levels. CAA concentrations mere positively associated with levels of IgG4 against AWA and SEA but not with levels of IgE, Age correlate d negatively with CAA concentrations and positively with levels of IgE to AWA. The balance of anti-AWA IgG4 and IgE was significantly correl ated to the CAA concentration, in particular in the older age group (1 1-13 years). This may suggest that protective immune mechanisms in S. haematobium infections become effective around the age of 12 years.