Because it is very difficult to define this point by cross-sectional epidemiologic surveys because of the variable origin of the primary sensitization (mites vs Ascaris), we are currently evaluating the early IgE responses to purified Ascaris and mite allergens in a birth cohort (Risk Factors for asthma and allergic diseases in the tropics, FRAAT) [80]. Here, IGHE is linked to allergic disease.