High levels of IL-5 are produced by PBMC and whole blood cell cultures stimulated in vitro with SWA [18], [19], [20], [21] and pre-treatment in vitro SWA specific IL-5 responses are associated with post-treatment SWA-IgE levels [22], suggesting that IL-5 responsiveness is a key component of human immunity to schistosomiasis. The gene discussed is IGHE; the disease is schistosomiasis.