We observed statistically significant inverse associations between SPT reactivity and living in an unhygienic environment (i.e. greater number of siblings, intestinal helminth infections, having household cat and rodent infestations, and infrequent garbage collection) among children with aeroallergen-specific IgE (sIgE) indicating that such an environment may be an important determinant of this dissociation. The gene discussed is IGHE; the disease is parasitic infectious disease.