IL4 and Allergy: In the allergy context, Poddighe et al. provided data supporting the rapid and systemic recruitment of basophils in blood, secondary lymphoid organs, and lung tissue in Balb/c-naive mice following the first encounter with Aspergillus fumigatus-derived aeroallergens; additionally, they showed that basophils might provide a priming source of IL-4, and basophil depletion may impair its early production and, thus, the consequent Th2 polarization of the adaptive immune response [34,52].