PIK3CD and allergic asthma: Consistent with this notion, several pre-clinical studies using genetic and pharmacological inactivation of p110δ have described an isoform-specific role for PI(3)Kδ in regulating mast cell activation and degranulation [60], allergen-induced Th2 cytokine production and eosinophil recruitment into the inflamed airways in vivo[35], [36], [61] – immunological responses that are reminiscent of allergic asthma in humans [62].