,7 These primed DCs induce polarization of type-2 T helper cells (Th2) at regional lymph nodes, and the Th2 cytokines IL-4, IL-5, and IL-13 subsequently promote asthma symptoms by inducing inflammatory cell recruitment, IgE production, excess mucus secretion, and airway smooth muscle cell contraction. This evidence concerns the gene IL5 and asthma.