This type of asthma is thought to arise from an imbalance in T helper type I (Th1)-Th2 immune regulation, resulting in increased levels of the Th2 cytokines interleukin (IL)-4, IL-5, and IL-13, which have been proven to be important drivers of allergic airway inflammation in asthma (1, 2). The gene discussed is IL4; the disease is asthma.