The pathogenesis of asthma has been related to an imbalance of cytokines released from T helper (Th) cells, [4] with an increase in Th2 type cytokines (Interleukin (IL) IL-4, IL-5, and IL-13) and a decrease in Th1 cytokines (IFN-γ and IL-2). The gene discussed is IL13; the disease is asthma.