T-helper type 2 (Th2) cytokines (such as IL-4, IL-5, IL-13 and IL-31), but also T-helper type 1(Th1) cytokines (such as IFN-γ and TNF-α) are overproduced in allergic dermatitis in humans and play an important role in the pathogenesis of this disease [6,7,8]. The gene discussed is IL4; the disease is atopic eczema.