CD4 and dermatitis: DS-Nh mice also develop a form of dermatitis and are considered to be a model of human atopic dermatitis (AD), with the following features: (i) superantigen-producing Staphylococcus aureus is one of the causes of dermatitis; (ii) significantly increased serum levels of IgE, interleukin (IL)-4 and IL-13; (iii) increased numbers of whole mast cells and CD4-bearing T cells; (iv) increased serum and tissue levels of nerve growth factor (NGF); and (v) itching behavior becomes significantly severe [8-11].