A Role of Staphyococcus aureus, Interleukin-18, Nerve Growth Factor and Semaphorin 3A, an Axon Guidance Molecule, in Pathogenesis and Treatment of Atopic Dermatitis

Staphylococcus aureus (SA) is usually present not only in the skin lesions of atopic dermatitis (AD) but also in the atopic dry skin. SA discharges various toxins and enzymes that injure the skin, results in activation of epidermal keratinocytes, which produce and release IL-18. IL-18 that induces the super Th1 cells secreting IFN-γ and IL-13 is supposed to be involved in development of AD and its pathogenesis. Indeed, the number of SA colonies on the skin surface and the serum IL-18 levels in patients with AD significantly correlated with the skin scores of AD lesions. Also, there is strong positive correlation between the skin scores and serum IL-18 levels in DS-Nh mice (P