41 S100A8/A9, a Damp Molecule Activated by IL-17 and House Dust Mite is Upregulated in Atopic Dermatitis

appears on the skin. We separated lymphocytes from the inflamed skin of NC/ Nga mice using collagenase I (Sigma-Aldrich) and counted the numbers of nuocytes (ST21/Sca-11/lineage marker-negative) by FACS. Results: (1) The reactions were hapten specific. Wild-type BALB/c mice showed both immediate and delayed-type reactions, whereas ST2 KO mice did not show any immediate reaction. (2) When IL-33 was administered subcutaneously, NC/Nga mice showed increase of serum IgE level. The number of nuocytes in inflamed skin of NC/Nga mice significantly increased compared to non-inflamed skin. The nuocytes showed very weak expression of ST2 in non-inflamed skin, whereas the expression of ST2 in inflamed skin was very significant. Conclusions: These results suggest that IL-33 may have an important role in the mechanism of immediate contact hypersensitivity, and nuocytes may contribute to the development of atopic dermatitis-like skin lesion in NC/Nga mice.