Large-scale DNA microarray analysis of atopic skin lesions shows overexpression of an epidermal differentiation gene cluster in the alternative pathway and lack of protective gene expression in the cornified envelope

Abstract

Background Atopic dermatitis (AD)‐specific genes have not yet been clarified. Objectives To identify gene expression specific to active atopic skin lesions. Methods We analysed 23 000 genes in skin biopsy samples from 17 patients with AD and four normal controls using Affymetrix oligonucleotide arrays. Results Four of the 10 genes with the greatest differences in expression between patients and controls, S100A8 and S100A7 (upregulated), and loricrin and filaggrin (downregulated), were epidermal differentiation genes located on 1q21, a locus previously reported to have a genetic linkage with AD. Conclusions Our results, showing downregulation of the cornified envelope genes and upregulation of the alternative keratinization pathway, are the first to suggest abnormal epidermal differentiation and defective defences as key abnormalities in AD.