Analysis of gene expression in peripheral blood eosinophils from patients with atopic dermatitis by differential display.

To identify the genes related to atopic dermatitis (AD), we compared gene expression in eosinophils from AD patients and healthy volunteers. RNA was prepared from peripheral blood eosinophils. Gene expression was monitored by fluorescent differential display (DD) and real-time RT-PCR. Eighteen new sequences, including expressed sequence tags (ESTs), were expressed at higher levels in eosinophils from AD patients than in those from healthy volunteers. The functions of most of these genes are unknown. We found no correlation between the expression of a particular gene and clinical markers such as the number of eosinophils and the amount of IgE. Multivariate analysis of the gene expression data in each sample showed a very high coefficient of correlation among the copy numbers of each gene. The genes under investigation were also expressed in cultured blood eosinophils after IL-4, IL-5 and IFN-gamma stimulation. We were able to predict the function of some of the sequences by scanning for homologies within either the human or mouse genome databases. The mouse counterpart of one of these genes, intersectin 2, was expressed dramatically, as measured by ear edema, in 1-fluoro-2,4-dinitrobenzene-induced mouse contact dermatitis and in NC/Nga mouse dermatitis.