ABNORMAL IL-4 GENE-EXPRESSION BY ATOPIC-DERMATITIS T-LYMPHOCYTES IS REFLECTED IN ALTERED NUCLEAR-PROTEIN INTERACTIONS WITH IL-4 TRANSCRIPTIONAL REGULATORY ELEMENT

Among the atopic diseases, atopic dermatitis is characterized by the h ighest levels of serum IgE and by increased peripheral blood T-cell in terleukin-4 (IL-4) production. IL-4 promotes IgE synthesis by B cells and stimulates the growth of IL-4-producing T cells and may contribute to the pathogenesis of this disease. In this study, in situ hybridiza tion established that atopic dermatitis patients have a higher frequen cy of IL-4-producing peripheral blood T cell when compared to normal s ubjects. These in vivo derived T cells were used to examine the signal ing requirements for IL-4 production and the nuclear factors that asso ciate with a critical IL-4 transcriptional regulatory element between -88 and -60 relative to the IL-4 transcription initiation site, the ac tivation responsive element. We demonstrate that, as in T-cell lines, proteins belonging to the NF-AT and AP-1 family of transcription facto rs are present in stimulated cell extracts and specifically associate with the activation responsive element. Dysregulated IL-4 production i s reflected in the nuclear proteins that associate with this element. Using gel shift assays, we found that 12 of 12 nuclear extracts from s timulated atopic T cells formed the activation-dependent protein-DNA c omplex, compared to only 2 of 12 normal T-cell extracts. Activation co mplex formation correlated with the relative level of IL-4 mRNA and pr otein produced in stimulated T cells, suggesting that abnormal IL-4 ge ne expression in atopic disease may be linked to alterations in nuclea r protein interactions with these promoter elements.