title: Enhanced IL-4 production and IL-4 receptor expression in atopic dermatitis and their modulation by interferon-gamma.
abstract: The in vivo and in vitro immunomodulatory effects of interferon gamma (IFN-gamma) treatment on peripheral blood mononuclear cells (PBMC) from patients with atopic dermatitis (AD) and elevated IgE levels were studied. As part of a double-blind placebo-controlled clinical trial, 14 AD patients were treated with IFN-gamma (n = 7) or saline (n = 7) for 12 weeks. To assess the in vivo effects of IFN-gamma treatment on interleukin (IL)-4-dependent lymphocyte function, we assessed the proliferation of AD PBMC in response to IL-4. Prior to IFN-gamma treatment, AD PBMC had proportionately decreased proliferative responses to IL-4 when compared to IL-2. After 12 weeks of in vivo treatment with IFN-gamma, there was an increase of IL-4- but not IL-2-induced lymphocyte proliferation in seven of eight AD patients. To further study the immunologic basis of these observations, we studied the expression of IL-4 receptor (IL-4R) mRNA and the production of IL-4 by PBMC from AD patients. PBMC from AD patients expressed higher levels of IL-4R mRNA and produced significantly higher amounts of IL-4 than normal controls (p less than 0.05). More importantly, the in vitro addition of IFN-gamma caused significant reduction in both IL-4R and mRNA expression and IL-4 production of PBMC from AD and non-atopic controls. These data indicate that AD is characterized by an in vivo overstimulation of the IL-4-IL-4R pathway. The poor proliferative responses of untreated AD PBMC to exogenous IL-4 may be due to increased levels of endogenous IL-4 production with constant occupancy on the IL-4R. Furthermore, in vivo and in vitro treatment with IFN-gamma down-regulates this pathway.
authors.affiliation: Department of Pediatrics, National Jewish Center for Immunology and Respiratory Medicine, Denver, CO 80206.
authors.forename: H
authors.initials: H
authors.lastname: Renz
authors.forename: K
authors.initials: K
authors.lastname: Jujo
authors.forename: K L
authors.initials: KL
authors.lastname: Bradley
authors.forename: J
authors.initials: J
authors.lastname: Domenico
authors.forename: E W
authors.initials: EW
authors.lastname: Gelfand
authors.forename: D Y
authors.initials: DY
authors.lastname: Leung
mesh_terms: D000293:Adolescent; D000328:Adult; D002455:Cell Division / Q000187:drug effects; D002648:Child; D003876:Dermatitis, Atopic / Q000378:metabolism* / Q000473:pathology*; D004311:Double-Blind Method; D006801:Humans; D007371:Interferon-gamma / Q000494:pharmacology*; D015847:Interleukin-4 / Q000378:metabolism*; D008875:Middle Aged; D009000:Monocytes / Q000166:cytology / Q000378:metabolism
chemical_list: D015847:Interleukin-4; D007371:Interferon-gamma