SELECTED ARTICLES FROM THE RECENT LITERATURE 2004
9/21/04
Another mechanism for the beneficial effects of corticosteroids in allergic diseases?
Summary
Background - It has been postulated that corticosteroids (CS) are particularly effective in treating allergic diseases because CS act at several loci of immune/inflammatory responses. It is also now recognized that T regulator (T reg) cell effects may be at least partially responsible for inhibition of the allergen-induced proliferation of T cells that mediate allergic responses.
Findings - Dao Nguyen and Robinson of the National Heart and Lung Institute in London, UK reported findings dealing with incubation of T cells with fluticasone propionate (FP) a corticosteroid used commonly as an inhaled steroid. They found that such interaction led to stimulation of CD4+ CD25+, T reg cells that could then suppress the proliferation of CD4+ CD25- T cells that would otherwise elaborate cytokines that enhanced allergic inflammation. This inhibitory activity of FP- incubated T reg cells is mediated at least in part by secretion of IL-10, a cytokine shown to down regulated allergic responses.
Reference
J Allergy Clin Immunol 2004; 114:296-301
Editor's Comments
These findings based on in vitro incubations of FP with T cells require support from studies of cells obtained from FP treated atopics to offer definitive evidence of the postulated mechanisms for CS activity in allergic inflammation. However, other recent studies have pointed to the elaboration of IL-10 as a major mechanism underlying normal suppression of T cell reactivity to aeroallergens in non-atopics. This mechanism may also be a major factor in the inhibition of such allergenic T cell responses during allergen immunotherapy in those originally sensitive to the allergen in question.
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