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  • Title: Heat shock protein 70 upregulation is related to HLA-DR expression in bronchial asthma. Effects of inhaled glucocorticoids.
    Author: Bertorelli G, Bocchino V, Zhuo X, Chetta A, Del Donno M, Foresi A, Testi R, Olivieri D.
    Journal: Clin Exp Allergy; 1998 May; 28(5):551-60. PubMed ID: 9645591.
    Abstract:
    BACKGROUND AND OBJECTIVE: Antigen processing determines the production of peptides from antigens - including allergens - and their binding to class II major histocompatibility complex molecules, that stimulate T-cell responses. Heat shock protein (hsp) 70 are recognized to have a role in chaperoning antigenic peptides and in facilitating class II peptide assembly. We studied the HLA-DR and hsp70 expression on BAL cells and bronchial biopsies from asthmatics, as well as the effect of low dose fluticasone propionate treatment. METHODS: Twenty-three asthmatics and eight normal subjects were selected. In each subject BAL and bronchial biopsies were performed. Eighteen out of 23 asthmatics, underwent the second bronchoscopy after 6 weeks of low dose inhaled fluticasone propionate treatment (250 microg b.d.) in a placebo-controlled double-blind study. BAL fluid and biopsies were processed to evaluate HLA-DR and hsp70 expression by immunochemistry methods. RESULTS: Hsp70 and HLA-DR upregulation was present on professional and non-professional antigen presenting cells (APCs). In asthmatics, the hsp70 and HLA-DR expression was higher in BAL (hsp70 P<0.001, HLA-DR P<0.001) and bronchial epithelium (hsp70 P<0.001, HLA-DR P<0.001) when compared with controls. We also observed a significant correlation between hsp70 and HLA-DR expression in BAL (P<0.005) and epithelium (P<0.001). Fluticasone propionate treatment down-regulated the hsp70 and HLA-DR expression in BAL (hsp70 P < 0.001, HLA-DR P < 0.05) and bronchial epithelium (hsp70 P < 0.05, HLA-DR P < 0.05). A serial section comparison study showed that CD1a+ cells and macrophages were positive for both hsp70 and HLA-DR in the submucosa. CONCLUSIONS: Our results support the hypothesis that hsp70 over-expression implies a potential role for these proteins in antigen processing and/or presentation resulting in an increased activity of APCs, which is essential for the initiation and modulation of the asthmatic immune response in chronic asthma. Fluticasone propionate induces downregulation of HLA-DR and hsp70 molecules thus regulating inflammation by affecting key mechanisms of the allergic response.
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