Bronchial gamma delta T-lymphocytes and expression of heat shock proteins in mild asthma

Abstract

Heat shock proteins (HSPs), which are important targets for gammadelta T-lymphocytes, are thought to play a role in inflammatory and immune diseases. The purpose of this study was to characterize, in asthma, the presence and distribution of alphabeta and gammadelta T-lymphocytes and of hsp60, hsp70 and hsp90 in bronchial biopsies, and to seek for a co-localization of gammadelta T-cells and HSPs. Ten subjects with mild atopic asthma and nine control subjects underwent fibreoptic bronchoscopy and bronchial biopsies, to which specific monoclonal antibodies and immunohistochemical techniques were applied. T-lymphocytes present in bronchi both of asthmatic and control subjects were predominantly of the alphabeta T-cell receptor phenotype (median 642 cells x mm(-2) (range 85-1,510 cells x mm(-2)), and 855 cells x mm(-2) (286-2,424 cells x mm(-2)), respectively), whereas, gammadelta T-lymphocytes were always rare (median 26 cells x mm(-2) (range 0-114 cells x mm(-2)), and 0 cells x mm(-2 (0-57 cells x mm(-2), respectively). Both in asthmatic and control subjects, bronchial epithelium was positive for hsp60, hsp70 and hsp90. There was no significant difference in the percentages of positive epithelial cells between asthmatic and control subjects. No co-localization of HSPs and gammadelta T-cells was observed. Our findings do not support the hypothesis that heat shock proteins and gammadelta T-cells play an important role in inflammatory and immune responses in mild asthma.