UNLABELLEDProminent eosinophil airway inflammation is important in the pathogenesis of asthma. There is increasing evidence that the disorder of eosinophil apoptosis contributes to the mechanism. But most of the studies have been done in vitro or on animal models, very few were done among the adult asthmatics in vivo.

OBJECTIVEThe aim of this study was to elucidate the relationship between the apoptotic eosinophils and Bcl-2 in asthmatic children in vivo.

METHODSEleven mild to moderate asthmatic patients were recruited and the range of age was 7 - 14 years (9 males, 2 females), meanwhile 7 patients with lower respiratory infection were recruited as control and the range of age was 9 - 14 years (5 males, 2 females). Before and after inhaled glucocorticoid (GC) induced sputum, bronchoalveolar lavage (BAL), bronchial mucosa specimens and peripheral blood were obtained for measuring and comparing the changes of apoptotic EG(2)(+) cell by combining the techniques of TUNEL and immunohistochemistry, meanwhile the expression of Bcl-2 in bronchial mucosa specimens was measured by using the immunohistochemical assay.

RESULTSBefore the inhalation of GC, the apoptotic EG(2)(+) cells in asthmatics were significantly lower than that in control group (P < 0.01), and the numbers of EG(2)(+) cell in asthmatics group were significantly higher than that in control group (P < 0.001). After the treatment apoptotic EG(2)(+) cells in asthmatics were increased (P < 0.01), and the numbers of EG(2)(+)cell were decreased (P < 0.01, P < 0.05 and P < 0.05, respectively), FEV(1)% was increased (P < 0.05). Before the inhalation of GC, the numbers of Bcl-2(+) cell in asthmatic airway submucosa were higher than that in control group (P < 0.05) but after the treatment the number of Bcl-2(+) cell did not change significantly. (4) Before and after GC treatment the percentages of apoptotic eosinophils of peripheral blood in vivo had no significant changes compared with those of control subjects (P > 0.05). There was a positive correlation between apoptosis of EG(2)(+) cell in sputum, BAL, airway submucosa and FEV(1)% (P < 0.05).

CONCLUSIONApoptosis of EG(2)(+) cell decreased in the airway of asthmatic children and inducing EOS apoptosis is one of the important mechanism of inhaled GC therapy for asthma.