Bcl-2 expression in sputum eosinophils in patients with acute asthma. Issue 5 (1st May 2000)

• Record Type: Journal Article
• Authors: Jang, An-Soo; Choi, Inseon-S; Lee, Soong; Seo, Jeong-Pyeong; Yang, Seung-Won; Park, Chang-Soo
• Is Part Of: Thorax. Volume 55:Issue 5(2000)
• Page Start: 370
• Page End: 374
• Publication Date: 2000-05-01
• Subjects: eosinophils -- apoptosis -- asthma -- sputum -- bcl-2; Chest -- Diseases -- Periodicals; Thorax; Chest -- Diseases; Periodicals; Periodicals; 617.54
• DOI: 10.1136/thorax.55.5.370
• Languages: English
• ISSNs: 0040-6376

Abstract

Abstract : BACKGROUND: Eosinophils play a pivotal role in asthmatic airway inflammation. Apoptosis is thought to be critically relevant in promoting the clearance of inflammatory cells and the resolution of inflammation. Bcl-2 inhibits apoptosis in cellular systems. A study was undertaken to determine whether bcl-2 expression in sputum reflects the clinical severity of patients with asthma. The relationship between bcl-2 expression in sputum eosinophils and eosinophil activation markers such as interleukin (IL)-5 and eosinophil cationic protein (ECP) levels in sputum supernatant was evaluated. METHODS: Sputum was obtained from 18 patients with asthma. Fresh expectorated sputum separated from saliva was treated with an equal volume of dithiothreitol 0.1%, cytospun for cell differentials and bcl-2 stain, and the supernatant was collected for biochemical assay. Bcl-2+ eosinophils were stained using immunocytochemistry, ECP was measured by fluoroimmunoassay, and IL-5 was detected by sandwich enzyme linked immunosorbant assay. RESULTS: Twelve patients with severe or life threatening asthma had more bcl-2+ eosinophils (mean difference 46.8% (95% CI 27.0 to 66.6), p<0.01) and a higher ECP level (p<0.01) in the sputum than those with mild to moderate asthma (n = 6). IL-5 was frequently detected in patients with severe or life threatening asthma (11/12 versus 1/6, p<0.01). There was a significant positive correlation between bcl-2+ eosinophils and ECP levels ( r = 0.61, p<0.01) and between bcl-2+ eosinophils and IL-5 levels ( r = 0.83, p<0.01). There was a significant negative correlation between bcl-2+ eosinophils and FEV1 /FVC ( r = –0.54, p<0.05). CONCLUSION: The increased expression of bcl-2 in eosinophils from sputum of subjects with severe asthma suggests that bcl-2 may prolong survival and decrease apoptosis of airway eosinophils in asthma.