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.
Full Text
The Full Text of this article is available as a PDF (161.4 KB).
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Adachi T., Motojima S., Hirata A., Fukuda T., Makino S. Eosinophil viability-enhancing activity in sputum from patients with bronchial asthma, Contributions of interleukin-5 and granulocyte/macrophage colony-stimulating factor. Am J Respir Crit Care Med. 1995 Mar;151(3 Pt 1):618–623. doi: 10.1164/ajrccm.151.3.7881646. [DOI] [PubMed] [Google Scholar]
- Chai H., Farr R. S., Froehlich L. A., Mathison D. A., McLean J. A., Rosenthal R. R., Sheffer A. L., Spector S. L., Townley R. G. Standardization of bronchial inhalation challenge procedures. J Allergy Clin Immunol. 1975 Oct;56(4):323–327. doi: 10.1016/0091-6749(75)90107-4. [DOI] [PubMed] [Google Scholar]
- Delia D., Aiello A., Soligo D., Fontanella E., Melani C., Pezzella F., Pierotti M. A., Della Porta G. bcl-2 proto-oncogene expression in normal and neoplastic human myeloid cells. Blood. 1992 Mar 1;79(5):1291–1298. [PubMed] [Google Scholar]
- Dewson G., Walsh G. M., Wardlaw A. J. Expression of Bcl-2 and its homologues in human eosinophils. Modulation by interleukin-5. Am J Respir Cell Mol Biol. 1999 Apr;20(4):720–728. doi: 10.1165/ajrcmb.20.4.3453. [DOI] [PubMed] [Google Scholar]
- Fahy J. V., Liu J., Wong H., Boushey H. A. Cellular and biochemical analysis of induced sputum from asthmatic and from healthy subjects. Am Rev Respir Dis. 1993 May;147(5):1126–1131. doi: 10.1164/ajrccm/147.5.1126. [DOI] [PubMed] [Google Scholar]
- Fleisher T. A. Apoptosis. Ann Allergy Asthma Immunol. 1997 Mar;78(3):245–250. doi: 10.1016/S1081-1206(10)63176-6. [DOI] [PubMed] [Google Scholar]
- Frigas E., Gleich G. J. The eosinophil and the pathophysiology of asthma. J Allergy Clin Immunol. 1986 Apr;77(4):527–537. doi: 10.1016/0091-6749(86)90341-6. [DOI] [PubMed] [Google Scholar]
- Frigas E., Gleich G. J. The eosinophil and the pathophysiology of asthma. J Allergy Clin Immunol. 1986 Apr;77(4):527–537. doi: 10.1016/0091-6749(86)90341-6. [DOI] [PubMed] [Google Scholar]
- Gleich G. J. The eosinophil and bronchial asthma: current understanding. J Allergy Clin Immunol. 1990 Feb;85(2):422–436. doi: 10.1016/0091-6749(90)90151-s. [DOI] [PubMed] [Google Scholar]
- Guesdon J. L., Ternynck T., Avrameas S. The use of avidin-biotin interaction in immunoenzymatic techniques. J Histochem Cytochem. 1979 Aug;27(8):1131–1139. doi: 10.1177/27.8.90074. [DOI] [PubMed] [Google Scholar]
- Hansel T. T., Walker C. The migration of eosinophils into the sputum of asthmatics: the role of adhesion molecules. Clin Exp Allergy. 1992 Mar;22(3):345–356. doi: 10.1111/j.1365-2222.1992.tb03096.x. [DOI] [PubMed] [Google Scholar]
- Lagasse E., Weissman I. L. bcl-2 inhibits apoptosis of neutrophils but not their engulfment by macrophages. J Exp Med. 1994 Mar 1;179(3):1047–1052. doi: 10.1084/jem.179.3.1047. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Naumovski L., Cleary M. L. Bcl2 inhibits apoptosis associated with terminal differentiation of HL-60 myeloid leukemia cells. Blood. 1994 Apr 15;83(8):2261–2267. [PubMed] [Google Scholar]
- Ochiai K., Kagami M., Matsumura R., Tomioka H. IL-5 but not interferon-gamma (IFN-gamma) inhibits eosinophil apoptosis by up-regulation of bcl-2 expression. Clin Exp Immunol. 1997 Jan;107(1):198–204. doi: 10.1046/j.1365-2249.1997.d01-884.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Plötz S. G., Dibbert B., Abeck D., Ring J., Simon H. U. Bcl-2 expression by eosinophils in a patient with hypereosinophilia. J Allergy Clin Immunol. 1998 Dec;102(6 Pt 1):1037–1040. doi: 10.1016/s0091-6749(98)70344-6. [DOI] [PubMed] [Google Scholar]
- Popov T., Gottschalk R., Kolendowicz R., Dolovich J., Powers P., Hargreave F. E. The evaluation of a cell dispersion method of sputum examination. Clin Exp Allergy. 1994 Aug;24(8):778–783. doi: 10.1111/j.1365-2222.1994.tb00990.x. [DOI] [PubMed] [Google Scholar]
- Reed J. A., Manahan L. J., Park C. S., Brigati D. J. Complete one-hour immunocytochemistry based on capillary action. Biotechniques. 1992 Sep;13(3):434–443. [PubMed] [Google Scholar]
- Vignola A. M., Chanez P., Chiappara G., Siena L., Merendino A., Reina C., Gagliardo R., Profita M., Bousquet J., Bonsignore G. Evaluation of apoptosis of eosinophils, macrophages, and T lymphocytes in mucosal biopsy specimens of patients with asthma and chronic bronchitis. J Allergy Clin Immunol. 1999 Apr;103(4):563–573. doi: 10.1016/s0091-6749(99)70225-3. [DOI] [PubMed] [Google Scholar]
- Wyllie A. H., Kerr J. F., Currie A. R. Cell death: the significance of apoptosis. Int Rev Cytol. 1980;68:251–306. doi: 10.1016/s0074-7696(08)62312-8. [DOI] [PubMed] [Google Scholar]