BACKGROUND: Induced sputum potentially allows monitoring of airway inflammation in patients with asthma in a non-invasive way. However, the relationship between the cellular content in sputum and airway tissue has not been fully clarified. OBJECTIVE: We compared the cellular compositions of hypertonic saline-induced sputum, bronchoalveolar lavage fluid (BAL) and bronchial biopsies in 18 clinically stable patients with mild to moderate atopic asthma (baseline FEV1: range 61-114%pred, PC20 methacholine: 0.04-4.7 mg/mL). They were treated with inhaled short-acting bronchodilators on demand, with (n = 8) or without (n = 10) regular inhaled steroids. METHODS: Each patient underwent sputum induction and fiberoptic bronchoscopy on separate days in random order. Differential cell counts of induced sputum, bronchoalveolar lavage and bronchial wash were determined on May-Grünwald-Giemsa stained cytospins. Flow cytometry was performed on sputum and BAL samples. Immunohistochemical techniques were used to stain inflammatory cells in 6 microm cryostat sections of bronchial biopsies. RESULTS:Sputum cell differentials were not different between the patients with and without inhaled steroids, and showed a median value of 19.4% squamous cells, with 1.0% eosinophils, 3.3% lymphocytes, 28.7% neutrophils, 49.4% macrophages and 6.9% cylindric epithelial cells (in percentage non-squamous cells). The percentage eosinophils in sputum was significantly correlated with their percentage in bronchial wash (Rs = 0.52, P = 0.03) and in BAL (Rs = 0.55, P= 0.02), whilst there was a trend towards such a correlation between the number of eosinophils/mL sputum and the number of EG2+ eosinophils/mm2 lamina propria in bronchial biopsies (Rs = 0.44, P = 0.07). In addition, the percentage of CD4+ lymphocytes correlated between sputum and BAL (Rs = 0.55, P = 0.03). CONCLUSION: We conclude that the eosinophil counts in hypertonic saline-induced sputum from patients with asthma are related to those in bronchial wash and BAL and, to a lesser extent, with the counts in bronchial biopsies. This suggests that induced sputum can be used to monitor the presence and severity of airway inflammation in asthma.
RCT Entities:
BACKGROUND: Induced sputum potentially allows monitoring of airway inflammation in patients with asthma in a non-invasive way. However, the relationship between the cellular content in sputum and airway tissue has not been fully clarified. OBJECTIVE: We compared the cellular compositions of hypertonic saline-induced sputum, bronchoalveolar lavage fluid (BAL) and bronchial biopsies in 18 clinically stable patients with mild to moderate atopic asthma (baseline FEV1: range 61-114%pred, PC20 methacholine: 0.04-4.7 mg/mL). They were treated with inhaled short-acting bronchodilators on demand, with (n = 8) or without (n = 10) regular inhaled steroids. METHODS: Each patient underwent sputum induction and fiberoptic bronchoscopy on separate days in random order. Differential cell counts of induced sputum, bronchoalveolar lavage and bronchial wash were determined on May-Grünwald-Giemsa stained cytospins. Flow cytometry was performed on sputum and BAL samples. Immunohistochemical techniques were used to stain inflammatory cells in 6 microm cryostat sections of bronchial biopsies. RESULTS: Sputum cell differentials were not different between the patients with and without inhaled steroids, and showed a median value of 19.4% squamous cells, with 1.0% eosinophils, 3.3% lymphocytes, 28.7% neutrophils, 49.4% macrophages and 6.9% cylindric epithelial cells (in percentage non-squamous cells). The percentage eosinophils in sputum was significantly correlated with their percentage in bronchial wash (Rs = 0.52, P = 0.03) and in BAL (Rs = 0.55, P= 0.02), whilst there was a trend towards such a correlation between the number of eosinophils/mL sputum and the number of EG2+ eosinophils/mm2 lamina propria in bronchial biopsies (Rs = 0.44, P = 0.07). In addition, the percentage of CD4+ lymphocytes correlated between sputum and BAL (Rs = 0.55, P = 0.03). CONCLUSION: We conclude that the eosinophil counts in hypertonic saline-induced sputum from patients with asthma are related to those in bronchial wash and BAL and, to a lesser extent, with the counts in bronchial biopsies. This suggests that induced sputum can be used to monitor the presence and severity of airway inflammation in asthma.
Authors: Larry C Lands; A Keith Tanswell; Sophie Laberge; Christine McCusker; Felix Ratjen Journal: Can Respir J Date: 2010 Mar-Apr Impact factor: 2.409
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Authors: Hongjun Jin; Teal S Hallstrand; Don S Daly; Melissa M Matzke; Parameswaran Nair; Diana J Bigelow; Joel G Pounds; Richard C Zangar Journal: J Immunol Methods Date: 2013-12-02 Impact factor: 2.303