Yusheng Qiu

Airway mucosal inflammation in COPD is similar in smokers and ex-smokers: a pooled analysis

Bronchial biopsy specimens from chronic obstructive pulmonary disease (COPD) patients demonstrate increased numbers of CD8+ T-lymphocytes, macrophages and, in some studies, neutrophils and eosinophils. Smoking cessation affects the rate of forced expiratory volume in one second (FEV1) decline in COPD, but the effect on inflammation is uncertain. Bronchial biopsy inflammatory cell counts were compared in current and ex-smokers with COPD. A pooled analysis of subepithelial inflammatory cell count data from three bronchial biopsy studies that included COPD patients who were either current or ex-smokers was performed. Cell count data from 101 subjects, 65 current smokers and 36 ex-smokers, were analysed for the following cell types: CD4+ and CD8+ T-lymphocytes, CD68+ (monocytes/macrophages), neutrophil elastase+ (neutrophils), EG2+ (eosinophils), mast cell tryptase+ and cells mRNA-positive for tumour necrosis factor-α. Current smokers and ex-smokers were similar in terms of lung function, as measured by FEV1 (% predicted), forced vital capacity (FVC) and FEV1/FVC. The results demonstrate that there were no significant differences between smokers and ex-smokers in the numbers of any of the inflammatory cell types or markers analysed. It is concluded that, in established chronic obstructive pulmonary disease, the bronchial mucosal inflammatory cell infiltrate is similar in ex-smokers and those that continue to smoke.

Bronchial mucosal inflammation and upregulation of CXC chemoattractants and receptors in severe exacerbations of asthma

Background: A study was undertaken to test the hypothesis that severe exacerbations of asthma are characterised by increased bronchial mucosal neutrophilia associated with upregulation of neutrophil chemoattractant ligands and their specific cell surface receptors. Methods: Immunohistology and in situ hybridisation were applied to endobronchial biopsy specimens from three groups: (1) 15 patients admitted to hospital with a severe exacerbation of asthma (E-asthma), (2) 15 with stable asthma (S-asthma) and (3) 15 non-atopic and non-smoker surgical controls (NSC). Results: There were significantly more neutrophils and eosinophils in the epithelium and subepithelium of patients in the E-asthma group (median (range) neutrophils 7 (0–380) and 78 (10–898)/mm2, eosinophils 31 (0–167) and 60 (6–351)/mm2, p⩽0.01 compared with NSC: 0 (0–10, 0–7, 0–18 and 0–3)/mm2, respectively), resulting in similar final densities of eosinophils and neutrophils. With respect to neutrophil chemoattractants and receptors, counts of CXCL5, CXCL8, CXCR1 and CXCR2 mRNA-positive cells in the subepithelium of the E-asthma group were, respectively, 5, 4, 4 and 18 times greater (p⩽0.01) than those of the NSC group. In the E-asthma group, cells expressing CXCL5 or CXCR2 were eightfold and threefold more frequent than those expressing CXCL8 or CXCR1 mRNA, respectively (p<0.01). CXCL5 and CXCR2 in E-asthma were associated with the number of eosinophils (r = 0.59 and 0.66, p<0.02 for both) rather than the number of neutrophils. Conclusion: In severe exacerbations of asthma there is a bronchial mucosal neutrophilia, eosinophilia and upregulation of CXC chemoattractants and their receptors. CXCL5 and CXCR2 have an association with eosinophila only, and these represent potentially new targets for treatment in exacerbations of asthma.

Airway inflammation in children with difficult asthma: relationships with airflow limitation and persistent symptoms

Background: The effective management and development of new treatments for children with difficult asthma requires investigation of the underlying airway pathology and its relationships with persistent symptoms and airflow limitation. Methods: The density of immunologically distinct inflammatory cells and cells expressing interleukin (IL)-4, IL-5, and RANTES was determined in paraffin-embedded endobronchial biopsy specimens from 27 children with difficult asthma (6–16 years) following treatment with systemic corticosteroids. Eleven non-asthmatic children (7–16 years) acted as controls. Reticular basement membrane (RBM) thickness was also recorded and forced expiratory volume in 1 second (FEV1) and exhaled nitric oxide (FENO) measured, the latter in asthmatic children only. Results: RBM thickness was greater in the asthmatic than the control group (median (range) 7.4 (3.1–11.1) v 5.1 (3.5–7.5) μm, p = 0.02). No other significant tissue difference was seen, nor was there a difference between asthmatic subjects with daily symptoms after systemic corticosteroids and those who became asymptomatic. CD4+ T lymphocyte density was higher in asthmatic subjects with persistent airflow limitation (post-bronchodilator FEV1<80% predicted) than in those without (9.1 (5.5–13.6) v 3.5 (0.6–34.9)%, p = 0.027). Analysing all asthmatic subjects together, there were negative correlations between CD4+ T lymphocytes and both pre-bronchodilator FEV1 (r  =  −0.57 (95% CI −0.79 to −0.23), p = 0.002) and post-bronchodilator FEV1 (r  =  −0.61 (95% CI −0.81 to −0.29), p<0.001). There were no significant correlations between FENO and inflammatory cells of any type. Conclusion: In children with difficult asthma treated with systemic corticosteroids, persistent airflow limitation is associated with a greater density of CD4+ T lymphocytes in endobronchial biopsy specimens.

Airway inflammation in patients with asthma with high-fixed or low-fixed plus as-needed budesonide/formoterol.

BACKGROUND Budesonide/formoterol maintenance and reliever therapy maintains asthma control and reduces exacerbation frequency compared with higher fixed-dose combination regimens. Its effects on eosinophilic airway inflammation and structure are unknown. OBJECTIVE We sought to compare the effects of budesonide/formoterol 200/6 microg twice daily plus as-needed with budesonide/formoterol 800/12 microg twice daily on airway eosinophils and remodeling. METHODS This 52-week, parallel-group, randomized, double-blind study of 127 asthma patients who were symptomatic despite therapy compared (1) the change between induced sputum percent eosinophils at baseline and the geometric mean of 4 on-treatment values and (2) the change in endobronchial biopsy eosinophil counts pre- and post-treatment. RESULTS Mean daily doses of budesonide/formoterol were 604/18 microg in the maintenance and reliever therapy group and 1,600/24 microg in the high fixed-dose group. In the former, the geometric mean percent sputum eosinophils remained unchanged (1.6% to 1.9%), whereas biopsy specimen subepithelial eosinophils increased (6.2 to 12.3 cells/mm(2)). Sputum and biopsy eosinophil counts decreased with high fixed-dose treatment (2.2% to 1.2% and 7.7 to 4.8 cells/mm(2), respectively), resulting in significant treatment differences of 0.7% (ratio, 1.8; 95% CI, 1.2-2.8; P = .0038) and 7.5 cells/mm(2) (ratio, 2.9; 95% CI, 1.6-5.3; P < .001), respectively. There were no between-treatment differences in reticular basement membrane thickness, exhaled nitric oxide, exacerbation frequency, or FEV(1). CONCLUSION Compared with fixed-dose combination treatment containing a 4-fold higher maintenance dose of budesonide, budesonide/formoterol maintenance and reliever therapy is associated with higher eosinophil counts, but these remain within the range associated with stable clinical control.

Distinct patterns of inflammation in the airway lumen and bronchial mucosa of children with cystic fibrosis

Background Studies in cystic fibrosis (CF) generally focus on inflammation present in the airway lumen. Little is known about inflammation occurring in the airway wall, the site ultimately destroyed in end-stage disease. Objective To test the hypothesis that inflammatory patterns in the lumen do not reflect those in the airway wall of children with CF. Methods Bronchoalveolar lavage (BAL) fluid and endobronchial biopsies were obtained from 46 children with CF and 16 disease-free controls. BAL cell differential was assessed using May-Gruenwald-stained cytospins. Area profile counts of bronchial tissue immunopositive inflammatory cells were determined. Results BAL fluid from children with CF had a predominance of neutrophils compared with controls (median 810×103/ml vs 1×103/ml, p<0.0001). In contrast, subepithelial bronchial tissue from children with CF was characterised by a predominance of lymphocytes (median 961 vs 717 cells/mm2, p=0.014), of which 82% were (CD3) T lymphocytes. In chest exacerbations, BAL fluid from children with CF had more inflammatory cells of all types compared with those with stable disease whereas, in biopsies, only the numbers of lymphocytes and macrophages, but not of neutrophils, were higher. A positive culture of Pseudomonas aeruginosa was associated with higher numbers of T lymphocytes in subepithelial bronchial tissue (median 1174 vs 714 cells/mm2, p=0.029), but no changes were seen in BAL fluid. Cell counts in BAL fluid and biopsies were positively correlated with age but were unrelated to each other. Conclusion The inflammatory response in the CF airway is compartmentalised. In contrast to the neutrophil-dominated inflammation present in the airway lumen, the bronchial mucosa is characterised by the recruitment and accumulation of lymphocytes.

Airway inflammation and illness severity in response to experimental rhinovirus infection in asthma.

Background: The nature of bronchial mucosal inflammation and its physiologic and clinical significance in rhinovirus-induced asthma exacerbations is unclear. We investigated bronchial mucosal inflammatory response and its association with physiologic and clinical outcomes in an experimental model of rhinovirus-induced asthma exacerbations. Methods: We used immunohistochemistry methods to detect phenotypes of inflammatory cells infiltrating the bronchial mucosa before and after experimental rhinovirus infection in 10 subjects with asthma and 15 normal subjects. Results: Compared with baseline, rhinovirus infection significantly increased the number of epithelial (P = .005) and subepithelial (P = .017) neutrophils in subjects with asthma only and subepithelial CD68+ macrophages in both subjects with asthma (P = .009) and normal subjects (P = .018) but more so in those with asthma (P = .021). Numbers of CD45+, CD68+, and CD20+ cells; neutrophils; and eosinophils at day 4 postinfection were positively associated with virus load (r = 0.50-0.72, P = .016-0.03). At acute infection in subjects with asthma, CD4+ cells correlated with chest symptom scores (r = 0.69, P = .029), the fall in the 10% fall in FEV1 (PC10) correlated with neutrophils (r = −0.89, P = .029), the PC10 correlated inversely with CD4+ (r = −0.67, P = .023) and CD8+ cells (r = −0.65, P = .03), the 20% fall in FEV1 was inversely associated with CD20+ cells (r = −0.65, P = .03), and higher epithelial CD8+ cell counts were significantly associated with a greater maximum fall in FEV1 (r = −0.72, P = .03), whereas higher subepithelial mast cell counts were significantly associated with a lower maximum percent fall in peak expiratory flow (r = 0.8, P = .024). Conclusions: In subjects with asthma, rhinovirus infection induces bronchial mucosal neutrophilia and more severe monocyte/macrophage infiltration than in normal subjects. Airway neutrophils, eosinophils, and T and B lymphocytes during infection are related to virus load and physiologic and clinical severity, whereas mast cells are related to greater lung function.

Variability of bronchial inflammation in chronic obstructive pulmonary disease: implications for study design

There is variability in the distribution of inflammatory cells in bronchial tissue in chronic obstructive pulmonary disease (COPD). Better strategies for biopsy sampling of the airway mucosa may improve the capacity to show a difference between study populations where variability in distribution exists. The current authors have examined sources of biological variability in the quantification of inflammatory cells in endobronchial biopsies using immunostained samples taken from 51 subjects with COPD, with a mean forced expiratory volume in one second of 1.71 L, 55% predicted. The distribution of variance contributed by different sources was similar for different inflammatory cell types. For CD8+ cells, a key inflammatory cell in COPD, the largest contribution to intra-subject variability (39%) was time (i.e. 10 weeks between biopsies of placebo-treated subjects), followed by airway generation (23%), biopsy (2.5%), zone (within section; 1.4%) and section (0.4%). Power calculations demonstrated that examining one section from one biopsy, from each of two airway generations, would require a sample size of 32 subjects per group to show a difference of one doubling or halving in CD8+ cells, compared with 47 subjects per group if only one airway generation was sampled. Therefore, biopsies from more than one airway generation should be examined in order to maximise statistical power to detect a difference between study groups.