Bronchial mucosal inflammation and illness severity in response to experimental rhinovirus infection in COPD.

BACKGROUND: Respiratory viral infection causes chronic obstructive pulmonary disease (COPD) exacerbations. We previously reported increased bronchial mucosa eosinophil and neutrophil inflammation in patients with COPD experiencing naturally occurring exacerbations. But it is unclear whether virus per se induces bronchial mucosal inflammation, nor whether this relates to exacerbation severity. OBJECTIVES: We sought to determine the extent and nature of bronchial mucosal inflammation following experimental rhinovirus (RV)-16-induced COPD exacerbations and its relationship to disease severity. METHODS: Bronchial mucosal inflammatory cell phenotypes were determined at preinfection baseline and following experimental RV infection in 17 Global Initiative for Chronic Obstructive Lung Disease stage II subjects with COPD and as controls 20 smokers and 11 nonsmokers with normal lung function. No subject had a history of asthma/allergic rhinitis: all had negative results for aeroallergen skin prick tests. RESULTS: RV infection increased the numbers of bronchial mucosal eosinophils and neutrophils only in COPD and CD8+ T lymphocytes in patients with COPD and nonsmokers. Monocytes/macrophages, CD4+ T lymphocytes, and CD20+ B lymphocytes were increased in all subjects. At baseline, compared with nonsmokers, subjects with COPD and smokers had increased numbers of bronchial mucosal monocytes/macrophages and CD8+ T lymphocytes but fewer numbers of CD4+ T lymphocytes and CD20+ B lymphocytes. The virus-induced inflammatory cells in patients with COPD were positively associated with virus load, illness severity, and reductions in lung function. CONCLUSIONS: Experimental RV infection induces bronchial mucosal eosinophilia and neutrophilia only in patients with COPD and monocytes/macrophages and lymphocytes in both patients with COPD and control subjects. The virus-induced inflammatory cell phenotypes observed in COPD positively related to virus load and illness severity. Antiviral/anti-inflammatory therapies could attenuate bronchial inflammation and ameliorate virus-induced COPD exacerbations.

Bronchial mucosal IFN-α/ß and pattern recognition receptor expression in patients with experimental rhinovirus-induced asthma exacerbations.

BACKGROUND: The innate immune system senses viral infection through pattern recognition receptors (PRRs), leading to type I interferon production. The role of type I interferon and PPRs in rhinovirus-induced asthma exacerbations in vivo are uncertain. OBJECTIVES: We sought to compare bronchial mucosal type I interferon and PRR expression at baseline and after rhinovirus infection in atopic asthmatic patients and control subjects. METHODS: Immunohistochemistry was used to detect expression of IFN-α, IFN-ß, and the PRRs: Toll-like receptor 3, melanoma differentiation-associated gene 5, and retinoic acid-inducible protein I in bronchial biopsy specimens from 10 atopic asthmatic patients and 15 nonasthmatic nonatopic control subjects at baseline and on day 4 and 6 weeks after rhinovirus infection. RESULTS: We observed IFN-α/ß deficiency in the bronchial epithelium at 3 time points in asthmatic patients in vivo. Lower epithelial IFN-α/ß expression was related to greater viral load, worse airway symptoms, airway hyperresponsiveness, and reductions in lung function during rhinovirus infection. We found lower frequencies of bronchial subepithelial monocytes/macrophages expressing IFN-α/ß in asthmatic patients during infection. Interferon deficiency at baseline was not accompanied by deficient PRR expression in asthmatic patients. Both epithelial and subepithelial PRR expression were induced during rhinovirus infection. Rhinovirus infection-increased numbers of subepithelial interferon/PRR-expressing inflammatory cells were related to greater viral load, airway hyperresponsiveness, and reductions in lung function. CONCLUSIONS: Bronchial epithelial IFN-α/ß expression and numbers of subepithelial IFN-α/ß-expressing monocytes/macrophages during infection were both deficient in asthmatic patients. Lower epithelial IFN-α/ß expression was associated with adverse clinical outcomes after rhinovirus infection in vivo. Increases in numbers of subepithelial cells expressing interferon/PRRs during infection were also related to greater viral load/illness severity.

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.

Lungs, bone marrow, and adipose tissue. A network approach to the pathobiology of chronic obstructive pulmonary disease.

Patients with chronic obstructive pulmonary disease (COPD) often suffer other concomitant disorders, such as cardiovascular diseases and metabolic disorders, that influence significantly (and independently of lung function) their health status and prognosis. Thus, COPD is not a single organ condition, and disturbances of a complex network of interorgan connected responses occur and modulate the natural history of the disease. Here, we propose a novel hypothesis that considers a vascularly connected network with (1) the lungs as the main external sensor of the system and a major source of "danger signals"; (2) the endothelium as an internal sensor of the system (also a potential target tissue); and (3) two key responding elements, bone marrow and adipose tissue, which produce both inflammatory and repair signals. According to the model, the development of COPD, and associated multimorbidities (here we focus on cardiovascular disease as an important example), depend on the manner in which the vascular connected network responds, adapts, or fails to adapt (dictated by the genetic and epigenetic background of the individual) to the inhalation of particles and gases, mainly in cigarette smoke. The caveats and limitations of the hypothesis, as well as the experimental and clinical research needed to test and explore the proposed model, are also briefly discussed.

Increased airway smooth muscle in preschool wheezers who have asthma at school age.

BACKGROUND: Increased airway smooth muscle (ASM) is a feature of established asthma in schoolchildren, but nothing is known about ASM in preschool wheezers. OBJECTIVE: We sought to determine endobronchial biopsy specimen ASM area fraction in preschool wheezers and its association with asthma at school age. METHODS: ASM area, reticular basement membrane thickness, and mucosal eosinophil and ASM mast cell values were quantified in endobronchial biopsy specimens previously obtained from preschool children undergoing clinically indicated bronchoscopy: severe recurrent wheezers (n=47; median age, 26 months) and nonwheezing control subjects (n=21; median age, 15 months). Children were followed up, and asthma status was established at age 6 to 11 years. Preschool airway pathology was examined in relation to asthma at school age. RESULTS: Forty-two (62%) of 68 children had 1 or more evaluable biopsy specimens for ASM. At school age, 51 of 68 children were followed up, and 15 (40%) of 37 preschool wheezers had asthma. Children who had asthma and an evaluable biopsy specimen had increased preschool ASM area fraction (n=8; median age, 8.2 years [range, 6-10.4 years]; median ASM, 0.12 [range, 0.08-0.16]) compared with that seen in children without asthma (n=24; median age, 7.3 years [range, 5.9-11 years]; median ASM, 0.07 [range, 0.02-0.23]; P=.007). However, preschool reticular basement membrane thickness and mucosal eosinophil or ASM mast cell values were not different between those who did or did not have asthma at school age. CONCLUSION: Increased preschool ASM is associated with those children who have asthma at school age. Thus a focus on early changes in ASM might be important in understanding the subsequent development of childhood asthma.

Cysteinyl leukotriene 1 receptor expression associated with bronchial inflammation in severe exacerbations of COPD.

BACKGROUND: Cysteinyl leukotriene 1 (CysLT1) receptor expression is known to be increased in the airway mucosa of patients with asthma, especially during exacerbations; however, nothing is known of its expression in COPD. METHODS: We applied immunohistochemistry and in situ hybridization to endobronchial biopsies to determine inflammatory cell CysLT1 receptor protein and mRNA expression in the following: (1) 15 nonsmoker control subjects (NSC), (2) 16 smokers with moderate to severe COPD in its stable phase (S-COPD), and (3) 15 smokers with COPD hospitalized for a severe exacerbation (SE-COPD). RESULTS: The total number of bronchial mucosal inflammatory cells (CD45+) and those expressing CysLT1 receptor protein were significantly greater in SE-COPD (CysLT1 receptor protein: median [range] = 139 [31-634]) as compared with S-COPD (32 [6-114]) or NSC (16 [4-66]) (P < .001 for both). CysLT1 receptor gene expression showed similar differences. A greater proportion of CD451 cells expressed CysLT1 receptor protein in SE-COPD (median [range] = 22% [8-81]) compared with S-COPD (10% [4-32]) (P < .03) or NSC (7% [1-19]) (P < .002). In SE-COPD, the relative frequencies of CysLT1 receptor-expressing cells were as follows: tryptase1 mast cells > CD681 monocytes/macrophage > neutrophils > CD201 B lymphocytes = EG21 eosinophils. Moreover, there were positive correlations between the numbers of cells expressing CysLT1 receptor protein and the numbers of CD451 cells (r = 0.78; P < .003) and tryptase1 mast cells (r = 0.62; P < .02). CONCLUSIONS: Bronchial mucosal CysLT1 receptor-positive inflammatory cells are present in the bronchial mucosa in COPD in greatest number in those experiencing a severe exacerbation.

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 810×10(3)/ml vs 1×10(3)/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/mm(2), 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/mm(2), 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.

Lung function, airway remodelling and inflammation in symptomatic infants: outcome at 3 years.

BACKGROUND: Relationships between early deficits of lung function, infant airway pathology and outcome in symptomatic infants are unclear. A study was undertaken to determine the associations between early lung function, airway histology and inflammation in symptomatic infants with the continuance of respiratory symptoms, lung function and subsequent use of inhaled asthma medication at the age of 3 years. METHODS: 53 children who underwent lung function measurements and bronchoscopy following referral to a specialist children's hospital for recurrent lower respiratory symptoms at a mean age of 1 year were followed up at 3 years of age. Assessments were made of respiratory symptoms during the previous year, lung function by oscillometry and atopy by skin prick testing. Individual data on the purchase of asthma medications were obtained from the Social Insurance Institution for the 12 months preceding the follow-up visit. RESULTS: 50 children (94%) were re-evaluated, of whom 40 had ongoing airway symptoms. 11/39 (28%) who underwent successful oscillometry had reduced lung function, 31/50 (62%) used inhaled corticosteroids (ICS) regularly and 12/50 (24%) used ICS intermittently. Abnormal lung function at infancy was associated with ongoing airway symptoms (p<0.001) and with the purchase of ICS (p=0.009) and ß agonists (p=0.002). Reticular basement membrane thickness in infancy and the numbers of mucosal mast cells, but not eosinophils, correlated significantly with the amount of ICS purchased at 3 years (p=0.003 and p=0.018, respectively). CONCLUSIONS: Reduced lung function, thickening of the reticular basement membrane and increased density of mucosal mast cells in infancy are associated with respiratory morbidity and treatment needs at age 3 years in this highly selected group of children.

Development of the bronchial epithelial reticular basement membrane: relationship to epithelial height and age.

BACKGROUND: The bronchial epithelium and underlying reticular basement membrane (RBM) have a close spatial and functional inter-relationship and are considered an epithelial-mesenchymal trophic unit (EMTU). An understanding of RBM development is critical to understanding the extent and time of appearance of its abnormal thickening that is characteristic of asthma. METHODS: RBM thickness and epithelial height were determined in histological sections of cartilaginous bronchi obtained postmortem from 47 preterm babies and infants (median age 40 weeks gestation (22 weeks gestation-8 months)), 40 children (2 years (1 month-17 years)) and 23 adults (44 (17-90) years) who had died from non-respiratory causes, and had no history of asthma. RESULTS: The RBM was visible by light microscopy at 30 weeks gestation. RBM thickness increased in successive age groups in childhood; in infants (r=0.63, p<0.001) and in children between 1 month and 17 years (r=0.82, p<0.001). After 18 years, RBM thickness decreased with increasing age (r=-0.42, p<0.05). Epithelial height showed a similar relationship with age, a positive relationship from preterm to 17 years (r=0.50, p<0.001) and a negative relationship in adulthood (r=-0.84, p<0.0001). There was a direct relationship between epithelial height and RBM thickness (r=0.6, p<0.001). CONCLUSIONS: The RBM in these subjects was microscopically identifiable by 30 weeks gestation. It thickened during childhood and adolescence. In adults, there was either no relationship with age, or a slow reduction in thickness in older age. Developmental changes of RBM thickness were accompanied by similar changes in epithelial height, supporting the close relationship between RBM and epithelium within the EMTU.

Airway remodelling and its relationship to inflammation in cystic fibrosis.

Pulmonary disease is the most important cause of morbidity and mortality in cystic fibrosis (CF). Most patients with CF die from respiratory failure with extensive airway destruction. Airway remodelling, defined as structural airway wall changes, begins early in life in CF but the sequence of remodelling events in the disease process is poorly understood. Airway remodelling in CF has traditionally been thought to be solely the consequence of repeated cycles of inflammation and infection. However, new evidence obtained from developmental, physiological and histopathological studies suggests that there might instead be multiple mechanisms leading to airway remodelling in CF including (1) changes related to infection and inflammation; (2) changes specific to CF as a result of CF transmembrane conductance regulator (CFTR) dysfunction in the airway wall, independent of infection and inflammation; and (3) protective responses to (1) and/or (2). Recent advances in bronchoscopic techniques have allowed airway mucosal (endobronchial) biopsies to be taken in children and even infants. Endobronchial biopsy studies may provide insight into the role and relative contribution of the different mechanisms of airway remodelling in CF, with the main limitation that they assess only changes in proximal large airways and not in peripheral small airways from where CF disease is thought to originate. Findings from biopsy studies could encourage the development of novel therapeutic strategies targeting structural changes in addition to infection and inflammation.

Co-ordinated role of TLR3, RIG-I and MDA5 in the innate response to rhinovirus in bronchial epithelium.

The relative roles of the endosomal TLR3/7/8 versus the intracellular RNA helicases RIG-I and MDA5 in viral infection is much debated. We investigated the roles of each pattern recognition receptor in rhinovirus infection using primary bronchial epithelial cells. TLR3 was constitutively expressed; however, RIG-I and MDA5 were inducible by 8-12 h following rhinovirus infection. Bronchial epithelial tissue from normal volunteers challenged with rhinovirus in vivo exhibited low levels of RIG-I and MDA5 that were increased at day 4 post infection. Inhibition of TLR3, RIG-I and MDA5 by siRNA reduced innate cytokine mRNA, and increased rhinovirus replication. Inhibition of TLR3 and TRIF using siRNA reduced rhinovirus induced RNA helicases. Furthermore, IFNAR1 deficient mice exhibited RIG-I and MDA5 induction early during RV1B infection in an interferon independent manner. Hence anti-viral defense within bronchial epithelium requires co-ordinated recognition of rhinovirus infection, initially via TLR3/TRIF and later via inducible RNA helicases.

Low-frequency ultrasound increases non-viral gene transfer to the mouse lung.

The aim of the study was to assess if low-frequency ultrasound (US), in the range of 30-35 kHz, increases non-viral gene transfer to the mouse lung. US is greatly attenuated in the lung due to large energy losses at the air/tissue interfaces. The advantages of low-frequency US, compared with high-frequency US are: (i) increased cavitation (responsible for the formation of transient pores in the cell membrane) and (ii) reduced energy losses during lung penetration. Cationic lipid GL67/plasmid DNA (pDNA), polyethylenimine (PEI)/pDNA and naked pDNA were delivered via intranasal instillation and the animals were then exposed to US (sonoporation) at 0.07 or 0.1 MPa for 10 min. Under these conditions, US did not enhance GL67 or PEI-mediated transfection. It did, however, increase naked pDNA gene transfer by approximately 4 folds. Importantly, this was achieved in the absence of microbubbles, which are crucial for the commonly used high-frequency (1 MHz) sonoporation but may not be able to withstand nebulization in a clinically relevant setup. Lung hemorrhage was also assessed and shown to increase with US pressure in a dose-dependent manner. We have thus, established that low-frequency US can enhance lung gene transfer with naked pDNA and this enhancement is more effective than the previously reported 1 MHz US.

Decreased sputum mature dendritic cells in healthy smokers and patients with chronic obstructive pulmonary disease.

BACKGROUND: Asthmatics who smoke have decreased pulmonary mature dendritic cells (DCs). Chronic obstructive pulmonary disease (COPD) patients have an increased amount of pulmonary immature DCs. We hypothesized that healthy smokers and patients with COPD have decreased pulmonary mature DCs. METHODS: We identified sputum DCs expressing the maturation markers CD83 and DC-lysosome associated membrane protein (DC-LAMP) and DC subpopulations (i.e. myeloid and plasmacytoid DCs) by flow cytometry in healthy smokers before they entered a smoking cessation trial (n = 30), in the same smokers after 6 months of smoking cessation (n = 11) and in COPD patients (n = 28, 14 current and 14 ex-smokers). 12 healthy never-smokers served as controls. DC numbers were expressed as percentage of total sputum CD45(+) leukocytes. RESULTS: CD83(+) and DC-LAMP(+) mature DCs were decreased in healthy smokers before they ceased smoking compared to after (p = 0.003 and p = 0.049, respectively) and in smokers before smoking cessation compared to never-smokers (p = 0.027 and p = 0.028, respectively). COPD patients, both current and ex-smokers, showed decreased CD83(+) mature DCs compared to never-smokers and smokers after cessation (p = 0.042 and p = 0.004, respectively). CONCLUSIONS: Cigarette smoking and COPD per se are associated with a decrease in pulmonary mature DCs. We speculate that this reduction is involved in the immunopathogenesis of smoking-related respiratory disorders, such as COPD.

Decreased small airway and alveolar CD83+ dendritic cells in COPD.

BACKGROUND: Dendritic cells (DCs) have been reported to be increased in the small airways of patients with COPD, but the maturity status of these cells is unclear. We have quantified the numbers of cells expressing markers associated with DC maturation. METHODS: Lung tissue was obtained at resection for lung cancer from 41 patients with COPD (30 current smokers and 11 ex-smokers; 32 steroid-treated patients and 9 steroid-naïve patients), 19 ex-smokers without COPD and 9 never-smokers without COPD. Tissue sections were immunostained for CD1a to mark immature DCs, and for CD83, fascin, and DC-lysosome-associated membrane protein (DC-LAMP) to delineate mature DCs. RESULTS: The volume density (ie, the volume of DCs as the percentage volume of the airway wall) comprising CD83+ DCs was significantly reduced in patients with COPD (median, 0; range, 0 to 5.1%) vs smokers (median, 2.8%; range, 0 to 10.2%) and never-smokers (median, 1.9%; range, 0.8 to 5.1%) without COPD (p = 0.000 and 0.012, respectively). Using a semiquantitative score for the alveolar wall, CD83+ DCs also were decreased in patients with COPD (median, 0; range, 0 to 2%) vs smokers (median, 1%; range, 0 to 2%) and never-smokers (median, 1%; range, 0.7 to 2%) without COPD (p = 0.004 and 0.04, respectively). No differences were detected in CD83+ DCs between current smokers and ex-smokers with COPD or between steroid-treated and steroid-naive patients. No differences were detected in CD1a+ DCs. Fascin and DC-LAMP were found to have poor specificity for mature DCs. CONCLUSIONS: COPD is associated with decreased numbers of (mature) CD83+ DCs in small airways and alveoli. The relevance of such a reduction on pulmonary immune responses requires further investigation.

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.

Expression of blood dendritic cell antigens (BDCAs) by CD1a+ human pulmonary cells.

BACKGROUND: Myeloid and plasmacytoid dendritic cell (DC) subsets have been recently identified in the human lung based on their differential expression of Blood DC Antigens 1-3 (BDCAs). We investigated the expression of these antigens by isolated human pulmonary CD1a(+) DCs, namely Langerhan's cells. METHODS: Using an in vitro cell culture system we successfully isolated a population of relatively pure (>70%) CD1a(+) cells from human lung tissue (n=5 subject samples) and stained these with antibodies against the myeloid DC markers BDCA1 (CD1c) and BDCA3 (CD303), the plasmacytoid DC marker BDCA2 (CD141), the Langerhan's cell marker Langerin and the maturation marker CD83. RESULTS: Among different subject samples, the isolated CD1a(+) cells showed variable expression of Langerin, BDCAs and CD83. Interestingly, in two subject samples, which contained >70% CD83(+) mature CD1a(+) cells, >50% of the cells were positive for all of the BDCAs. CONCLUSIONS: We conclude that isolated pulmonary CD1a(+) DCs in vitro have the capacity to express both myeloid and plasmacytoid BDCA markers and that rather than subset restriction in pulmonary DCs, a significant degree of flexibility/plasticity can be induced, albeit experimentally.

Rhinovirus-induced lower respiratory illness is increased in asthma and related to virus load and Th1/2 cytokine and IL-10 production.

Acute exacerbations are the major cause of asthma morbidity, mortality, and health-care costs and are difficult to treat and prevent. The majority of asthma exacerbations are associated with rhinovirus (RV) infection, but evidence supporting a causal relationship is weak and mechanisms are poorly understood. We hypothesized that in asthmatic, but not normal, subjects RV infection would induce clinical, physiologic, and pathologic lower airway responses typical of an asthma exacerbation and that these changes would be related to virus replication and impaired T helper 1 (Th1)/IL-10 or augmented Th2 immune responses. We investigated physiologic, virologic, and immunopathologic responses to experimental RV infection in blood, induced sputum, and bronchial lavage in 10 asthmatic and 15 normal volunteers. RV infection induced significantly greater lower respiratory symptoms and lung function impairment and increases in bronchial hyperreactivity and eosinophilic lower airway inflammation in asthmatic compared with normal subjects. In asthmatic, but not normal, subjects virus load was significantly related to lower respiratory symptoms, bronchial hyperreactivity, and reductions in blood total and CD8(+) lymphocytes; lung function impairment was significantly related to neutrophilic and eosinophilic lower airway inflammation. The same virologic and clinical outcomes were strongly related to deficient IFN-gamma and IL-10 responses and to augmented IL-4, IL-5, and IL-13 responses. This study demonstrates increased RV-induced clinical illness severity in asthmatic compared with normal subjects, provides evidence of strong relationships between virus load, lower airway virus-induced inflammation and asthma exacerbation severity, and indicates augmented Th2 or impaired Th1 or IL-10 immunity are likely important mechanisms.

Dendritic cells in chronic obstructive pulmonary disease: new players in an old game.

Dendritic cells (DCs) are professional antigen-presenting cells responsible for immune homeostasis. In the lung's responses to tissue damage or infection, they initiate and orchestrate innate and adaptive immunity. There are immature and mature states and at least three phenotypic and functional subsets. DCs circulate in the blood and localize to mucosal surfaces in immature form where they act as sentinels, sampling constituents of the external environment that breach the epithelium. With internalization of antigen, they are activated, mature, and migrate to draining lymph nodes to induce the proliferation and regulate the balance of Th1/Th2 T cells or to induce a state of tolerance, the last dependent on maturation status, extent of cell surface costimulatory molecule expression, and cytokine release. Cigarette smoke has modulatory effects varying with species, dose, the location examined within the lung, and the marker or technique used to identify DCs. Healthy smokers (and smokers with asthma) have reduced numbers of large airway mature DCs. In chronic obstructive pulmonary disease, the number of immature DCs is increased in small airways, whereas in smokers with chronic obstructive pulmonary disease, the total number of DCs appears to be reduced in large airways. We hypothesize that the long-term effects of cigarette smoke include reduction of DC maturation and function, changes that favor repeated infection, increased exacerbation frequency, and the altered (CD8(+) T-cell predominant) pattern of inflammation associated with this progressive chronic disease.

Nasal abnormalities in cystic fibrosis mice independent of infection and inflammation.

It is not known whether the progressive airway changes in cystic fibrosis (CF) are all secondary to infection and inflammation. The CF mouse nose shares electrophysiologic and cellular properties with human CF airway epithelium. In the present work, we tested the hypothesis that structural abnormalities in the nasal mucosa of CF mice develop independent of infection and inflammation. We performed nasal lavage and subsequent serial coronal section through the nasal tissue of adult CF (mutations Cftr(TgHm1G551D) and Cftr(tm1Unc)-TgN((FABPCFTR))) and wild-type mice raised under normal housing conditions. Nasal tissue was also obtained from Day 17 embryos and newborn pups. Detailed histologic examination of the respiratory and olfactory epithelium within the nasal cavity was performed. Bacterial culture, cell count, and macrophage inflammatory protein-2 (MIP-2) concentration were assessed in nasal lavage fluid. Significantly thickened respiratory epithelium and increased mucous cell density was found in adult CF mice of both mutations compared with wild-type animals. In contrast, the olfactory epithelium was thinner, with a decreased cell density. Areas of lymphoid aggregates were found in CF mice but not in non-CF mice. There were no differences in bacterial growth, cell count, or MIP-2 concentrations. No genotype differences were observed in the embryonic or newborn periods. There are significant histologic changes in the nasal mucosa of adult CF mice, not associated with increased lumenal inflammation or bacterial content, and which are not present perinatally. These may be novel therapeutic targets.