Impaired Innate COPD Alveolar Macrophage Responses and Toll-Like Receptor-9 Polymorphisms.

BACKGROUND: Dysfunctional innate responses of alveolar macrophages to nontypeable Haemophilus influenzae, Moraxella catarrhalis and Streptococcus pneumoniae contribute to morbidity in chronic obstructive pulmonary disease (COPD). Our earlier studies discovered impaired COPD alveolar macrophage responses to Toll-like receptor (TLR) ligands of nontypeable H. influenzae and provide rationale for further evaluation of TLR signaling. While the role of TLR single nucleotide polymorphisms is increasingly recognized in inflammatory diseases, TLR single nucleotide polymorphisms in COPD have only recently been explored. We hypothesized that specific TLR polymorphisms are associated with dysfunctional innate immune COPD alveolar macrophage responses and investigated polymorphisms of TLR2(Arg753Gln), TLR4(Thr399Ile; Asp299Gly), and TLR9(T1486C; T1237C). METHODS: DNA was purified from cells of 1) healthy nonsmokers (n = 20); 2) COPD ex-smokers (n = 83); 3) COPD active smokers (n = 93). DNA amplifications (polymerase chain reaction) were performed for each SNP. Alveolar macrophages from each group were incubated with nontypeable H. influenzae, M. catarrhalis and S. pneumoniae. Cytokine induction of macrophage supernatants was measured and the association with TLR single nucleotide polymorphism expression was determined. RESULTS: No significant inter-group differences in frequency of any TLR SNP existed. However both TLR9 single nucleotide polymorphisms were expressed in high frequency. Among COPD ex-smokers, diminished IL-8 responsiveness to nontypeable H. influenzae, M. catarrhalis and S. pneumoniae was strongly associated with carriage of TLR9(T1237C) (p = 0.02; p = 0.008; p = 0.02), but not TLR9(T1486C). Carriage of TLR9(T1237C), but not TLR9(T1486C), correlated with diminished FEV1%predicted (p = 0.037). CONCLUSION: Our results demonstrate a notable association of TLR9(T1237C) expression with dysfunctional innate alveolar macrophage responses to respiratory pathogens and with severity of COPD.

IL-17A and the Promotion of Neutrophilia in Acute Exacerbation of Chronic Obstructive Pulmonary Disease.

RATIONALE: Nontypeable Haemophilus influenzae (NTHi) causes acute exacerbation of chronic obstructive pulmonary disease (AECOPD). IL-17A is central for neutrophilic inflammation and has been linked to COPD pathogenesis. OBJECTIVES: We investigated whether IL-17A is elevated in NTHi-associated AECOPD and required for NTHi-exacerbated pulmonary neutrophilia induced by cigarette smoke. METHODS: Experimental studies with cigarette smoke and NTHi infection were pursued in gene-targeted mice and using antibody intervention. IL-17A was measured in sputum collected from patients with COPD at baseline, during, and after AECOPD. MEASUREMENTS AND MAIN RESULTS: Exacerbated airway neutrophilia in cigarette smoke-exposed mice infected with NTHi was associated with an induction of IL-17A. In agreement, elevated IL-17A was observed in sputum collected during NTHi-associated AECOPD, compared with samples collected before or after the event. NTHi-exacerbated neutrophilia and induction of neutrophil chemoattractants over the background of cigarette smoke, as observed in wild-type mice, was absent in Il17a(-/-) mice and in mice treated with a neutralizing anti-IL-17A antibody. Further studies revealed that IL-1 receptor (R)1 signaling was required for IL-17A-dependent neutrophilia. Moreover, deficiency or therapeutic neutralization of IL-17A did not increase bacterial burden or delay bacterial clearance. CONCLUSIONS: IL-17A is induced during NTHi-associated AECOPD. Functionally, IL-1R1-dependent IL-17A is required for NTHi-exacerbated pulmonary neutrophilia induced by cigarette smoke. Targeting IL-17A in AECOPD may thus be beneficial to reduce neutrophil recruitment to the airways.

Bacterial colonization increases daily symptoms in patients with chronic obstructive pulmonary disease.

RATIONALE: Respiratory pathogens are frequently isolated from the airways of patients with chronic obstructive pulmonary disease (COPD) in the absence of an exacerbation. This bacterial "colonization" by potential pathogens is associated with host inflammatory and immune responses, which could increase respiratory symptoms. OBJECTIVES: To study whether bacterial colonization impacts daily respiratory symptoms in COPD. METHODS: In a longitudinal prospective observational study of COPD, patients recorded daily symptoms electronically on the Breathlessness, Cough, and Sputum Scale (BCSS). Sputum cultures and quantitative polymerase chain reaction (PCR) were performed every 2 weeks. The relationship of BCSS and bacterial colonization was analyzed with generalized linear mixed effects models, after controlling for exacerbations, weather conditions, lung function, and demographic variables. MEASUREMENTS AND MAIN RESULTS: A total of 41 patients recorded daily symptoms for 12,527 days. The average BCSS score was higher during the periods of colonization, determined by sputum culture with one or more of the following pathogens: nontypeable Haemophilus influenzae, Moraxella catarrhalis, Streptococcus pneumoniae, and Pseudomonas aeruginosa, compared to periods without colonization (5.28 vs. 4.46; P = 0.008) after controlling for confounding variables. The finding did not change when colonization was defined by quantitative PCR (average BCSS, 4.77 vs. 4.25; P = 0.006). Sputum IL-8 levels were elevated with bacterial colonization. CONCLUSIONS: Even in the absence of clinical exacerbation, colonization by bacterial pathogens in COPD was associated with a clinically significant moderate increase in daily symptoms, likely mediated by increased airway inflammation. Novel therapies that decrease bacterial colonization in COPD could improve daily symptoms and quality of life.

Moraxella catarrhalis acquisition, airway inflammation and protease-antiprotease balance in chronic obstructive pulmonary disease.

BACKGROUND: Moraxella catarrhalis causes approximately 10% of exacerbations in chronic obstructive pulmonary disease (COPD) and also colonizes the lower airway in stable patients. Little is known about the effects of colonization by M. catarrhalis on airway inflammation and protease-antiprotease balance, and how these changes compare to those seen during exacerbations. Since COPD is a progressive inflammatory disease, elucidating the effects of bacterial colonization and exacerbation on airway inflammation is relevant to understanding disease progression in COPD. Our aims were (1) Analyze changes in airway inflammation in colonization and exacerbation of COPD due to M. catarrhalis; (2) Explore protease-antiprotease balance in colonization and exacerbation due to M. catarrhalis. Our hypothesis were (1) Acquisition of a new strain of M. catarrhalis in COPD increases airway inflammation from baseline and alters the protease-antiprotease balance towards a more proteolytic environment; (2) These changes are greater during exacerbations associated with M. catarrhalis as compared to colonization. METHODS: Thirty-nine consecutive COPD patients with 76 acquisitions of a new strain of M. catarrhalis over a 6-year period were identified in a prospective study. Seventy-six pre-acquisition sputum supernatant samples, obtained just before acquisition of M catarrhalis, and 76 acquisition samples (34 were associated with exacerbation, 42 with colonization) were analyzed for IL-8, TNF-alpha, Neutrophil Elastase (NE) and Secretory leukocyte protease inhibitor (SLPI). Changes were compared in paired samples from each patient. RESULTS: IL-8, TNF-alpha and NE were significantly elevated after acquisition of M. catarrhalis, compared to pre-acquisition samples (p =< 0.001 for all three). These changes were present in colonization (p = 0.015 for IL-8; p =< 0.001 for TNF-alpha and NE) as well as in exacerbation (p =< 0.001 for all three), compared to pre-acquisition levels. SLPI was significantly lower after acquisition (p =< 0.001), in colonization (p =< 0.001) as well as in exacerbation (p = 0.004), compared to pre-acquisition levels. SLPI levels correlated negatively with NE levels (R2 = 0.07; p = 0.001). CONCLUSION: Acquisition of M. catarrhalis in COPD causes increased airway inflammation and worsening protease-antiprotease imbalance during exacerbations and also in colonization, even in the absence of increased symptoms. These effects could contribute to progression of airway disease in COPD.

Inflammatory profile of new bacterial strain exacerbations of chronic obstructive pulmonary disease.

RATIONALE: Whether the airway and systemic inflammatory profile in bacterial exacerbations of chronic obstructive pulmonary disease (COPD) is distinct from nonbacterial exacerbations is unclear. Previous studies have not used molecular typing of bacterial pathogens, which is required to accurately define bacterial infection in COPD. The relationship between clinical severity and course of exacerbation and inflammation is also not fully understood. OBJECTIVES: To determine if (1) systemic and airway inflammation is distinct in new bacterial strain exacerbations and (2) clinical severity and resolution of exacerbations is related to airway and systemic inflammation. METHODS: In a prospective longitudinal cohort study in COPD, sputum and serum samples obtained before, at, and following exacerbations during a 2-year period were studied. MEASUREMENTS AND MAIN RESULTS: Clinical information, molecular typing of bacterial pathogens, sputum IL-8, tumor necrosis factor (TNF)-alpha and neutrophil elastase, and serum C-reactive protein. From 46 patients, 177 exacerbations were grouped as new strain, preexisting strain, other pathogen, and pathogen negative. New strain exacerbations were associated with significantly greater increases from baseline in sputum TNF-alpha and neutrophil elastase, and in serum C-reactive protein compared with the other three groups. Increases in inflammatory markers were similar among the other three groups. Clinical resolution was accompanied by resolution of inflammation to preexacerbation levels, whereas persistent symptoms were paralleled by persistently elevated inflammation. Clinical exacerbation severity was significantly correlated with levels of all four markers. CONCLUSIONS: Neutrophilic airway inflammation and systemic inflammation are more intense with well-defined bacterial exacerbations than with nonbacterial exacerbations. Clinical course of exacerbation and inflammation are closely linked.

Impaired alveolar macrophage response to Haemophilus antigens in chronic obstructive lung disease.

RATIONALE: Interactions of nontypeable Haemophilus influenzae (NTHI) with macrophages are implicated in the pathogenesis of chronic obstructive pulmonary disease (COPD). However, the immunologic mechanisms that mediate NTHI-macrophage inflammation are poorly understood. Outer membrane protein (OMP) P6 and lipooligosaccharide (LOS) of NTHI are potent immunomodulators. We theorized that alveolar macrophages in COPD possess fundamental immune defects that permit NTHI to evade host responses. OBJECTIVE: To test this hypothesis, we obtained human alveolar and blood macrophages from exsmokers with COPD, exsmokers without COPD, and nonsmokers. METHODS: Alveolar and blood macrophages from each donor were incubated with purified LOS and OMP P6 and with OMP P2 and the total outer membrane preparation (0.1-1 microg/ml). MEASUREMENTS: Supernatants (24 h) were assayed for IL-1beta, TNF-alpha, IL-10, IL-12, and IL-8 by multianalyte multiplexed flow cytometry. RESULTS: Comparative induction of COPD and non-COPD alveolar macrophages by LOS and OMP P6 revealed diminished IL-8, TNF-alpha, and IL-1beta responses of COPD alveolar macrophages (p < or = 0.03 for each). COPD alveolar macrophages also had diminished responses to total outer membrane (p < or = 0.03 for each). In contrast, COPD blood macrophages had no significant differences among donor groups in IL-8, TNF-alpha, or IL-1beta responsiveness to NTHI antigens. Diminished IL-12 responses of COPD blood macrophages to NTHI antigens, compared with nonsmokers, could not be independently dissociated from group differences in age and pack-years. CONCLUSIONS: These findings support a paradigm of defective immune responsiveness of alveolar macrophages, but not blood macrophages, in COPD.

Airway inflammation and bronchial bacterial colonization in chronic obstructive pulmonary disease.

RATIONALE: Inflammation is now recognized as an integral part of the pathogenesis of chronic obstructive pulmonary disease (COPD). In contrast to the sterile airways of normal lungs, bacterial pathogens are often isolated from the airways in stable COPD. This "colonization" of the tracheobronchial tree, currently believed to be innocuous, could serve as an inflammatory stimulus, independent of current tobacco smoke exposure. OBJECTIVE: To test the hypothesis that bacterial colonization is associated with airway inflammation in stable COPD. METHODS: Bronchoscopy with bronchoalveolar lavage (BAL) was performed in three groups of subjects: 26 ex-smokers with stable COPD (COPD), 20 ex-smokers without COPD (ex-smokers), and 15 healthy nonsmokers (nonsmokers). Quantitative bacterial cultures, cell counts, chemokine, cytokine, proteinase/antiproteinase, and endotoxin levels in the BAL fluid were compared. RESULTS: Potentially pathogenic bacteria were recovered at > or = 100 cfu/ml in 34.6% of COPD, 0% of ex-smokers, and in 6.7% of nonsmokers (p = 0.003). All values are expressed as median (interquartile range). Subjects with colonized COPD had significantly greater relative (12.0 [28.4] vs. 3.0 [7.8]%, p = 0.03) and absolute (4.98 [5.26] x 10(4)/ml vs. 3.04 [2.82] x 10(4)/ml, p = 0.02) neutrophil counts, interleukin 8 (33.8 [189.8] vs. 16.9 [20.1] pg/ml, p = 0.005), active matrix metalloproteinase-9 (2.16 [4.30] vs. 0.84 [0.99] U/ml, p = 0.03), and endotoxin (36.0 [72.6] vs. 3.55 [7.17] mEU/ml, p = 0.004) levels in the BAL than the subjects with noncolonized COPD. These inflammatory constituents of BAL were also significantly elevated in subjects with colonized COPD when compared with ex-smokers and nonsmokers. CONCLUSIONS: Bacterial colonization is associated with neutrophilic airway lumen inflammation in ex-smokers with COPD and could contribute to progression of airway disease in COPD.

Outer membrane protein P6 of nontypeable Haemophilus influenzae is a potent and selective inducer of human macrophage proinflammatory cytokines.

Interactions of nontypeable Haemophilus influenzae (NTHI) with human macrophages contribute to the pathogenesis of NTHI-induced infection in humans. However, the immunologic mechanisms that initiate and perpetuate NTHI-mediated macrophage responses have not been well explored. Outer membrane protein (OMP) P6 is a conserved lipoprotein expressed by NTHI in vivo that possesses a Pam(3)Cys terminal motif, characteristic of immunoactive bacterial lipoproteins associated with Toll-like receptor signaling. We theorized that OMP P6 is a potent immunomodulator of human macrophages. To test this hypothesis, we purified OMP P6 as well as OMP P2, the predominant NTHI outer membrane protein, and lipooligosaccharide (LOS), the specific endotoxin of NTHI, from NTHI strain 1479. Human blood monocyte-derived macrophages, purified from healthy donors, were incubated with each outer membrane constituent, and cytokine production of macrophage supernatants interleukin-1beta (IL-1beta), tumor necrosis factor alpha (TNF-alpha), IL-10, IL-12, and IL-8 was measured. OMP P6 selectively upregulated IL-10, TNF-alpha, and IL-8. While OMP P6 (0.1 mug/ml for 8 h) elicited slightly greater concentrations of IL-10, it resulted in over ninefold greater concentrations of TNF-alpha and over fourfold greater concentrations of IL-8 than did OMP P2. OMP P6 at doses as low as 10 pg/ml was still effective at induction of macrophage IL-8, while OMP P2 and LOS were not. OMP P6 of NTHI is a specific trigger of bacteria-induced human macrophage inflammatory events, with IL-8 and TNF-alpha as key effectors of P6-induced macrophage responses.

Strain-specific immune response to Haemophilus influenzae in chronic obstructive pulmonary disease.

Previous studies of immune response to Haemophilus influenzae after exacerbations of chronic obstructive pulmonary disease (COPD) have yielded contradictory results. Using homologous (infecting) strains and immunoassays to surface-exposed epitopes, we tested the hypothesis that adults with COPD make new antibodies to strain-specific, surface-exposed epitopes on H. influenzae after exacerbations. We collected clinical information, sputum, and serum monthly and during exacerbations from 81 patients with COPD over 56 months. Serum antibodies to H. influenzae after exacerbations associated with H. influenzae in sputum were detected with whole bacterial cell ELISA and bactericidal assays. An immune response to homologous H. influenzae occurred after 22 of 36 (61.1%) exacerbations with newly acquired strains compared with 7 of 33 (21.2%) exacerbations with preexisting strains (odds ratio [OR] = 4.4; 95%, 1.8 to 10.8; p = 0.001). An absence of an immune response was strongly associated with complement sensitivity (OR = 0.03; 95% confidence interval, 0.003 to 0.22; p = 0.001). New bactericidal antibodies developed after exacerbations were highly strain specific, showing bactericidal activity for only 11 of 90 (12.2%) heterologous strains. Development of an immune response to H. influenzae supports its role in causing exacerbations. The strain specificity of the immune response likely represents a mechanism of recurrent exacerbations.