Idiopathic pulmonary fibrosis (IPF) is characterized by progressive deposition of extracellular matrix, worsening dyspnea, and eventual mortality. Pathogenesis of IPF is poorly understood and the role inflammation and activated leukocytes play in the disease process is controversial. Previous studies demonstrated that activated leukocyte subsets characterize IPF patients. We sought to validate this observation in a well-defined cohort of 35 IPF patients and to correlate the observed leukocyte phenotypes with robust parameters of disease progression. We demonstrate that in univariate and multivariate analyses, increases in the CD14hi, CD16hi subset of monocytes measured at baseline correlated with disease progression, with a threshold value >0.5% of the total peripheral blood mononuclear cells being a significant predictor for worse outcome. In addition, several T cell subsets, including CD25 expressing CD4 cells, and CXCR3 expressing CD4 and CD8 subsets correlated with disease progression when found in increased percentages in the peripheral blood of IPF patients when sampled at baseline. Somewhat surprising in comparison to previous literature, the CD4 T cells did not appear to have lost expression of the co-stimulatory molecule, CD28, but the CD8 T cells did. Taken together, these results are consistent with the presence of an inflammatory process in IPF patients who eventually progress. However, when longitudinal measurements of these same markers were examined, there was significant heterogeneity of expression and these biomarkers did not necessarily remain elevated in IPF patients with progressive disease. We interpret this heterogeneity to suggest that IPF patients experience episodic inflammatory events that once triggered, may lead to disease progression. This longitudinal heterogeneity in biomarker analyses may explain why such markers are not consistently measured in all IPF cohorts.
lung; lymphocyte; monocyte; interstitial lung disease; peripheral blood
Culture-independent microbiological techniques have revealed a previously unappreciated complexity to the bacterial microbiome of the respiratory tract, forcing reconsideration of the interactions between host, bacteria and the pathogenesis of exacerbations of chronic lung disease. The composition of the lung microbiome is determined by microbial immigration, elimination, and the relative growth rates of its members; all of these change dramatically in chronic lung disease and further during exacerbations. Exacerbations lack key features of bacterial infections, including increased bacterial burden and decreased community diversity. We propose instead that exacerbations are occasions of respiratory dysbiosis: a disordered respiratory microbial ecosystem with negative effects on host biology. Respiratory dysbiosis provokes a dysregulated host immune response, which in turn alters microbial growth conditions in patient airways, further promoting dysbiosis and perpetuating a coupled cycle of inflammation and disordered microbiota. Differences in baseline respiratory microbiota may help explain the “frequent-exacerbator” phenotype observed across multiple disease states, and may provide novel targets for therapeutic intervention.
The median survival of patients with idiopathic pulmonary fibrosis (IPF) continues to be approximately 3 years from the time of diagnosis, underscoring the lack of effective medical therapies for this disease. In the United States alone, approximately 40,000 patients die of this disease annually. In November 2012, the NHLBI held a workshop aimed at coordinating research efforts and accelerating the development of IPF therapies. Basic, translational, and clinical researchers gathered with representatives from the NHLBI, patient advocacy groups, pharmaceutical companies, and the U.S. Food and Drug Administration to review the current state of IPF research and identify priority areas, opportunities for collaborations, and directions for future research. The workshop was organized into groups that were tasked with assessing and making recommendations to promote progress in one of the following six critical areas of research: (1) biology of alveolar epithelial injury and aberrant repair; (2) role of extracellular matrix; (3) preclinical modeling; (4) role of inflammation and immunity; (5) genetic, epigenetic, and environmental determinants; (6) translation of discoveries into diagnostics and therapeutics. The workshop recommendations provide a basis for directing future research and strategic planning by scientific, professional, and patient communities and the NHLBI.
idiopathic pulmonary fibrosis; alveolar epithelial cells; extracellular matrix; interstitial lung disease; inflammation
N-acetylcysteine (NAC) has been suggested as a beneficial treatment for idiopathic pulmonary fibrosis (IPF). A placebo-controlled study of this agent administrated orally alone in an IPF population has not been conducted.
An initially designed three-arm randomized, double-blind, placebo-controlled trial of prednisone plus azathioprine plus NAC (three-drug regimen) versus NAC versus placebo in IPF patients with mild-moderate impairment in pulmonary function was interrupted due to safety concerns associated with the three-drug regimen. The trial continued as a two-arm design (NAC vs. placebo) without other changes and enrolled 133 and 131 patients in the NAC and placebo arms, respectively. The primary outcome measure was the change in forced vital capacity (FVC) over a 60-week period.
Over the 60-week treatment period, there was no difference between the NAC and placebo groups in the decline of FVC (60-week change of −0.18 liters for NAC vs. −0.19 liters for placebo, p=0.77). In addition, there were no significant differences between NAC and placebo for mortality (6 [4.9%] vs. 3 [2.5%] events, p=0.50) or acute exacerbation (3 [2.3%] vs. 3 [2.3%] events, p>0.99).
Compared to placebo NAC offered no benefit for the preservation of FVC in IPF patients with mild-to-moderate physiological abnormalities.
Recent studies have revealed that bronchoalveolar lavage (BAL) fluid contains previously unappreciated communities of bacteria. In vitro and in vivo studies have shown that host inflammatory signals prompt bacteria to disperse from cell-associated biofilms and adopt a virulent free-living phenotype. The proportion of the lung microbiota that is cell-associated is unknown.
Forty-six BAL specimens were obtained from lung transplant recipients and divided into two aliquots: ‘whole BAL’ and ‘acellular BAL,’ the latter processed with a low-speed, short-duration centrifugation step. Both aliquots were analyzed via bacterial 16S rRNA gene pyrosequencing. The BAL specimens represented a wide spectrum of lung health, ranging from healthy and asymptomatic to acutely infected. Bacterial signal was detected in 52% of acellular BAL aliquots, fewer than were detected in whole BAL (96%, p ≤ 0.0001). Detection of bacteria in acellular BAL was associated with indices of acute infection [BAL neutrophilia, high total bacterial (16S) DNA, low community diversity, p < 0.01 for all] and, independently, with low relative abundance of specific taxonomic groups (p < 0.05). When whole and acellular aliquots from the same bronchoscopy were directly compared, acellular BAL contained fewer bacterial species (p < 0.05); whole and acellular BAL similarity was positively associated with evidence of infection and negatively associated with relative abundance of several prominent taxa (p < 0.001). Acellular BAL contained decreased relative abundance of Prevotella spp. (p < 0.05) and Pseudomonas fluorescens (p < 0.05).
We present a novel methodological and analytical approach to the localization of lung microbiota and show that prominent members of the lung microbiome are cell-associated, potentially via biofilms, cell adhesion, or intracellularity.
Lung microbiome; Bronchoalveolar lavage; 16S; Pyrosequencing; Pneumonia
CD56+ natural killer (NK) and CD56+ T cells, from sputum or bronchoalveolar lavage of subjects with chronic obstructive pulmonary disease (COPD) are more cytotoxic to highly susceptible NK targets than those from control subjects. Whether the same is true in lung parenchyma, and if NK activity actually contributes to emphysema progression are unknown. To address these questions, we performed two types of experiments on lung tissue from clinically-indicated resections (n = 60). First, we used flow cytometry on fresh single-cell suspension to measure expression of cell-surface molecules (CD56, CD16, CD8, NKG2D and NKp44) on lung lymphocytes and of the 6D4 epitope common to MICA and MICB on lung epithelial (CD326+) cells. Second, we sequentially isolated CD56+, CD8+ and CD4+ lung lymphocytes, co-cultured each with autologous lung target cells, then determined apoptosis of individual target cells using Annexin-V and 7-AAD staining. Lung NK cells (CD56+ CD3−) and CD56+ T cells (CD56+ CD3+) were present in a range of frequencies that did not differ significantly between smokers without COPD and subjects with COPD. Lung NK cells had a predominantly “cytotoxic” CD56+ CD16+ phenotype; their co-expression of CD8 was common, but the percentage expressing CD8 fell as FEV1 % predicted decreased. Greater expression by autologous lung epithelial cells of the NKG2D ligands, MICA/MICB, but not expression by lung CD56+ cells of the activating receptor NKG2D, correlated inversely with FEV1 % predicted. Lung CD56+ lymphocytes, but not CD4+ or CD8+ conventional lung T cells, rapidly killed autologous lung cells without additional stimulation. Such natural cytotoxicity was increased in subjects with severe COPD and was unexplained in multiple regression analysis by age or cancer as indication for surgery. These data show that as spirometry worsens in COPD, CD56+ lung lymphocytes exhibit spontaneous cytotoxicity of autologous structural lung cells, supporting their potential role in emphysema progression.
The 2011 Global Strategy for the Diagnosis, Management, and Prevention of COPD (GOLD) consensus report uses symptoms, exacerbation history and FEV1% to define four categories: A, low symptoms/low risk; B, high symptoms/low risk; C, low symptoms/high risk; and D, high symptoms/high risk where risk refers to exacerbations, hospitalization and death. Our objective was to determine (1) the influence of symptom instrument on category membership and (2) prospective exacerbation risk by category.
4,484 COPD subjects from COPDGene were analyzed. All subjects had smoking history ≥ 10 pack-years and FEV1/FVC<0·7. Categories were defined using the modified Medical Research Council Dyspnea [mMRC] (0–1 versus ≥ 2) and the Saint George’s Respiratory Questionnaire [SGRQ] (≥25 versus <25 as a surrogate for the COPD Assessment Test ≥ 10 versus <10) in addition to COPD exacerbations in the prior year (<2 versus ≥ 2), and FEV1% predicted (≥50 versus <50).
Category assignment using mMRC versus SGRQ were similar but not identical. Using the mMRC, category assignments were 34% A, 21% B, 8% C and 38% D and for SGRQ were 29% A, 25% B, 5% C and 41% D (kappa=0·77). Significant heterogeneity in exacerbation rates (exacerbations/person-year) were seen particularly within the D group, depending on the risk factor that determined category assignment (lung function (0·89), prior exacerbation history (1·34) or both (1·86), p<0·001.
The GOLD classification emphasizes the importance of symptoms and exacerbation risk in assessing COPD severity. The choice of symptom measure influences category assignment. The relative number of subjects with low symptoms and high risk for exacerbations (category C) is low. Differences in exacerbation rates for subjects in the highest risk category D were seen depending on whether risk was based on lung function, exacerbation history or both.
Lung CD8+ T cells might contribute to progression of chronic obstructive
pulmonary disease (COPD) indirectly via IFN-γ production or directly via cytolysis
but evidence for either mechanism is largely circumstantial. To gain insights into these
potential mechanisms, we analyzed clinically-indicated lung resections from three human
cohorts, correlating findings with spirometrically-defined disease severity. Expression by
lung CD8+ T cells of IL-18R and CD69 correlated with severity, as did mRNA transcripts for
perforin and granzyme B, but not Fas ligand. These correlations persisted after correction
for age, smoking history, presence of lung cancer, recent respiratory infection, or
inhaled corticosteroid use. Analysis of transcripts for KLRG1, IL-7 receptor and CD57
implied that lung CD8+ T cells in COPD do not belong to the terminally-differentiated
effector populations associated with chronic infections or extreme age. In vitro
stimulation of lung CD8+ T cells with IL-18 plus IL-12 markedly increased production of
IFN-γ and TNF-α, whereas IL-15 stimulation induced increased intracellular
perforin expression. Both IL-15 and IL-18 protein expression could be measured in whole
lung tissue homogenates, but neither correlated in concentration with spirometric
severity. Although lung CD8+ T cell expression of mRNA for both T-bet and GATA-3 (but not
ROR-γ or ROR–α) increased with spirometric severity, stimulation
of lung CD8+ T cells via CD3ε induced secretion of IFN-γ, TNF-α
and GM-CSF, but not IL-5, IL-13, IL-17A. These findings suggest that the production of
pro-inflammatory cytokines and cytotoxic molecules by lung resident CD8+ T cells
contributes to COPD pathogenesis.
The composite physiologic index(CPI) was derived to represent the extent of fibrosis on high resolution computed tomography, adjusting for emphysema in patients with idiopathic pulmonary fibrosis(IPF). We hypothesized longitudinal change in CPI would better predict mortality than forced expiratory volume in 1 second(FEV1), forced vital capacity(FVC), or diffusing capacity for carbon monoxide(DLCO) in all patients with IPF, and especially in those with combined pulmonary fibrosis and emphysema(CPFE).
Cox proportional hazard models were performed on pulmonary function data from IPF patients at baseline (n=321), 6 months (n=211) and 12 months (n=144). Presence of CPFE was determined by high resolution computed tomography.
A 5 point increase in CPI over 12 months predicted subsequent mortality (HR 2.1, p=0.004). At 12 months, a 10% relative decline in FVC, a 15% relative decline in DLCO or an absolute increase in CPI of 5 points all discriminated median survival by 2.1 to 2.2 years versus patients with lesser change. Half our cohort had CPFE. In patients with moderate/severe emphysema, only a 10% decline in FEV1 predicted mortality (HR 3.7, p=0.046).
In IPF, a 5 point increase in CPI over 12 months predicts mortality similarly to relative declines of 10% in FVC or 15% in DLCO. For CPFE patients, change in FEV1 was the best predictor of mortality.
Chronic Obstructive Pulmonary Disease; Idiopathic Pulmonary Fibrosis; Prognosis; Pulmonary Function; Survival
Abnormal acid gastroesophageal reflux is common in idiopathic pulmonary fibrosis and is considered a risk factor for its development. Retrospective studies have suggested improved outcomes in patients treated with anti-acid therapy. The aim of this study was to determine the association between anti-acid therapy and disease progression in idiopathic pulmonary fibrosis.
Patients with IPF were identified from the placebo arms of the three IPFnet randomized clinical trials. Case report forms were designed to prospectively capture data regarding gastroesophageal reflux diagnosis and treatment. These data were analyzed to determine the relationship between use of anti-acid therapy (i.e. proton pump inhibitors and histamine-2 blockers) and change in forced vital capacity using a longitudinal repeated-measures model. Secondary outcomes analyzed included acute exacerbation, all-cause hospitalization, and all-cause mortality.
Two hundred and forty-two patients with idiopathic pulmonary fibrosis were randomized to receive placebo therapy. Fifty-one percent were taking anti-acid therapy upon enrollment. There were no significant differences in demographics and pulmonary physiology between patients taking and not taking anti-acid therapy. After adjustment for sex, baseline forced vital capacity %predicted, and baseline diffusing capacity for carbon monoxide %predicted, patients taking anti-acid therapy at baseline had a slower decline in forced vital capacity (estimated change over 30-weeks of -0.06 liters vs. -0.12 liters, p-value = 0.05). Patients taking anti-acid therapy at baseline had fewer acute exacerbations (no events versus nine events, p-value <0.01) during the study period.
The use of anti-acid therapy was associated with a slower decline in forced vital capacity over time and fewer acute exacerbations in patients with idiopathic pulmonary fibrosis. These findings support the hypothesis that abnormal acid gastroesophageal reflux contributes to disease progression and suggest that anti-acid therapy may be beneficial in patients with idiopathic pulmonary fibrosis.
The coexistence of gastroesophageal reflux disease (GERD) and COPD has been recognized, but there has been no comprehensive evaluation of the impact of GERD on COPD-related health status and patient-centered outcomes.
Cross-sectional and longitudinal study of 4,483 participants in the COPDGene cohort who met GOLD criteria for COPD. Physician-diagnosed GERD was ascertained by questionnaire. Clinical features, spirometry and imaging were compared between COPD subjects without versus with GERD. We evaluated the relationship between GERD and symptoms, exacerbations and markers of microaspiration in univariate and multivariate models. Associations were additionally tested for the confounding effect of covariates associated with a diagnosis of GERD and the use of proton-pump inhibitor medications (PPIs). To determine whether GERD is simply a marker for the presence of other conditions independently associated with worse COPD outcomes, we also tested models incorporating a GERD propensity score.
GERD was reported by 29% of subjects with female predominance. Subjects with GERD were more likely to have chronic bronchitis symptoms, higher prevalence of prior cardiovascular events (combined myocardial infarction, coronary artery disease and stroke 21.3% vs. 13.4.0%, p < 0.0001). Subjects with GERD also had more severe dyspnea (MMRC score 2.2 vs. 1.8, p < 0.0001), and poorer quality of life (QOL) scores (St. George’s Respiratory Questionnaire (SGRQ) total score 41.8 vs. 34.9, p < 0.0001; SF36 Physical Component Score 38.2 vs. 41.4, p < 0.0001). In multivariate models, a significant relationship was detected between GERD and SGRQ (3.4 points difference, p < 0.001) and frequent exacerbations at baseline (≥2 exacerbation per annum at inclusion OR 1.40, p = 0.006). During a mean follow-up time of two years, GERD was also associated with frequent (≥2/year exacerbations OR 1.40, p = 0.006), even in models in which PPIs, GERD-PPI interactions and a GERD propensity score were included. PPI use was associated with frequent exacerbator phenotype, but did not meaningfully influence the GERD-exacerbation association.
In COPD the presence of physician-diagnosed GERD is associated with increased symptoms, poorer QOL and increased frequency of exacerbations at baseline and during follow-up. These associations are maintained after controlling for PPI use. The PPI-exacerbations association could result from confounding-by-indication.
COPD; Gastroesophageal reflux; Comorbidity; Exacerbations; Quality-of-life; Chronic bronchitis
Idiopathic pulmonary fibrosis (IPF) is a devastating disease that probably involves several genetic loci. Several rare genetic variants and one common single nucleotide polymorphism (SNP) of MUC5B have been associated with the disease. Our aim was to identify additional common variants associated with susceptibility and ultimately mortality in IPF.
First, we did a three-stage genome-wide association study (GWAS): stage one was a discovery GWAS; and stages two and three were independent case-control studies. DNA samples from European-American patients with IPF meeting standard criteria were obtained from several US centres for each stage. Data for European-American control individuals for stage one were gathered from the database of genotypes and phenotypes; additional control individuals were recruited at the University of Pittsburgh to increase the number. For controls in stages two and three, we gathered data for additional sex-matched European-American control individuals who had been recruited in another study. DNA samples from patients and from control individuals were genotyped to identify SNPs associated with IPF. SNPs identified in stage one were carried forward to stage two, and those that achieved genome-wide significance (p<5 × 10−8) in a meta-analysis were carried forward to stage three. Three case series with follow-up data were selected from stages one and two of the GWAS using samples with follow-up data. Mortality analyses were done in these case series to assess the SNPs associated with IPF that had achieved genome-wide significance in the meta-analysis of stages one and two. Finally, we obtained gene-expression profiling data for lungs of patients with IPF from the Lung Genomics Research Consortium and analysed correlation with SNP genotypes.
In stage one of the GWAS (542 patients with IPF, 542 control individuals matched one-by-one to cases by genetic ancestry estimates), we identified 20 loci. Six SNPs reached genome-wide significance in stage two (544 patients, 687 control individuals): three TOLLIP SNPs (rs111521887, rs5743894, rs5743890) and one MUC5B SNP (rs35705950) at 11p15.5; one MDGA2 SNP (rs7144383) at 14q21.3; and one SPPL2C SNP (rs17690703) at 17q21.31. Stage three (324 patients, 702 control individuals) confirmed the associations for all these SNPs, except for rs7144383. Linkage disequilibrium between the MUC5B SNP (rs35705950) and TOLLIP SNPs (rs111521887 [r2=0.07], rs5743894 [r2=0.16], and rs5743890 [r2=0.01]) was low. 683 patients from the GWAS were included in the mortality analysis. Individuals who developed IPF despite having the protective TOLLIP minor allele of rs5743890 carried an increased mortality risk (meta-analysis with fixed-effect model: hazard ratio 1.72 [95% CI 1.24–2.38]; p=0.0012). TOLLIP expression was decreased by 20% in individuals carrying the minor allele of rs5743890 (p=0.097), 40% in those with the minor allele of rs111521887 (p=3.0 × 10−4), and 50% in those with the minor allele of rs5743894 (p=2.93 × 10−5) compared with homozygous carriers of common alleles for these SNPs.
Novel variants in TOLLIP and SPPL2C are associated with IPF susceptibility. One novel variant of TOLLIP, rs5743890, is also associated with mortality. These associations and the reduced expression of TOLLIP in patients with IPF who carry TOLLIP SNPs emphasise the importance of this gene in the disease.
National Institutes of Health; National Heart, Lung, and Blood Institute; Pulmonary Fibrosis Foundation; Coalition for Pulmonary Fibrosis; and Instituto de Salud Carlos III.
Rationale: The predictive value of longitudinal change in BODE (Body mass index, airflow Obstruction, Dyspnea, and Exercise capacity) index has received limited attention. We hypothesized that decrease in a modified BODE (mBODE) would predict survival in National Emphysema Treatment Trial (NETT) patients.
Objectives: To determine how the mBODE score changes in patients with lung volume reduction surgery versus medical therapy and correlations with survival.
Methods: Clinical data were recorded using standardized instruments. The mBODE was calculated and patient-specific mBODE trajectories during 6, 12, and 24 months of follow-up were estimated using separate regressions for each patient. Patients were classified as having decreasing, stable, increasing, or missing mBODE based on their absolute change from baseline. The predictive ability of mBODE change on survival was assessed using multivariate Cox regression models. The index of concordance was used to directly compare the predictive ability of mBODE and its separate components.
Measurements and Main Results: The entire cohort (610 treated medically and 608 treated surgically) was characterized by severe airflow obstruction, moderate breathlessness, and increased mBODE at baseline. A wide distribution of change in mBODE was seen at follow-up. An increase in mBODE of more than 1 point was associated with increased mortality in surgically and medically treated patients. Surgically treated patients were less likely to experience death or an increase greater than 1 in mBODE. Indices of concordance showed that mBODE change predicted survival better than its separate components.
Conclusions: The mBODE demonstrates short- and intermediate-term responsiveness to intervention in severe chronic obstructive pulmonary disease. Increase in mBODE of more than 1 point from baseline to 6, 12, and 24 months of follow-up was predictive of subsequent mortality. Change in mBODE may prove a good surrogate measure of survival in therapeutic trials in severe chronic obstructive pulmonary disease.
Clinical trial registered with www.clinicaltrials.gov (NCT 00000606).
chronic obstructive pulmonary disease; survival; multidimensional index
Multiple independent culture-based studies have identified the presence of Pseudomonas aeruginosa in respiratory samples as a positive risk factor for bronchiolitis obliterans syndrome (BOS). Yet, culture-independent microbiological techniques have identified a negative association between Pseudomonas species and BOS. Our objective was to investigate whether there may be a unifying explanation for these apparently dichotomous results.
We performed bronchoscopies with bronchoalveolar lavage (BAL) on lung transplant recipients (46 procedures in 33 patients) and 26 non-transplant control subjects. We analyzed bacterial communities in the BAL fluid using qPCR and pyrosequencing of 16S rRNA gene amplicons and compared the culture-independent data with the clinical metadata and culture results from these subjects.
Route of bronchoscopy (via nose or via mouth) was not associated with changes in BAL microbiota (p = 0.90). Among the subjects with positive Pseudomonas bacterial culture, P. aeruginosa was also identified by culture-independent methods. In contrast, a distinct Pseudomonas species, P. fluorescens, was often identified in asymptomatic transplant subjects by pyrosequencing but not detected via standard bacterial culture. The subject populations harboring these two distinct pseudomonads differed significantly with respect to associated symptoms, BAL neutrophilia, bacterial DNA burden and microbial diversity. Despite notable differences in culturability, a global database search of UM Hospital Clinical Microbiology Laboratory records indicated that P. fluorescens is commonly isolated from respiratory specimens.
We have reported for the first time that two prominent and distinct Pseudomonas species (P. fluorescens and P. aeruginosa) exist within the post-transplant lung microbiome, each with unique genomic and microbiologic features and widely divergent clinical associations, including presence during acute infection.
Chronic obstructive pulmonary disease (COPD) is a progressive disease with studies of disease progression generally focusing on measures of airflow and mortality. In nonsmokers, maximal lung function is attained around age 15 to 25 years, and after a variable plateau phase, subsequently declines at approximately 20 to 25 ml/year. Smoking may reduce the maximal FEV1 achieved, shorten or eliminate the plateau phase, and may accelerate the rate of decline in lung function in a dose-dependent manner. Some smokers are predisposed to more rapid declines in lung function than others, and recent reports suggest that females may be at higher risk of lung damage related to smoke exposure than males. Progressive deterioration in dyspnea, functional status, and health-related quality of life (HRQL) in patients with COPD is well known, but the magnitude and rate of decline and its association with severity of airflow obstruction remains poorly defined. Many studies have identified pulmonary function, in particular the FEV1, as the single best predictor of survival. An impaired diffusing capacity and overall impairment in functional status have also been associated with impaired survival in COPD. The National Emphysema Treatment Trial has provided additional insight into these features in a large, well-characterized group of patients with severe airflow obstruction and structural emphysema.
emphysema; natural history; survival; pulmonary function; quality of life
Lung CD4+ T cells accumulate as chronic obstructive pulmonary disease (COPD) progresses, but their role in pathogenesis remains controversial. To address this controversy, we studied lung tissue from 53 subjects undergoing clinically-indicated resections, lung volume reduction, or transplant. Viable single-cell suspensions were analyzed by flow cytometry or underwent CD4+ T cell isolation, followed either by stimulation with anti-CD3 and cytokine/chemokine measurement, or by real-time PCR analysis. In lung CD4+ T cells of most COPD subjects, relative to lung CD4+ T cells in smokers with normal spirometry: (a) stimulation induced minimal IFN-γ or other inflammatory mediators, but many subjects produced more CCL2; (b) the T effector memory subset was less uniformly predominant, without correlation with decreased IFN-γ production. Analysis of unstimulated lung CD4+ T cells of all subjects identified a molecular phenotype, mainly in COPD, characterized by markedly reduced mRNA transcripts for the transcription factors controlling TH1, TH2, TH17 and FOXP3+ T regulatory subsets and their signature cytokines. This mRNA-defined CD4+ T cell phenotype did not result from global inability to elaborate mRNA; increased transcripts for inhibitory CD28 family members or markers of anergy; or reduced telomerase length. As a group, these subjects had significantly worse spirometry, but not DLCO, relative to subjects whose lung CD4+ T cells expressed a variety of transcripts. Analysis of mRNA transcripts of unstimulated lung CD4+ T cell among all subjects identified two distinct molecular correlates of classical COPD clinical phenotypes: basal IL-10 transcripts correlated independently and inversely with emphysema extent (but not spirometry); by contrast, unstimulated IFN-γ transcripts correlated independently and inversely with reduced spirometry (but not reduced DLCO or emphysema extent). Aberrant lung CD4+ T cells polarization appears to be common in advanced COPD, but also exists in some smokers with normal spirometry, and may contribute to development and progression of specific COPD phenotypes.
ClinicalTrials.gov as NCT00281229
The prevalence of chronic obstructive pulmonary disease (COPD) in women is increasing, as is hospitalization for COPD. The number of women dying of COPD in the United States now surpasses men. Despite this, research suggests that physicians are still more likely to correctly diagnose men with COPD than women. Increased tobacco use in women likely explains some of the increase in the prevalence of COPD in women, but data suggest that women may actually be at greater risk of smoking-induced lung function impairment, more severe dyspnea, and poorer health status for the same level of tobacco exposure. The degree to which these observations represent biologic, physiologic, or sociologic differences is not known. Nonsmokers with COPD are also more likely to be female. In addition, new evidence is emerging that men and women may be phenotypically different in their response to tobacco smoke, with men being more prone to an emphysematous phenotype and women an airway predominant phenotype. Inasmuch as COPD is a disease of inflammation, it is also possible that sexual dimorphism of the human immune response may also be responsible for gender differences in the disease. More data are still needed on what the implications of these findings are on therapy. In this clinical commentary, we present current knowledge regarding how gender influences the epidemiology, diagnosis, and presentation of COPD in addition to physiologic and psychologic impairments and we attempt to offer insight into why these differences might exist and how this may influence therapeutic management.
tobacco susceptibility; smoking; sex; obstructive lung disease
Acute exacerbations of chronic obstructive pulmonary disease (COPD) are important events in the natural history of this chronic lung disorder. These events can be caused by a large number of infectious and noninfectious agents and are associated with an increased local and systemic inflammatory response. Their frequency and severity have been linked to progressive deterioration in lung function and health status. Infectious pathogens ranging from viral to atypical and typical bacteria have been implicated in the majority of episodes. Most therapeutic regimens to date have emphasized broad, nonspecific approaches to bronchoconstriction and pulmonary inflammation. Increasingly, therapy that targets specific etiologic pathogens has been advocated. These include clinical and laboratory-based methods to identify bacterial infections. Further additional investigation has suggested specific pathogens within this broad class. As specific antiviral therapies become available, better diagnostic approaches to identify specific pathogens will be required. Furthermore, prophylactic therapy for at-risk individuals during high-risk times may become a standard therapeutic approach. As such, the future will likely include aggressive diagnostic algorithms based on the combination of clinical syndromes and rapid laboratory modalities to identify specific causative bacteria or viruses.
chronic obstructive pulmonary disease; acute exacerbations; virus; bacteria; therapy
Technology offers opportunities to improve healthcare, but little is known about Internet use by COPD patients. We tested two hypotheses: Internet access is associated with socio-demographic disparities and frequency of use is related to perceived needs.
We analyzed data from a 2007–2008 national convenience sample survey of COPD patients to determine the relationship between Internet access and frequency of use with demographics, socio-economic status, COPD severity, and satisfaction with healthcare.
Among survey respondents (response rate 7.2%; n = 914, 59.1% women, mean age 71.2 years), 34.2% reported lack of Internet access, and an additional 49% had access but used the Internet less than weekly. Multivariate models showed association between lack of access and older age (OR 1.10, 95% CI 1.07, 1.13), lower income (income below $30,000 OR 2.47, 95% CI 1.63, 3.73), less education (high school highest attainment OR 2.30, 95% CI 1.54, 3.45), comorbid arthritis or mobility-related disease (OR 1.56, 95% CI 1.05, 2.34). More frequent use (at least weekly) was associated with younger age (OR 0.95, 95% CI 0.93, 0.98), absence of cardiovascular disease (OR 0.48, 95% CI 0.29, 0.78), but with perception of needs insufficiently met by the healthcare system, including diagnostic delay (OR 1.72, 95% CI 1.06, 2.78), feeling treated poorly (OR 2.46, 95% CI 1.15, 5.24), insufficient physician time (OR 2.29, 95% CI 1.02, 5.13), and feeling their physician did not listen (OR 3.14, 95% CI 1.42, 6.95).
An analysis of the characteristics associated with Internet access and use among COPD patients identified two different patient populations. Lack of Internet access was a marker of socioeconomic disparity and mobility-associated diseases, while frequent Internet use was associated with less somatic disease but dissatisfaction with care.
Chronic obstructive pulmonary disease; Internet; Elderly adults; Chronic disease management; Multimorbidity; Health information seeking; Digital divide
Chronic obstructive pulmonary disease (COPD) is a leading cause of death and disability worldwide. The Global Burden of Disease study has concluded that COPD will become the third leading cause of death worldwide by 2020, and will increase its ranking of disability-adjusted life years lost from 12th to 5th. Acute exacerbations of COPD (AECOPD) are associated with impaired quality of life and pulmonary function. More frequent or severe AECOPDs have been associated with especially markedly impaired quality of life and a greater longitudinal loss of pulmonary function. COPD and AECOPDs are characterized by an augmented inflammatory response. Macrolide antibiotics are macrocyclical lactones that provide adequate coverage for the most frequently identified pathogens in AECOPD and have been generally included in published guidelines for AECOPD management. In addition, they exert broad-ranging, immunomodulatory effects both in vitro and in vivo, as well as diverse actions that suppress microbial virulence factors. Macrolide antibiotics have been used to successfully treat a number of chronic, inflammatory lung disorders including diffuse panbronchiolitis, asthma, noncystic fibrosis associated bronchiectasis, and cystic fibrosis. Data in COPD patients have been limited and contradictory but the majority hint to a potential clinical and biological effect. Additional, prospective, controlled data are required to define any potential treatment effect, the nature of this effect, and the role of bronchiectasis, baseline colonization, and other cormorbidities.
macrolide therapy; antibiotics; AECOPD
Rationale: Limited data on sex differences in advanced COPD are available.
Objectives: To compare male and female emphysema patients with severe disease.
Methods: One thousand fifty-three patients (38.8% female) evaluated for lung volume reduction surgery as part of the National Emphysema Treatment Trial were analyzed.
Measurements and Main Results: Detailed clinical, physiological, and radiological assessment, including quantitation of emphysema severity and distribution from helical chest computed tomography, was completed. In a subgroup (n = 101), airway size and thickness was determined by histological analyses of resected tissue. Women were younger and exhibited a lower body mass index (BMI), shorter smoking history, less severe airflow obstruction, lower Dlco and arterial Po2, higher arterial Pco2, shorter six-minute walk distance, and lower maximal wattage during oxygen-supplemented cycle ergometry. For a given FEV1% predicted, age, number of pack-years, and proportion of emphysema, women experienced greater dyspnea, higher modified BODE, more depression, lower SF-36 mental component score, and lower quality of well-being. Overall emphysema was less severe in women, with the difference from men most evident in the outer peel of the lung. Females had thicker small airway walls relative to luminal perimeters.
Conclusions: In patients with severe COPD, women, relative to men, exhibit anatomically smaller airway lumens with disproportionately thicker airway walls, and emphysema that is less extensive and characterized by smaller hole size and less peripheral involvement.
chronic obstructive pulmonary disease; emphysema; computed tomography; pulmonary function; gender
COPD has a profound impact on daily life, yet remains underdiagnosed and undertreated. We set out to develop a brief, reliable, self-scored questionnaire to identify individuals likely to have COPD. COPD-PS™ development began with a list of concepts identified for inclusion using expert opinion from a clinician working group comprised of pulmonologists (n = 5) and primary care clinicians (n = 5). A national survey of 697 patients was conducted at 12 practitioner sites. Logistic regression identified items discriminating between patients with and without fixed airflow obstruction (AO, postbronchodilator FEV1/FVC < 70%). ROC analyses evaluated screening accuracy, compared scoring options, and assessed concurrent validity. Convergent and discriminant validity were assessed via COPD-PS and SF-12v2 score correlations. For known-groups validation, COPD-PS differences between clinical groups were tested. Test-retest reliability was evaluated in a 20% sample. Of 697 patients surveyed, 295 patients met expert review criteria for spirometry performance; 38% of these (n = 113) had results indicating AO. Five items positively predicted AO (p < 0.0001): breathlessness, productive cough, activity limitation, smoking history, and age. COPD-PS scores accurately classified AO status (area under ROC curve = 0.81) and reliable (r = 0.91). Patients with spirometry indicative of AO scored significantly higher (6.8, SD = 1.9; p < 0.0001) than patients without AO (4.0, SD = 2.3). Higher scores were associated with more severe AO, bronchodilator use, and overnight hospitalization for breathing problems. With the prevalence of COPD in the studied cohort, a score on the COPD-PS of greater than five was associated with a positive predictive value of 56.8% and negative predictive value of 86.4%. The COPD-PS accurately classified physician-reported COPD (AUC = 0.89). The COPD-PS is a brief, accurate questionnaire that can identify individuals likely to have COPD.
Pulmonary Disease; Chronic Obstructive; Spirometry; Health Survey; Questionnaire; Screening
The natural history of idiopathic pulmonary fibrosis (IPF) has been characterized as a steady, predictable decline in lung function over time. Recent evidence suggests that some patients may experience a more precipitous course, with periods of relative stability followed by acute deteriorations in respiratory status. Many of these acute deteriorations are of unknown etiology and have been termed acute exacerbations of IPF. This perspective is the result of an international effort to summarize the current state of knowledge regarding acute exacerbations of IPF. Acute exacerbations of IPF are defined as acute, clinically significant deteriorations of unidentifiable cause in patients with underlying IPF. Proposed diagnostic criteria include subjective worsening over 30 days or less, new bilateral radiographic opacities, and the absence of infection or another identifiable etiology. The potential pathobiological roles of infection, disordered cell biology, coagulation, and genetics are discussed, and future research directions are proposed.
acute exacerbation; pulmonary fibrosis; diagnosis; definition
Purpose: Limited data exist describing risk factors for mortality in patients having predominantly emphysema.
Subjects and Methods: A total of 609 patients with severe emphysema (ages 40–83 yr; 64.2% male) randomized to the medical therapy arm of the National Emphysema Treatment Trial formed the study group. Cox proportional hazards regression analysis was used to investigate risk factors for all-cause mortality. Risk factors examined included demographics, body mass index, physiologic data, quality of life, dyspnea, oxygen utilization, hemoglobin, smoking history, quantitative emphysema markers on computed tomography, and a modification of a recently described multifunctional index (modified BODE).
Results: Overall, high mortality was seen in this cohort (12.7 deaths per 100 person-years; 292 total deaths). In multivariate analyses, increasing age (p = 0.001), oxygen utilization (p = 0.04), lower total lung capacity % predicted (p = 0.05), higher residual volume % predicted (p = 0.04), lower maximal cardiopulmonary exercise testing workload (p = 0.002), greater proportion of emphysema in the lower lung zone versus the upper lung zone (p = 0.005), and lower upper-to-lower-lung perfusion ratio (p = 0.007), and modified BODE (p = 0.02) were predictive of mortality. FEV1 was a significant predictor of mortality in univariate analysis (p = 0.005), but not in multivariate analysis (p = 0.21).
Conclusion: Although patients with advanced emphysema experience significant mortality, subgroups based on age, oxygen utilization, physiologic measures, exercise capacity, and emphysema distribution identify those at increased risk of death.
chronic obstructive pulmonary disease; computed tomography; mortality; prognosis; pulmonary function
Diffuse parenchymal lung diseases are a group of disorders that involve the space between the epithelial and endothelial basement membranes and are generally segregated into four major categories. These include the idiopathic interstitial pneumonias, which are further categorized into seven clinical/radiologic/pathologic subsets. These disorders generally share a common pattern of physiologic abnormality characterized by a restrictive ventilatory defect and reduced diffusing capacity (DLCO). Pulmonary function testing is often used and recommended in their assessment and management. The potential clinical application of physiologic testing includes to aid in diagnosis, although its value in differential diagnosis is limited. Pulmonary function testing also aids in establishing disease severity and in defining prognosis. In nonspecific interstitial pneumonia and idiopathic pulmonary fibrosis, severely decreased DLCO has proven valuable in this regard. Similarly, exertional desaturation to less than 88% at baseline testing and a decrease in FVC (greater than 10%) over the course of short-term follow-up identify patients at particular risk of mortality. Finally, physiologic testing, especially spirometry and DLCO, have demonstrated value in monitoring response to therapy and identifying disease progression.
nonspecific interstitial pneumonia; prognosis; pulmonary function; survival