Kerri A. Johannson

Acute exacerbation of idiopathic pulmonary fibrosis associated with air pollution exposure

Acute exacerbations of idiopathic pulmonary fibrosis are associated with high mortality and are of unknown cause. The effect of air pollution on exacerbations of interstitial lung disease is unknown. This study aims to define the association of air pollution exposure with acute exacerbation of idiopathic pulmonary fibrosis. Patients with idiopathic pulmonary fibrosis and corresponding air pollution data were identified from a longitudinal cohort. Air pollution exposures were assigned to each patient for ozone, nitrogen dioxide, particulate matter, sulfur dioxide and carbon monoxide based on geo-coded residential addresses. Cox proportional hazards models were used to estimate the association of air pollution exposures and acute exacerbations. Acute exacerbation was significantly associated with antecedent 6-week increases in mean level, maximum level and number of exceedances above accepted standards of ozone (hazard ratio (HR) 1.57, 95% CI 1.09–2.24; HR 1.42, 95% CI 1.11–1.82; and HR 1.51, 95% CI 1.17–1.94, respectively) and nitrogen dioxide (HR 1.41, 95% CI 1.04–1.91; HR 1.27, 95% CI 1.01–1.59; and HR 1.20, 95% CI 1.10–1.31, respectively). Increased ozone and nitrogen dioxide exposure over the preceding 6 weeks was associated with an increased risk of acute exacerbation of idiopathic pulmonary fibrosis, suggesting that air pollution may contribute to the development of this clinically meaningful event. Acute exacerbation of idiopathic pulmonary fibrosis is associated with increased ozone and nitrogen dioxide exposure http://ow.ly/t1vzw

Role of IL-17A and neutrophils in fibrosis in experimental hypersensitivity pneumonitis

BACKGROUND Chronic hypersensitivity pneumonitis is characterized by pulmonary inflammation and fibrosis in response to repeated inhalation of mainly organic antigens. It is recognized that IL-17A is crucial for the development of pulmonary inflammation in murine models of experimental hypersensitivity pneumonitis, but its role in the development of pulmonary fibrosis has not been determined. Furthermore, the main cell type(s) that produce IL-17A in experimental hypersensitivity pneumonitis have not yet been identified. OBJECTIVE Our objectives were to test the hypothesis that IL-17A plays a central role in the development of pulmonary fibrosis in experimental hypersensitivity pneumonitis and to determine the main inflammatory cell type(s) responsible for IL-17A production. METHODS We used a mouse model of experimental hypersensitivity pneumonitis in which IL-17A was inhibited or neutrophils were depleted. We also used IL-17RA-deficient and RAG-2-deficient mice. Lung IL-17A-producing cells were identified by fluorescence-activated cell sorting of myeloid versus lymphoid cell populations, intracellular IL-17A staining, flow cytometry, and quantitative reverse transcription PCR for IL-17A mRNA. RESULTS We found that the development of pulmonary fibrosis depended on IL-17A and was significantly attenuated by neutrophil depletion. Neutrophils and monocytes/macrophages were the main cell types that expressed IL-17A in our model. CONCLUSIONS We have identified the central roles of IL-17A and neutrophils in the pathogenesis of fibrosis in experimental hypersensitivity pneumonitis. We have also established that nonlymphocytic innate immune cells, specifically neutrophils and monocytes/macrophages, rather than TH17 lymphocytes, are the predominant source of IL-17A in experimental hypersensitivity pneumonitis.

The use of pretest probability increases the value of high-resolution CT in diagnosing usual interstitial pneumonia

Background Recent studies have suggested that non-definitive patterns on high-resolution CT (HRCT) scan provide sufficient diagnostic specificity to forgo surgical lung biopsy in the diagnosis of idiopathic pulmonary fibrosis (IPF). The objective of this study was to determine test characteristics of non-definitive HRCT patterns for identifying histopathological usual interstitial pneumonia (UIP). Methods Patients with biopsy-proven interstitial lung disease (ILD) and non-definitive HRCT scans were identified from two academic ILD centres. Test characteristics for HRCT patterns as predictors of UIP on surgical lung biopsy were derived and validated in independent cohorts. Results In the derivation cohort, 64/385 (17%) had possible UIP pattern on HRCT; 321/385 (83%) had inconsistent with UIP pattern. 113/385 (29%) patients had histopathological UIP pattern in the derivation cohort. Possible UIP pattern had a specificity of 91.2% (95% CI 87.2% to 94.3%) and a positive predictive value (PPV) of 62.5% (95% CI 49.5% to 74.3%) for UIP pattern on surgical lung biopsy. The addition of age, sex and total traction bronchiectasis score improved the PPV. Inconsistent with UIP pattern demonstrated poor PPV (22.7%, 95% CI 18.3% to 27.7%). HRCT pattern specificity was nearly identical in the validation cohort (92.7%, 95% CI 82.4% to 98.0%). The substantially higher prevalence of UIP pattern in the validation cohort improved the PPV of HRCT patterns. Conclusions A possible UIP pattern on HRCT has high specificity for UIP on surgical lung biopsy, but PPV is highly dependent on underlying prevalence. Adding clinical and radiographic features to possible UIP pattern on HRCT may provide sufficient probability of histopathological UIP across prevalence ranges to change clinical decision-making.

Air Pollution Exposure: A Novel Environmental Risk Factor for Interstitial Lung Disease?

Air pollution exposure is a well-established risk factor for several adverse respiratory outcomes, including airways diseases and lung cancer. Few studies have investigated the relationship between air pollution and interstitial lung disease (ILD) despite many forms of ILD arising from environmental exposures. There are potential mechanisms by which air pollution could cause, exacerbate, or accelerate the progression of certain forms of ILD via pulmonary and systemic inflammation as well as oxidative stress. This article will review the current epidemiologic and translational data supporting the plausibility of this relationship and propose a new conceptual framework for characterizing novel environmental risk factors for these forms of lung disease.

Antacid therapy in idiopathic pulmonary fibrosis: more questions than answers?

Idiopathic pulmonary fibrosis (IPF) is a progressive parenchymal lung disease of complex cause. Gastro-oesophageal reflux (GER) and microaspiration have been proposed as risk factors for the development and progression of IPF, but robust definitive data are few. A recent international guideline conditionally recommended the use of antacid therapy (proton pump inhibitors or histamine-2-receptor antagonists) for patients with IPF, in the absence of oesophageal reflux or symptoms. In this Position Paper, we summarise the literature addressing the association between GER and IPF, and also identify future research priorities that could clarify this issue. We shed light on the process through which the guideline recommendation was achieved and aim to contextualise the recommendation for providers caring for patients with IPF.

A diagnostic model for chronic hypersensitivity pneumonitis

The objective of this study was to develop a diagnostic model that allows for a highly specific diagnosis of chronic hypersensitivity pneumonitis using clinical and radiological variables alone. Chronic hypersensitivity pneumonitis and other interstitial lung disease cases were retrospectively identified from a longitudinal database. High-resolution CT scans were blindly scored for radiographic features (eg, ground-glass opacity, mosaic perfusion) as well as the radiologists diagnostic impression. Candidate models were developed then evaluated using clinical and radiographic variables and assessed by the cross-validated C-statistic. Forty-four chronic hypersensitivity pneumonitis and eighty other interstitial lung disease cases were identified. Two models were selected based on their statistical performance, clinical applicability and face validity. Key model variables included age, down feather and/or bird exposure, radiographic presence of ground-glass opacity and mosaic perfusion and moderate or high confidence in the radiographic impression of chronic hypersensitivity pneumonitis. Models were internally validated with good performance, and cut-off values were established that resulted in high specificity for a diagnosis of chronic hypersensitivity pneumonitis.

Use of Mycophenolate Mofetil or Azathioprine for the Management of Chronic Hypersensitivity Pneumonitis

BACKGROUND: The treatment of chronic hypersensitivity pneumonitis (cHP) often includes systemic oral corticosteroids, but the optimal pharmacologic management remains unclear. The morbidity associated with prednisone has motivated the search for alternative therapies. We aimed to determine the effect of treatment with mycophenolate mofetil (MMF) or azathioprine (AZA) on lung function in patients with cHP. METHODS: Patients with cHP treated with either MMF or AZA were retrospectively identified from four interstitial lung disease centers. Change in lung function before and after treatment initiation was analyzed using linear mixed‐effects modeling (LMM), adjusting for age, sex, smoking history, and prednisone use. RESULTS: Seventy patients were included: 51 were treated with MMF and 19 with AZA. Median follow‐up after treatment initiation was 11 months. Prior to treatment initiation, FVC and diffusion capacity of the lung for carbon monoxide (Dlco) % predicted were declining at a mean rate of 0.12% (P < .001) and 0.10% (P < .001) per month, respectively. Treatment with either MMF or AZA was not associated with improved FVC (0.5% at 1 year; P = .46) but was associated with a statistically significant improvement in Dlco of 4.2% (P < .001) after 1 year of treatment. Results were similar in the subgroup of patients treated with MMF for 1 year; the FVC increased nonsignificantly by 1.3% (P = .103) and Dlco increased by 3.9% (P < .001). CONCLUSIONS: Treatment with MMF or AZA is associated with improvements in Dlco in patients with cHP. Prospective randomized trials are needed to validate their effectiveness for cHP.

Pathologic Findings and Prognosis in a Large Prospective Cohort of Chronic Hypersensitivity Pneumonitis

BACKGROUND: The ability of specific histopathologic features to predict mortality or lung transplantation in patients with chronic hypersensitivity pneumonitis (HP) is unknown. METHODS: Patients with chronic HP diagnosed by surgical lung biopsy were identified from an ongoing longitudinal cohort. The surgical lung biopsy slides were evaluated prospectively by an experienced thoracic pathologist using a standardized checklist to differentiate the major pathologic patterns and score the presence of specific histopathologic features. Cox proportional hazard analysis was used to identify independent predictors of transplant‐free survival, and Kaplan‐Meier analysis was used to visualize outcomes. RESULTS: One hundred nineteen patients were identified. Patients with a fibrotic nonspecific interstitial pneumonia (f‐NSIP) pattern, bronchiolocentric fibrosis (BF) pattern, or usual interstitial pneumonia (UIP) pattern had significantly worse transplant‐free survival than did those with a cellular NSIP (c‐NSIP) pattern or peribronchiolar inflammation with poorly formed granulomas (PI‐PFG) pattern. No survival difference among patients with an f‐NSIP pattern, a BF pattern, or a UIP pattern was found. Fibroblastic foci were identified in a subset of biopsy samples from all pathologic patterns. Peribronchiolar fibrosis was noted in all UIP cases. Independent predictors of time to death or transplantation included the presence of fibroblast foci or dense collagen fibrosis. CONCLUSIONS: Histopathologic patterns of c‐NSIP and PI‐PFG had a better transplant‐free survival than did patterns of UIP, f‐NSIP, and BF. The presence of fibroblast foci or dense collagen fibrosis correlated with progression to death or lung transplantation. Identification of fibroblast foci on biopsy samples, regardless of the underlying histopathologic pattern, may be a clinically useful predictor of survival in patients with HP.

Diagnostic accuracy of a clinical diagnosis of idiopathic pulmonary fibrosis: an international case–cohort study

We conducted an international study of idiopathic pulmonary fibrosis (IPF) diagnosis among a large group of physicians and compared their diagnostic performance to a panel of IPF experts. A total of 1141 respiratory physicians and 34 IPF experts participated. Participants evaluated 60 cases of interstitial lung disease (ILD) without interdisciplinary consultation. Diagnostic agreement was measured using the weighted kappa coefficient (κw). Prognostic discrimination between IPF and other ILDs was used to validate diagnostic accuracy for first-choice diagnoses of IPF and were compared using the C-index. A total of 404 physicians completed the study. Agreement for IPF diagnosis was higher among expert physicians (κw=0.65, IQR 0.53–0.72, p<0.0001) than academic physicians (κw=0.56, IQR 0.45–0.65, p<0.0001) or physicians with access to multidisciplinary team (MDT) meetings (κw=0.54, IQR 0.45–0.64, p<0.0001). The prognostic accuracy of academic physicians with >20 years of experience (C-index=0.72, IQR 0.0–0.73, p=0.229) and non-university hospital physicians with more than 20 years of experience, attending weekly MDT meetings (C-index=0.72, IQR 0.70–0.72, p=0.052), did not differ significantly (p=0.229 and p=0.052 respectively) from the expert panel (C-index=0.74 IQR 0.72–0.75). Experienced respiratory physicians at university-based institutions diagnose IPF with similar prognostic accuracy to IPF experts. Regular MDT meeting attendance improves the prognostic accuracy of experienced non-university practitioners to levels achieved by IPF experts. Academic status, access to MDT meetings and clinician experience predict accuracy of a clinical diagnosis of IPF http://ow.ly/k43W30cTMg1

Home monitoring improves endpoint efficiency in idiopathic pulmonary fibrosis

The objective of this study was to investigate the reliability, feasibility and analytical impact of home-based measurement of forced vital capacity (FVC) and dyspnoea as clinical endpoints in idiopathic pulmonary fibrosis (IPF). Patients with IPF performed weekly home-based assessment of FVC and dyspnoea using a mobile hand-held spirometer and self-administered dyspnoea questionnaires. Weekly variability in FVC and dyspnoea was estimated, and sample sizes were simulated for a hypothetical 24-week clinical trial using either traditional office-based interval measurement or mobile weekly assessment. In total, 25 patients were enrolled. Mean adherence to weekly assessments over 24 weeks was greater than 90%. Compared with change assessment using baseline and 24-week measurements only, weekly assessment of FVC resulted in enhanced precision and power. For example, a hypothetical 24-week clinical trial with FVC as the primary endpoint would require 951 patients using weekly home spirometry compared with 3840 patients using office spirometry measures at weeks 1 and 24 only. The ability of repeated measures to reduce clinical trial sample size was influenced by the correlation structure of the data. Home monitoring can improve the precision of endpoint assessments, allowing for greater efficiency in clinical trials of therapeutics for IPF. Home monitoring improves endpoint efficiency in idiopathic pulmonary fibrosis #AdvancesinILD @ERSTalk http://ow.ly/F5L930bUypH