Longitudinal changes in serum immunoglobulin G testing in patients with fibrotic avian hypersensitivity pneumonitis

BACKGROUND

Evaluation of the antigen responsible for fibrotic hypersensitivity pneumonitis (HP) is challenging. Serum immunoglobulin (Ig) G testing against HP-associated antigens is performed. Although single-serum IgG testing has been investigated, multiple-serum IgG testing has not yet been studied.

METHODS

This study included patients who underwent histopathological examination and positive inhalation challenge test as well as those with moderate or high HP guideline confidence level. Serum IgG testing against pigeon serum was conducted twice using two methods: enzyme linked-immunosorbent assay (ELISA) and ImmunoCAP. The association between changes in serum IgG antibody titers and changes in forced vital capacity (FVC) and other parameters was investigated.

RESULTS

In this study, 28 patients (mean age, 64.5 years; mean FVC, 85.3%) with fibrotic avian HP were selected, of whom 20 and 8 underwent surgical lung biopsy and transbronchial lung cryobiopsy, respectively. Of the 28 patients, 19 had been keeping birds for more than 6 months. A correlation was observed between the annual changes in serum IgG antibody titers by ELISA and changes in relative FVC (r =  - 0.6221, p < 0.001). Furthermore, there was a correlation between the annual changes in serum IgG antibody titers by ImmunoCAP and changes in relative FVC (r =  - 0.4302, p = 0.022). Multiple regression analysis revealed that the change in serum IgG antibody titers by both ELISA and ImmunoCAP also influenced the relative FVC change (p = 0.012 and p = 0.015, respectively). Moreover, 13 patients were given additional treatments between the first and second blood test; however, the additional treatment group was not significantly different in relative FVC change compared to the group with no additional treatment (p = 0.982).

CONCLUSIONS

In patients with fibrotic avian HP, the annual changes in serum IgG testing were correlated with FVC changes, highlighting the importance of serum IgG testing over time.

Mechanisms and management of cough in interstitial lung disease

INTRODUCTION

Many patients with interstitial lung diseases (ILDs), especially fibrotic ILDs, experience chronic cough. It negatively impacts both physical and psychological well-being. Effective treatment options are limited.

AREAS COVERED

The pathophysiology of chronic cough in IPF is complex and involves multiple mechanisms, including mechanical distortion of airways, parenchyma, and nerve fibers. The pathophysiology of cough in other fibrosing ILDs is poorly understood and involves various pathways. The purpose of this review is to highlight mechanisms of chronic cough and to present therapeutic evidence for its management in the most commonly occurring diffuse fibrosing lung diseases including idiopathic pulmonary fibrosis (IPF), connective tissue disease-related interstitial lung disease (CTD-ILD), sarcoidosis-related ILD (Sc-ILD), chronic hypersensitivity pneumonitis-related ILD (CHP-ILD), and post-COVID-19-related interstitial lung disease (PC-ILD).

EXPERT OPINION

This review guides the management of chronic cough in fibrosing ILDs. In this era of precision medicine, chronic cough management should be individualized in each interstitial lung disease.

Acute Exacerbation and Proposed Criteria for Progressive Pulmonary Fibrosis in Patients with Fibrotic Hypersensitivity Pneumonitis and Idiopathic Pulmonary Fibrosis

BACKGROUND

Acute exacerbation (AE) occasionally develops in the course of fibrotic hypersensitivity pneumonitis (HP).

OBJECTIVE

The aim of the study was to compare AE of fibrotic HP with that of idiopathic pulmonary fibrosis (IPF).

METHODS

Consecutive patients with pathologically confirmed fibrotic HP and IPF diagnosed based on a multidisciplinary discussion were included in the analysis. AE in patients with fibrotic HP and IPF was evaluated retrospectively.

RESULTS

This study included 309 and 160 patients with fibrotic HP and IPF, respectively. Their 50% survival times were 96.1 and 78.0 months, respectively (hazard ratio [HR]: 0.54 [95% confidence interval, CI: 0.36-0.77], log-rank test; p < 0.001). Notably, the cumulative AE rates of fibrotic HP were 3% at 1 year and 10% at 3 years. Moreover, the corresponding rates of IPF were 8% at 1 year and 20% at 3 years (HR: 0.66 [95% CI: 0.45-0.93], log-rank test; p = 0.034). The 90-day survival rates from the AE onset of fibrotic HP and IPF were 75% and 64%, respectively (HR: 0.51 [95% CI: 0.31-0.83], log-rank test; p = 0.006). The respiratory function test on the physiological criteria of progressive pulmonary fibrosis (PPF) was a predictor of AE in fibrotic HP. However, the high-resolution CT (HRCT) changes in the criteria of PPF were not. Nevertheless, both the physiological and radiological criteria of PPF were a predictor of AE of IPF.

CONCLUSION

AE of fibrotic HP has a lesser prognostic effect than that of IPF. HRCT criteria for PPF were not a risk factor for AE in patients with fibrotic HP.

Serum Immunoglobulin G Testing against Pigeon Egg in Stable Fibrotic Hypersensitivity Pneumonitis

INTRODUCTION

The accuracy of serum immunoglobulin (Ig) G testing for diagnosis of stable bird-related fibrotic hypersensitivity pneumonitis (HP) is controversial. Furthermore, avian serum, extracts, or feathers were employed as antigens in bird-related HP; however, the usage of egg whites has not been reported. We investigated the utility of IgG testing against pigeon egg whites in patients with stable bird-related fibrotic HP.

METHODS

Patients having a positive inhalation test for pigeon antigen and a histological investigation with diagnostic confidence of fibrotic HP greater than moderate confidence were included. The control group consisted of patients with interstitial lung diseases (ILDs) other than HP. To select patients in the stable phase, patients with fibrotic HP were excluded if they were clinically considered to be in the acute exacerbation or acute phase. The IgG testing against pigeon egg whites by enzyme-linked immunosorbent assay and the commercialized anti-pigeon IgG testing by fluorescence enzyme immunoassay were investigated.

RESULTS

In this study, 37 patients with stable bird-related fibrotic HP and 32 patients with ILDs other than HP participated. Serum IgG testing for pigeon egg whites revealed that the control group's optical density was 0.147 and the group with bird-related fibrotic HP had a mean value of 0.207 (p = 0.011). IgG testing in bronchial alveolar lavage fluid was not significantly higher in the bird-related fibrotic HP group than in controls (p = 0.42). No significant difference in area under the curve between an IgG testing against pigeon egg whites and a commercialized anti-pigeon IgG testing was observed (p = 0.24). Test accuracy for stable bird-related fibrotic HP ranged from 62% to 76% sensitivity and 59-66% specificity.

CONCLUSION

IgG testing to identify the inciting antigen in patients with stable bird-related fibrotic HP had relatively low accuracy.

Impact of antigen avoidance test for fibrotic hypersensitivity pneumonitis in stable phase

BACKGROUND

The antigen avoidance has been used in the diagnosis and treatment of hypersensitivity pneumonitis (HP); however, its usefulness in stable fibrotic HP is controversial.

OBJECTIVE

To investigate the usefulness of the antigen avoidance test in patients with fibrotic HP in stable phase.

METHODS

The antigen avoidance test was conducted during a 2-week hospitalization comparing clinical parameters at admission and before discharge. A retrospective review of patients who underwent surgical lung biopsy or transbronchial lung cryobiopsy, who were diagnosed with fibrotic HP by multi-disciplinary discussion, and whose disease progression was stable for more than two months before the antigen avoidance test was done.

RESULTS

Between 2016 and 2021, 40 patients met the criteria, and 17 (43%) patients had a positive antigen avoidance test. The patients with positive in the antigen avoidance test had significantly greater annual forced vital capacity (FVC) decline than those with negative before the test (- 6.5% vs. - 0.3%, p = 0.045). The patients with positive antigen avoidance test had less annual FVC decline than those with negative in the year following the test (0.8% vs. - 5.0%, p = 0.048). The differences in annual improvement were found for serum Krebs von den Lungen-6 between the positive and negative patients in the year following the test (- 27% vs. - 5%, p = 0.049). In multivariate Cox hazard regression analysis, a negative result of the antigen avoidance test was a risk factor for death or acute exacerbation of fibrotic HP (HR = 0.26 [95% CI: 0.07-0.90], p = 0.034).

CONCLUSIONS

In fibrotic HP patients in stable phase, the antigen avoidance test under a 2-week hospitalization was valuable in predicting prognosis.

Quantitative CT and machine learning classification of fibrotic interstitial lung diseases

OBJECTIVES

To evaluate quantitative computed tomography (QCT) features and QCT feature-based machine learning (ML) models in classifying interstitial lung diseases (ILDs). To compare QCT-ML and deep learning (DL) models' performance.

METHODS

We retrospectively identified 1085 patients with pathologically proven usual interstitial pneumonitis (UIP), nonspecific interstitial pneumonitis (NSIP), and chronic hypersensitivity pneumonitis (CHP) who underwent peri-biopsy chest CT. Kruskal-Wallis test evaluated QCT feature associations with each ILD. QCT features, patient demographics, and pulmonary function test (PFT) results trained eXtreme Gradient Boosting (training/validation set n = 911) yielding 3 models: M1 = QCT features only; M2 = M1 plus age and sex; M3 = M2 plus PFT results. A DL model was also developed. ML and DL model areas under the receiver operating characteristic curve (AUC) and 95% confidence intervals (CIs) were compared for multiclass (UIP vs. NSIP vs. CHP) and binary (UIP vs. non-UIP) classification performances.

RESULTS

The majority (69/78 [88%]) of QCT features successfully differentiated the 3 ILDs (adjusted p ≤ 0.05). All QCT-ML models achieved higher AUC than the DL model (multiclass AUC micro-averages 0.910, 0.910, 0.925, and 0.798 and macro-averages 0.895, 0.893, 0.925, and 0.779 for M1, M2, M3, and DL respectively; binary AUC 0.880, 0.899, 0.898, and 0.869 for M1, M2, M3, and DL respectively). M3 demonstrated statistically significant better performance compared to M2 (∆AUC: 0.015, CI: [0.002, 0.029]) for multiclass prediction.

CONCLUSIONS

QCT features successfully differentiated pathologically proven UIP, NSIP, and CHP. While QCT-based ML models outperformed a DL model for classifying ILDs, further investigations are warranted to determine if QCT-ML, DL, or a combination will be superior in ILD classification.

KEY POINTS

• Quantitative CT features successfully differentiated pathologically proven UIP, NSIP, and CHP. • Our quantitative CT-based machine learning models demonstrated high performance in classifying UIP, NSIP, and CHP histopathology, outperforming a deep learning model. • While our quantitative CT-based machine learning models performed better than a DL model, additional investigations are needed to determine whether either or a combination of both approaches delivers superior diagnostic performance.

Quantitative CT Analysis in Chronic Hypersensitivity Pneumonitis: A Convolutional Neural Network Approach

RATIONALE AND OBJECTIVES

Chronic hypersensitivity pneumonitis (cHP) is a heterogeneous condition, where both small airway involvement and fibrosis may simultaneously occur. Computer-aided analysis of CT lung imaging is increasingly used to improve tissue characterization in interstitial lung diseases (ILD), quantifying disease extension, and progression. We aimed to quantify via a convolutional neural network (CNN) method the extent of different pathological classes in cHP, and to determine their correlation to pulmonary function tests (PFTs) and mosaic attenuation pattern.

MATERIALS AND METHODS

The extension of six textural features, including consolidation (C), ground glass opacity (GGO), fibrosis (F), low attenuation areas (LAA), reticulation (R) and healthy regions (H), was quantified in 27 cHP patients (age: 56 ± 11.5 years, forced vital capacity [FVC]% = 57 ± 17) acquired at full-inspiration via HRCT. Each class extent was correlated to PFTs and to mosaic attenuation pattern.

RESULTS

H showed a positive correlation with FVC%, FEV1% (forced expiratory volume), total lung capacity%, and diffusion of carbon monoxide (DLCO)% (r = 0.74, r = 0.78, r = 0.73, and r = 0.60, respectively, p < 0.001). GGO, R and C negatively correlated with FVC% and FEV1% with the highest correlations found for R (r = -0.44, and r = -0.46 respectively, p < 0.05); F negatively correlated with DLCO% (r = -0.42, p < 0.05). Patients with mosaic attenuation pattern had significantly more H (p = 0.04) and lower R (p = 0.02) and C (p = 0.0009) areas, and more preserved lung function indices (higher FVC%; p = 0.04 and DLCO%; p = 0.05), but did not show more air trapping in lung function tests.

CONCLUSION

CNN quantification of pathological tissue extent in cHP improves its characterization and shows correlation with PFTs. LAA can be overestimated by visual, qualitative CT assessment and mosaic attenuation pattern areas in cHP represents patchy ILD rather than small-airways disease.

Computed Tomography Findings as Determinants of Local and Systemic Inflammation Biomarkers in Interstitial Lung Diseases: A Retrospective Registry-Based Descriptive Study

PURPOSE

To evaluate the association of peripheral blood (PBL) and broncho-alveolar lavage (BAL) biomarkers with inflammatory versus fibrotic high-resolution computed tomography (HRCT) findings in interstitial lung disease (ILD) patients.

METHODS

HRCT findings of 127 consecutive ILD-board patients were semi-quantitatively evaluated: reticulation/honeycombing (RET), traction bronchiectasis (TBR) and emphysema (EMP) were classified as non-inflammatory/fibrotic; consolidations (CON), ground glass opacities (GGO), parenchymal nodules (NDL) and mosaic attenuation (MOS) as active inflammatory. Each HRCT finding was assessed in six distinct lung regions, resulting scores were graded as minimal (0-1 regions involved), medium (2-4) or extensive (5-6). Associations of routinely assessed PBL/BAL biomarkers with these HRCT scores were evaluated using Spearman correlation coefficients and graphical presentation; significance was tested by applying Kruskal-Wallis tests.

RESULTS

Blood neutrophil, lymphocyte and eosinophil fraction, neutrophil to lymphocyte ratio (NLR) and BAL lymphocyte fraction consistently showed opposite correlations with inflammatory versus non-inflammatory/fibrotic HRCT finding scores. Blood lymphocyte fraction significantly differed by graded GGO (p = 0.032) and CON (p = 0.027) extent, eosinophil fraction by TBR (p = 0.006) and NLR by CON (p = 0.009). C-reactive protein was significantly related to GGO (p = 0.023) and CON (p = 0.004), BAL lymphocyte fraction to GGO (p = 0.017) extent.

CONCLUSION

Blood lymphocyte and eosinophil fraction, NLR, CRP and BAL lymphocyte fraction may aid to differentiate inflammatory from non-inflammatory/fibrotic ILD patterns.

TRIAL REGISTRATION

This evaluation was based on data from the ILD registry of Kepler University Hospital Linz, as approved by the ethics committee of the Federal State of Upper-Austria (EK Number. I-26-17).

Establishing content-validity of a disease-specific health-related quality of life instrument for patients with chronic hypersensitivity pneumonitis

Background

Chronic Hypersensitivity Pneumonitis (CHP) is caused by an immune mediated response in the lung tissue after exposure to an inhaled environmental antigenic stimulant. We previously documented the ways in which CHP impacts patients’ lives and have now developed a disease-specific instrument, the CHP-HRQOL instrument, to measure health-related quality of life (HRQOL). The objective of this study was to assess content validity for the CHP-HRQOL.

Methods

Cognitive interviews were conducted among adults with CHP. The instrument was revised and refined between each round of interviews. Feedback was obtained on the instructions, items, response options, and recall period. Items where participants had difficulty with comprehension, wording, or misinterpretation were marked by the interviewer and participant feedback was reviewed to make revisions, add or delete items when appropriate. Readability statistics were calculated using Flesch-Kincaid grade level and reading ease scores.

Results

Ten participants were interviewed over three rounds, with revisions made to the questionnaire in an iterative process. In the initial 39 item instrument, we identified 7 items where two or more participants reported difficulty. Participants preferred a four-week recall period (compared to a two-week recall period) and response options with a 5-point response scale. The final version of the CHP-HRQOL includes 40 items with a median reading level between 6th and 7th grade.

Conclusion

The CHP-HRQOL instrument demonstrated high content validity and is ready for psychometric testing in further validation studies.

Supplementary Information

The online version contains supplementary material available at 10.1186/s41687-020-00282-x.

Identification of Chronic Hypersensitivity Pneumonitis Biomarkers with Machine Learning and Differential Co-expression Analysis

AIMS

We would like to identify the biomarkers for chronic hypersensitivity pneumonitis (CHP) and facilitate the precise gene therapy of CHP.

BACKGROUND

Chronic hypersensitivity pneumonitis (CHP) is an interstitial lung disease caused by hypersensitive reactions to inhaled antigens. Clinically, the tasks of differentiating between CHP and other interstitial lungs diseases, especially idiopathic pulmonary fibrosis (IPF), were challenging.

OBJECTIVE

In this study, we analyzed the public available gene expression profile of 82 CHP patients, 103 IPF patients, and 103 control samples to identify the CHP biomarkers.

METHOD

The CHP biomarkers were selected with advanced feature selection methods: Monte Carlo Feature Selection (MCFS) and Incremental Feature Selection (IFS). A Support Vector Machine (SVM) classifier was built. Then, we analyzed these CHP biomarkers through functional enrichment analysis and differential co-expression analysis.

RESULT

There were 674 identified CHP biomarkers. The co-expression network of these biomarkers in CHP included more negative regulations and the network structure of CHP was quite different from the network of IPF and control.

CONCLUSION

The SVM classifier may serve as an important clinical tool to address the challenging task of differentiating between CHP and IPF. Many of the biomarker genes on the differential co-expression network showed great promise in revealing the underlying mechanisms of CHP.

Bronchoalveolar lavage and serum KL-6 concentrations in chronic hypersensitivity pneumonitis: correlations with radiological and immunological features

Chronic hypersensitivity pneumonitis (cHP) is a fibrotic interstitial lung disease (ILD) resulting from inhalation of different organic substances and chemical compounds determining an inflammatory and immunological response in sensitized individuals. KL-6, a human mucin protein expressed by type 2 pneumocytes, has been proposed as a prognostic biomarker of cHP. Assessment of usefulness KL-6 in ILD has been investigated primarily in Asiatic population. The aim of this study was to evaluate clinical utility of KL-6 in serum and bronchoalveolar lavage (BAL). In this study, we retrospectively analysed clinical, radiological and immunological data of a cohort of 42 patients affected by cHP: KL-6 concentrations were collected from serum and BAL. KL-6 clinical value was assessed through the analysis of association between KL-6 concentrations and clinical, functional, immunological and radiological features. KL-6 serum concentration results increased in 28/34 patients (82%). A positive direct correlation was observed between KL-6 concentrations in BAL and serum (r = 0.62, p < 0.05). In our study population we found that patients with extensive presence of ground glass opacities and centrilobular nodules at high-resolution computed tomography (HRCT) showed the highest concentrations of KL-6 in BAL and a predominantly CD3+ CD8+ BAL lymphocytosis. BAL lymphocytosis and KL-6 concentrations showed a direct correlation. BAL KL-6, a result of alveolar damage, caused in cHP by CD3+ CD8+ mediated flogosis and suggested by radiological evidence of ground-glass opacities and centrilobular nodules, can be considered a useful biomarker to assess, along with BAL cellular analysis and HRCT findings, disease activity.

Histology is critical but not always for the diagnosis of chronic hypersensitivity pneumonitis

BACKGROUND

The diagnosis of chronic hypersensitivity pneumonitis (CHP) is often based on the pathology, but evidence is scarce that a pathological diagnosis of CHP may mislead the multidisciplinary diagnosis.

METHOD

We enrolled patients from the consultation case archive whose pathological findings were suggestive of CHP but had a multidisciplinary diagnosis of non-CHP. The histopathological slides were sent to another pathologist, and the ones confirmed with CHP were sent for an additional multidisciplinary discussion (MDD). We examined clinicopathological features of the cases confirmed to be non-CHP through MDD.

RESULTS

Among the 243 cases, five were diagnosed as non-CHP through an additional MDD. The most common causes of discrepancy were the presence of strong autoimmune features, a low lymphocyte level in the bronchoalveolar lavage fluid, and a lack of nodular shadow or mosaic attenuation on computed tomography.

CONCLUSIONS

Cases of suspected CHP on pathology may be determined to be non-CHP through MDD.

Chronic hypersensitivity pneumonitis in the southeastern United States: an assessment of how clinicians reached the diagnosis

Background

Chronic hypersensitivity pneumonitis (cHP) is a disease caused by exposure to inhaled environmental antigens. Diagnosis of cHP is influenced by the awareness of the disease prevalence, which varies significantly in different regions, and how clinicians utilize relevant clinical information. We conducted a retrospective study to evaluate how clinicians in the Southeast United States, where the climate is humid favoring mold growth, diagnosed cHP using items identified in the international modified Delphi survey of experts, i.e., environmental exposure, CT imaging and lung pathology,

Methods

We searched Duke University Medical Center database for patients over the age of 18 with a diagnosis of cHP (ICD-9 code: 495) between Jan. 1, 2008 to Dec. 31, 2013 using a query tool, Duke Enterprise Data Unified Content Explorer (DEDUCE).

Results

Five hundred patients were identified and 261 patients had cHP confirmed in clinic notes by a pulmonologist or an allergist. About half of the patients lived in the Research Triangle area where our medical center is located, giving an estimated prevalence rate of 6.5 per 100,000 persons. An exposure source was mentioned in 69.3% of the patient. The most common exposure sources were environmental molds (43.1%) and birds (26.0%). We used Venn diagram to evaluate how the patients met the three most common cHP diagnostic criteria: evidence of environmental exposures (history or precipitin) (E), chest CT imaging (C) and pathology from lung biopsies (P). Eighteen patients (6.9%) met none of three criteria. Of the remaining 243 patients, 135 patients (55.6%) had one (E 35.0%, C 3.3%, P 17.3%), 81 patients (33.3%) had two (E + C 12.3%, E + P 17.3%, C + P 4.9%), and 27 patients (11.1%) had all three criteria (E + C + P). Overall, 49.4% of patients had pathology from lung biopsy compared to 31.6% with CT scan.

Conclusions

Environmental mold was the most common exposure for cHP in the Southeast United States. Lung pathology was available in more than half of cHP cases in our tertiary care center, perhaps reflecting the complexity of referrals. Differences in exposure sources and referral patterns should be considered in devising future diagnostic pathways or guidelines for cHP.

Comparative survival analysis between idiopathic pulmonary fibrosis and chronic hypersensitivity pneumonitis

INTRODUCTION

Chronic hypersensitivity pneumonitis (CHP) is an interstitial lung disease with limited treatment response and bad prognosis. Sometimes it is indistinguishable from idiopathic pulmonary fibrosis (IPF) becoming one of the main differential diagnosis. The aim of our study is to compare survival and functional decline between these two entities.

METHODS

Survival and functional decline more than 10% in FVC were compared using Kaplan Meier (KM) method between patients with CHP and IPF. Cox proportional hazard analysis was used to identify independent predictors of survival and functional decline.

RESULTS

146 patients were included, 54 with CHP and 92 with IPF. KM rate for 2 years survival was 0.71 (CI 95% 0,6-0,8) for CHP group and 0,83 (CI 95% 0,66 - 0,92) for IPF (p=0,027). Nevertheless this difference disappeared using Cox proportional hazard analysis, the adjusted HR for survival among CHP patients was 0,53 (CI 95% 0,25-1,15) (p=0,11). There was no difference in functional evolution between the two groups. KM rate for a decline more than or equal to 10% was 0,64 for CHP (CI 95% 0,43-0,79) and 0,78 for IPF (IC 95% 0,6-0,88) (p=0,22). This observation did not change after using Cox proportional hazard analysis.

CONCLUSIONS

Our study shows that both IPF and CHP are fibrosing interstitial diseases with a similar evolution and survival. It might be possible that therapeutic approach in patients with CHP should change in the light of these observations.

Usefulness of new diagnostic criteria for chronic hypersensitivity pneumonitis established on the basis of a Delphi survey: A Japanese cohort study

BACKGROUND

Chronic hypersensitivity pneumonitis (CHP) is a fibrotic interstitial lung disease (ILD) caused by repeated exposure to a variety of organic particles. In November 2017, new criteria for CHP diagnosis were proposed by Morisset et al. based on a modified Delphi survey of ILD experts. However, it remains unclear whether these criteria are useful to accurately diagnose CHP. We aimed to evaluate the newly proposed CHP diagnostic criteria.

METHODS

We retrospectively applied Morisset's CHP diagnostic criteria to consecutive Japanese patients who underwent surgical lung biopsy for diagnosis of ILD from 2008 to 2015. All patients underwent bronchoalveolar lavage and pulmonary function testing. Patients who had connective tissue disease complications or showed an acute or subacute disease onset were excluded.

RESULTS

A total of 251 patients were included. The diagnoses based on multidisciplinary discussion (MDD) were CHP (n = 27), idiopathic pulmonary fibrosis (n = 117), unclassifiable interstitial pneumonia (IP) (n = 65), and other diagnoses (n = 42). Of the 27 MDD-CHP patients, 14 were classified as a CHP group with diagnostic confidence >50% and 13 were not categorized (sensitivity, 51.9%; specificity, 77.7%). Morisset's CHP diagnostic criteria could help avoid SLB for the diagnosis of CHP in seven patients. Of the 13 MDD-CHP patients who were not categorized in the CHP group with diagnostic confidence >50%, the reason for the exclusion was an inconsistent with UIP pattern without CHP features.

CONCLUSIONS

Half of the MDD-CHP patients were diagnosed with CHP using Morisset's CHP diagnostic criteria. Further investigation will be important for developing improved diagnostic criteria for CHP.

Clinical features of chronic summer-type hypersensitivity pneumonitis and proposition of diagnostic criteria

BACKGROUND

Trichosporon asahii (T. asahii) causes chronic summer-type hypersensitivity pneumonitis (C-SHP); however, little is known about the clinical features of this condition. We aimed to elucidate the clinical features of C-SHP and propose practical diagnostic criteria for C-SHP based on the presence of serum anti-T. asahii antibody (TaAb).

METHODS

Patients diagnosed with C-SHP and idiopathic pulmonary fibrosis (IPF) between January 2010 and May 2017 were reviewed retrospectively. Clinical findings were compared between the two groups. Criteria for C-SHP were proposed on the basis of significant characteristics and applied to the development and validation cohorts.

RESULTS

Thirty-one patients with C-SHP and 26 with TaAb-negative IPF were identified. C-SHP patients were more likely to live in wooden houses; their serum Krebs von den Lungen-6 (KL-6) and serum surfactant protein-D (SP-D) levels were higher than those of IPF patients. C-SHP patients were more likely to have subpleural consolidation, micronodules, and extensive ground-glass opacification on high-resolution computed tomography (HRCT). The following 3 items were considered to have diagnostic value: I) TaAb positivity; II) an HRCT pattern consistent with chronic hypersensitivity pneumonitis, including mosaic attenuation or micronodules; and III) elevated serum biomarker levels (KL-6 > 1500 U/mL or SP-D > 250 ng/mL). We defined cases satisfying I) and II) as "probable C-SHP" and those satisfying all 3 criteria as "confident clinical diagnosis of C-SHP". The areas under the receiver-operating curve were 0.965 and 0.993 in the development and validation cohorts, respectively, which suggested that these criteria had good discriminative ability in clinical evaluations.

CONCLUSIONS

Clinical features could be useful for distinguishing C-SHP from IPF and other etiologies of ILDs.

Periostin as a predictor of prognosis in chronic bird-related hypersensitivity pneumonitis

BACKGROUND

Periostin is an established biomarker of Th2 immune response and fibrogenesis. Recent research has indicated that periostin plays an important role in the pathogenesis of idiopathic interstitial pneumonias. To clarify the relationship between periostin and pathogenesis in chronic bird-related hypersensitivity pneumonitis (HP) and to reveal the usefulness of serum periostin levels in diagnosing and managing chronic bird-related HP.

METHODS

We measured serum periostin in 63 patients with chronic bird-related HP, 13 patients with idiopathic pulmonary fibrosis, and 113 healthy volunteers. We investigated the relationship between serum periostin and clinical parameters, and evaluated if the baseline serum periostin could predict the prognosis.

RESULTS

Serum periostin was significantly higher in patients with chronic bird-related HP compared to the healthy volunteers. In chronic bird-related HP, serum periostin had significant positive correlations with serum KL-6 levels, the CD4/CD8 ratio in bronchoalveolar lavage fluid, and fibrosis score on HRCT, and a significant negative correlation with the diffusing capacity of the lungs for carbon monoxide. Chronic bird-related HP patients with serum periostin levels exceeding ≥92.5 ng/mL and ≥89.5 ng/mL had a significantly worse prognosis and significantly higher frequency of acute exacerbation, respectively. Higher serum periostin (92.5 ng/mL or higher; binary response for serum periostin) was an independent prognostic factor in multivariate analysis.

CONCLUSIONS

Serum periostin may reflect the extent of lung fibrosis and play an important role in pathogenesis of chronic bird-related HP. Elevated serum periostin could be a predictor of prognosis in patients with chronic bird-related HP.

The aging lung: tissue telomere shortening in health and disease

Background

Telomere shortening has been associated with several lung diseases. However, telomere length is generally measured in peripheral blood leucocytes rather than in lung tissue, where disease occurs. Consequently, telomere dynamics have not been established for the normal human lung nor for diseased lung tissue. We hypothesized an age- and disease-dependent shortening of lung tissue telomeres.

Methods

At time of (re-)transplantation or autopsy, 70 explant lungs were collected: from unused donors (normal, n = 13) and patients with cystic fibrosis (CF, n = 12), chronic obstructive pulmonary disease (COPD, n = 11), chronic hypersensitivity pneumonitis (cHP, n = 9), bronchiolitis obliterans syndrome (BOS) after prior transplantation (n = 11) and restrictive allograft syndrome (RAS) after prior transplantation (n = 14). Lungs were inflated, frozen and then scanned using CT. Four tissue cores from distinct lung regions were sampled for analysis. Disease severity was evaluated using CT and micro CT imaging. DNA was extracted from the samples and average relative telomere length (RTL) was determined using real-time qPCR.

Results

The normal lungs showed a decrease in RTL with age (p < 0.0001). Of the diseased lungs, only BOS and RAS showed significant RTL decrease with increasing lung age (p = 0.0220 and p = 0.0272 respectively). Furthermore, we found that RTL showed considerable variability between samples within both normal and diseased lungs. cHP, BOS and RAS lungs had significant shorter RTL in comparison with normal lungs, after adjustment for lung age, sex and BMI (p < 0.0001, p = 0.0051 and p = 0.0301 respectively). When investigating the relation between RTL and regional disease severity in CF, cHP and RAS, no association was found.

Conclusion

These results show a progressive decline in telomere length with age in normal, BOS and RAS lungs. cHP, BOS and RAS lungs demonstrated shorter RTL compared to normal lungs. Lung tissue RTL does not associate with regional disease severity within the lung. Therefore, tissue RTL does not seem to fully reflect peripheral blood telomere length.

Electronic supplementary material

The online version of this article (10.1186/s12931-018-0794-z) contains supplementary material, which is available to authorized users.

Chronic hypersensitivity pneumonitis: identification of key prognostic determinants using automated CT analysis

Background

Chronic hypersensitivity pneumonitis (CHP) has a variable disease course. Computer analysis of CT features was used to identify a subset of CHP patients with an outcome similar to patients with idiopathic pulmonary fibrosis (IPF).

Methods

Consecutive patients with a multi-disciplinary team diagnosis of CHP (n = 116) had pulmonary function tests (FEV1, FVC, DLco, Kco, and a composite physiologic index [CPI]) and CT variables predictive of mortality evaluated by analysing visual and computer-based (CALIPER) parenchymal features: total interstitial lung disease (ILD) extent, honeycombing, reticular pattern, ground glass opacities, pulmonary vessel volume (PVV), emphysema, and traction bronchiectasis. Mean survival was compared between both CHP and IPF patients (n = 185).

Results

In CHP, visual/CALIPER measures of reticular pattern, honeycombing, visual traction bronchiectasis, and CALIPER ILD extent were predictive of mortality (p < 0 · 05) on univariate analysis. PVV was strongly predictive of mortality on univariate (p < 0 · 0001) and multivariate analysis independent of age, gender and disease severity (represented by the CPI [p < 0 · 01]). CHP patients with a PVV threshold >6 · 5% of the lung had a mean survival (35 · 3 ± 6 · 1 months; n = 20/116 [17%]) and rate of disease progression that closely matched IPF patients (38 · 4 ± 2 · 2 months; n = 185).

Conclusions

Pulmonary vessel volume can identify CHP patients at risk of aggressive disease and a poor IPF-like prognosis.

Electronic supplementary material

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Factors associated with positive inhalation provocation test results in subjects suspected of having chronic bird-related hypersensitivity pneumonitis

BACKGROUND

Chronic bird-related hypersensitivity pneumonitis (BRHP) is often misdiagnosed as other interstitial lung diseases. While the utility of the inhalation provocation test (IPT) has been reported, the test is not commonly performed. In this study, we aimed to identify significant clinical variables associated with positive inhalation provocation test results in subjects suspected of having chronic BRHP. This would help clinicians decide whether to perform IPT in patients suspected of having chronic BRHP in real-life practice.

METHODS

We retrospectively evaluated 107 patients who underwent the IPT for suspected chronic BRHP. We used the IPT as the gold standard diagnostic tool for chronic BRHP.

RESULTS

Specific antibodies against pigeon dropping extract were documented in 52% of the IPT-positive patients but also in 38% of the IPT-negative patients (p=0.172). By using the logistic regression model, three significant predictors of IPT results were identified as follows: (1) a history of raising birds (odds ratio [OR] 3.112), (2) exposure to birds from the surrounding environment (OR 7.321), (3) white blood cell count (×10²/μl; OR 0.959).

CONCLUSIONS

This study demonstrates that current or past exposure to avian antigens is a positive predictor of positive IPT results in patients suspected of having chronic BRHP.

Antigen avoidance tests for diagnosis of chronic hypersensitivity pneumonitis

BACKGROUND

Chronic hypersensitivity pneumonitis (HP) is induced by the inhalation of specific antigens. Patients with chronic HP may be able to improve their prognosis by avoiding these antigens. Chronic HP is often difficult to distinguish from idiopathic interstitial pneumonias (IIPs).

OBJECTIVE

This study was performed to find out how antigen avoidance tests contribute to the diagnosis of chronic HP.

METHODS

A retrospective analysis was conducted on 265 patients who underwent 2-week antigen avoidance tests between April 2002 and March 2012. The patients were classified into the following categories: acute HP, chronic HP, collagen vascular disease-associated interstitial pneumonia (CVD-IP), lung dominant connective tissue disease (LD-CTD), and IIPs. The following seven clinical parameters were evaluated: vital capacity, alveolar-arterial oxygen pressure difference, Krebs von den Lungen-6, surfactant protein-D, white blood cell count, C-reactive protein, and body temperature. These parameters were compared between the chronic HP group and a control group consisting of CVD-IP, LD-CTD, and IIPs.

RESULTS

One-hundred and ninety-six patients with chronic HP and 43 control subjects were evaluated. All clinical parameters improved significantly in the chronic HP group but showed no significant changes in the control group. Four of the parameters changed significantly compared with the control group. Diagnostic criteria established using these data had a sensitivity of 51.0% and a specificity of 80.7%.

CONCLUSIONS

It was difficult to diagnose chronic HP based solely on 2-week antigen avoidance tests; however, improved clinical parameters among patients supported the diagnosis of HP.