Diagnosis of Hypersensitivity Pneumonitis in Adults. An Official ATS/JRS/ALAT Clinical Practice Guideline

Polymorphisms and haplotypes of TOLLIP and MUC5B are associated with susceptibility and survival in patients with fibrotic hypersensitivity pneumonitis

INTRODUCTION AND OBJECTIVES

Hypersensitivity pneumonitis (HP) is an interstitial lung disease with diverse clinical features that can present a fibrotic phenotype similar to idiopathic pulmonary fibrosis (IPF) in genetically predisposed individuals. While several single nucleotide polymorphisms (SNPs) have been associated with IPF, the genetic factors contributing to fibrotic HP (fHP) remain poorly understood. This study investigated the association of MUC5B and TOLLIP variants with susceptibility, clinical presentation and survival in Portuguese patients with fHP.

MATERIAL AND METHODS

A case-control study was undertaken with 97 fHP patients and 112 controls. Six SNPs residing in the MUC5B and TOLLIP genes and their haplotypes were analyzed. Associations with risk, survival, and clinical, radiographic, and pathological features of fHP were probed through comparisons among patients and controls.

RESULTS

MUC5B rs35705950 and three neighboring TOLLIP variants (rs3750920, rs111521887, and rs5743894) were associated with increased susceptibility to fHP. Minor allele frequencies were greater among fHP patients than in controls (40.7% vs 12.1%, P<0.0001; 52.6% vs 40.2%, P = 0.011; 22.7% vs 13.4%, P = 0.013; and 23.2% vs 12.9%, P = 0.006, respectively). Haplotypes formed by these variants were also linked to fHP susceptibility. Moreover, carriers of a specific haplotype (G-T-G-C) had a significant decrease in survival (adjusted hazard ratio 6.92, 95% CI 1.73-27.64, P = 0.006). Additional associations were found between TOLLIP rs111521887 and rs5743894 variants and decreased lung function at baseline, and the MUC5B SNP and radiographic features, further highlighting the influence of genetic factors in fHP.

CONCLUSION

These findings suggest that TOLLIP and MUC5B variants and haplotypes may serve as valuable tools for risk assessment and prognosis in fibrotic hypersensitivity pneumonitis, potentially contributing to its patient stratification, and offer insights into the genetic factors influencing the clinical course of the condition.

The clinical meaning of the UIP pattern in fibrotic hypersensitivity pneumonitis on cryobiopsy: A multicentre retrospective study

Fibrotic hypersensitivity pneumonitis (f-HP) is an interstitial lung disease in which various antigens in susceptible individuals may play a pathogenetic role. This study evaluates the role of transbronchial lung cryobiopsy (TBLC) and bronchoalveolar lavage (BAL) in identifying a UIP-like pattern and its association with fibrosis progression. We conducted a multicentre retrospective cohort study of patients diagnosed with f-HP who underwent BAL and TBLC between 2011 and 2023. A UIP-like pattern was defined by the presence of (A) patchy fibrosis and fibroblastic foci or (B) honeycombing ± (A). We investigated BAL's role in predicting UIP-like patterns within a clinical-radiological-serological framework, examining disease progression in these patients using spirometry and mortality data. A total of 195 patients were enrolled, 59 (30%) of whom exhibited a UIP-like pattern. These patients showed greater lung function decline, lower BAL lymphocytosis (14.4% vs. 37.4%, p < 0.001), higher nintedanib prescription (35% vs. 14%, p < 0.001), and higher 10-year mortality (HR 2.8, 95% CI 1.3-5.8, p = 0.004). f-HP patients with a UIP-like pattern exhibit worse clinical outcomes and higher mortality. In cases of low BAL lymphocytosis with a high pre-test clinical suspicion of f-HP, lung biopsy may not be necessary as it increases the likelihood of identifying a UIP-like pattern.

Diagnostic yield and safety of transbronchial lung cryobiopsy for diffuse parenchymal lung diseases diagnosis: Comparison between 1.7-mm and 1.9-mm probes

Purpose of the research: transbronchial lung cryobiopsy has been recently accepted as a valid and less invasive alternative to surgical lung biopsy. The purpose of this randomized controlled study was to evaluate, for the first time, the quality and safety of biopsy specimens obtained by using the new disposable 1.7-mm cryoprobe compared with the standard re-usable 1.9 mm cryoprobe in the diagnosis of diffuse parenchymal lung diseases. Methods: 60 consecutive patients were prospectively enrolled and randomly assigned to two different groups: 1.9 mm (group A) and 1.7 mm (group B); primary endpoints were pathological and multidisciplinary diagnostic yield, sample size and complication rate. Principal results: the pathological diagnostic yield of cryobiopsy was 100% in group A and 93.3% in group B (p = 0.718); cryobiopsy median diameter was 6.8 mm in group A and 6.7 mm in group B (p = 0,5241). Pneumothorax occurred in 9 patients in group A and 10 in group B (p = 0.951); mild-to-moderate bleeding in 7 cases and 9 cases in group A and B respectively (p = 0.559). No death or severe adverse events were observed. Conclusions: there was no statistically significant difference between the two groups, regarding diagnostic yield, adverse events and sampling adequacy.

Interstitial Lung Disease in Connective Tissue Disease

Connective tissue disease, also referred to as collagen vascular disease, encompasses a group of systemic inflammatory disorders characterized by autoimmune-mediated end-organ damage. Connective tissue diseases may result in a variety of interstitial lung disease patterns on computed tomography including usual interstitial pneumonia, nonspecific interstitial pneumonia (NSIP), organizing pneumonia and lymphoid interstitial pneumonia, with NSIP being the most common. As interstitial lung disease may be the only manifestation of connective tissue disease or present years before positive serologies, radiologists must be familiar with these patterns to provide diagnostic value.

Mechanisms on How Matricellular Microenvironments Sustain Idiopathic Pulmonary Fibrosis

In a susceptible individual, persistent, low-level injury to the airway epithelium initiates an exaggerated wound repair response, ultimately leading to idiopathic pulmonary fibrosis (IPF). The mechanisms driving this fibroproliferative response are not fully understood. Here, we review recent spatially resolved transcriptomics and proteomics studies that provide insight into two distinct matricellular microenvironments important in this pathological fibroproliferation. First, in response to alveolar epithelial injury, alveolar differentiation intermediate (ADI) basal cells arising from Secretoglobin (Scgb1a1) progenitors re-populate the injured alveolus remodeling the extracellular matrix (ECM). ADI cells exhibit an interconnected cellular stress response involving the unfolded protein response (UPR), epithelial-mesenchymal transition (EMT) and senescence pathways. These pathways reprogram cellular metabolism to support fibrillogenic ECM remodeling. In turn, the remodeled ECM tonically stimulates EMT in the ADI population, perpetuating the transitional cell state. Second, fibroblastic foci (FF) are a distinct microenvironment composed of activated aberrant "basaloid" cells supporting transition of adjacent mesenchyme into hyaluronan synthase (HAShi)-expressing fibroblasts and myofibroblasts. Once formed, FF are the major matrix-producing factories that invade and disrupt the alveolar airspace, forming a mature scar. In both microenvironments, the composition and characteristics of the ECM drive persistence of atypical epithelium sustaining matrix production. New approaches to monitor cellular trans-differentiation and matrix characteristics using positron emission tomography (PET)-magnetic resonance imaging (MRI) and optical imaging are described, which hold the potential to monitor the effects of therapeutic interventions to modify the ECM. Greater understanding of the bidirectional interrelationships between matrix and cellular phenotypes will identify new therapeutics and diagnostics to affect the outcomes of this lethal disease.

Silicosarcoidosis: Histologic and Clinical Features of an Occupational Granulomatous Disease

Sarcoidosis is a multisystem inflammatory disease of unknown etiology. Growing evidence indicates that occupational exposure to respirable crystalline silica (RCS) is associated with an increased incidence of sarcoidosis. Yet a diagnosis of sarcoidosis rarely prompts investigation to identify preventable exposures. We sought to elucidate features that identify this important clinical syndrome of silicosarcoidosis. We assembled a multinational case series of workers with sarcoidosis who also reported occupational RCS exposure. We characterized clinical and histopathologic findings using a standardized instrument. We also assessed lung specimens using a novel quantitative microscopy technique to measure birefringent dust density in silicosarcoidosis cases and compared them to control groups. We identified 35 silicosarcoidosis cases (97% male, mean age 48 years) from the United States, Israel, and Taiwan who reported 21 ± 9 years of RCS exposure. On histology scoring, 25/29 (86%) had granulomas and 17/18 (94%) with evaluable lung tissue had lymphocytic inflammation and/or lymphoid aggregates. Common lung interstitial findings included silicotic nodules (39%), mixed-dust macules/nodules (44%), and birefringent dust (50%). Quantitative birefringent dust density was significantly greater (p < 0.001) in silicosarcoidosis cases compared with healthy controls (147 ± 179 vs. 12 ± 9 particles/mm2) but lower than in coal miners with silica-related progressive massive fibrosis (623 ± 777). We found significant differences in the frequency of histologic abnormalities in large versus small biopsy specimens, with fewer findings of RCS exposure in smaller tissue samples. The use of the term silicosarcoidosis should enhance recognition of this significant exposure-related granulomatous lung disease and will help guide clinical management that addresses exposure prevention in combination with appropriate pharmacologic treatment.

Impact of Storage Conditions on Bronchoalveolar Lavage Fluid Analysis: A Human Study

Background: Bronchoalveolar lavage fluid (BALF) analysis is essential for the accurate diagnosis and management of interstitial lung diseases (ILDs). Despite established guidelines, variability in sample handling may affect diagnostic accuracy. This study aimed to evaluate how different storage conditions impact BALF cell counts and differentials to guide optimal sample handling practices. Methods: Forty patients who underwent BAL at Chiba University Hospital from June to December 2024 were included. BALF samples were allocated into five groups based on processing conditions: immediate analysis within 1 h, storage at either at 4 °C or room temperature (RT) for 6 h, or storage at 4 °C or RT for 24 h. Total cell counts (TCC) and differential counts were measured and compared among conditions. Results: TCC remained stable over 24 h at both 4 °C (p = 0.86) and RT (p = 0.90). Similarly, the percentages of eosinophils, lymphocytes, and macrophages did not significantly change at either temperature (all p > 0.05). Notably, neutrophil percentages showed a significant decline over time under both storage conditions-at 4 °C (p = 0.02) and at room temperature (p < 0.01). Post hoc tests revealed a notable decreasing trend at 6 h and significant reductions by 24 h at 4 °C (p = 0.09 and p = 0.02, respectively), and significant decreases at both 6 and 24 h at RT (p = 0.01, <0.01). Conclusions: Among the various cell types in BALF, neutrophil proportions are particularly susceptible to storage conditions, showing a significant decline over time-especially at room temperature-while other cell types remain stable for up to 24 h. Therefore, prompt processing or appropriate refrigeration of BALF is essential to ensure reliable cytological analysis and accurate clinical interpretation.

Clinical impact of radiological pleuroparenchymal fibroelastosis-like lesions in fibrotic hypersensitivity pneumonitis and efficacy of antigen avoidance

BACKGROUND

Pleuroparenchymal fibroelastosis (PPFE)-like lesions are frequently observed on high-resolution computed tomography in patients with fibrotic hypersensitivity pneumonitis (f-HP). This study aimed to evaluate the association of these lesions with overall survival and disease progression in f-HP patients and to examine the efficacy of antigen avoidance.

METHODS

A retrospective observational study of patients with f-HP was conducted in a single center. High-resolution computed tomography was used to assess the presence of radiological PPFE-like lesions.

RESULTS

Radiological PPFE-like lesions were detected in 48 of the 107 patients analyzed (44.9 %). Lesions were significantly associated with death from any cause (hazard ratio, 2.32; 95 % confidence interval [CI], 1.13-4.95; p = 0.024) and disease progression (odds ratio, 2.90; 95 % CI, 1.17-7.50; p = 0.024). Antigen non-avoidance was a significant predictor of worse overall survival (hazard ratio, 2.67; 95 % CI, 1.31-5.76; p = 0.008) and disease progression (odds ratio, 3.62; 95 % CI, 1.52-8.96; p = 0.004). Overall survival was significantly better (p = 0.116) and annual decline in forced vital capacity was significantly smaller (p = 0.002) in patients with radiological PPFE-like lesions who achieved antigen avoidance than in those who did not.

CONCLUSIONS

Radiological PPFE-like lesions were associated with worse survival and decline in forced vital capacity in patients with f-HP. Antigen avoidance may improve survival and prevent disease progression in f-HP patients with lesions.

Fibrotic Hypersensitivity Pneumonitis: A Diagnostic Challenge Leading to Lung Transplantation

Background/Objectives: Hypersensitivity pneumonitis (HP), a subtype of interstitial lung disease (ILD), is often misdiagnosed as idiopathic pulmonary fibrosis (IPF), particularly when the causative antigen cannot be identified. Typically resulting from chronic exposure to inhaled organic particles smaller than 5 microns, HP presents a diagnostic challenge. This report outlines a case of fibrotic HP initially misclassified as asthma. No triggering antigen was identified despite extensive investigation. The disease progressed despite corticosteroid, immunosuppressive, and antifibrotic therapy, ultimately leading to an advanced fibrotic stage and requiring lung transplantation. This clinical course is rare and infrequently reported, particularly in cases requiring lung transplantation without an identifiable causative antigen. Such progression is uncommon and underreported, especially in patients initially misclassified as having asthma. Methods: Medical records of 24 patients diagnosed with HP were reviewed. Only one case demonstrated progression to fibrotic HP; this case was selected for detailed analysis. Results: Clinical and functional deterioration occurred despite standard therapy. Given the advanced stage of fibrosis and treatment resistance, lung transplantation was deemed the next appropriate therapeutic option. Conclusions: HP remains underdiagnosed due to difficulties in identifying the causative antigen and overlapping features with other ILDs. Early and accurate differentiation from IPF is essential, particularly in progressive fibrotic forms unresponsive to conventional therapies.

ITGAV, a specific biomarker associated with the pathogenesis of idiopathic pulmonary fibrosis

Objective Idiopathic pulmonary fibrosis (IPF), which radiologically/pathologically manifests mainly as usual interstitial pneumonia (UIP), is easily confused with chronic hypersensitivity pneumonitis (CHP) and collagenous vascular disease in clinical settings, affecting the physician's diagnosis and treatment. Accurate identification of IPF from various diseases presenting as UIP is essential for effective diagnosis and therapy. Methods Gene expression data of CHP, IPF, and rheumatoid arthritis-UIP samples were downloaded from the GEO database, and specific biomarkers were identified to differentiate idiopathic UIP/IPF from secondary UIP. We compared gene expression of specific biomarkers between control, secondary UIP, and IPF groups. The mechanism of specific biomarkers in PF was explored by immunohistochemistry, quantitative polymerase chain reaction, immunofluorescence, and flow cytometry. Results We identified integrin alpha V (ITGAV) as a specific biomarker for distinguishing IPF from secondary UIP. We observed a gradual increase in ITGAV expression across the control, secondary UIP, and IPF groups. Animal studies indicated that the elevated expression of ITGAV in various immune cells, particularly in monocyte-derived macrophages, contributed to the development of PF. Conclusion ITGAV is a specific biomarker linked to the pathogenesis of IPF. The identification of ITGAV provides new perspectives for clinical diagnosis, mechanistic studies and new drug development in IPF.

Exploring the Potential of a P2X3 Receptor Antagonist: Gefapixant in the Management of Persistent Cough Associated with Interstitial Lung Disease

Background: Interstitial lung disease (ILD) is characterized by pulmonary inflammation and fibrosis associated with persistent and refractory cough that significantly hinders quality of life. Conventional treatments for ILD-associated cough have shown limited efficacy, necessitating alternative therapeutic approaches. Gefapixant, a P2X3 receptor antagonist, can potentially alleviate chronic cough by inhibiting the ATP-mediated activation of sensory C-fibers, but its efficacy in ILD-associated cough remains unclear. This study observed the effects of gefapixant on ILD-associated refractory chronic cough. Methods: This prospective study enrolled patients with ILD-associated refractory chronic cough who received gefapixant at Sapporo Medical University Hospital between July 2022 and November 2023. Cough frequency, Leicester Cough Questionnaire (LCQ) score, cough severity visual analog scale (Cough VAS), and taste VAS were evaluated at baseline and at 2, 4, and 8 weeks after gefapixant administration. Results: Six patients completed the study. Their ILD subtypes included idiopathic pulmonary fibrosis (IPF), nonspecific interstitial pneumonia (NSIP), and connective tissue disease-associated ILDs (CTD-ILDs). After 8 weeks, the cough frequency decreased from 88.5 to 44.3 episodes per 30 min, LCQ scores increased from 8.3 to 13.6, and cough VAS scores decreased from 75.8 to 40.2. However, statistical significance was not reached due to high interindividual variability, with gefapixant being effective in some and ineffective in others. The most common adverse event was taste disorder, leading to discontinuation in one patient, but symptoms tended to lessen over the course of treatment. Conclusions: Gefapixant appears to be effective in reducing refractory cough related to ILD, although these results were not statistically significant because its effectivity widely varied across individuals. Further investigation is needed to identify patient subgroups with the greatest potential for treatment responsiveness.

Hypersensitivity pneumonitis associated with home mold exposure: A retrospective cohort analysis

BACKGROUND

Home mold exposure is a commonly overlooked cause of hypersensitivity pneumonitis. This is in part due to the limited literature supporting the association as well as the lack of exposure characterization available in reported cases. Notably, climate change, extreme weather patterns and frequent flooding continue to create conditions that promote home mold growth. As remediation has the potential to improve outcomes, clinicians need to remain vigilant in searching for and identifying potential mold exposure in suspected HP patients. The purpose of this study is to describe a large retrospective cohort of patients with home mold associated HP.

METHODS

HP patients were identified retrospectively from our single center interstitial lung disease (ILD) database between 2011-2019. Patients with a moderate, high, or definite confidence diagnosis of HP were included. The presence of residential mold exposure was confirmed by medical chart review by a pulmonologist trained in exposure assessment.

RESULTS

Home mold exposure was identified as the culprit antigen in 54 of 231 hypersensitivity pneumonitis patients. An invasive procedure (bronchoalveolar lavage, transbronchial biopsy, and/or surgical lung biopsy) was performed to confirm the diagnosis of HP in 85.7% of the cohort. Home mold was principally caused by chronic and/or recurring water intrusion. The most common locations of mold within the home included the bathroom, bedroom, and air conditioning unit. Transplant free survival was 97.7 months, which did not differ from the 50 HP patients in our cohort with HP associated with a mold exposure outside the home or patients in our cohort with HP associated with avian antigen exposure. Of the 41 patients who removed the exposure, 5 (12.2%) had a > 10% improvement in FVC, including 4 with fibrotic HP.

CONCLUSION

Our study is the largest to report an association between HP and home mold exposure and is the first report from the region of north Texas. As climate change continues to disrupt weather patterns causing storms and flooding in certain areas, clinicians should remain alert to the presence of mold and its potential contribution to development of HP.

The Role of Bronchoscopy in the Diagnosis of Interstitial Lung Disease: A State-of-the-Art Review

The diagnostic evaluation of interstitial lung diseases (ILDs) remains challenging due to their heterogeneous etiologies and overlapping clinical and radiographic patterns. A confident diagnosis often necessitates histopathological sampling, particularly when high-resolution computed tomography and serologic assessments are inconclusive. While surgical lung biopsy (SLB) has long been considered the diagnostic gold standard, its invasiveness, associated morbidity, and limited feasibility in high-risk patients have driven the pursuit of less invasive alternatives. Here, we review the current applications, diagnostic yield, procedural techniques, and complications of several bronchoscopic modalities. Bronchoalveolar lavage (BAL) aids in characterizing inflammatory profiles and differentiating among conditions such as hypersensitivity pneumonitis, sarcoidosis, and eosinophilic pneumonia. Endobronchial biopsies (EBBs) and endobronchial ultrasound transbronchial needle aspiration (EBUS-TBNA) are valuable in diagnosing granulomatous diseases with lymphadenopathy. Transbronchial lung biopsy (TBLB) is effective for peribronchial and centrilobular diseases but is limited by small sample size and tissue distortion. Transbronchial lung cryobiopsy (TBC) enables acquisition of larger, well-preserved parenchymal tissue samples from the peripheral lung. Over recent years, studies have demonstrated that TBC, when interpreted within a multidisciplinary discussion (MDD), achieves diagnostic concordance rates with SLB exceeding 75%, and up to 95% in cases where high diagnostic confidence is reached. When performed in experienced centers using standardized protocols, TBC is considered a viable first-line histopathologic tool in the diagnostic evaluation of ILD. Adequate training and standardization of the TBC procedure are needed to ensure low complication rates and a high yield.

Evaluation of efficacy and safety of rituximab in patients with progressive interstitial lung disease (ILD) with inflammatory component (EvER-ILD2): A multicentre double-blind placebo-controlled randomized trial

INTRODUCTION

Progressive interstitial lung diseases (ILDs) are rare but severe diseases, with high mortality and morbidity, with no effective pharmacological treatment allowing for long-term remission, and therefore no clear therapeutic recommendations. Several ILDs present inflammatory components (ILDic), which may justify the use of anti-inflammatory and immunosuppressive drugs, as first-step therapy. Except for systemic sclerosis (SSc)-ILD and sarcoidosis, the evidence in favor of this approach is very weak. The EvER-ILD2 study is the first one to prospectively evaluate the efficacy and safety of rituximab (RTX) versus placebo in a broad range of progressive ILD outside sarcoidosis and connective tissue diseases. A pharmacokinetic-pharmacodynamic analysis based on RTX serum concentrations will allow identification of potential factors associated with therapeutic response and/or adverse effects.

METHODS

EvER-ILD2 study is a French multicentre, prospective, randomized, double blind, placebo-controlled, superiority trial. Patients with progressive ILDic will be randomized into 2 groups of treatment: one course of RTX (RTX group) and one course of placebo (Placebo group). The primary outcome is the change in Forced Vital Capacity (FVC, mL) from baseline to 6 months. Several clinical, biological, and quality of life secondary outcomes will be measured at 3 and 6 months. A sample size of 126 patients (63 patients per group) would allow to show a 100 mL difference between groups in the change of FVC from baseline to 6 months, based on a common standard deviation for FVC change of 200 mL with a power of 80% and a two-sided alpha of 5%.

ETHICS AND DISSEMINATION

The protocol was approved by the French Research Ethics Committee (CPP Ile de France VI) on September 27, 2022, and by the French competent authority on October 02, 2022. This article refers to protocol V1, dated September 2022. An independent data safety monitoring board will review safety data for the duration of the trial. Results will be disseminated via peer reviewed publication and presentation at international conferences.

TRIAL REGISTRATION NUMBER

NCT05596786 (clinicaltrials.gov), EU-CT number 2022-500,375-31-00 (European Medicines agency).

Acute Pulmonary Injury: An Imaging and Clinical Review

Acute pulmonary injury can occur in response to any number of inciting factors. The body's response to these insults is much less diverse and usually categorizable as one of several patterns of disease defined by histopathology, with corresponding patterns on chest CT. Common patterns of acute injury include diffuse alveolar damage, organizing pneumonia, acute eosinophilic pneumonia, and hypersensitivity pneumonitis. The ultimate clinical diagnosis is multidisciplinary, requiring a detailed history and relevant laboratory investigations from referring clinicians, identification of injury patterns on imaging by radiologists, and sometimes tissue evaluation by pathologists. In this review, several clinical diagnoses will be explored, grouped by imaging pattern, with a representative clinical presentation, a review of the current literature, and a discussion of typical imaging findings. Additional information on terminology and disambiguation will be provided to assist with comprehension and standardization of descriptions. The focus will be on the acute phase of illness from presentation to diagnosis; treatment methods and chronic sequela of acute disease are beyond the scope of this review.

Advances in Concept and Imaging of Interstitial Lung Disease

Although idiopathic pulmonary fibrosis (IPF) is a type of idiopathic interstitial pneumonia (IIP), it is different from other IIPs. IPF also differs from interstitial lung disease (ILD) with known causes, including connective tissue disease, exposure, cysts and/or airspace filling disease, and sarcoidosis. More than 90% of IPFs demonstrate progressive disease. Non-IPF ILD has been classified as progressive pulmonary fibrosis on the basis of disease behavior (progressive disease that gets worse over time) as opposed to classification based on cause and/or morphologic characteristics. Progressive fibrosis predictors in ILD include demographic characteristics, underlying connective tissue disease, more extensive disease at CT, honeycombing and usual interstitial pneumonia (UIP) pattern at CT, and greater impairment of lung function. Hypersensitivity pneumonitis (HP), a type of ILD, is separated into fibrotic and nonfibrotic types. Extensive peribronchiolar metaplasia supports the diagnosis of fibrotic HP over UIP, as does predominantly peribronchiolar disease with relative subpleural sparing at CT. Interstitial lung abnormality (ILA) is incidentally identified at CT; thus, ILA is under radiologist purview. Subpleural fibrotic ILA is a prognostic imaging biomarker, predictive of worse prognosis. Photon-counting CT can provide high spatial resolutions of up to 125 μm (in-plane) and 200 μm (through-plane) for improved evaluation of abnormalities.

Progressive course of anti-nuclear matrix protein-2 (NXP-2) positive-interstitial lung disease

BACKGROUND

Evaluating the etiology of interstitial lung disease (ILD) commonly involves ordering a myositis panel containing myositis-specific antibodies (MSAs), including anti-NXP-2. However, little is known about the presentation of patients with ILD and anti-NXP-2 positivity. We sought to define the course of anti-NXP-2-positive ILD in order to guide prognosis and potential treatment strategies.

METHODS

We performed a retrospective chart review of patients with positive anti-NXP-2 antibodies who presented to two ILD referral centers in Boston, MA between 2012 and 2024. Patients were identified by query of the electronic medical record for patients positive for anti-NXP-2. We included those anti-NXP-2 positive patients with ILD on chest computed tomography (CT). Data regarding clinical presentation and disease course were abstracted from the medical record. For patients following longitudinally in the ILD clinic, we conducted survival analyses for ILD progression (composite of PFT progression, hospitalization, or death) using Kaplan-Meier curves and log-rank tests. Additionally, we used a Cox proportional-hazards model, adjusting for age, gender, forced vital capacity (FVC) at baseline, and immunosuppression to calculate hazard ratios. ILD patients with MSA-positive, NXP-2-negative ILD served as the comparator group.

RESULTS

31 patients were identified (mean 70 years, SD 9). Three were diagnosed with dermatomyositis (DM) prior to presentation, but the remaining had ILD as the only manifestation of connective tissue disease. Most (97%) patients were symptomatic with dyspnea and/or cough at presentation. Other autoantibody positivity was common; only 42% were positive for anti-NXP-2 alone without positivity for other autoimmune serologies, including MSAs known to be associated with ILD. Clinical follow up data were available for 28 patients for a median follow up period of 24 months (range <1 month-13 years). A majority (61%) were treated with immunosuppression, antifibrotics, or both. Over one third experienced acute exacerbation of ILD or death (N = 11, 35%). Progression-free survival was similar to that of other MSA-positive ILD patients, regardless of whether anti-NXP-2 was positive alone or co-positive for other autoantibodies.

CONCLUSIONS

We present the largest single series of anti-NXP-2-positive ILD. Anti-NXP-2-positive ILD can occur in the absence of DM/PM and can manifest as progressive pulmonary disease that is similar to other MSA-positive ILDs.

Challenges in recognizing airway-centered fibrosis: Observer concordance and its role in fibrotic hypersensitivity pneumonitis

BACKGROUND

The interobserver agreement regarding airway-centered fibrosis (ACF), the key diagnostic feature of fibrotic hypersensitivity pneumonitis (fHP) has not been sufficiently addressed to date. We applied digital image analysis to investigate this issue and extracted histological features of ACF to correlate with fHP diagnosis.

METHODS

A total of 111 selected glass slides from 17 fHP and 30 idiopathic pulmonary fibrosis (IPF) were scanned and seven expert pulmonary pathologists were tasked with digital annotation of ACF. Interobserver agreement on annotated ACF was assessed using Fleiss' kappa value. ACF recognized by majority of pathologists (4 or more) were considered as consensus ACF (cACF), and their frequencies were compared between fHP and IPF cases.

RESULTS

Fleiss' kappa agreement in ACF recognition was 0.32 among seven pathologists. A significant difference between cryobiopsy and VATS specimens regarding an average ACF count per slide (p = 0.012) was found. The number of cACFs in a single case ranged from 0 to 20 (mean 5.71) for fHP cases and 0 to 13 (mean 1.80) for IPF cases (p = 0.011). When limited to surgical biopsies, the average number of cACF was 10.3 for fHP vs. 1.68 for IPF (p < 0.001). The common characteristic features of cACF in fHP were their confinement to the vicinity of respiratory bronchioles, frequent association with peribronchiolar metaplasia, and mild to moderate lymphocytic infiltration.

CONCLUSIONS

The recognition of ACF varies widely among pathologists. We identified common histologic features of ACF in fHP cases, proposing criteria for ACF recognition in fHP.

Assessment of lung function and severity grading in interstitial lung diseases (% predicted versus z-scores) and association with survival: A retrospective cohort study of 6,808 patients

BACKGROUND

Pulmonary function tests (PFTs) are essential for predicting outcomes in interstitial lung disease (ILD). In 2022, an expert panel recommended using z-scores instead of the traditional % predicted cut-off values to interpret the severity of PFT abnormalities which may lead to discordant classifications in some patients. To assess the magnitude and prognostic impact of this phenomenon we compared these two approaches in predicting all-cause mortality in a large cohort of patients with ILDs.

METHODS AND FINDINGS

We retrospectively analyzed data from a tertiary referral center for patients with ILDs. Absolute FEV1, FVC, TLC, and TLCO values from patients' first presentations were transformed and presented as % predicted and z-scores using the most recent global lung initiative (GLI) reference values. Results were categorized for severity according to % predicted and z-score levels. Predictors of all-cause mortality over a 14-year follow-up were determined using Kaplan-Meier survival analysis and Cox proportional hazards regression. Between January 2009 and March 2023, 6,808 patients with ILDs were evaluated at the National TB and Lung Diseases Research Institute in Warsaw, Poland. Most were diagnosed with sarcoidosis, fibrotic ILD, or non-fibrotic ILD. At their first presentation, 13.2% had airway obstruction, 23.1% had low FVC (indicative of restriction by spirometry), and 45.6% had a reduced lung transfer factor (TLCO). Reclassification of spirometric indices occurred in 26.8% of patients for FEV1 and 24.6% for FVC among those with abnormal results, with most being reassigned to a less severe categories. For TLCO, 28.1% of patients with reduced values were reclassified, with most shifting to more severe categories. During the follow-up, 1,525 (22.4%) of patients died. Both low FVC and low TLCO predicted all-cause mortality, with z-score thresholds showing stronger associations with mortality. A one-unit decrease in the FVC z-score was associated with a 10.3% increase in the risk of death, while a one-unit decrease in TLCO z-score was linked to an over 30% increase in mortality risk. Limitations of this retrospective single-center study include lack of data on cause-specific mortality, potential residual confounding, and limited generalizability to non-Caucasian or younger populations.

CONCLUSIONS

The recently recommended use of z-scores leads to significant reclassification of lung function results in patients with ILDs, largely driven by age. This approach is justified by its stronger prognostic associations. Severe TLCO impairment remains a robust predictor of mortality in ILDs.

Impact of biopsy number and radiologic pattern on diagnostic yield and complications of transbronchial lung cryobiopsy in interstitial lung diseases: a multi-center retrospective study

Background

Given that transbronchial lung cryobiopsy (TBLC) is recommended as a surrogate for surgical lung biopsy (SLB) in the diagnosis of interstitial lung disease (ILD), few studies have evaluated the optimal number of biopsy sample or the impact of radiologic pattern on the diagnostic yield and postoperative complications. This study aimed to investigate how biopsy sample number and radiologic patterns affect diagnostic yield and complications.

Methods

We conducted a multi-center retrospective study including 334 consecutive ILD patients who underwent TBLC. The impact of number of biopsy sample and radiologic pattern on diagnosis yields and postoperative complications was assessed. Logistic regression analyses were used to explore the risk factors for complications.

Results

The histopathologic and multidisciplinary discussion (MDD) diagnostic yields were 70.06% (234/334) and 86.23% (288/334). Moderate-severe bleeding and pneumothorax occurred in 39 (11.68%) and 29 (8.68%) cases, respectively. The MDD diagnostic yield was higher in patients with non-fibrotic pattern on high-resolution computed tomography (HRCT) compared to those with a fibrotic pattern (88.11% vs. 75.00%, P=0.02). However, the diagnostic yields or postoperative complications were comparable when obtaining three or more than three biopsy samples. Multiple lobe biopsy and number of biopsy samples were associated with bleeding [odds ratio (OR) =3.675, 95% confidence interval (CI): 1.414-9.553, P=0.008; OR =0.649, 95% CI: 0.470-0.895, P=0.009], while a fibrotic pattern increased the risk of pneumothorax (OR =3.479, 95% CI: 1.210-10.005, P=0.02).

Conclusions

This study showed that obtaining three biopsy samples is appropriate to achieve an adequate diagnostic yield, while procedure methods are associated with complications. Further well-designed studies are required to standardize TBLC procedures.

Expert consensus on cancer treatment-related lung injury

Background

Although advancements in cancer therapies have substantially improved the survival of cancer patients, these treatments may also result in acute or chronic lung injury. Cancer treatment-related lung injury (CTLI) presents with a diverse array of clinical manifestations and can involve multiple sites. Due to the lack of specific diagnostic protocols, CTLI can deteriorate rapidly and may be life-threatening if not promptly addressed. Unfortunately, there is no universally accepted consensus document on the diagnosis and management of CTLI.

Methods

A multidisciplinary panel comprising experts from respiratory and critical care medicine, oncology, radiation oncology, thoracic surgery, radiology, pathology, infectious diseases, pharmacy, and rehabilitation medicine participated in this consensus development. Through a systematic literature review and detailed panel discussions, the team formulated nine key recommendations.

Results

This consensus document addresses the concept, epidemiology, pathogenesis, risk factors, diagnostic approach, evaluation workflow, management strategies, differential diagnosis, type-specific management and clinical staging of CTLI. Emphasis is placed on raising awareness among clinicians and therapeutic practices through comprehensive guidelines.

Conclusions

The consensus provides a detailed diagnostic protocol for CTLI and introduces a structured management framework based on grading, typing, and staging. It highlights the critical role of multidisciplinary team (MDT) collaboration and emphasizes the need for individualized, whole-process patient care strategies to optimize clinical outcomes.

Alveolar cell composition in interstitial lung disease and the development of a pulmonary progressive fibrosing phenotype: a retrospective cohort study

BACKGROUND

Immunological bronchoalveolar lavage (iBAL) is a frequently employed diagnostic tool in interstitial lung disease (ILD). The association between iBAL cellular composition and disease progression remains elusive. We evaluated whether the alveolar cellular composition at initial diagnosis is predictive of the development of progressive pulmonary fibrosis (PPF) in patients with ILD.

METHODS

A retrospective analysis of 111 patients diagnosed with ILD who underwent iBAL for diagnostic purposes between January 2018 and January 2023 was conducted. The identification of PPF was based on the criteria outlined in the ATS/ERS/JRS/ALAT clinical practice guidelines. Clinical data, pulmonary function tests, radiological imaging, and BAL cellular composition were collected. Groups were compared using the non-parametric Wilcoxon rank sum test. Linear mixed-effect modelling was used to assess the association between baseline cell composition and longitudinal lung function decline.

RESULTS

A total of 33.3% of patients exhibited a PPF phenotype. A significant association between baseline iBAL CD4 + and CD8 + T cell percentages and forced vital capacity (FVC) decline within the first year was observed. Other cell types were not associated with ILD progression within one-year of follow-up.

CONCLUSIONS

CD4 + and CD8 + T cell percentages significantly correlated with FVC changes in patients with fibrotic ILD. No further associations were found between the baseline iBAL cellular profiles and disease progression. These findings suggest that baseline iBAL cellular profiles may hold some promise in predicting fibrotic ILD disease progression. Further (prospective) studies using larger cohorts may be needed to elucidate the association between the cellular composition of iBAL fluid and pulmonary fibrosis progression.

Advances in management of pulmonary fibrosis

Pulmonary fibrosis care, affecting both idiopathic pulmonary fibrosis and other forms of interstitial lung disease (ILD) characterised by fibrosis, has transformed with a range of innovations that affect the diagnosis, treatment and prognosis of this condition. Pharmacotherapeutic options have expanded, with increased indications for the application of effective antifibrotic therapy in non-IPF progressive pulmonary fibrosis as a solo treatment or combined with immunosuppression, emerging evidence for immunomodulatory therapy including biologic agents and greater access to clinical trials. The diagnostic approach to unclassifiable ILD now includes transbronchial lung cryobiopsy, a less invasive method to obtain histopathology with reduced morbidity and mortality compared to surgical lung biopsy. A multidisciplinary approach optimises the care of people with ILD and includes non-pharmacological management, addressing significant comorbidities, symptom care and advanced care planning. This review will summarise recent updates in pulmonary fibrosis management.

Complete Blood Cell Count Parameters Predict Mortality in Patients with Hypersensitivity Pneumonitis

Background: Hypersensitivity pneumonitis (HP) represents a chronic lung disease with an unpredictable clinical course. There is a pressing need for clinically applicable prognostic biomarkers in patients with HP. Methods: This was an observational, retrospective study. We investigated the prognostic potential of complete blood count parameters in treatment-naïve patients diagnosed with HP between 15 December 2010 and 1 October 2023. Receiver operating characteristic (ROC) curve analysis identified the optimal cut-off thresholds for each parameter in terms of mortality prediction. Results: We included 129 patients diagnosed with HP [median age: 68.0 years (95% CI: 65.0 to 69.0), fibrotic HP: n = 85, 65.9%]. Patients with HP and an eosinophil count > 160 cells/μL [ROC curve, area under curve (AUC): 0.61] exhibited increased mortality risk compared to patients with HP and an eosinophil count ≤ 160 cells/μL [Kaplan-Meier, HR: 2.95 (95% CI: 1.36 to 6.42), p = 0.006]. Patients with HP and a monocyte count > 350 cells/μL (ROC curve, AUC: 0.52) had worse survival compared to patients with HP and a monocyte count lower than this threshold [Kaplan-Meier, HR: 2.48 (95% CI: 1.03 to 5.09), p = 0.04]. Patients with HP and an eosinophil-lymphocyte ratio (ELR) > 0.09 (ROC curve, AUC: 0.64) had a higher risk of mortality compared to patients with HP and ELR ≤ 0.09 [Kaplan-Meier, HR: 2.75 (95% CI: 1.3 to 5.78), p = 0.008]. Conclusions: This study demonstrated that eosinophil count, monocyte count, and ELR could be prognostic biomarkers in patients with HP. Further studies aiming to validate the prognostic potential of complete blood count parameters in patients with HP are greatly anticipated.

Diagnostic Utility of Bronchoalveolar Lavage Flow Cytometric Leukocyte Profiling in Interstitial Lung Disease and Infection

Interstitial lung diseases (ILD) represent a diverse group of disorders that primarily affect the pulmonary interstitium and, less commonly, involve the alveolar and vascular epithelium. Overlapping clinical, radiological and histopathological features make proper classification difficult, requiring multiple complementary methodologies, including flow cytometry of bronchoalveolar lavages (BAL). This retrospective study analyzed BAL flow cytometry data from 1074 real-life patients, quantifying alveolar macrophages, CD4/CD8 lymphocytes, neutrophils, eosinophils, and CD1a+ Langerhans cells, with the aim of evaluating its diagnostic utility in ILD and pulmonary infection. Clustering and logistic regression analyses identified seven distinct leukocyte profiles: lymphocytic (associated with hypersensitivity pneumonitis, cryptogenic organizing pneumonia, and lymphocytic interstitial pneumonia), sarcoidosis, macrophagic (including nonspecific interstitial pneumonia, desquamative interstitial pneumonitis, pneumoconiosis, and unclassifiable ILD), neutrophilic (including usual interstitial pneumonia, respiratory bronchiolitis ILD, and acute interstitial pneumonia), infectious diseases, eosinophilic ILD, and Langerhans cell histiocytosis. The estimated leukocyte profiles were associated with different overall survival (OS) outcomes. Neutrophilic profiles, both infectious and non-infectious, correlated with poorer OS, particularly in patients without pulmonary fibrosis. Furthermore, corticosteroids and other immunosuppressive therapies did not show significant OS differences across leukocyte profiles. Although the gold standard in BAL cytology continues to be cytopathology, these results support BAL flow cytometry as a rapid and reliable complementary tool to aid in the classification of interstitial lung diseases based on immune cell profiles, providing valuable predictive information and contributing to personalized therapeutic approaches.

Early intervention of nutritional education for idiopathic pleuroparenchymal fibroelastosis of interstitial lung disease

BACKGROUND

Lower body mass index (BMI) and weight loss are associated with disease progression and poor prognosis in patients with interstitial lung diseases (ILDs). Particularly in typically slim patients with idiopathic pleuroparenchymal fibroelastosis (iPPFE), prompt nutritional support may be essential.

METHODS

We screened 93 consecutive patients diagnosed with PPFE at our hospital and included 63 patients with idiopathic PPFE in the final analysis. They were categorized into two groups-early intervention and non-early intervention-based on whether they received nutritional education by dietitian nutritionists within 6 months of diagnosis. We assessed risk factors for mortality using Cox regression analysis and evaluated body weight trajectories over time using individual scatter plots with regression lines.

RESULTS

Among the 63 patients, 22 received early intervention and 41 did not. Early intervention in patients at an initial stage-defined in this study as FVC ≥70 % and no significant weight loss in the past year-was associated with a significantly slower rate of body weight decline compared to non-early intervention. However, survival did not differ significantly between groups regardless of FVC or weight loss status at diagnosis.

CONCLUSIONS

We outlined a structured nutritional education program delivered by dietitian nutritionists at our hospital. While the intervention did not improve survival, early nutritional education in patients at an initial stage slowed the rate of weight loss, which may contribute to improved prognosis. Maintaining body weight through early nutritional support may be an important therapeutic strategy in the management of iPPFE.

A case of hypersensitivity pneumonitis caused by a humidifier: diagnosis and management in rural practice

Hypersensitivity Pneumonitis (HP) is an allergic interstitial lung disease that arises from type III and IV allergic reactions. During the COVID-19 outbreak, HP was established as having similar manifestations to COVID-19. In remote rural regions of Japan, where respiratory specialists are not readily accessible, HP is not always easy to differentiate, and establishing a definitive diagnosis can be challenging due to insufficient laboratory examinations. Herein, we present a case of a moderately definite diagnosis of acute non-fibrosing HP. The foundation of treatment included antigen avoidance, which necessitates a comprehensive analysis of the patient's medical history. In instances where anomalous chest imaging outcomes are observed, it is imperative to conduct a comprehensive review of the patient's medical history, and to consider the possibility of HP.

ESR Essentials: imaging in fibrotic lung diseases-practice recommendations by the European Society of Thoracic Imaging

Fibrotic lung diseases (FLDs) represent a subgroup of interstitial lung diseases (ILDs), which can progress over time and carry a poor prognosis. Imaging has increased diagnostic discrimination in the evaluation of FLDs. International guidelines have stated the role of radiologists in the diagnosis and management of FLDs, in the context of the interdisciplinary discussion. Chest computed tomography (CT) with high-resolution technique is recommended to correctly recognise signs, patterns, and distribution of individual FLDs. Radiologists may be the first to recognise the presence of previously unknown interstitial lung abnormalities (ILAs) in various settings. A systematic approach to CT images may lead to a non-invasive diagnosis of FLDs. Careful comparison of serial CT exams is crucial in determining either disease progression or supervening complications. This 'Essentials' aims to provide radiologists a concise and practical approach to FLDs, focusing on CT technical requirements, pattern recognition, and assessment of disease progression and complications. Hot topics such as ILAs and progressive pulmonary fibrosis (PPF) are also discussed. KEY POINTS: Chest CT with high-resolution technique is the recommended imaging modality to diagnose pulmonary fibrosis. CT pattern recognition is central for an accurate diagnosis of fibrotic lung diseases (FLDs) by interdisciplinary discussion. Radiologists are to evaluate disease behaviour by accurately comparing serial CT scans.

The lung microbiome in interstitial lung disease

Interstitial lung disease (ILD) is a heterogeneous chronic form of lung disease. The pathogenesis of ILD is poorly understood and a common form of ILD, idiopathic pulmonary fibrosis (IPF) is associated with poor prognosis. There is evidence for substantial dysregulated immune responses in ILD. The microbiome is a key regulator of the immune response, and the lung microbiome correlates with alveolar immunity and clinical outcomes in ILD. Most observational lung microbiome studies have been conducted in patients with IPF. A consistent observation in these studies is that the bacterial burden of the lung is elevated in patients with IPF and predicts mortality. However, our understanding of the mechanism is incomplete and our understanding of the role of the lung microbiome in other forms of ILD is limited. The microbiomes of the oropharynx and gut may have implications for the lung microbiome and pulmonary immunity in ILD but require substantial further research. Here, we discuss the studies supporting a role for the lung microbiome in the pathogenesis of IPF, and briefly describe the putative role of the oral-lung axis and the gut-lung axis in ILD.

Elevated serum tumor-associated antigens in patients with interstitial lung disease: a retrospective study on clinical features and prognosis

BACKGROUND

Elevated serum tumor-associated antigens (TAAs) were reported to be common in patients with interstitial lung disease (ILD) and correlated with pulmonary involvement or malignancy development. However, there were no adequate longitudinal studies on the association between elevated TAAs and various types of ILDs in Chinese patients.

RESEARCH DESIGN AND METHODS

The treatment-naïve ILD patients were retrospectively enrolled. The clinical, laboratory, imaging characteristics, and prognosis were analyzed and compared among those with normal and different number of elevated TAAs.

RESULTS

An increase of at least one TAA was present in 169/308 (54.87%) of our patients. Both baseline alveolar and interstitial scores were much higher, and lung involvement tended to be worse during follow-up in patients with two and three or more elevated TAAs than in normal TAAs. Patients with three or more elevated TAAs had the highest interstitial scores and a higher all-cause mortality during follow-up than those with one elevated TAA or normal TAAs. The occurrence of malignancy was similar in all patients.

CONCLUSION

Elevated TAAs were present in 54.87% of ILD patients and associated with lung interstitial lesions, which might be a marker for lung involvement progression, while not for malignancy development in ILD.

Anti-chicken and anti-pigeon immunoglobulin G testing in patients with bird-related fibrotic hypersensitivity pneumonitis

BACKGROUND

One of the inciting antigens for fibrotic hypersensitivity pneumonitis (HP) is avian. It is controversial whether chickens are the inciting antigen of bird-related fibrotic HP; the anti-chicken immunoglobulin (Ig) G testing for bird-related fibrotic HP patients was investigated.

METHODS

Anti-pigeon IgG and anti-chicken IgG antibodies by mainly enzyme-linked immunosorbent assay (ELISA) were measured in patients with bird-related fibrotic HP. We included bird-related fibrotic HP patients who had undergone histopathological examination and who had a positive inhalation challenge test.

RESULTS

We included 44 patients with bird-related fibrotic HP and 48 with fibrotic interstitial lung diseases other than fibrotic HP. The mean titers of anti-pigeon IgG antibody by ELISA were 0.659 ± 0.381 and 0.494 ± 0.187 in the bird-related fibrotic HP and control groups, respectively (p = 0.012). Those of anti-chicken IgG antibody were 0.345 ± 0.189 and 0.376 ± 0.167, respectively (p = 0.457). No significant correlation was found between anti-pigeon IgG testing by ELISA and anti-chicken IgG testing (r = 0.45, p = 0.45). In patients with bird-related fibrotic HP, annual FVC changes were significantly different (p = 0.001), with the higher titer group improving by 0.4 % and the lower titer group decreasing by 4 %. Similarly, no significant differences in annual FVC changes were observed between the higher and lower anti-chicken IgG antibody titer groups among bird-related fibrotic HP patients.

CONCLUSION

Serum IgG testing for chicken serum was less effective in diagnosing or predicting the disease progression of bird-related fibrotic HP than that for pigeon serum.

Ex Vivo Overactivation of Lymphocyte Subsets in Fibrotic Hypersensitivity Pneumonitis Is Blunted by a Sphingosine-1-Phosphate Receptor Ligand

Lymphocytes are central to the pathogenesis of hypersensitivity pneumonitis and a strong body of evidence supports that lymphocytes are modulated by sphingosine-1-phosphate receptor-modifying drugs. This exploratory study aimed to determine if a pharmacological sphingosine-1-phosphate receptor ligand interfered with the activation of lymphocytes obtained from fibrotic hypersensitivity pneumonitis patients. Peripheral blood mononuclear cells of 12 patients and 10 control subjects were submitted to CD3/CD28 stimulation, isolated B cells were incubated with a TLR9 ligand; and we tested how these stimulations were impacted by ozanimod, a sphingosine-1-phosphate receptor ligand. T cell and B cell subsets from patients overexpressed CD69 and cytokines such as TNF and IL-4 in response to CD3/CD28 stimulation, compared to controls. In patients with fibrotic hypersensitivity pneumonitis, ozanimod alleviated CD3/CD28 induction of CD69, IL-4, and TNF in CD8, but not CD4 T cells. In isolated B cells stimulated with a TLR9 ligand, ozanimod reduced cell surface expression of CD69, CD86, and CD40, as well as TNF and IL-6 accumulation in supernatant. We conclude that lymphocyte subsets are functionally impacted in patients with fibrotic hypersensitivity pneumonitis and that ozanimod can interfere ex vivo with the overactivation of B cells and CD8 T cells in response to specific stimuli.

Transbronchial lung cryobiopsy for diagnosing interstitial lung disease: a cross-sectional, comparative study

OBJECTIVES

Transbronchial lung cryobiopsy (TBLC) has been identified to be a new technique to diagnosis interstitial lung disease (ILD). The study was conducted to investigate the safety and the diagnostic accuracy of TBLC contrast with transbronchial lung biosy (TBLB) in patients with ILD.

METHODS

In a cross-sectional and comparative study, patients with suspected ILD who underwent TBLC or TBLB were evaluated from June 2018 to September 2022 in Nanjing drum tower hospital. TBLC and TBLB procedure details and clinical multidisciplinary discussion (MDD) diagnosis based on clinical, radiological, and histopathological information were retrospectively analyzed. Diagnostic yield and complications of TBLC and TBLB were evaluated.

RESULTS

187 patients who underwent TBLC and 176 patients who underwent TBLB following a standardized protocol were enrolled. The diagnostic yield of TBLC and TBLB in patients with ILD were 85.0% and 63.1%, respectively. In TBLC, 162 patients (86.6%) had no or mild bleeding and 25 patients (13.4%) had moderate bleeding. None of the patients had severe bleeding and the rate of pneumothorax was 14.4%. Comparatively, pooled incidences of complications were 91.5% for no or mild bleeding, 8.5% for moderate bleeding and 5.1% for pneumothorax after TBLB. There was no difference in the occurrence of bleeding among TBLC group and TBLB group.

CONCLUSIONS

This study indicated that the clinical applicability of TBLC in ILD diagnostic algorithms, with a diagnostic yield of 85.0% and an acceptable safety profile.

Paprika-Induced Hypersensitivity Pneumonitis: A Report of a Rare Case

Hypersensitivity pneumonitis (HP) is an interstitial lung disease caused by exposure to environmental antigens in susceptible individuals. It is a type IV hypersensitivity reaction. The antigens involved in HP are numerous, but their identification is challenging. We report the first clinical case of HP associated with exposure to paprika. The diagnosis was confirmed based on the patient's exposure history, chest imaging, bronchoalveolar lavage fluid analysis, and pathological findings. Avoidance of antigens and treatment with glucocorticoids resulted in symptom relief. Follow-up chest imaging showed no ideal improvement; immunosuppressants or antifibrotic drugs may be considered in combination if necessary. The case highlights that individuals working in paprika production and processing should take preventive measures to avoid chronic pulmonary fibrosis.

Clinical impact of pre-determined guideline selection for the diagnosis of fibrotic hypersensitivity pneumonitis

INTRODUCTION AND OBJECTIVES

International guidelines for the diagnosis of Hypersensitivity Pneumonitis (HP) have improved the diagnostic standardization of this heterogeneous interstitial lung disease. Our goal was to determine how the final multidisciplinary discussion confidence level for suspected fibrotic HP (fHP) can be impacted by the application of different guidelines validated in this context.

MATERIALS AND METHODS

Retrospective study including patients submitted to transbronchial lung cryobiopsy (TBLC) with a final multidisciplinary meeting diagnosis of fHP. Both guidelines were applied to all patients in a stepwise fashion and directly compared according to the level of confidence in a fHP diagnosis.

RESULTS

A total of 170 patients were diagnosed with fHP after TBLC and subsequent multidisciplinary discussion. Overall, there was a statistically significant change in proportion towards higher confidence diagnostic levels using the CHEST guideline (p < 0.0001). Changes were significant at three different levels: ATS/JRS/ALAT's "fHP not excluded" subgroup significantly upscaled to CHEST's "provisional low-confidence" subgroup (76.2 % increase; p < 0.001) and the proportion of patients in ATS/JRS/ALAT's "low confidence" subgroup significantly upscaled to both CHEST's "provisional high-confidence" (67.4 % increase; p < 0.001) and "definitive fHP" (50 % increase; p < 0.001) subgroups. The alternative application of the CHEST guideline in multidisciplinary discussion would have resulted in 73 less TBLC (42.9 % decrease versus the ATS/JRS/ALAT-oriented decision).

CONCLUSIONS

This study suggests a significant increase in definite fHP diagnosis when applying the CHEST versus the ATS/JRS/ALAT guideline, resulting in almost a 43 % decrease in referrals to TBLC when compared with the latter due to a combination of less strict radiological criteria and a more prominent role of BAL.

CT Honeycombing and Traction Bronchiectasis Extent Independently Predict Survival across Fibrotic Interstitial Lung Disease Subtypes

Background Prognostic value of radiologic features in interstitial lung disease (ILD) has been predominantly studied in idiopathic pulmonary fibrosis, but findings vary. The relative importance of features versus guideline-defined patterns in predicting outcomes is unknown. Purpose To identify radiologic features that are independently associated with transplant-free survival beyond clinical predictive factors across all ILD subtypes, and to identify whether individual features versus patterns are more important for prognostication. Materials and Methods This is a secondary analysis of the prospective Canadian Registry for Pulmonary Fibrosis. Consecutive patients with ILD were evaluated in standardized multidisciplinary discussions between January 2021 and March 2022. Radiologic features on thin-section CT images were quantified, and guideline-defined usual interstitial pneumonia (UIP) and fibrotic hypersensitivity pneumonitis (fHP) patterns were assigned. Multivariable Cox analysis was used to assess the associations of radiologic features with transplant-free survival, and nested models were used to test the relative importance of features compared with patterns. Results A total of 1593 patients (mean age, 66 years ± 12 [SD]; 800 male) were included. The following four features were associated with transplant-free survival: extent of honeycombing (hazard ratio, 1.20; 95% CI; 1.06, 1.36 per 10% increase in lung involvement; P = .005), extent of traction bronchiectasis (hazard ratio, 1.18; 95% CI: 1.10, 1.26 per 10% increase; P < .001), pulmonary artery diameter (hazard ratio, 1.03; 95% CI: 1.01; 1.04 per 1-mm increase; P = .002), and presence of subpleural sparing (hazard ratio, 0.76; 95% CI: 0.56, 0.96; P = .03). Guideline-defined patterns were not independently associated with survival in a model that included these four radiologic features, each of which retained its prognostic value. Conclusion The extent of fibrosis was predictive of worse outcomes across all ILD subtypes in a dose-dependent fashion and independent of well-recognized clinical prognostic factors. Guideline-defined UIP and fHP patterns each helped risk-stratify patients in isolation but lost prognostic value when accounting for the extent of fibrosis, suggesting that their previous association with mortality is based on these patterns acting as surrogates for a greater extent of fibrosis. © RSNA, 2025 Supplemental material is available for this article. See also the editorial by Wells in this issue.

Predictive factors of fibrotic interstitial lung abnormality on high-resolution computed tomography scans: a prospective observational study

BACKGROUND

Fibrotic types of interstitial lung abnormalities seen on high-resolution computed tomography scans, characterised by traction bronchiolectasis/bronchiectasis with or without honeycombing, are predictors of progression and poor prognostic factors of interstitial lung abnormalities. There are no reports on the clinical characteristics of fibrotic interstitial lung abnormalities on high-resolution computed tomography scans. Therefore, we aimed to examine these clinical characteristics and clarify the predictive factors of fibrotic interstitial lung abnormalities on high-resolution computed tomography scans.

METHODS

Clinical and paraclinical data of 164 patients enrolled in the initial year of a multicentre prospective observational study (Kumamoto interstitial lung abnormalities study in Japan) involving over 62,000 examinees during routine health examinations were analysed. Clinical laboratory evaluations are expressed as medians and interquartile ranges for each evaluation time point, and boxplots were created for graphical representation. The percentages of abnormal clinical laboratory results were compared between the groups using chi-square or Fisher's exact tests. Univariate or multivariate logistic regression analyses were performed to analyse the relationship between fibrotic interstitial lung abnormalities and other clinical factors.

RESULTS

Fibrotic interstitial lung abnormalities were observed on high-resolution computed tomography scans in 135 (82%) patients at the time of diagnosis. Multivariate analysis showed that older age (Odds ratio, 1.06; 95% confidence interval, 1.01-1.12; p = 0.021), auscultatory fine crackles (Odds ratio, 3.39; 95% confidence interval, 1.33-8.65; p < 0.01), and elevated serum surfactant protein-D (Odds ratio, 2.68; 95% confidence interval, 1.02-8.64; p = 0.045) were independent predictive factors of fibrotic interstitial lung abnormalities. The predicted area under the curve of the fibrotic interstitial lung abnormalities based on these three factors was 0.77 (95% confidence interval, 0.68-0.86). The proportion of undecided diagnoses in the fibrotic interstitial lung abnormalities group (14%) was significantly lower than that in the non-fibrotic interstitial lung abnormalities group (41%) (p = 0.0027).

CONCLUSIONS

Fine crackles on auscultation and elevated serum surfactant protein-D levels are predictors of fibrotic interstitial lung abnormalities in older patients with interstitial lung abnormalities. These findings may assist non-radiological physicians in referring patients to specialists for early intervention in progressive fibrotic interstitial lung diseases.

TRIAL REGISTRATION NUMBER/DATE

UMIN000045149/2021.12.1.

Predictors of Severe Coughing and Its Impact on Bronchoalveolar Lavage and Transbronchial Lung Biopsy in Patients with Diffuse Lung Disease: Evaluation of Bronchoscopy Safety

Background/Objectives: Bronchoscopy is an invasive procedure, and patient coughing during the examination has been reported to cause significant distress. This study aimed to identify predictors of coughing severity and assess its impact on the procedure during bronchoalveolar lavage (BAL) and transbronchial lung biopsy (TBLB). Methods: We conducted a prospective study involving 119 consecutive patients with diffuse lung disease who underwent BAL and TBLB at Kyorin University Hospital from April 2019 to December 2023. Cough severity was scored on a scale of 0 to 3, with scores of 0-1 considered mild and 2-3 considered severe. Multivariate logistic regression analysis was performed to identify factors associated with severe coughing during the procedure. Results: Severe coughing was significantly associated with Grade 2 or higher bleeding (OR 6.230, 95% CI 2.220-17.400, p < 0.001), fewer TBLB specimens collected (OR 0.708, 95% CI 0.530-0.945, p = 0.019), and pre-procedural dyspnea (OR 2.560, 95% CI 1.110-5.870, p = 0.027). Conclusions: Severe coughing during bronchoscopy is associated with increased bleeding and reduced specimen collection. For patients with pre-procedural dyspnea, proactive cough management may improve procedural safety and outcomes.

The Impact of Adverse Events in Transbronchial Lung Cryobiopsy on Histopathological Diagnosis

Background: Transbronchial lung cryobiopsy (TBLC) has a high incidence of adverse events. This study aimed to investigate the relationship between the occurrence of these events and the condition of the pathology samples or pathological diagnosis in TBLC. Methods: We studied 102 patients who underwent TBLC for the diagnosis of interstitial lung disease. We analyzed the association between the condition or diagnosis of pathology samples and the occurrence of TBLC-related adverse events, including hemorrhage, pneumothorax, and acute exacerbation of interstitial lung disease. Results: The adverse events occurred in 19 patients (18.6%), of which hemorrhage was the most common (14 patients, 13.7%). The patients who experienced adverse events, especially hemorrhage, were less likely to have successful sampling with TBLC and showed lower diagnostic confidence in the pathology results. The diagnostic confidence was level A in 50 cases (49.0%) and level C in 23 cases (22.6%). TBLC-related adverse events, including hemorrhage, were significantly more common in patients with lower pathological confidence levels. Conclusions: TBLC-related adverse events, particularly hemorrhage, can lead to fewer successful samples and lower levels of diagnostic confidence.

Immunopathological characteristics and therapeutic effects of UC-MSCs in a pigeon breeder's lung mouse model

Hypersensitivity pneumonitis (HP), including pigeon breeder's lung (PBL), often progresses from acute inflammation to fibrosis, impairing lung function and limiting targeted therapeutic strategies. Mechanistic studies on PBL progression are limited by the lack of preclinical animal models and a predominant focus on patient data. This study explores the immunopathological characteristics of all stages of PBL in mice and evaluates the therapeutic potential of human umbilical cord-derived mesenchymal stem cells (UC-MSCs) during the non-fibrotic stage. PBL models are created in A/J mice through tracheal instillation of pigeon dropping extract (PDE) protein powder. Different doses (0.4 × 10 6, 0.8 × 10 6, and 1.6 × 10 6 cells per animal) and frequencies (1-2 times) are administered to the model. The immunopathological characteristics of PBL and the therapeutic effects of UC-MSCs are assessed using micro-CT, pulmonary function, histopathology, cell counts in BALF, HYP levels, inflammatory factor levels, immunohistochemistry, and fibrosis marker expression in lung tissues. The results show that PDE exposure consistently impairs pulmonary function and increases the levels of inflammation and fibrosis markers as the disease progresses. Model mice experience non-fibrotic stages (acute inflammation) from days 0-36, mild fibrosis from days 37-77, and severe fibrosis from day 78 onwards. UC-MSCs, particularly at the highest dose (1.6 × 10 6 cells), effectively treat non-fibrotic PBL by improving pulmonary function (lung ventilation area recovers) and reducing inflammation and fibrosis. This study successfully establishes PBL mouse models reflecting both the acute (inflammatory) and chronic (fibrotic) stages, and UC-MSCs have the potential to delay fibrosis, providing new therapeutic options for PBL and other inflammation-induced lung fibrotic diseases.

Evaluating the Diagnostic Value of Lymphocyte Subsets in Bronchoalveolar Lavage Fluid and Peripheral Blood Across Various Diffuse Interstitial Lung Disease Subtypes

Diffuse interstitial lung diseases (ILD) include conditions with identifiable causes such as chronic eosinophilic pneumonia (CEP), sarcoidosis (SAR), chronic hypersensitivity pneumonitis (CHP), and connective tissue disease-associated interstitial pneumonia (CTD), as well as idiopathic interstitial pneumonia (IIP) of unknown origin. In non-IIP diffuse lung diseases, bronchoalveolar lavage (BAL) fluid appearance is diagnostic. This study examines lymphocyte subsets in BAL fluid and peripheral blood of 56 patients with diffuse ILD, excluding idiopathic pulmonary fibrosis (IPF), who underwent BAL for diagnostic purposes. Patients were classified into CEP, SAR, CHP, CTD, and IIP groups, and clinical data, BAL cell analysis, and peripheral blood mononuclear cell analysis were compared. Eosinophils and type 3 innate lymphocytes (ILC3s) were significantly increased in the BAL fluid of the CEP group. Receiver operating characteristic curve analysis identified eosinophils ≥ 8% in BAL cells and ILC3s ≥ 0.0176% in the BAL lymphocyte fraction as thresholds distinguishing CEP. SAR patients exhibited significantly elevated CD4/CD8 ratios in the BAL fluid, with a ratio of 3.95 or higher and type 1 innate lymphoid cell frequency ≥ 0.254% as differentiation markers. High Th1 cell frequency (≥17.4%) in BAL lymphocytes in IIP, elevated serum KL-6 (≥2081 U/mL) and SP-D (≥261 ng/mL) in CHP, and increased BAL neutrophils (≥2.0%) or a low CD4/CD8 ratio (≤1.2) in CTD serve as distinguishing markers for each ILD. Excluding CEP and SAR, CD4+ T cell frequencies, including Th1, Th17, and Treg cells in peripheral blood, may differentiate IIP, CHP, and CTD.

The bronchoalveolar lavage fluid CD44 as a marker for pulmonary fibrosis in diffuse parenchymal lung diseases

Introduction

Diffuse parenchymal lung diseases (DPLD) cover heterogeneous types of lung disorders. Among many pathological phenotypes, pulmonary fibrosis is the most devastating and represents a characteristic sign of idiopathic pulmonary fibrosis (IPF). Despite a poor prognosis brought by pulmonary fibrosis, there are no specific diagnostic biomarkers for the initial development of this fatal condition. The major hallmark of lung fibrosis is uncontrolled activation of lung fibroblasts to myofibroblasts associated with extracellular matrix deposition and the loss of both lung structure and function.

Methods

Here, we used this peculiar feature in order to identify specific biomarkers of pulmonary fibrosis in bronchoalveolar lavage fluids (BALF). The primary MRC-5 human fibroblasts were activated with BALF collected from patients with clinically diagnosed lung fibrosis; the activated fibroblasts were then washed rigorously, and further incubated to allow secretion. Afterwards, the secretomes were analysed by mass spectrometry.

Results

In this way, the CD44 protein was identified; consequently, BALF of all DPLD patients were positively tested for the presence of CD44 by ELISA. Finally, biochemical and biophysical characterizations revealed an exosomal origin of CD44. Receiver operating characteristics curve analysis confirmed CD44 in BALF as a specific and reliable biomarker of IPF and other types of DPLD accompanied with pulmonary fibrosis.

Evaluation of a content-based image retrieval system for radiologists in high-resolution CT of interstitial lung diseases

BACKGROUND

This retrospective study aims to evaluate the impact of a content-based image retrieval (CBIR) application on diagnostic accuracy and confidence in interstitial lung disease (ILD) assessment using high-resolution computed tomography CT (HRCT).

METHODS

Twenty-eight patients with verified pattern-based ILD diagnoses were split into two equal datasets (1 and 2). The images were assessed by two radiology residents (3rd and 5th year) and one expert radiologist in four sessions. Dataset 1 was used for sessions A and C, assessing diagnostic accuracy and confidence with mandatory and without CBIR software. Dataset 2 was used for sessions B and D with optional CBIR use, assessing time spending and frequency of CBIR usage. Accuracy was assessed on the CT pattern level, comparing readers' diagnoses with reference diagnoses and CBIR results with region-of-interest (ROI) patterns.

RESULTS

Diagnostic accuracy and confidence of readers showed an increasing trend with CBIR use compared to no CBIR use (53.6% versus 35.7% and 50.0% versus 32.2%, respectively). Time for reading significantly decreased in both datasets (A versus C: 104 s versus 54 s, p < 0.001; B versus D: 88.5 s versus 70 s, p = 0.009), whereas time for research increased with CBIR software use (A versus C: 31 s versus 81 s, p = 0.040). CBIR results showed a high pattern-based accuracy of overall 73.4%. Comparison between readers indicates a slightly higher accuracy of CBIR results when more than one ROI was used as input (77.7% versus 70.1%).

CONCLUSION

CBIR software improves in-training radiologist diagnostic accuracy and confidence while reducing interpretation time in ILD assessment.

RELEVANCE STATEMENT

Content-based image retrieval software improves the assessment of interstitial lung diseases (ILD) in high-resolution CT, especially for radiology residents, by increasing diagnostic accuracy and confidence while reducing interpretation time. This can provide educational benefits and more time-efficient management of complex cases.

KEY POINTS

A content-based image retrieval (CBIR) software improves diagnostic accuracy and confidence for in-training radiologists for interstitial lung disease (ILD) assessment on computed tomography (CT). A CBIR application provides condensed information about similar HRCT cases reducing time for ILD assessment. CBIR algorithms benefit from the input of multiple regions of interest per ILD case.