Influence of autoimmune biomarkers on interstitial lung diseases: A tertiary referral center based case-control study

Surgical lung biopsy for suspected interstitial lung disease with video-assisted thoracoscopic surgery is safe, providing exact histological and disease specific diagnosis for tailoring treatment

Background

Surgical lung biopsy (SLB) is required for diagnosis in patients with suspected interstitial lung disease (ILD) if other less invasive diagnostic methods are non-conclusive. We evaluated the outcome of SLB by using centralized databases in a whole-nation patient-cohort.

Methods

A population-based retrospective study on 68 consecutive patients (mean age 58 years, 58.8% males) that underwent SLB in Iceland between the years 2008 and 2020. Patient information was obtained from patient charts and peri- and postoperative complications were registered together with 30- and 90-day mortality. Computed tomography (CT) scans, histological biopsies and spirometry results were reviewed, and overall survival (Kaplan-Meier) estimated. Mean follow-up was 61.3 months (range, 3-155 months).

Results

Out of 68 SLB-patients 41 (60.3%) had preoperatively undergone non-conclusive transbronchial biopsies (TBB) obtained with bronchoscopy. Spirometry showed forced vital capacity (FVC) 3.0 L and forced expiratory volume in 1 second (FEV1) 2.3 L, or 73.0% and 71.6% of predicted value, respectively. Video-assisted thoracoscopic surgery (VATS) technique was used in all cases and provided a histologic and disease specific diagnosis in 92.6% of cases; most often being nonspecific interstitial pneumonia (NSIP) (29.4%) and usual interstitial pneumonia (UIP) (23.5%). One patient (1.5%) sustained a major postoperative complication (excessive bleeding) and seven patients (10.3%) minor complications. Median chest tube time and length of stay was 1 and 2 days, respectively. No patients died <90 days postoperatively. Overall survival at 1 and 5 years was 95.6% and 73.5%, respectively, and 5-year survival for NSIP and UIP was 85% and 43.7%, respectively. Long-term mortality for UIP was four times higher when compared with NSIP and other diagnosis.

Conclusions

Lung biopsy with VATS-technique provided a definitive histological and disease specific diagnosis in majority of cases. The procedure is safe, reflected in low complication-rates and short hospital stay, and can therefore be used to diagnose and tailor treatment of ILD patients.

A 35-Year-Old Man with Chronic Cough and Worsening Dyspnea

A 35-Year-Old Man with Chronic Cough and DyspneaA 35-year-old man presented for evaluation of chronic cough and worsening dyspnea. How do you approach the evaluation, and what is the diagnosis?

Heterogeneity in Unclassifiable Interstitial Lung Disease. A Systematic Review and Meta-Analysis

RATIONALE

Accurate diagnosis of interstitial lung disease is necessary to identify the most appropriate management strategy and to inform prognosis. Many patients cannot be provided a confident diagnosis, despite an exhaustive search for potential etiologies and review in a multidisciplinary conference, and are consequently labeled with unclassifiable interstitial lung disease.

OBJECTIVES

To systematically review and meta-analyze previous studies reporting on the diagnostic criteria, prevalence, clinical features, and outcome of unclassifiable interstitial lung disease.

METHODS

MEDLINE, Embase, and the Cochrane Central Register of Controlled Trials databases were systematically searched for all studies related to unclassifiable interstitial lung disease published before September 1, 2017. Two authors independently screened each citation for eligibility criteria, serially reviewing the title, abstract, and full-text manuscript, and then abstracted data pertaining to the study objectives from eligible studies. Articles were stratified by risk of selection bias, whether the publication stated that patients were reviewed in a multidisciplinary discussion, and by the frequency of surgical lung biopsy. Meta-analyses and meta-regression were performed to calculate the pooled prevalence of unclassifiable interstitial lung disease within an interstitial lung disease population and within specific subgroups to identify reasons for across-study heterogeneity.

RESULTS

The search identified 10,130 unique citations, 313 articles underwent full-text review, and eligibility criteria were met in 88 articles. Twenty-two studies were deemed low risk of selection bias, including 1,060 patients with unclassifiable interstitial lung disease from a total of 10,174 patients with interstitial lung disease. The terminology and definition of unclassifiable interstitial lung disease varied substantially across publications, with inconsistent diagnostic criteria and evaluation processes. The prevalence of unclassifiable interstitial lung disease was 11.9% (95% confidence interval, 8.5-15.6%), with lower prevalence in centers that reported use of a formal multidisciplinary discussion of cases (9.5% vs. 14.5%). Four articles reported survival of unclassifiable interstitial lung disease, with 1-year, 2-year, and 5-year survival of 84% to 89%, 70% to 76%, and 46% to 70%, respectively.

CONCLUSIONS

This systematic review and meta-analysis shows that unclassifiable interstitial lung disease is common but has substantial heterogeneity and inconsistent definitions across interstitial lung disease cohorts. These findings highlight important limitations in multicenter studies of fibrotic interstitial lung disease and the need for a standardized approach to interstitial lung disease diagnostic classification.

Prognosticating Outcomes in Interstitial Lung Disease by Mediastinal Lymph Node Assessment. An Observational Cohort Study with Independent Validation

RATIONALE

Mediastinal lymph node (MLN) enlargement on chest computed tomography (CT) is prevalent in patients with interstitial lung disease (ILD) and may reflect immunologic activation and subsequent cytokine-mediated immune cell trafficking.

OBJECTIVES

We aimed to determine whether MLN enlargement on chest CT predicts clinical outcomes and circulating cytokine levels in ILD.

METHODS

MLN measurements were obtained from chest CT scans of patients with ILD at baseline evaluation over a 10-year period. Patients with sarcoidosis and drug toxicity-related ILD were excluded. MLN diameter and location were assessed. Plasma cytokine levels were analyzed in a subset of patients. The primary outcome was transplant-free survival (TFS). Secondary outcomes included all-cause and respiratory hospitalizations, lung function, and plasma cytokine concentrations. Cox regression was used to assess mortality risk. Outcomes were assessed in three independent ILD cohorts.

MEASUREMENTS AND MAIN RESULTS

Chest CT scans were assessed in 1,094 patients (mean age, 64 yr; 52% male). MLN enlargement (≥10 mm) was present in 66% (n = 726) and strongly predicted TFS (hazard ratio [HR], 1.53; 95% confidence interval [CI], 1.12-2.10; P = 0.008) and risk of all-cause and respiratory hospitalizations (internal rate of return [IRR], 1.52; 95% CI, 1.17-1.98; P = 0.002; and IRR, 1.71; 95% CI, 1.15-2.53; P = 0.008, respectively) when compared with subjects with MLN <10 mm. Patients with MLN enlargement had lower lung function and decreased plasma concentrations of soluble CD40L (376 pg/ml vs. 505 pg/ml, P = 0.001) compared with those without MLN enlargement. Plasma IL-10 concentration >45 pg/ml predicted mortality (HR, 4.21; 95% CI, 1.21-14.68; P = 0.024). Independent analysis of external datasets confirmed these findings.

CONCLUSIONS

MLN enlargement predicts TFS and hospitalization risk in ILD and is associated with decreased levels of a key circulating cytokine, soluble CD40L. Incorporating MLN and cytokine findings into current prediction models might improve ILD prognostication.

ILDgenDB: integrated genetic knowledge resource for interstitial lung diseases (ILDs)

Interstitial lung diseases (ILDs) are a diverse group of ∼200 acute and chronic pulmonary disorders that are characterized by variable amounts of inflammation, fibrosis and architectural distortion with substantial morbidity and mortality. Inaccurate and delayed diagnoses increase the risk, especially in developing countries. Studies have indicated the significant roles of genetic elements in ILDs pathogenesis. Therefore, the first genetic knowledge resource, ILDgenDB, has been developed with an objective to provide ILDs genetic data and their integrated analyses for the better understanding of disease pathogenesis and identification of diagnostics-based biomarkers. This resource contains literature-curated disease candidate genes (DCGs) enriched with various regulatory elements that have been generated using an integrated bioinformatics workflow of databases searches, literature-mining and DCGs–microRNA (miRNAs)–single nucleotide polymorphisms (SNPs) association analyses. To provide statistical significance to disease-gene association, ILD-specificity index and hypergeomatric test scores were also incorporated. Association analyses of miRNAs, SNPs and pathways responsible for the pathogenesis of different sub-classes of ILDs were also incorporated. Manually verified 299 DCGs and their significant associations with 1932 SNPs, 2966 miRNAs and 9170 miR-polymorphisms were also provided. Furthermore, 216 literature-mined and proposed biomarkers were identified. The ILDgenDB resource provides user-friendly browsing and extensive query-based information retrieval systems. Additionally, this resource also facilitates graphical view of predicted DCGs–SNPs/miRNAs and literature associated DCGs–ILDs interactions for each ILD to facilitate efficient data interpretation. Outcomes of analyses suggested the significant involvement of immune system and defense mechanisms in ILDs pathogenesis. This resource may potentially facilitate genetic-based disease monitoring and diagnosis.

Database URL: http://14.139.240.55/ildgendb/index.php

Morphologic Aspects of Interstitial Pneumonia With Autoimmune Features

Context.—

Interstitial lung disease, a common complication observed in several connective tissue diseases, causes significant morbidity and mortality. Similar to individuals with connective tissue diseases, a significant subgroup of patients with clinical and serologic characteristics suggestive of autoimmunity but without confirmed specific connective tissue disease presents with associated interstitial lung disease. These patients have been classified using different controversial nomenclatures, such as undifferentiated connective tissue disease–associated interstitial lung disease, lung-dominant connective tissue disease, and autoimmune featured interstitial lung disease. The need for a better understanding and standardization of this entity, interstitial lung disease with autoimmune features, and the need for an adequate management protocol for patients resulted in the introduction of a new terminology in 2015: interstitial pneumonia with autoimmune features. This new classification requires a better comprehension of its diagnostic impact and the influence of its morphologic aspects on the prognosis of patients.

Objective.—

To review the diagnostic criteria for interstitial pneumonia with autoimmune features, with an emphasis on morphologic aspects.

Data Sources.—

The review is based on the available literature, and on pathologic, radiologic, and clinical experience.

Conclusions.—

The interstitial pneumonia with autoimmune features classification seems to identify a distinct subgroup of patients with different prognoses. Studies show that nonspecific interstitial pneumonia and usual interstitial pneumonia are the most prevalent morphologic patterns and show discrepant results on the impact of the usual interstitial pneumonia pattern on survival. Prospective investigations are necessary to better define this subgroup and to determine the prognosis and appropriate clinical management of these patients.

Interstitial pneumonia with autoimmune features: a critical appraisal of the new definition

PURPOSE OF REVIEW

We review the newly formulated and published research classification criteria for interstitial pneumonia with autoimmune features and appraise these criteria in light of findings from recent investigations.

RECENT FINDINGS

Previous studies demonstrated that interstitial pneumonia may be caused by an autoimmune process with a variety of names and criteria utilized for this entity. To standardize terminology and provide a definition for future research, a multidisciplinary task force formulated criteria by which patients with interstitial lung disease and autoimmune features might be recognized. The interstitial pneumonia with autoimmune features criteria require the presence of an interstitial pneumonia on chest imaging or surgical lung biopsy, exclusion of an alternate cause, the absence of a defined connective tissue disease and at least one feature suggestive of autoimmunity from at least two of three domains: clinical with specific extra-thoracic features, serologic with positive autoantibodies and morphologic as demonstrated by chest imaging, histopathology, or multicompartment involvement. Although recent studies provide insight into features of significance, these criteria have not undergone formal validation.

SUMMARY

A uniform name and set of research criteria for interstitial pneumonia with autoimmune features may identify patients with treatment responsive interstitial lung disease and an improved prognosis. These criteria require validation before they can be applied in the clinical setting.

Idiopathic Interstitial Pneumonia Associated With Autoantibodies: A Large Case Series Followed Over 1 Year

BACKGROUND

Some patients with autoimmune characteristics and idiopathic interstitial pneumonia, particularly usual interstitial pneumonia (UIP), do not fit neatly into the category of connective tissue disease-associated interstitial lung disease (CTD-ILD), idiopathic pulmonary fibrosis (IPF), or recently proposed yet to be validated criteria for interstitial pneumonia with autoimmune features (IPAF). Outcomes of these patients are unknown.

METHODS

This was a retrospective single-center study. Analyses of variance compared differences in mean change in FVC and diffusion capacity (Dlco) over 1 year among 124 well-defined patients (20 patients with positive autoantibodies with or without symptoms of connective tissue disease [AI-ILD], 15 patients with IPAF, 36 patients with CTD-ILD, and 53 patients with IPF with negative CTD serologies [Lone-IPF]).

RESULTS

Of the patients, 75% with AI-ILD, 33% with IPAF, and 33% with CTD-ILD had UIP. Initial FVC and Dlco were similarly moderately reduced across groups. Mean change in FVC over 12 months was as follows: -60 mL (IPAF), -110 mL (AI-ILD), -10 mL (CTD-ILD), and -90 mL (Lone-IPF) (P = .52). Mean change in Dlco was as follows: 2.39 mL/mm Hg/min (IPAF), -1.15 mL/mm Hg/min (AI-ILD), -0.27 mL/mm Hg/min (CTD-ILD), and -1.05 mL/mm Hg/min (Lone-IPF) (P < .001). By pattern of disease, the mean change in FVC was as follows: -140 mL (UIP), 10 mL (nonspecific interstitial pneumonia), and 12 mL (unclassifiable/other) (P = .001).

CONCLUSIONS

No clinically significant differences in pulmonary function to distinguish between patients with AI-ILD, IPAF, CTD-ILD, and Lone-IPF were observed after 1 year. Longer periods of follow-up are needed to understand the outcomes of these patients. It is not yet clear whether AI-ILD is a distinct phenotype or a variant of the newly proposed entity IPAF.