CT Findings, Radiologic-Pathologic Correlation, and Imaging Predictors of Survival for Patients With Interstitial Pneumonia With Autoimmune Features

Microvascular alterations of the ocular surface and retina in connective tissue disease-related interstitial lung disease

AIM

To examine the disparities in macular retinal vascular density between individuals with connective tissue disease-related interstitial lung disease (CTD-ILD) and healthy controls (HCs) by optical coherence tomography angiography (OCTA) and to investigate the changes in microvascular density in abnormal eyes.

METHODS

For a retrospective case-control study, a total of 16 patients (32 eyes) diagnosed with CTD-ILD were selected as the ILD group. The 16 healthy volunteers with 32 eyes, matched in terms of age and sex with the patients, were recruited as control group. The macular retina's superficial retinal layer (SRL) and deep retinal layer (DRL) were examined and scanned using OCTA in each individual eye. The densities of retinal microvascular (MIR), macrovascular (MAR), and total microvascular (TMI) were calculated and compared. Changes in retinal vascular density in the macular region were analyzed using three different segmentation methods: central annuli segmentation method (C1-C6), hemispheric segmentation method [uperior right (SR), superior left (SL), inferior left (IL), and inferior right (IR)], and Early Treatment Diabetic Retinopathy Study (ETDRS) methods [superior (S), inferior (I), left (L), and right (R)]. The data were analyzed using Version 9.0 of GraphPad prism and Pearson analysis.

RESULTS

The OCTA data demonstrated a statistically significant difference (P<0.05) in macular retinal microvessel density between the two groups. Specifically, in the SRL and DRL analyses, the ILD group exhibited significantly lower surface density of MIR and TMI compared to the HCs group (P<0.05). Furthermore, using the hemispheric segmentation method, the ILD group showed notable reductions in SL, SR, and IL in the superficial retina (P<0.05), as well as marked decreases in SL and IR in the deep retina (P<0.05). Similarly, when employing the ETDRS method, the ILD group displayed substantial drops in superficial retinal S and I (P<0.05), along with notable reductions in deep retinal L, I, and R (P<0.05). In the central annuli segmentation method, the ILD group exhibited a significant decrease in the superficial retinal C2-4 region (P<0.05), whereas the deep retina showed a notable reduction in the C3-5 region (P<0.05). Additionally, there was an observed higher positive likelihood ratio in the superficial SR region and deep MIR. Furthermore, there was a negative correlation between conjunctival vascular density and both deep and superficial retinal TMI (P<0.001).

CONCLUSION

Patients with CTD-ILD exhibits a significantly higher conjunctival vascular density compared to the HCs group. Conversely, their fundus retinal microvascular density is significantly lower. Furthermore, CTD-ILD patients display notably lower superficial and deep retinal vascular density in comparison to the HCs group. The inverse correlation between conjunctival vascular density and both superficial and deep retinal TMI suggests that detecting subtle changes in ocular microcirculation could potentially serve as an early diagnostic indicator for connective tissue diseases, thereby enhancing disease management.

Connective tissue disease-associated interstitial lung disease

Connective tissue disease-associated interstitial lung disease (CTD-ILD) represents a group of systemic autoimmune disorders characterized by immune-mediated organ dysfunction. Systemic sclerosis, rheumatoid arthritis, idiopathic inflammatory myositis, and Sjögren's syndrome are the most common CTDs that present with pulmonary involvement, as well as with interstitial pneumonia with autoimmune features. The frequency of CTD-ILD varies according to the type of CTD, but the overall incidence is 15%, causing an important impact on morbidity and mortality. The decision of which CTD patient should be investigated for ILD is unclear for many CTDs. Besides that, the clinical spectrum can range from asymptomatic findings on imaging to respiratory failure and death. A significant proportion of patients will present with a more severe and progressive disease, and, for those, immunosuppression with corticosteroids and cytotoxic medications are the mainstay of pharmacological treatment. In this review, we summarized the approach to diagnosis and treatment of CTD-ILD, highlighting recent advances in therapeutics for the various forms of CTD.

Low Rates of Reproductive Counseling Documentation in Women With Interstitial Pneumonia With Autoimmune Features

BACKGROUND/OBJECTIVE

Women with interstitial pneumonia with autoimmune features (IPAFs), a subset of interstitial lung disease (ILD), are at risk for pregnancy complications. Family planning discussions improve pregnancy outcomes in women with ILD. The objective of this study was to evaluate the documentation of reproductive counseling in IPAF female patients of childbearing age by pulmonary and rheumatology providers at an academic medical center.

METHODS

We conducted a medical record review study of pulmonary and rheumatology encounters in reproductive-aged women with IPAF to evaluate documentation of family planning discussions and contraceptive use. We used nonparametric measures of association and logistic regression to evaluate the relationship between patient characteristics and the presence of reproductive counseling documentation by providers.

RESULTS

Thirty-one women met IPAF classification and were ≤50 years at initial ILD clinic visit. Twenty-five (81%) of these women had risk factors for adverse pregnancy outcomes. Ten women (32%) had a record of reproductive counseling during any visit with their pulmonary provider. Of the 21 patients who also saw a rheumatology provider, 12 (57%) women had a record of reproductive counseling during any visit with their rheumatology provider. No baseline characteristics were associated with odds of reproductive counseling documentation.

CONCLUSIONS

Neither pulmonary nor rheumatology providers consistently discussed family planning/contraceptive use with reproductive-aged women with IPAF. There was a trend for rheumatology providers to discuss reproductive issues with IPAF patients more frequently than pulmonary providers. Efforts should focus on educating providers about the need for reproductive counseling in women with IPAF of childbearing age.

Interstitial lung disease progression after genomic usual interstitial pneumonia testing

BACKGROUND

A genomic classifier for usual interstitial pneumonia (gUIP) has been shown to predict histological UIP with high specificity, increasing diagnostic confidence for idiopathic pulmonary fibrosis (IPF). Whether those with positive gUIP classification exhibit a progressive, IPF-like phenotype remains unknown.

METHODS

A pooled, retrospective analysis of patients who underwent clinically indicated diagnostic bronchoscopy with gUIP testing at seven academic medical centres across the USA was performed. We assessed the association between gUIP classification and 18-month progression-free survival (PFS) using Cox proportional hazards regression. PFS was defined as the time from gUIP testing to death from any cause, lung transplant, ≥10% relative decline in forced vital capacity (FVC) or censoring at the time of last available FVC measure. Longitudinal change in FVC was then compared between gUIP classification groups using a joint regression model.

RESULTS

Of 238 consecutive patients who underwent gUIP testing, 192 had available follow-up data and were included in the analysis, including 104 with positive gUIP classification and 88 with negative classification. In multivariable analysis, positive gUIP classification was associated with reduced PFS (hazard ratio 1.58, 95% CI 0.86-2.92; p=0.14), but this did not reach statistical significance. Mean annual change in FVC was -101.8 mL (95% CI -142.7- -60.9 mL; p<0.001) for those with positive gUIP classification and -73.2 mL (95% CI -115.2- -31.1 mL; p<0.001) for those with negative classification (difference 28.7 mL, 95% CI -83.2-25.9 mL; p=0.30).

CONCLUSIONS

gUIP classification was not associated with differential rates of PFS or longitudinal FVC decline in a multicentre interstitial lung disease cohort undergoing bronchoscopy as part of the diagnostic evaluation.

The utility of transbronchial lung biopsies to guide the treatment decision in patients with rheumatic inflammatory diseases: a retrospective cross-sectional study

The role of transbronchial lung biopsies (TBB) in the diagnostic workup of systemic inflammatory rheumatic disease-associated interstitial lung disease (SIRD-ILD) is unclear and TBB is not generally recommended. The study objective was to examine the utility of TBB to guide treatment in a population of patients with SIRD-ILD. All patients from the Department of Rheumatology, Rigshospitalet, Denmark, who had TBB performed, from 2002 to 2016 were identified. Patient demographics as well as smoking status, previous lung disease, pulmonary function test, SIRD-diagnosis, imaging results and immunomodulatory therapy pre- and post-bronchoscopy were obtained. Histology findings were used to dichotomize patients into a high-inflammatory group or a low-inflammatory group. The high-inflammation group primarily consisted of non-specific interstitial pneumonia, organizing pneumonia, lymphocytic infiltrating pneumonia and granulomatous inflammation whereas the low inflammation group primarily consisted of histological findings of usual interstitial pneumonitis and biopsies describing fibrosis and/or sparse unspecific inflammation. Therapeutic consequence was defined as intensification of therapy. Differences in treatment intensification were calculated using a binominal logistic regression model. Ninety-six patients had TBB performed. Biopsies from 55 patients were categorized as high inflammatory and 41 as low inflammatory, respectively. In the high-inflammatory group, 38 (69%) had their therapy intensified compared to 6 (14%) in the low-inflammatory group (Odds ratio 8.0, 95% confidence limits 3.2-20.0, P < 0.001). No procedure-related complications were registered. TBB findings can guide treatment strategy in SIRD-ILD patients with suspected activity in the pulmonary disease. TBB appears safe and could be considered as part of the diagnostic workup.

Interstitial pneumonia with autoimmune features: challenges and controversies

The presence of clinical, serological and/or radiological features suggestive, but not confirmatory, of a defined connective tissue disease in patients with interstitial lung disease is a relatively frequent occurrence. In 2015, the European Respiratory Society and the American Thoracic Society proposed classification criteria for the interstitial pneumonia with autoimmune features (IPAF) research entity to capture such patients in a standardised manner, with the intention of nurturing clinical research. This initiative resulted in the publication of several series of IPAF patients, with significant variation between cohorts in clinical characteristics, outcome and the application of IPAF criteria in patient selection. From this increasing body of published work, it has become apparent that revision of IPAF criteria is now required in order to justify the eventual designation of IPAF as a standalone diagnostic term, as opposed to a provisional entity put forward as a basis for clinical research. This review covers the current state of IPAF, conclusions that can and cannot be drawn from the IPAF evidence base, and ongoing uncertainties that require further expert group consideration.

Lung fibrosis in autoimmune diseases and hypersensitivity: how to separate these from idiopathic pulmonary fibrosis

Lung involvement in autoimmune diseases (AID) is uncommon, but may precede other organ manifestations. A diagnostic problem is chronicity presenting with lung fibrosis. A new category of interstitial pneumonia with autoimmune features for patients with clinical symptoms of AID and presenting with usual interstitial pneumonia (UIP) enables antifibrotic treatment for these patients. Hypersensitivity pneumonia (HP) and other forms of lung fibrosis were not included into this category. As these diseases based on adverse immune reactions often present with unspecific clinical symptoms, a specified pathological diagnosis will assist the clinical evaluation. We aimed to establish etiology-relevant differences of patterns associated with AID or HP combined with lung fibrosis. We retrospectively evaluated 51 cases of AID, and 29 cases of HP with lung fibrosis, and compared these to 24 cases of idiopathic pulmonary fibrosis (UIP/IPF). Subacute AID and HP most often presented with organizing pneumonia (OP), whereas chronicity was associated with UIP. Unspecified fibrosis was seen in a few cases, whereas NSIP pattern was rare. In 9 cases, the underlying etiology could not be defined. Statistically significant features differentiating chronic AID or HP from UIP/IPF are lymphocytic infiltrations into myofibroblastic/fibroblastic foci. Other features significantly associated with AID and HP were granulomas, isolated Langhans giant cells, and protein deposits, but seen in only a minority of cases. A combination of UIP with one of these features enabled a specific etiology-based diagnosis. Besides the antifibrotic drug regimen, additional therapies might be considered.

Characterization of Interstitial Lung Disease Associated With Anti-Ribonucleoprotein Antibodies

OBJECTIVES

Interstitial lung disease (ILD) is a common feature of mixed connective tissue disease. However, many patients do not meet the criteria for mixed connective tissue disease and thus may be diagnosed as interstitial pneumonia with autoimmune features. The aim of this study was to characterize ILD associated with anti-ribonucleoprotein (RNP) antibodies.

METHODS

Chest computed tomography scans of patients with anti-RNP antibody who were seen between January 2011 and October 2015 were reviewed. The underlying disease was classified with international criteria using clinical and serological features.

RESULTS

Among 544 patients with anti-RNP antibodies, 188 had a chest computed tomography scan, and 48 (26%) of them had radiological features of ILD. The presence of ILD was significantly associated with dyspnea, crackles, arthritis, Raynaud phenomenon, myositis, and sicca syndrome. The most frequent pattern was nonspecific interstitial pneumonia in 39 patients (81%). Among patients with ILD, 17 (35%) had a radiological pattern consisting of cysts and ground-glass attenuation not fulfilling the lymphoid interstitial pneumonia criteria. In 3 patients, cysts were related to fibrosis; in 14 patients, cysts corresponded to an original ILD pattern.

CONCLUSIONS

Interstitial lung disease was found in 26% of patients with anti-RNP antibodies independently of the underlying disease. Anti-RNP-associated ILD mainly corresponds to nonspecific interstitial pneumonia or an original pattern consisting of cysts and ground-glass attenuation.

Vessel-related structures predict UIP pathology in those with a non-IPF pattern on CT

OBJECTIVES

To determine if a quantitative imaging variable (vessel-related structures [VRS]) could identify subjects with a non-IPF diagnosis CT pattern who were highly likely to have UIP histologically.

METHODS

Subjects with a multidisciplinary diagnosis of interstitial lung disease including surgical lung biopsy and chest CT within 1 year of each other were included in the study. Non-contrast CT scans were analyzed using the Computer-Aided Lung Informatics for Pathology Evaluation and Rating (CALIPER) program, which quantifies the amount of various abnormal CT patterns on chest CT. Quantitative data were analyzed relative to pathological diagnosis as well as the qualitative CT pattern.

RESULTS

CALIPER-derived volumes of reticulation (p = 0.012), honeycombing (p = 0.017), and VRS (p < 0.001) were associated with a UIP pattern on pathology on univariate analysis but only VRS was associated with a UIP pathology on multivariable analysis (p = 0.013). Using a VRS cut-off of 173 cm³, the sensitivity and specificity for pathological UIP were similar to those for standard qualitative CT assessment (55.9% and 80.4% compared to 60.6% and 80.4%, respectively). VRS differentiated pathological UIP cases in those with a non-IPF diagnosis CT category (p < 0.001) but not in other qualitative CT patterns (typical UIP, probable UIP, and indeterminate for UIP). The rate of pathological UIP in those with VRS greater than 173 cm³ (84.2%) was nearly identical to those who had a qualitative CT pattern of probable UIP (88.9%).

CONCLUSIONS

VRS may be an adjunct to CT in predicting pathology in patients with interstitial lung disease.

KEY POINTS

• Volume of vessel-related structures (VRS) was associated with usual interstitial pneumonia (UIP) on pathology. • This differentiation arose from those with CT scans with a non-IPF diagnosis imaging pattern. • Higher VRS has similar diagnostic ramifications for UIP as probable UIP, transitively suggesting in patients with high VRS, pathology may be obviated.

Visual and quantitative assessment of HRCT pulmonary changes in idiopathic interstitial pneumonia with PFT correlation

Background

Our study was designed to correlate the degree of parenchymal affection in idiopathic interstitial pneumonia using visual and semi-quantitative HRCT assessment with pulmonary function test results.

The study involved 50 patients diagnosed as idiopathic interstitial pneumonia. They were referred from a chest outpatient clinic to the Radiology Department in the Faculty of Medicine, Cairo University for HRCT assessment in the period from January 2017 to March 2019. Variable lung parenchymal affection was studied using HRCT and variable post acquisition processing (multi-planar reconstruction, volumetric assessment, 3D color-coded images).

Results

Usual interstitial pneumonia was the most common type of IP, found in approximately 40 patients (80% of cases) followed by nonspecific interstitial pneumonia found in 5 patients (10% of cases) and lymphocytic interstitial pneumonia found in 3 patients (6% of cases), and desquamative interstitial pneumonia was the least common type of IP, found only in 2 patients (4% of cases).

Honeycombing was significantly correlated with FVC%, FEV1%, and FEV1/FVC% (p = 0.013, p = <0.001, p = 0.002 respectively). Also, reticular was significantly correlated with FVC% (p = 0.041).

Conclusion

Semi-quantitative image analysis, including the use of machine learning, provides a great deal of promise in the ILD field; such methods may be used together with visual analysis to obtain the most accurate diagnostic and prognostic information.

Summary/keywords

HRCT is most sensitive in the detection of ILD than chest radiography or conventional chest computed tomography (CT). Advances in HRCT scanning and interpretation have facilitated and improved accuracy for use in diagnosing idiopathic pulmonary fibrosis (IPF), eliminating the need for a surgical biopsy in many patients. Consequently, HRCT scans became sufficient to allow a confident IPF diagnosis

It is important to note that there are potential differences in interpretation of HRCT patterns between thoracic radiologists. However, these differences seem to be in general within a clinically acceptable range of observer variation and can be partially mitigated by review of difficult cases at ILD referral centers.

Semi-quantitative CT assessment is increasingly being used in ILD to identify pulmonary abnormalities and diagnose specific ILDs; recent studies showed that outcomes of computer-assisted imaging can be correlated with lung function tests and degree of dyspnea and functional disability

This study was designed to correlate the degree of parenchymal affection in IP using visual and semi-quantitative HRCT assessment with PFT results. Semi-quantitative imaging, including color-coded images (HU related), is a new and promising approach in the field of ILD diagnosis and prognosis.

Automated CT Analysis of Major Forms of Interstitial Lung Disease

This study aimed to determine diagnostic and prognostic differences in major forms of interstitial lung disease using quantitative CT imaging. A retrospective study of 225 subjects with a multidisciplinary diagnosis of idiopathic pulmonary fibrosis (IPF), interstitial pneumonia with autoimmune features (IPAF), connective tissue disease (CTD), or chronic hypersensitivity pneumonitis (cHP) was conducted. Non-contrast CT scans were analyzed using the Computer Aided Lung Informatics for Pathology Evaluation and Rating (CALIPER) program. Resulting data were analyzed statistically using ANOVA and Student’s t-test. Univariate, multivariable, and receiver operating characteristic analyses were conducted on patient mortality data. CALIPER analysis of axial distribution on CT scans in those with IPF demonstrated greater peripheral volumes of reticulation than either CTD (p = 0.033) or cHP (p = 0.007). CTD showed lower peripheral ground-glass opacity than IPF (p = 0.005) and IPAF (p = 0.004). Statistical analysis of zonal distributions revealed reduced lower zone ground-glass opacity in cHP than IPF (p = 0.044) or IPAF (p = 0.018). Analysis of pulmonary vascular-related structure (VRS) volume by diagnosis indicated greater VRS volume in IPF compared to CTD (p = 0.003) and cHP (p = 0.003) as well as in IPAF compared to CTD (p = 0.007) and cHP (p = 0.007). Increased reticulation (p = 0.043) and ground glass opacity (p = 0.032) were predictive of mortality on univariate analysis. Increased pulmonary VRS volume was predictive of mortality (p < 0.001) even after multivariate analysis (p = 0.041). Quantitative CT imaging revealed significant differences between ILD diagnoses in specific CT findings in axial and, to a lesser degree, zonal distributions. Increased pulmonary VRS volume seems to be associated with both diagnosis and survival.

Connective Tissue Disease Related Interstitial Lung Disease

Patients with connective tissue diseases may have pulmonary involvement, including interstitial lung disease. Various patterns of interstitial lung disease have been classically described in certain connective tissue diseases. It is now recognized that there is significant overlap between patterns of interstitial lung disease observed in the various connective tissue diseases. Differentiating idiopathic from connective tissue disease-related interstitial lung disease is challenging but of clinical importance. New concepts in the diagnosis of connective tissue disease related interstitial lung disease may prove useful in making the diagnosis.

The extended utility of antifibrotic therapy in progressive fibrosing interstitial lung disease

INTRODUCTION

The approval of two antifibrotic treatment agents for delaying disease progression in idiopathic pulmonary fibrosis (IPF), has prompted researchers to look at expanding the role of antifibrotic therapy to other fibrosing interstitial lung disease (ILD). Similarities in the pathological mechanisms that lead to the development of IPF have been implicated in other progressive fibrosing ILD (PF-ILD) such as chronic hypersensitivity pneumonitis, connective tissues disease associated ILD, sarcoidosis, occupational ILD and idiopathic non-specific interstitial pneumonia (iNSIP). This has prompted the rationale to use antifibrotic therapy to target similar molecular pathways in these diseases.

AREAS COVERED

This review will summarise the available evidence from randomised controlled trials that have evaluated the use of antifibrotic therapy in PF-ILD outside the realm of IPF.

EXPERT OPINION

There is promising data for antifibrotic therapy as a therapeutic option for non IPF PF-ILD. The new therapy option does provide some challenges that need to be addressed such as timing of initiation of therapy, clarifying the strategy for overlap or combination with existing immunosuppressive therapies and potential drug interactions. There is an unmet need to determine accurate predictors of disease progression to allow early intervention for the preservation of lung function and mortality reduction.

Interstitial Pneumonia with Autoimmune Features

Interstitial pneumonia with autoimmune features (IPAF) is a research classification proposed by the European Respiratory Society/American Thoracic Society Task Force on Undifferentiated Forms of Connective Tissue Disease-associated Interstitial Lung Disease as an initial step to uniformly define, identify, and study patients with interstitial lung disease (ILD) who have features of autoimmunity, yet fall short of a characterizable connective tissue disease. Since its publication in July 2015, there has been substantial interest in IPAF. Centers from around the world have published their findings of retrospectively identified cohorts of patients who fulfill IPAF criteria, suggestions for modification of the criteria have been offered, and patients who fulfill IPAF criteria are being included as a subset in the ongoing phase II multicenter unclassifiable ILD treatment trial with pirfenidone. The IPAF designation represents an important first step toward studying and furthering our understanding of the natural history of this cohort of patients with ILD using uniform nomenclature and a standardized set of criteria. Prospective evaluations and, ideally, interdisciplinary and multicenter collaborations will inform best practices for treatment and management and will guide future refinement to the IPAF criteria. This review focuses on the relevant background that led to the development of IPAF, summarizes the proposed criteria, discusses cohort studies of patients with IPAF published to date and what they have taught us about the IPAF phenotype, and offers insights into future directions in this arena. Clinical trial registered with www.clinicaltrials.gov (NCT03099187).

Interstitial Pneumonia with Autoimmune Features

The European Respiratory Society/American Thoracic Society Task Force on Undifferentiated Forms of Connective Tissue Disease-associated Interstitial Lung Disease put forth the research classification interstitial pneumonia with autoimmune features as a step toward uniformly describing these patients. Diverse nomenclature and classification schemes had been proposed to characterize them. This classification has provided uniform nomenclature and criteria, fostering interdisciplinary engagement and research. Longitudinal surveillance is needed; some patients evolve to a defined connective tissue disease. This review discusses cohort studies of interstitial pneumonia with autoimmune features and what they have taught us about the phenotype, and offers insights into future directions.

Impact of a systematic evaluation of connective tissue disease on diagnosis approach in patients with interstitial lung diseases

To date, there is no clear agreement regarding which is the best method to detect a connective tissue disease (CTD) during the initial diagnosis of interstitial lung diseases (ILD). The aim of our study was to explore the impact of a systematic diagnostic strategy to detect CTD-associated ILD (CTD-ILD) in clinical practice, and to clarify the significance of interstitial pneumonia with autoimmune features (IPAF) diagnosis in ILD patients.Consecutive patients evaluated in an ILD Diagnostic Program were divided in 3 groups: IPAF, CTD-ILD, and other ILD forms. Clinical characteristics, exhaustive serologic testing, high resolution computed tomography (HRCT) images, lung biopsy specimens, and follow-up were prospectively collected and analyzed.Among 139 patients with ILD, CTD was present in 21 (15.1%), 24 (17.3%) fulfilled IPAF criteria, and 94 (67.6%) were classified as other ILD forms. Specific systemic autoimmune symptoms such as Raynaud phenomenon (19%), inflammatory arthropathy (66.7%), and skin manifestations (38.1%) were more frequent in CTD-ILD patients than in the other groups (all P < .001). Among autoantibodies, antinuclear antibody was the most frequently found in IPAF (42%), and CTD-ILD (40%) (P = .04). Nonspecific interstitial pneumonia, detected by HRCT scan, was the most frequently seen pattern in patients with IPAF (63.5%), or CTD-ILD (57.1%) (P < .001). In multivariate analysis, a suggestive radiological pattern by HRCT scan (odds ratio [OR] 15.1, 95% confidence interval [CI] 4.7-48.3, P < .001) was the strongest independent predictor of CTD-ILD or IPAF, followed by the presence of clinical features (OR 14.6, 95% CI 4.3-49.5, P < .001), and serological features (OR 12.4, 95% CI 3.5-44.0, P < .001).This systematic diagnostic strategy was useful in discriminating an underlying CTD in patients with ILD. The defined criteria for IPAF are fulfilled by a considerable proportion of patients referred for ILD.

Systematic review and meta-analysis of the prognosis and prognostic factors of interstitial pneumonia with autoimmune features

OBJECTIVE

To clarify the prognosis and prognostic factors of interstitial pneumonia with autoimmune features (IPAF) in comparison to idiopathic pulmonary fibrosis (IPF), the most common idiopathic interstitial pneumonia, and connective tissue disease-associated interstitial pneumonia (CTD-IP).

DESIGN

A systematic review and meta-analysis.

DATA SOURCES

Electronic databases such as Medline and Embase were searched from 2015 through 6 September 2019.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

Primary studies that comparatively investigated the prognosis or prognostic factors of IPAF were eligible.

DATA EXTRACTION AND ANALYSIS

Two reviewers extracted relevant data and assessed the risk of bias independently. A meta-analysis was conducted using a random-effects model. The quality of presented evidence was assessed by the Grades of Recommendation, Assessment, Development, and Evaluation system.

RESULTS

Out of a total of 656 records retrieved, 12 studies were reviewed. The clinical features of IPAF were diverse between studies, which included a radiological and/or pathological usual interstitial pneumonia (UIP) pattern of between 0% and 73.8%. All studies contained some risk of bias. There was no significant difference of all-cause mortality between IPAF-UIP and IPF in all studies, although the prognosis of IPAF in contrast to IPF or CTD-IP varied between studies depending on the proportion of UIP pattern. Among the potential prognostic factors identified, age was significantly associated with all-cause mortality of IPAF by a pooled analysis of univariate results with a hazard ratio (HR) of 1.06 (95% confidence interval (CI) 1.04 to 1.07). The adjusted effect of age was also significant in all studies. The quality of presented evidence was deemed as very low.

CONCLUSION

There was no significant difference of all-cause mortality between IPAF-UIP and IPF. Age was deemed as a prognostic factor for all-cause mortality of IPAF. The findings should be interpreted cautiously due to the low quality of the presented evidence.

PROSPERO REGISTRATION NUMBER

CRD42018115870.

Antifibrotic therapy for fibrotic lung disease beyond idiopathic pulmonary fibrosis

Two antifibrotic medications (nintedanib and pirfenidone) were recommended (conditionally) for the treatment of patients with idiopathic pulmonary fibrosis (IPF) in the 2015 IPF evidence-based guidelines. These medications have been shown to reduce the rate of decline in forced vital capacity among patients with IPF over time and are the only two disease-modulating pharmacological agents approved by regulatory agencies and available for clinical use worldwide. With the evolved standard of care for interstitial lung disease evaluation including routine use of high-resolution computed tomography, fibrotic lung diseases other than IPF are increasingly recognised. In addition, it is becoming evident that genetic and pathophysiological mechanisms as well as disease behaviour in patients manifesting other "non-IPF progressive fibrotic interstitial lung diseases" (non-IPF-PF) may be similar to those in patients with IPF. Thus, it is biologically plausible that pharmacological agents with antifibrotic properties may be efficacious in non-IPF-PF. Indeed, studies are underway or planned to assess the safety and efficacy of nintedanib or pirfenidone among patients with several non-IPF fibrotic lung diseases. In this review, we briefly summarise the use of pirfenidone and nintedanib in IPF as well as the rationale and potential for use of these medications in non-IPF-PF that are being investigated in ongoing and upcoming clinical trials.

Critical reappraisal of underlying histological patterns in patients with suspected idiopathic pulmonary fibrosis

PURPOSE OF REVIEW

Usual interstitial pneumonia (UIP) pattern is the histologic marker of idiopathic pulmonary fibrosis (IPF), but usefulness of ancillary histologic findings may discriminate idiopathic from secondary UIP.

RECENT FINDINGS

Alternative less invasive procedures may identify UIP pattern preventing conventional surgical lung biopsy, whereas genomic analysis may recognize UIP pattern from otherwise poorly diagnostic samples.

SUMMARY

High-resolution computed tomography identifies a 'definite' UIP pattern in about half of cases, failing to recognize UIP in the absence of honeycombing or in limited disease. Although radiologic criteria for UIP need redefinition to improve their diagnostic yield, histologic features of UIP did not significantly change from the 1960s but continue to represent a major diagnostic tool, particularly in challenging interstitial lung diseases. A careful recognition of some histologic ancillary findings in UIP (e.g., cellular/follicular bronchiolitis with germinal centers, chronic pleuritis, interstitial granulomas/giant cells, bridging fibrosis) may be helpful in supporting secondary forms (e.g., connective tissue disease, chronic hypersensitivity pneumonia) from IPF. Cryobiopsy and awake-biopsy are promising approaches to obtain representative lung tissue preventing conventional surgical lung biopsy. Genomic techniques have recently demonstrated good-to-high sensitivity and specificity to disclose UIP pattern starting from RNA obtained in transbronchial biopsy, possibly replacing and/or flanking soon traditional histology.

Interstitial pneumonia with autoimmune features show better survival and less exacerbations compared to idiopathic pulmonary fibrosis

BACKGROUND

Patients with interstitial lung disease (ILD) who show features related to autoimmunity without meeting criteria for a defined connective tissue disease are categorized as interstitial pneumonia with autoimmune features (IPAF). The present study compared clinical characteristics and clinical outcomes of patients with IPAF to patients with connective tissue disease related-interstitial lung disease (CTD-ILD) and patients with idiopathic pulmonary fibrosis (IPF).

METHODS

ILD patients who were consecutively enrolled in a single institution ILD cohort between 2008 and 2015 were evaluated for the study. Clinical data had been prospectively collected, while radiologic imaging and pathologic findings were re-reviewed for the present study.

RESULTS

Out of 305 patients with ILD, 54 (17.7%) patients met the classification of IPAF, 175 (57.4%) patients had IPF, and 76 (24.9%) patients were diagnosed with CTD-ILD. Compared to IPF, incidences of acute exacerbations in 1,3 and 5 years were significantly less in the IPAF group (p = 0.022, p = 0.026 and p = 0.007, respectively). From multivariate analysis for mortality, age (p = 0.034, HR 1.022, 95% CI: 1.002-1.044), FVC (p < 0.001, HR 0.970, 95% CI: 0.955-0.984), ILD exacerbation (p = 0.001, HR 2.074, 95% CI: 1.366-3.148), and ILD type (p = 0.047, HR 0.436, 95% CI: 0.192-0.984 (IPAF vs IPF), respectively) showed significant association.

CONCLUSIONS

Compared to the other ILD groups, IPAF showed distinct clinical characteristics. The IPAF group showed better survival and less episodes of exacerbation when compared to the IPF group.

Differential diagnoses of fibrosing lung diseases

OBJECTIVES

To describe the challenges inherent in diagnosing fibrosing lung diseases (FLD) on CT imaging and methodologies by which the diagnostic process may be simplified.

METHODS

Extensive searches in online scientific databases were performed to provide relevant and contemporary evidence that describe the current state of knowledge related to FLD diagnosis. This includes descriptions of the utility of a working diagnosis for an individual case discussed in a multidisciplinary team (MDT) setting and challenges associated with the lack of consensus guidelines for diagnosing chronic hypersensitivity pneumonitis.

RESULTS

As well as describing imaging features that indicate the presence of a fibrosing lung disease, those CT characteristics that nuance a diagnosis of the various FLDs are considered. The review also explains the essential information that a radiologist needs to convey to an MDT when reading a CT scan. Lastly, we provide some insights as to the future directions the field make take in the upcoming years.

CONCLUSIONS

This review outlines the current state of FLD diagnosis and emphasizes areas where knowledge is limited, and more evidence is required. Fundamentally, however, it provides a guide for radiologists when tackling CT imaging in a patient with FLD.

ADVANCES IN KNOWLEDGE

This review encompasses advice from recent guideline statements and evidence from the latest studies in FLD to provide an up-to-date manual for radiologists to aid the diagnosis of FLD on CT imaging in an MDT setting.

Role of imaging in progressive-fibrosing interstitial lung diseases

Imaging techniques are an essential component of the diagnostic process for interstitial lung diseases (ILDs). Chest radiography is frequently the initial indicator of an ILD, and comparison of radiographs taken at different time points can show the rate of disease progression. However, radiography provides only limited specificity and sensitivity and is primarily used to rule out other diseases, such as left heart failure. High-resolution computed tomography (HRCT) is a more sensitive method and is considered central in the diagnosis of ILDs. Abnormalities observed on HRCT can help identify specific ILDs. HRCT also can be used to evaluate the patient's prognosis, while disease progression can be assessed through serial imaging. Other imaging techniques such as positron emission tomography-computed tomography and magnetic resonance imaging have been investigated, but they are not commonly used to assess patients with ILDs. Disease severity may potentially be estimated using quantitative methods, as well as visual analysis of images. For example, comprehensive assessment of disease staging and progression in patients with ILDs requires visual analysis of pulmonary features that can be performed in parallel with quantitative analysis of the extent of fibrosis. New approaches to image analysis, including the application of machine learning, are being developed.

Imaging techniques, particularly HRCT, are the cornerstone for ILD diagnosis and new approaches to analysing HRCT images, including machine-learning technology, are being developedhttp://ow.ly/1R1e30mOqhn

Interstitial Pneumonia With Autoimmune Features: An Emerging Challenge at the Intersection of Rheumatology and Pulmonology

Interstitial lung disease (ILD) remains a cause of significant morbidity and mortality in patients with connective tissue disease (CTD)-associated ILD. While some patients meet clear classification criteria for a systemic rheumatic disease, a subset of patients do not meet classification criteria but still benefit from immunosuppressive therapy. In 2015, the American Thoracic Society and European Respiratory Society described classification criteria for interstitial pneumonia with autoimmune features (IPAF) to identify patients with lung-predominant CTD who lack sufficient features of a systemic rheumatic disease to meet classification criteria. Although these criteria are imperfect, they are an important attempt to classify the patient with undifferentiated disease for future study. Rheumatologists play a key role in the evaluation of potential IPAF in patients, especially as many patients with a myositis-spectrum disease (e.g., non-Jo-1 antisynthetase syndrome, anti-melanoma differentiation-associated protein 5 antibody inflammatory myositis, or anti-PM/Scl antibody-associated inflammatory myositis) would be classified under IPAF using the currently available criteria for inflammatory myositis, and would therefore benefit from rheumatologic comanagement. The aim of this review was to describe the historical context that led to the development of these criteria and to discuss the limitations of the current criteria, diagnostic challenges, treatment options, and strategies for disease monitoring.

Diagnosis of Idiopathic Pulmonary Fibrosis in a Possible Usual Interstitial Pneumonia Pattern: a meta-analysis

This study aimed to determine whether a surgical lung biopsy is essential for IPF diagnosis with the possible UIP CT pattern. We performed literature searches of the MEDLINE and EMBASE databases and included studies that conducted a radiologic-pathologic evaluation of IPF according to the 2011 guideline. Outcomes were pooled using a random-effects model. Twelve studies were included. Pooled proportions of IPF for a UIP pattern were 99% (95%CI, 93% to 100%; I² = 51.7%) and for a possible UIP pattern were 94% (scenario inclusive of probable IPF; 95%CI, 87% to 99%; I² = 82.9%) and 88% (scenario exclusive of probable IPF; 95%CI, 79% to 95%; I² = 82.7%). The pooled percentage difference in the proportion of IPF between the UIP and possible UIP patterns was −2% (95%CI, −4% to 1%; I² = 0.0%) in the former scenario and 4% (95%CI, 0% to 8%; I² = 0.1%) in the latter scenario. The proportion of IPF with the possible UIP pattern was moderately correlated with the prevalence of IPF (correlation coefficient, 0.605; 95%CI, 0.550–0.860). There was a negligible pooled percentage difference in the proportion of IPF between the UIP and possible UIP patterns, indicating that IPF diagnosis can be confirmed without biopsy in suspected IPF cases with the possible UIP pattern.

The Four Corners Sign: A Specific Imaging Feature in Differentiating Systemic Sclerosis-related Interstitial Lung Disease From Idiopathic Pulmonary Fibrosis

PURPOSE

Differentiating between systemic sclerosis-related interstitial lung disease (SSc-ILD) and idiopathic pulmonary fibrosis (IPF) is important because of the differences in workup, prognosis, and treatment. However, there is much overlap in the appearance of these 2 entities on high-resolution computed tomography. We propose that inflammation and/or fibrosis focally or disproportionately involving the bilateral anterolateral upper lobes and posterosuperior lower lobes ["Four Corners" Sign (FCS)] is specific for SSc-ILD.

MATERIALS AND METHODS

Randomized high-resolution computed tomography studies from 74 IPF and 73 SSc-ILD cases were evaluated by 2 thoracic radiologists blinded to all patient data. For each case the reviewers noted whether the FCS was present and assigned a confidence level on the basis of a 7-point Likert scale. The same process was then performed on a randomized external validation group of 42 SSc-ILD and 42 IPF cases.

RESULTS

For Likert scores of 6 or 7 ("mostly agree" or "entirely agree" that the FCS is present, respectively) the sensitivity in SSc was 16.4% (95% confidence interval, 9.7%, 26.6%), specificity 100.0% (95% confidence interval, 95.1%, 100.0%). There was a significant association between a confidently present FCS and SSc compared with a confidently present FCS and IPF (P=0.0003). Analysis on an external validation group of 42 SSc and 42 IPF cases conferred similarly high specificity for SSc in cases characterized as FCS with high confidence.

CONCLUSION

The FCS, a pattern of focal or disproportionate inflammation and/or fibrosis involving the bilateral anterolateral upper lobes and posterosuperior lower lobes, is specific for SSc-ILD when readers are confident of its presence.

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.

State of the art in interstitial pneumonia with autoimmune features: a systematic review on retrospective studies and suggestions for further advances

The term interstitial pneumonia with autoimmune features (IPAF) has been proposed to define patients with interstitial lung disease (ILD) associated with autoimmune signs not classifiable for connective tissue diseases (CTDs). This new definition overcomes previous nomenclatures and provides a uniform structure for prospective studies through specific classification criteria.This work evaluates the characteristics of IPAF patients reported in the literature, to highlight potential limits through a comparative analysis and to suggest better performing classification criteria.Four retrospective studies on the IPAF population have been considered. The study subjects differed in age, sex, smoking habit, ILD pattern and outcomes. Another important difference lies in the diverse items considered in the classification criteria. The retrospective design of the studies and the absence from some of them of a rheumatologist clearly involved in the diagnosis may have influenced the data, but current IPAF criteria seem to include a rather heterogeneous population. To overcome these discrepancies, this review suggests a limitation in the use of single items and the exclusion of extremely specific CTD criteria. This should avoid the definition of IPAF for those diseases at different stages or at early onset. The investigation of a functional or morphological cut-off of pulmonary involvement would be useful.

CT-Pathologic Correlation of Major Types of Pulmonary Fibrosis: Insights for Revisions to Current Guidelines

OBJECTIVE

The purpose of this study was to assess the diagnostic significance of CT patterns that cannot be classified according to current idiopathic pulmonary fibrosis (IPF) guidelines and of specific findings of the inconsistent with usual interstitial pneumonitis (UIP) pattern.

MATERIALS AND METHODS

Subjects with a multidisciplinary diagnosis of interstitial lung disease who had undergone surgical lung biopsy and chest CT within 1 year of each other were included in the study. The predominant distribution and pattern of disease were scored. Cases were classified as UIP, possible UIP, or inconsistent with UIP at chest CT according to 2011 IPF guidelines. Cases that could not be confidently categorized with current guidelines were annotated as indeterminate.

RESULTS

UIP, possible UIP, and inconsistent with UIP CT patterns were associated with pathologic UIP in 89.6%, 81.6%, and 60.0% of subjects. An indeterminate CT pattern (7.7% [20/259]) was associated with a UIP pathologic diagnosis in 55.0% of cases. This finding was not statistically different from the findings in the group with the inconsistent with UIP CT pattern (p = 0.677) but was different from the findings in the UIP (p < 0.001) and possible UIP (p = 0.031) groups. In regard to specific findings of the inconsistent with UIP CT category, ground-glass opacity, air-trapping, consolidation, and axial distribution were associated with a non-UIP pathologic diagnosis; however, there was no significant association with zonal distribution.

CONCLUSION

A substantial minority of cases cannot be confidently categorized according to current guidelines for IPF and differ diagnostically from the possible UIP and UIP CT categories. The term "inconsistent with UIP" is misleading and should be renamed.

Phenotypic Clusters Predict Outcomes in a Longitudinal Interstitial Lung Disease Cohort

BACKGROUND

The current interstitial lung disease (ILD) classification has overlapping clinical presentations and outcomes. Cluster analysis modeling is a valuable tool in identifying distinct clinical phenotypes in heterogeneous diseases. However, this approach has yet to be implemented in ILD.

METHODS

Using cluster analysis, novel ILD phenotypes were identified among subjects from a longitudinal ILD cohort, and outcomes were stratified according to phenotypic clusters compared with subgroups according to current American Thoracic Society/European Respiratory Society ILD classification criteria.

RESULTS

Among subjects with complete data for baseline variables (N = 770), four clusters were identified. Cluster 1 (ie, younger white obese female subjects) had the highest baseline FVC and diffusion capacity of the lung for carbon monoxide (Dlco). Cluster 2 (ie, younger African-American female subjects with elevated antinuclear antibody titers) had the lowest baseline FVC. Cluster 3 (ie, elderly white male smokers with coexistent emphysema) had intermediate FVC and Dlco. Cluster 4 (ie, elderly white male smokers with severe honeycombing) had the lowest baseline Dlco. Compared with classification according to ILD subgroup, stratification according to phenotypic clusters was associated with significant differences in monthly FVC decline (Cluster 4, -0.30% vs Cluster 2, 0.01%; P < .0001). Stratification by using clusters also independently predicted progression-free survival (P < .001) and transplant-free survival (P < .001).

CONCLUSIONS

Among adults with diverse chronic ILDs, cluster analysis using baseline characteristics identified four distinct clinical phenotypes that might better predict meaningful clinical outcomes than current ILD diagnostic criteria.

Interstitial pneumonia with autoimmune features: an additional risk factor for ARDS?

Background

Interstitial pneumonia with autoimmune features (IPAF) identifies a recently recognized autoimmune syndrome characterized by interstitial lung disease and autoantibodies positivity, but absence of a specific connective tissue disease diagnosis or alternative etiology. We retrospectively reviewed the clinical presentation, diagnostic workup and management of seven critically ill patients who met diagnostic criteria for IPAF. We compared baseline characteristics and clinical outcome of IPAF patients with those of the population of ARDS patients admitted in the same period.

Results

Seven consecutive patients with IPAF admitted to intensive care unit for acute respiratory distress syndrome (ARDS) were compared with 78 patients with ARDS secondary to a known risk factor and with eight ARDS patients without recognized risk factors. Five IPAF patients (71%) survived and were discharged alive from ICU: Their survival rate was equal to that of patients with a known risk factor (71%), while the subgroup of patients without risk factors had a markedly lower survival (38%). According to the Berlin definition criteria, ARDS was severe in four IPAF patients and moderate in the remaining three. All had multiple organ dysfunction at presentation. The most frequent autoantibody detected was anti-SSA/Ro52. All patients required prolonged mechanical ventilation (median duration 49 days, range 10–88); four received extracorporeal membrane oxygenation and one received low-flow extracorporeal CO₂ removal. All patients received immunosuppressive therapy.

Conclusions

This is the first description of a cohort of critical patients meeting the diagnostic criteria for IPAF presenting with ARDS. This diagnosis should be considered in any critically ill patient with interstitial lung disease of unknown origin. While management is challenging and level of support high, survival appears to be good and comparable to that of patients with ARDS associated with a known clinical insult

Electronic supplementary material

The online version of this article (doi:10.1186/s13613-017-0320-3) contains supplementary material, which is available to authorized users.

Interstitial Pneumonia with Autoimmune Features: Overview of proposed criteria and recent cohort characterization

The accurate diagnosis of interstitial lung disease (ILD) is essential for optimal prognostication and management. While connective tissue disease (CTD) is among the most common causes of ILD, some patients have features suggestive of autoimmunity without meeting criteria for a specific CTD. To help define and study this disease entity more uniformly, a 2015 research statement proposed consensus-based criteria and coined the term "interstitial pneumonia with autoimmune features" (IPAF). In this review, we summarize and compare previously proposed criteria to characterize these patients, provide an overview of the IPAF criteria and highlight recent investigations aimed at characterizing IPAF cohorts. We then call attention to questions that have arisen with the application of the IPAF criteria and discuss future areas of study.