Clinical, serological and radiological features of a prospective cohort of Interstitial Pneumonia with Autoimmune Features (IPAF) patients

Relationship between idiopathic interstitial pneumonias (IIPs) and connective tissue disease-related interstitial lung disease (CTD-ILD): A narrative review

While idiopathic interstitial pneumonia (IIP) centering on idiopathic pulmonary fibrosis (IPF) is the most prevalent interstitial lung disease (ILD), especially in the older adult population, connective tissue disease (CTD)-related ILD is the second most prevalent ILD. The pathogenesis of IPF is primarily fibrosis, whereas that of other ILDs, particularly CTD-ILD, is mainly inflammation. Therefore, a precise diagnosis is crucial for selecting appropriate treatments, such as antifibrotic or immunosuppressive agents. In addition, some patients with IIP have CTD-related features, such as arthritis and skin eruption, but do not meet the criteria for any CTD, this is referred to as interstitial pneumonia with autoimmune features (IPAF). IPAF is closely associated with idiopathic nonspecific interstitial pneumonia (iNSIP) and cryptogenic organizing pneumonia (COP). Furthermore, patients with iNSIP or those with NSIP with OP overlap frequently develop polymyositis/dermatomyositis after the diagnosis of IIP. Acute exacerbation of ILD, the most common cause of death, occurs more frequently in patients with IPF than in those with other ILDs. Although acute exacerbation of CTD-ILD occurs at a low rate of incidence, patients with rheumatoid arthritis, microscopic polyangiitis, or systemic sclerosis experience more acute exacerbation of CTD-ILD than those with other CTD. In this review, the features of each IIP, focusing on CTD-related signatures, are summarized, and the pathogenesis and appropriate treatments to improve the prognoses of patients with various ILDs are discussed.

Characteristics and risk factors of interstitial pneumonia with autoimmune features

BACKGROUND

Interstitial pneumonia with autoimmune features (IPAF) has features of connective tissue disease-associated interstitial lung disease (CTD-ILD), but without meeting criteria for a specific CTD. We compared baseline characteristics, survival, and response to treatment of IPAF to both CTD-ILD and unclassifiable ILD.

METHODS

Measurements were extracted from a prospective registry. Baseline features and survival were compared in IPAF against both CTD-ILD and unclassifiable ILD. Linear trajectory of lung function decline (%-predicted forced vital capacity [FVC%] and diffusion capacity of the lung for carbon monoxide [DLCO%]) before and after initiation of mycophenolate or azathioprine were compared in IPAF against both CTD-ILD and unclassifiable ILD using linear mixed models.

RESULTS

Compared to CTD-ILD (n = 1240), patients with IPAF (n = 128) were older, more frequently male, and had greater smoking history. Compared to unclassifiable ILD (n = 665), patients with IPAF were younger, more frequently female, and had worse baseline lung function. IPAF had higher mortality compared to CTD-ILD and similar risk of mortality compared to unclassifiable ILD. Mycophenolate initiation was associated with stabilization of FVC% and DLCO% in all ILD subtypes except for FVC% in patients with IPAF, and azathioprine initiation with stabilization of FVC% and DLCO% in all ILD subtypes except for FVC% decline in IPAF and DLCO% decline in CTD-ILD.

CONCLUSION

Patients with IPAF had worse survival compared to those with CTD-ILD and similar mortality to unclassifiable ILD, with treatment being associated with stabilization in lung function in all three ILDs. It is uncertain whether IPAF should be considered a distinct ILD diagnostic subgroup.

Unclassifiable interstitial lung disease and autoimmunity: Towards IPAF in children?

INTRODUCTION

Interstitial pneumonia with autoimmune features (IPAF) has been defined for adults with interstitial lung disease (ILD) and autoimmunity who do not meet the criteria for a specific connective tissue disease (CTD). We aimed to determine whether IPAF criteria could apply to children.

METHODS

We retrospectively studied patients with ILD and autoimmunity followed at Necker Hospital between 2008 and 2019. Children were classified according to specific CTD and IPAF criteria. The epidemiology and course of the disease were studied according to the final diagnosis.

RESULTS

Among 27 patients, 6 fulfilled the criteria for IPAF and represented 4.5% of all patients with ILD during the study period. Other diagnoses included juvenile dermatomyositis (30%), overlap syndromes (19%), systemic lupus erythematosus (15%), systemic sclerosis (7%), mixed CTD (4%), and rheumatoid arthritis (4%). IPAF patients were more frequently boys versus CTD-ILD patients (67% vs. 14%, p = .02). Two patients had severe respiratory distress that led to death for one of them. The course was favorable for the others, with a good response to steroids. The course tended to be more favorable for IPAF patients than for those with CTD-ILD (0% lung fibrosis in the IPAF group vs. 43% in the CTD-ILD group, p = .07).

CONCLUSION

We confirmed the existence of IPAF in children. Its prevalence was lower than in adults but comparable to that found for other pediatric series. Boys were more highly represented than in CTD-ILD. The course was favorable for most cases. Larger and more prospective studies are needed to confirm these results.

[Interstitial pneumonia with autoimmune features: monocentric prospective study]

AIM

To study demographic, clinical, serological and morphological features of interstitial pneumonia with autoimmune features (IPAF), compare survival in IPAF and interstitial lung disease in connective tissue diseases (CTD-ILD), and identify predictors of mortality and transformation to CTD in the IPAF group.

MATERIALS AND METHODS

The IPAF group included 48 patients (75.0% women, median age 57.5 years), CTD-ILD - 49 patients (79.6% women, median age 60.0 years). The analysis of demographic, clinical, laboratory and instrumental data was performed, as well as comparison of survival with the Kaplan-Meier method and the log-rank test in the IPAF and CTD-ILD groups. In the IPAF group, predictors of mortality and the development of CTD were studied with multivariate regression analysis.

RESULTS

Duration of observation period did not differ significantly in the IPAF and CTD-ILD groups (40.0 and 37.0 months, respectively). Clinical criteria of IPAF were observed in 25 (52.1%) patients, serological - in 44 (91.7%), morphological - in 44 (91.7%). Mortality in the IPAF group was significantly higher than in the CTD-ILD group (29.2 and 6.1%, respectively; p=0.023). The presence of diabetes mellitus, CT-pattern of usual interstitial pneumonia, and an initial low forced vital capacity value were independent predictors of mortality in the IPAF group. During the observation period, the development of CTD was noted in 4 (8.3%) patients with IPAF. The independent predictor of the CTD development was the increased C-reactive protein level.

CONCLUSION

IPAF is characterized by a lower survival rate compared to CTD-ILD, and a relatively low risk of CTD transformation.

Clinical Characterization and Predictive Factors for Progression in a Cohort of Patients with Interstitial Lung Disease and Features of Autoimmunity: The Need for a Revision of IPAF Classification Criteria

Background and Objectives: The "interstitial pneumonia with autoimmune features" (IPAF) criteria have been criticized because of the exclusion of usual interstitial pneumonia (UIP) patients with a single clinical or serological feature. To classify these patients, the term UIPAF was proposed. This study aims to describe clinical characteristics and predictive factors for progression of a cohort of interstitial lung disease (ILD) patients with at least one feature of autoimmunity, applying criteria for IPAF, specific connective tissue diseases (CTD), and a definition of UIPAF when possible. Methods: We retrospectively evaluated data on 133 consecutive patients with ILD at onset associated with at least one feature of autoimmunity, referred by pulmonologists to rheumatologists from March 2009 to March 2020. Patients received 33 (16.5-69.5) months of follow-up. Results: Among the 101 ILD patients included, 37 were diagnosed with IPAF, 53 with ILD-onset CTD, and 11 with UIPAF. IPAF patients had a lower prevalence of UIP pattern compared to CTD-ILD and UIPAF patients (10.8% vs. 32.1% vs. 100%, p < 0.01). During the follow-up, 4 IPAF (10.8%) and 2 UIPAF (18.2%) patients evolved into CTD-ILD. IPAF patients presented features not included in IPAF criteria, such as sicca syndrome (8.1%), and were more frequently affected by systemic hypertension (p < 0.01). Over one year, ILD progression (greater extent of fibrosis on HRCT and/or decline in PFTs) was less frequent in the IPAF group compared to CTD-ILD and UIPAF (32.3% vs. 58.8% vs. 72.7, p = 0.02). A UIP pattern and an IPAF predicted a faster (OR: 3.80, p = 0.01) and a slower (OR: 0.28, p = 0.02) ILD progression, respectively. Conclusions: IPAF criteria help identify patients who might develop a CTD-ILD, even though a single clinical or serological feature is respected. Future revisions of IPAF criteria should include sicca syndrome and separate UIP-pattern into a different definition (UIPAF), given its association with a different prognosis, independently from ILD classification.

[Interstitial Lung Disease]

Diffuse interstitial lung diseases (ILD) are a heterogeneous group of respiratory disorders that are usually classified together because they have similar clinical, radiological, physiological or pathological manifestations. In the last decade there have been important scientific advances in the study of these entities, which has led to a better understanding of their pathophysiology and to the appearance of treatments that have brought about a paradigm shift in the disease. This document presents a series of questions and answers on ILD, with special emphasis on the most relevant changes in terms of pathophysiology, diagnosis, and treatment.

Clinical implications of interstitial pneumonia with autoimmune features diagnostic criteria in idiopathic pulmonary fibrosis: A case control study

Background

A subgroup of IPF patients can meet IPAF criteria (features suggesting an underlying autoimmune process without fulfilling established criteria for a CTD). This study was aimed to evaluate whether IPAF/IPF patients compared to IPF patients differ in clinical profile, prognosis and disease course.

Methods

This is a retrospective, single center, case-control study. We evaluated 360 consecutive IPF patients (Forlì Hospital, between 1/1/2002 and 28/12/2016) and compared characteristics and outcome of IPAF/IPF to IPF.

Results

Twenty-two (6%) patients met IPAF criteria. IPAF/IPF patients compared to IPF were more frequently females (N = 9/22, 40.9% vs. N = 68/338, 20.1%, p = 0.02), suffered more frequently from gastroesophageal reflux (54.5% vs. 28.4%, p = 0.01), and showed a higher prevalence of arthralgias (86.4% vs. 4.8%, p < 0.0001), myalgias (14.3% vs. 0.3%, p = 0.001) and fever (18.2% vs. 1.9%, p = 0.002). The serologic domain was detected in all cases (the most frequent were ANA in 17 and RF in nine cases) and morphologic domain (histology features) was positive in 6 out of 10 lung biopsies (lymphoid aggregates). Only patients with IPAF/IPF evolved to CTD at follow-up (10/22, 45.5%; six rheumatoid arthritis, one Sjögren's and three scleroderma). The presence of IPAF was a positive prognostic determinant (HR 0.22, 95% CI 0.08-0.61, p = 0.003), whereas the isolated presence of circulating autoantibody did not impact prognosis (HR 1.00, 95% CI 0.67-1.49, p = 0.99).

Conclusion

The presence of IPAF criteria in IPF has a major clinical impact correlating with the risk of evolution to full blown-CTD during follow-up and identifying a subgroup of patients with a better prognosis.

Identification and Prognosis of Patients With Interstitial Pneumonia With Autoimmune Features

BACKGROUND/OBJECTIVE

Patients classified as interstitial pneumonia with autoimmune features (IPAF) have interstitial lung disease (ILD) and features of autoimmunity but do not fulfill criteria for connective tissue diseases (CTDs). Our goal was to identify patients classifiable as IPAF, CTD-ILD, and idiopathic pulmonary fibrosis (IPF) from a preexisting pulmonary cohort and evaluate the prognosis of patients with IPAF.

METHODS

We reviewed the medical records of 456 patients from a single-center pulmonary ILD cohort whose diagnoses were previously established by a multidisciplinary panel that did not include rheumatologists. We reclassified patients as IPAF, CTD-ILD, or IPF. We compared transplant-free survival using Kaplan-Meier methods and identified prognostic factors using Cox models.

RESULTS

We identified 60 patients with IPAF, 113 with CTD-ILD, and 126 with IPF. Transplant-free survival of IPAF was not statistically significantly different from that of CTD-ILD or IPF. Among IPAF patients, male sex (hazard ratio, 4.58 [1.77-11.87]) was independently associated with worse transplant-free survival. During follow-up, only 10% of IPAF patients were diagnosed with CTD-ILD, most commonly antisynthetase syndrome.

CONCLUSION

Despite similar clinical characteristics, most patients with IPAF did not progress to CTD-ILD; those who did often developed antisynthetase syndrome, highlighting the critical importance of comprehensive myositis autoantibody testing in this population. As in other types of ILD, male sex may portend a worse prognosis in IPAF. The routine engagement of rheumatologists in the multidisciplinary evaluation of ILD will help ensure the accurate classification of these patients and help clarify prognostic factors.

Clinical characteristics of idiopathic interstitial pneumonias with anti-Ro52/tripartite motif-containing 21 antibodies

Antibodies to Ro52/tripartite motif-containing 21 (TRIM21), referred to as anti-Ro52, are found in patients diagnosed with diverse systemic autoimmune rheumatic disease and associated with interstitial lung diseases. However, little is known about the clinical characteristics of anti-Ro52 in patients with idiopathic interstitial pneumonias (IIPs). We aimed to analyze the prevalence, co-existent autoantibodies, and clinical characteristics of anti-Ro52 in patients with IIP. The study enrolled 288 patients diagnosed with IIP. Clinical, laboratory and radiographic findings of IIP patients were compared between anti-Ro52 positives and negatives. Anti-Ro52 (20/288; 6.9%), anti-ARS (18/288; 6.3%), and anti-Ro60/SS-A (16/288; 5.6%) were the most common autoantibodies detected in IIP patients. Among 20 IIP patients who had anti-Ro52, anti-ARS was present in 8 (40%) patients. The criteria for interstitial pneumonia with autoimmune features (IPAF) were significantly better fulfilled by patients with anti-Ro52 than those without (P = 0.001). Meeting serological domain (P < 0.001) and Raynaud’s phenomenon (P = 0.009) were significantly more common in the anti-Ro52-positive patients. Anti-Ro52-positive IIP patients have clinical features consistent with IPAF. Anti-Ro52 may have an important role in detecting the autoimmune phenotype in IIP patients.

The shadow zone of capillaroscopy in the classification of the Raynaud's phenomenon

Raynaud's phenomenon (RP) is a frequent clinical finding in the general population that can be observed across multiple medical specialties and nailfold videocapillaroscopy is a first line imaging tool to early differenziate primitive and secondary forms of RP. According to the criteria of LeRoy and Medsger normal nailfold capillaries characterize a primary RP. The recognition of vascular alterations at capillaroscopy is the key to a correct framing of the phenomenon. Capillaroscopy is of significant practical value as it allows a reliable predictive assessment of the developmental risk of the disorder. However, to date, the variety of nomenclature for subjects affected by RP generates uncertainty in patient management and in the possibility of comparing studies. The capillaroscopic findings have a very broad range of normality and a significant presence of non specific microvascular abnormalities are reported also in patients with primary RP. The presence of these non specific vascular changes can make it difficult to differenziate primary and secondary RP. Here we highlight some critical points in the capillaroscopic distinction of primary and secondary RP and relaunch the debate on the classification of the RP because it is likely that what we identify today as the primary RP (pRP) collects different clinical entities with different prognostic significance and different therapeutic needs.

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.

Review: Serum Biomarkers of Lung Fibrosis in Interstitial Pneumonia with Autoimmune Features-What Do We Already Know?

Interstitial pneumonia with autoimmune features (IPAF) belongs to a group of diseases called interstitial lung diseases (ILDs), which are disorders of a varied prognosis and course. Finding sufficiently specific and sensitive biomarkers would enable the progression to be predicted, the natural history to be monitored and patients to be stratified according to their treatment. To assess the significance of pulmonary fibrosis biomarkers studied thus far, we searched the PubMed, Medline and Cochrane Library databases for papers published between January 2015 and June 2021. We focused on circulating biomarkers. A primary review of the databases identified 38 articles of potential interest. Overall, seven articles fulfilled the inclusion criteria. This review aims to assess the diagnostic and prognostic value of molecules such as KL-6, SP-A, SP-D, circulating fibrocytes, CCL2, CXCL13, CXCL9, CXCL10 and CXCL11. All of these biomarkers have previously been studied in idiopathic pulmonary fibrosis (IPF) and connective tissue disease-associated interstitial lung disease (CTD-ILD). IPAF is a disorder of a heterogeneous nature. It explains the lack of coherent observations in terms of correlations with functional parameters. There is still no meta-analysis of pulmonary fibrosis biomarkers in IPAF. This is mainly due to the heterogeneity of the methodology and groups analysed in the research. More research in this area is needed.

Autoimmune Progressive Fibrosing Interstitial Lung Disease: Predictors of Fast Decline

A subset of interstitial lung diseases (ILDs) with autoimmune traits-including connective tissue disease-associated ILD (CTD-ILD) and interstitial pneumonia with autoimmune features (IPAF)-develops progressive fibrosing (PF)-ILD. The aim of our study was to evaluate the clinical characteristics and predictors of longitudinal lung function (LF) changes in autoimmune PF-ILD patients in a real-world setting. All ILD cases with confirmed or suspected autoimmunity discussed by a multidisciplinary team (MDT) between January 2017 and June 2019 (n = 511) were reviewed, including 63 CTD-ILD and 44 IPAF patients. Detailed medical history, LF test, diffusing capacity of the lung for carbon monoxide (DLCO), 6-min walk test (6MWT), blood gas analysis (BGA), and high-resolution computer tomography (HRCT) were performed. Longitudinal follow-up for functional parameters was at least 2 years. Women were overrepresented (70.1%), and the age of the IPAF group was significantly higher as compared to the CTD-ILD group (p < 0.001). Dyspnea, crackles, and weight loss were significantly more common in the IPAF group as compared to the CTD-ILD group (84.1% vs. 58.7%, p = 0.006; 72.7% vs. 49.2%, p = 0.017; 29.6% vs. 4.8%, p = 0.001). Forced vital capacity (FVC) yearly decline was more pronounced in IPAF (53.1 ± 0.3 vs. 16.7 ± 0.2 ml; p = 0.294), while the majority of patients (IPAF: 68% and CTD-ILD 82%) did not deteriorate. Factors influencing progression included malignancy as a comorbidity, anti-SS-A antibodies, and post-exercise pulse increase at 6MWT. Antifibrotic therapy was administered significantly more often in IPAF as compared to CTD-ILD patients (n = 13, 29.5% vs. n = 5, 7.9%; p = 0.007), and importantly, this treatment reduced lung function decline when compared to non-treated patients. Majority of patients improved or were stable regarding lung function, and autoimmune-associated PF-ILD was more common in patients having IPAF. Functional decline predictors were anti-SS-A antibodies and marked post-exercise pulse increase at 6MWT. Antifibrotic treatments reduced progression in progressive fibrosing CTD-ILD and IPAF, emphasizing the need for guidelines including optimal treatment start and combination therapies in this special patient group.

Assessing the Role for Nailfold Videocapillaroscopy in Interstitial Lung Disease Classification: A Systematic Review and Meta-Analysis

OBJECTIVES

The nailfold videocapillaroscopy (NVC) has been known to assist with Interstitial Lung Disease (ILD) classification. However, evidence on its diagnostic efficacy is limited, particularly in some connective tissue disease-related interstitial lung diseases (CTD-ILD), and in interstitial pneumonia with autoimmune features (IPAF). This study aimed to address this limitation by conducting a meta-analysis on the efficacy of the NVC in ILD subgroups of CTD-ILD, IPAF and idiopathic pulmonary fibrosis (IPF).

METHODS

MEDLINE, EMBASE, CENTRAL were screened from inception to December 2020 according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Studies that report prevalence of nailfold abnormalities (NVC+) in CTD-ILD, IPAF and IPF cohorts were included. Data were presented as prevalence ratio (PR) with 95% CI using a random-effects model. Quality of evidence was assessed using GRADE criteria.

RESULTS

Twenty one studies were eligible. Prevalence of NVC+ was highest in CTD-ILD; PR [95 CI%] 80.4% [74.3%, 85.3%], followed by IPAF; 27.4% [10.9%, 53.7%], and IPF; 13.8% [5.7%, 29.9%]. Late Scleroderma pattern was the most prevalent nailfold pattern; 40.4% [28.1%, 54.1%] in our CTD-ILD cohort. Quality of evidence was low for CTD-ILD, IPAF and IPF cohorts, moderate for the Late Scleroderma Pattern cohort.

CONCLUSION

NVC can increase the diagnostic accuracy of ILD when used in a multi-disciplinary setting, and appears to have greatest utility in CTD-ILD, followed by IPAF and IPF. The Late Scleroderma Pattern was the most frequent nailfold capillary pattern in SSc-ILD. Future research will allow for greater understanding of the prognostic value of the NVC in ILD.

2020 guide for the diagnosis and treatment of interstitial lung disease associated with connective tissue disease

The prognosis of patients with connective tissue disease (CTD) has improved significantly in recent years, but interstitial lung disease (ILD) associated with connective tissue disease (CTD-ILD) remains a refractory condition, which is a leading cause of mortality. Because it is an important prognostic factor, many observational and interventional studies have been conducted to date. However, CTD is a heterogeneous group of conditions, which makes the clinical course, treatment responses, and prognosis of CTD-ILD extremely diverse. To summarize the current understanding and unsolved questions, the Japanese Respiratory Society and the Japan College of Rheumatology collaborated to publish the world's first guide focusing on CTD-ILD, based on the evidence and expert consensus of pulmonologists and rheumatologists, along with radiologists, pathologists, and dermatologists. The task force members proposed a total of 27 items, including 7 for general topics, 9 for disease-specific topics, 3 for complications, 4 for pharmacologic treatments, and 4 for non-pharmacologic therapies, with teams of 2-4 authors and reviewers for each item to prepare a consensus statement based on a systematic literature review. Subsequently, public opinions were collected from members of both societies, and a critical review was conducted by external reviewers. Finally, the task force finalized the guide upon discussion and consensus generation. This guide is expected to contribute to the standardization of CTD-ILD medical care and is also useful as a tool for promoting future research by clarifying unresolved issues.

Interstitial Lung Diseases and the Impact of Gender

Interstitial lung diseases encompass an amalgamated group of heterogeneous lung disorders, characterized by variable clinical and radiologic patterns. Despite an increase in our knowledge, pathogenesis of interstitial lung diseases remains largely unknown. Experimental evidence on the role of sex hormones in lung development and epidemiologic associations of gender differences with interstitial lung diseases prevalence fueled studies investigating the role of gender and sex hormones in the pathogenesis and treatment of pulmonary fibrosis. This review summarizes experimental and clinical data for the impact of gender and sex hormones on interstitial lung diseases and highlights future perspectives in the field.

Clinical spectrum of children with interstitial pneumonia with autoimmune features

BACKGROUND

Interstitial pneumonia with autoimmune features (IPAF) is a term used to describe adult patients with interstitial lung disease (ILD) who display some clinical or serological features of autoimmune diseases and who do not meet the full criteria for a specific connective tissue disease (CTD). The aim of this study was to define the demographic, clinical, radiologic, serologic and histopathologic features and assess treatment in children with IPAF.

METHODS

This retrospective cohort study was conducted at a tertiary referral pediatric pulmonology center between January 2010 and August 2020. Children with proven interstitial pneumonia with no known etiologies were evaluated for IPAF according to European Respiratory Society/American Thoracic Society research statement of IPAF.

RESULTS

Among 132 children with ILD, 17 patients were evaluated in detail for IPAF criteria and six patients were further diagnosed as having IPAF. The incidence of IPAF in our patients with ILD was 4.5%. Four of these patients were female. The median age at the time of ILD diagnosis was 10.5 years. The most common initial symptom was shortness of breath, and the most common physical examination sign was crackles in both lungs. Steroid therapy was given to all patients and four patients received other immunosuppressive agents for steroid sparing. Two of those patients died because of respiratory insufficiency during the follow-up.

CONCLUSION

Children with interstitial pneumonia and certain clinical, serologic, and/or morphologic features should raise suspicion for the presence of an underlying systemic autoimmune disease. IPAF is also seen in children and should be categorized in chILD classifications.

Feasibility, face, and content validity of quantitative computed tomography in interstitial lung disease related to connective tissue diseases

OBJECTIVES

Quantitative computed tomography (QCT) is a promising tool for objective assessment of interstitial lung disease (ILD) related to connective tissue diseases (CTD). However, its validity was never investigated. The aim of this study was to assess QCT feasibility, face, and content validity evaluation concerning CTD-ILD.

METHODS

A rheumatologist and a chest radiologist conceived an online survey with nine statements: Two about general issue involving CTD-ILD, one for the face validity, three both for content validity and feasibility. Each statement had to be rated with a score from 0 to 100, respectively, (complete disagreement and agreement). We considered a statement supported by the experts if the median score was ≥75.0.

RESULTS

A panel of 14 experts (11 from Europe, three from America) with a nine years median experience was enrolled. All the statements about feasibility, face and content validity were supported, except for QCT capability to recognize elementary lesions.

CONCLUSIONS

The panel of experts supported feasibility, face, and content validity of QCT assessment concerning CTD-ILD. This may stimulate a greater use in clinical practice and further studies to confirm its discriminative properties and its construct validity.

Prospective nationwide multicentre cohort study of the clinical significance of autoimmune features in idiopathic interstitial pneumonias

BACKGROUND

Some patients with idiopathic interstitial pneumonia (IIP) show autoimmune features. Interstitial pneumonia with autoimmune features (IPAF) was recently proposed as a research concept in these patients. However, retrospective studies reported conflicting results of its prognosis. Therefore, this study was conducted to prospectively evaluate the clinical significance of autoimmune features in patients with IIP.

METHODS

This nationwide multicentre study prospectively enrolled consecutive patients with IIP. At the diagnosis, we systematically evaluated 63 features suggestive of connective tissue diseases using a checklist including symptoms/signs and autoantibodies, which contained most items of the IPAF criteria and followed up with the patients. Clinical phenotypes were included in a cluster analysis.

RESULTS

In 376 patients with IIP enrolled, 70 patients (18.6%) met the IPAF criteria. The proportion of patients with IPAF was significantly lower in idiopathic pulmonary fibrosis (IPF) than in non-IPF (6.0% vs 24.3%, respectively). During a median observation period of 35 months, patients with IPAF more frequently developed systemic autoimmune diseases and had less frequent acute exacerbation of IIPs than patients with non-IPAF. IPAF diagnosis was significantly associated with better survival and was an independent positive prognostic factor in total and patients with non-IPF. Cluster analysis by similarity of clinical phenotypes identified a cluster in which there was a higher number of women, and patients had more autoimmune features and a better prognosis than other clusters.

INTERPRETATION

These observations suggest that some patients with IIP show autoimmune features with distinct characteristics and favourable prognosis. However, we were not able to determine the appropriate therapies for these patients.

Interstitial pneumonia with autoimmune features: from research classification to diagnosis

PURPOSE OF REVIEW

The term interstitial pneumonia with autoimmune features (IPAF) was first proposed by an international task force in 2015 as a research classification to standardise nomenclature regarding patients with idiopathic interstitial pneumonia and features of connective tissue disease. However, how the use of this term and its proposed definition translates to clinical practice remains uncertain. This review will provide a comprehensive overview of studies of IPAF cohorts to date, discuss the consideration of IPAF as a distinct diagnostic entity and outline a suggested approach to patient management.

RECENT FINDINGS

Considerable heterogeneity exists between published IPAF cohorts, with some cohorts exhibiting similarities to those with connective tissue disease-associated interstitial lung disease (CTD-ILD), and others more similar to idiopathic interstitial pneumonias including idiopathic pulmonary fibrosis (IPF). Little data exist to inform the management of patients who fulfil the IPAF criteria. Preliminary data supports pragmatic management of these patients as having a working clinical diagnosis of either idiopathic interstitial pneumonia or CTD-ILD. Future research studies into this approach are required.

SUMMARY

The term IPAF, and its definition, have been of fundamental benefit to facilitating research in this diverse patient group. However, to date, there remain many unanswered questions regarding their natural histories and response to treatment.

Recent advances in the diagnosis and management of interstitial pneumonia with autoimmune features: the perspective of rheumatologists

Interstitial pneumonia with autoimmune feature (IPAF) is a recently established disease entity that is comprised of interstitial lung diseases with evidence of autoimmune features but that does not fulfill the criteria for definite autoimmune rheumatic diseases. The classification criteria for IPAF were defined by the European Respiratory Society and American Thoracic Society in 2015. However, further studies to establish IPAF subgroups and treatment modalities for each subgroup are still needed. In this review, we discuss recent advances regarding IPAF and raise critical points for the diagnosis and management of patients with IPAF from the perspective of rheumatologists.

Interstitial pneumonia with autoimmune features: A case series and overview

The topic of interstitial pneumonia with autoimmune features (IPAF) is a research classification proposed by the European Respiratory Society/American Thoracic Society Task Force: this includes patients with idiopathic interstitial pneumonia (IIP) and clinical features, suggesting an underlying autoimmune process, but who do not meet established criteria for a connective tissue disease (CTD). We aimed to perform a detailed characterization of clinical, serological, and radiological features for our patients with IPAF criteria. Six patients were included, and a comprehensive description of these cases revealed a heterogeneous group in terms of clinical and treatment options. In most patients, it was possible to identify other features and disorders with an autoimmune “background,” which may support the inclusion of these patients in the IPAF classification. No deaths or significant decline in lung function occurred, and thus no definitive diagnosis of CTD could be found over 35 months of median follow-up. Therefore, IPAF is a recent concept, with many questions still open in regard to its usage in the ILD field.

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IPAF allows to group who presents with IIP and features suggesting an underlying autoimmune process, but do not meet criteria for a CTD.

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A detailed clinical history is crucial to identify other features or disorders with an autoimmune “background”.

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Our cases reveal a heterogeneous population, with a “benign” disease behavior, similar to CTD-ILD.

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The multidisciplinary meeting and follow-up are essential, so that an IPF diagnosis (if UIP pattern is present), or an evolution to CTD-ILD, are not missed.

Krebs von den Lungen-6 and surfactant protein-A in interstitial pneumonia with autoimmune features

Interstitial pneumonia with autoimmune features (IPAF) is a special subtype of interstitial lung disease that has received worldwide attention. Krebs von den Lungen-6 (KL-6) and surfactant protein-A (SP-A) can be used as an important biomarker of interstitial lung disease, but its exact relationship with IPAF is poorly understood.A total of 65 IPAF patients were included in the study and were followed up for 52 weeks. The KL-6 and SP-A were evaluated by chemiluminescence enzyme immunoassay. The above indicators were tested at 2 time points, baseline (the first admission of patients) and 52 weeks. We also collected the indicators of antinuclear antibodies and rheumatoid factor. Based on high-resolution computed tomography evaluations, patients were divided into: aggravation, stable, and improvement group. At same time, 30 age-matched normal people as normal control were recruited, the same information was collected. Correlations among the groups were compared and analyzed.The KL-6 and SP-A level in IPAF patients were significantly higher than normal controls (fold increase = 11.35 and 1.39, both P < .001) and differed significantly at baseline and 52 weeks in IPAF (difference ratio = 37.7% and 21.3%, P < .05, both). There were significant differences at baseline and 52 weeks (r values of aggravation, improvement, and stable groups for KL-6 were 0.705, 0.770, and 0.344, P = .001, .001, and .163, and for SP-A the r value were 0.672, 0.375, and 0.316, P = .001, .126, and .152). In aggravation group, KL-6 and SP-A were correlated with CT scores (both P < .05). Diffusing capacity of the lung for carbon monoxide (DLCO) and forced vital capacity (FVC), % predicted showed a progressive downward trend, with a significant difference at baseline and 52 weeks in IPAF patients (difference ratio = 23.8% and 20.6%, both P < .05). There was a significant correlation between KL-6 and FVC % predicted and DLCO (both P < .05), SP-A showed negatively correlated with DLCO, but not significantly correlated with FVC % predicted (P < .05 and .47).This study demonstrated that KL-6 and SP-A can reflect disease progression, and both 2 play a key role at reflection of lung epithelial cell injury and fibrosis degree in IPAF.

Interstitial Pneumonia with Autoimmune Features: Why Rheumatologist-Pulmonologist Collaboration Is Essential

In 2015 the European Respiratory Society (ERS) and the American Thoracic Society (ATS) “Task Force on Undifferentiated Forms of Connective Tissue Disease-associated Interstitial Lung Disease” proposed classification criteria for a new research category defined as “Interstitial Pneumonia with Autoimmune Features” (IPAF), to uniformly define patients with interstitial lung disease (ILD) and features of autoimmunity, without a definite connective tissue disease. These classification criteria were based on a variable combination of features obtained from three domains: a clinical domain consisting of extra-thoracic features, a serologic domain with specific autoantibodies, and a morphologic domain with imaging patterns, histopathological findings, or multicompartment involvement. Features suggesting a systemic vasculitis were excluded. Since publication of ERS/ATS IPAF research criteria, various retrospective studies have been published focusing on prevalence; clinical, morphological, and serological features; and prognosis of these patients showing a broad heterogeneity in the results. Recently, two prospective, cohort studies were performed, confirming the existence of some peculiarities for this clinical entity and the possible progression of IPAF to a defined connective tissue disease (CTD) in about 15% of cases. Moreover, a non-specific interstitial pneumonia pattern, an anti-nuclear antibody positivity, and a Raynaud phenomenon were the most common findings. In comparison with idiopathic pulmonary fibrosis (IPF), IPAF patients showed a better performance in pulmonary function tests and less necessity of oxygen delivery. However, at this stage of our knowledge, we believe that further prospective studies, possibly derived from multicenter cohorts and through randomized control trials, to further validate the proposed classification criteria are needed.

A Dangerous Consequence of the Recent Pandemic: Early Lung Fibrosis Following COVID-19 Pneumonia - Case Reports

The outbreak of the novel severe acute respiratory syndrome coronavirus (SARS-CoV-2) started in China in December 2019. COVID-19 patients at presentation show a wide spectrum of clinical and pathological involvement. We report two cases of respiratory insufficiency due to COVID-19 pneumonia that occurred in adults without a history of respiratory diseases. Although these patients improved and were discharged from the acute ward, during the hospitalization they both progressed with a subsequent clinical and radiological worsening, pointing out one of the main concerns for these patients at discharge: the possibility of developing persistent lung abnormalities also in healthy people not having other risk factors. In conclusion, these cases represent two examples of early lung fibrosis in patients with COVID-19 pneumonia with different severity disease evolution and highlight the need for long-term follow-up strategies. The etiology of this fibrosis is under discussion: we suppose that it could be due to either a possible outcome of natural history of lung damage produced by ARDS, or to the lung injury related to high oxygen level or to the lung damage directly induced by viral infection or finally to the autoimmune response. At this moment, it is not possible to predict how many people will have consequences due to COVID-19 pneumonia, and therefore we believe that careful follow-up should be mandatory.

Interstitial Pneumonia with Autoimmune Features (IPAF): A Single-Centre, Prospective Study

Objectives

Interstitial pneumonia with autoimmune features (IPAF) refers to patients with interstitial lung disease and autoimmune features not fulfilling the classification criteria for a specific connective tissue disease. We sought to study the characteristics, disease progression, response to treatment and complications of patients with IPAF in 1-year follow-up period.

Methods

Clinical and laboratory findings, comorbidities, medications, pulmonary function tests (PFTs), chest HRCT and complications during the one-year follow-up period were documented for each of the 39 enrolled patients with IPAF.

Results

The mean age at the time of IPAF diagnosis was 63.2 (±11) years, and 62% of patients were female. The most common clinical features were arthritis (82%) and rash (54%-not included in the IPAF criteria). Antinuclear antibodies (ANA) (59%) and non-specific interstitial pneumonia (NSIP-61.5%) were the most prevalent autoantibodies and radiological pattern respectively. PFTs at 12 months from baseline stabilized or improved in 79.5% of patients (p> 0.05). Infections were observed in 23.1% of patients during the first and in 12.8% during the second semester of follow-up. Two patients (5.1%) required hospitalization. All infections occurred in patients with non-usual interstitial pneumonia (UIP) pattern (p=0.02).

Conclusions

Arthritis and rash are among the most common features in IPAF suggesting rash could be included into IPAF criteria. Almost 80% of patients had stable/improved PFTs at the end of follow-up. Infections occurred mainly in the first semester of treatment and in patients with non-UIP radiological pattern probably due to higher doses of corticosteroids used in these patients.

Interstitial pneumonia with autoimmune features

Interstitial lung disease (ILD) is an umbrella term for lung disease characterised by inflammation and fibrosis of the interstitium. ILD can be idiopathic or secondary to connective tissue disorders, drugs or environmental exposures. Before labelling it as idiopathic we have to rule out secondary causes. ILD is one of the most common extra-articular manifestations of connective tissue diseases (CTDs), causing significant morbidity and mortality. Patients with pre-existing CTD can develop ILD; some patients develop ILD against the background of either one or two clinical features of a CTD or isolated auto-antibody positivity. The current terminology for such an entity is interstitial pneumonia with autoimmune features (IPAF). The current criterion is based on three domains: clinical, serologic and morphologic. To satisfy the IPAF classification criteria, one needs to satisfy the mandatory criterion with one feature from two of the three domains. Classifying patients with this criterion helps in early initiation of immunosuppression and in monitoring them closely for development of features of a well defined CTD. There are a few limitations like the clinical domain being more skewed towards systemic sclerosis and in˜flammatory myositis, exclusion of antineutrophilic cytoplasmic antibody (ANCA) and cytoplasmic pattern in antinuclear antibody (ANA). There are no clear protocols for treatment of IPAF and most of the data has been extrapolated from the management of systemic sclerosis (SSc) ILD and idiopathic non-specific c interstitial pneumonia (NSIP). Progressive disease in spite of treatment demands stronger immunosuppressive agents. Studies on the role of antifibrotics in IPAF are underway, with few small studies showing positive outcomes. There are con˜flicting reports on the survival and outcome of the IPAF cohort. Certain studies suggest that they have better survival compared with idiopathic pulmonary fibrosis (IPF) though other studies contradict this statement.

Myositis-specific Antibodies Identify A Distinct Interstitial Pneumonia with Autoimmune Features Phenotype

Interstitial pneumonia with autoimmune features (IPAF) characterises individuals with interstitial lung disease (ILD) and features of connective tissue disease (CTD) who fail to satisfy CTD criteria. Inclusion of myositis-specific antibodies (MSAs) in the IPAF criteria has generated controversy, as these patients also meet proposed criteria for an anti-synthetase syndrome. Whether MSAs and myositis associated antibodies (MAA) identify phenotypically distinct IPAF subgroups remains unclear.A multi-center, retrospective investigation was conducted to assess clinical features and outcomes in patients meeting IPAF criteria stratified by the presence of MSAs and MAAs. IPAF subgroups were compared to cohorts of patients with idiopathic inflammatory myopathy-ILD (IIM-ILD), idiopathic pulmonary fibrosis (IPF) and non-IIM CTD-ILDs. The primary endpoint assessed was three-year transplant-free survival. Two hundred sixty-nine patients met IPAF criteria, including 35 (13%) with MSAs and 65 (24.2%) with MAAs. Survival was highest among patients with IPAF-MSA and closely approximated those with IIM-ILD. Survival did not differ between IPAF-MAA and IPAF without MSA/MAA cohorts. Usual interstitial pneumonia (UIP) morphology was associated with differential outcome risk, with IPAF patients with non-UIP morphology approximating survival observed in non-IIM CTD-ILDs. MSAs, but not MAAs identified a unique IPAF phenotype characterised by clinical features and outcomes similar to IIM-ILD. UIP morphology was a strong predictor of outcome in others meeting IPAF criteria. Because IPAF is a research classification without clear treatment approach, these findings suggest MSAs should be removed from the IPAF criteria and such patients should be managed as an IIM-ILD.

IPAF should receive early treatment for sharing similar clinical characteristics as CTD-ILD: a report from 273 Chinese patients

OBJECTIVES

The clinical characteristics of interstitial pneumonia with autoimmune features (IPAF) and connective tissue disease interstitial lung disease (CTD-ILD) have not been adequately compared. We compared the clinical characteristics of these two conditions and analyzed the changes in lung function before and after treatment of IPAF.

METHODS

A total of 412 patients were enrolled in the study, and their clinical characteristics were assessed. The treatment-related changes in 12 cases of IPAF were analyzed.

RESULTS

Complete clinical data were available for 126 patients with CTD-ILD and 147 with IPAF. All IPAF patients showed autoantibody positivity. The proportion of patients showing extrapulmonary symptoms in the CTD-ILD group was higher than that in the IPAF group (P < 0.05). Patients with IPAF demonstrated lower P(A-a)O₂ and higher PaO₂ and PaCO₂ than those with CTD-ILD (P < 0.05 for all comparisons). Forced vital capacity (FVC) and diffusing capacity of the lungs for carbon monoxide (D_LCO) in IPAF patients were higher than those in CTD-ILD patients (P = 0.023 for FVC; P = 0.011 for D_LCO). Among patients with IPAF, only the proportions of honeycombing and nodules were lower than those in CTD-ILD patients (P < 0.05). Both FVC and D_LCO values increased after treatment in patients with IPAF (P < 0.05).

CONCLUSION

IPAF showed autoantibody positivity and similar computed tomography (CT) findings as CTD-ILD, and lung function in patients with IPAF improved after immunosuppressive treatment, indicating that IPAF should receive attention and early immunosuppressive treatment like CTD-ILD, even though IPAF exhibits no extrapulmonary symptoms. Key Points • Clinical characteristics of IPAF.

Diagnostic approach of fibrosing interstitial lung diseases of unknown origin

Interstitial lung diseases encompass a broad range of numerous individual conditions, some of them characterized histologically by fibrosis, especially idiopathic pulmonary fibrosis, nonspecific interstitial pneumonia, chronic hypersensitivity pneumonia, interstitial lung disease associated with connective tissue diseases, and unclassifiable interstitial lung disease. The diagnostic approach relies mainly on the clinical evaluation, especially assessment of the patient's demographics, history, smoking habits, occupational or domestic exposures, use of drugs, and on interpretation of high-quality HRCT of the chest. Imaging is key to the initial diagnostic approach, and often can confirm a definite diagnosis, particularly a diagnosis of idiopathic pulmonary fibrosis when showing a pattern of usual interstitial pneumonia in the appropriate context. In other cases, chest HRCT may orientate toward an alternative diagnosis and appropriate investigations to confirm the suspected diagnosis. Autoimmune serology helps diagnosing connective disease. Indications for bronchoalveolar lavage and for lung biopsy progressively become more restrictive, with better considerations for their discriminate value, of the potential risk associated with the procedure, and of the anticipated impact on management. Innovative techniques and genetics are beginning to contribute to diagnosing interstitial lung disease and to be implemented routinely in the clinic. Multidisciplinary discussion, enabling interaction between pulmonologists, chest radiologists, pathologists and often other healthcare providers, allows integration of all information available. It increases the accuracy of diagnosis and prognosis prediction, proposes a first-choice diagnosis, may suggest additional investigations, and often informs the management. The concept of working diagnosis, which can be revised upon additional information being made available especially longitudinal disease behaviour, helps dealing with diagnostic uncertainty inherent to interstitial lung diseases and facilitates management decisions. Above all, the clinical approach and how thoroughly the patient's history and possible exposures are assessed determine the possibility of an accurate diagnosis.

Sex-Based Differences in Interstitial Lung Disease

Interstitial lung diseases comprise a family of progressive pulmonary disorders that are often idiopathic or associated with various systemic diseases and that is characterized by bilateral lung involvement with inflammation and tissue remodeling or fibrosis. The impact of sex, including the anatomic and physiologic traits that one is born with, on the development and progression of interstitial lung diseases is not entirely clear. Variances between men and women are driven by differences in male and female biology and sex hormones, among other differences, but their role remains uncertain. In this review, we summarize sex-related differences in the epidemiology and progression of certain interstitial lung diseases with a focus on the connective tissue related interstitial lung diseases, idiopathic pulmonary fibrosis, and sarcoidosis. We also discuss cellular and pre-clinical studies that might shed light on the potential mechanisms responsible for these differences in the hope of unveiling potential targets for intervention and stimulating research in this needed field of investigation.

Nailfold Videocapillaroscopy is a Useful Tool to Recognize Definite Forms of Systemic Sclerosis and Idiopathic Inflammatory Myositis in Interstitial Lung Disease Patients

Nailfold videocapillaroscopy (NVC) is an easy tool used for the assessment of patients with Raynaud's phenomenon (RP) as possibly associated with systemic sclerosis (SSc). Recent insights have also highlighted its role in the diagnostic assessment of idiopathic inflammatory myopathies (IIMs). The aim of this study is to describe the diagnostic role of NVC in a series of 361 consecutive patients with interstitial lung disease (ILD). All the patients were assessed by clinical pulmonary and rheumatic examinations, blood exams, high-resolution computed tomography and NVC. NVC was considered positive only in the presence of avascular areas or giant capillaries, but also, the presence of bushy capillaries (BCs) was recorded. NVC was positive in 17.7% of ILD patients and in 78.1% of ILD patients associated with a diagnosis of connective tissue disease (CTD). In 25% of SSc-ILD patients, NVC proved necessary for a correct diagnosis. The presence of BCs and/or NVC positivity in ILD patients with normal levels of creatine phosphokinase is associated with amyopathic IIM, regardless the presence of RP. In conclusion, NVC is useful for the diagnostic assessment of incomplete forms of CTD and in amyopathic IIMs. NVC should be considered in the diagnostic assessment of ILD patients regardless of the presence of RP.

Patients with Interstitial Lung Disease Secondary to Autoimmune Diseases: How to Recognize Them?

The diagnostic assessment of patients with Interstitial Lung Disease (ILD) can be challenging due to the large number of possible causes. Moreover, the diagnostic approach can be limited by the severity of the disease, which may not allow invasive exams. To overcome this issue, the referral centers for ILD organized Multidisciplinary Teams (MDTs), including physicians and experts in complementary discipline, to discuss the management of doubtful cases of ILD. MDT is currently considered the gold standard for ILD diagnosis, but it is not often simple to organize and, furthermore, rheumatologists are still not always included. In fact, even if rheumatologic conditions represent a common cause of ILD, they are sometimes difficult to recognize, considering the variegated clinical features and their association with all possible radiographic patterns of ILD. The first objective of this review is to describe the clinical, laboratory, and instrumental tests that can drive a diagnosis toward a possible rheumatic disease. The secondary objective is to propose a set of first-line tests to perform in all patients in order to recognize any possible rheumatic conditions underlying ILD.

Multidisciplinary Approach in the Early Detection of Undiagnosed Connective Tissue Diseases in Patients With Interstitial Lung Disease: A Retrospective Cohort Study

Interstitial lung disease (ILD) encompasses a wide range of parenchymal lung pathologies with different clinical, histological, radiological, and serological features. Follow-up, treatment, and prognosis are strongly influenced by the underlying pathogenesis. Considering that an ILD may complicate the course of any connective tissue disease (CTD) and that CTD's signs are not always easily identifiable, it could be useful to screen every ILD patient for a possible CTD. The recent definition of interstitial pneumonia with autoimmune features is a further confirmation of the close relationship between CTD and ILD. In this context, the multidisciplinary approach is assuming a growing and accepted role in the correct diagnosis and follow-up, to as early as possible define the best therapeutic strategy. However, despite clinical advantages, until now, the pathways of the multidisciplinary approach in ILD patients are largely heterogeneous across different centers and the best strategy to apply is still to be established and validated. Aims of this article are to describe the organization of our multidisciplinary group for ILD, which is mainly focused on the early identification and management of CTD in patients with ILD and to show our results in a 1 year period of observation. We found that 15% of patients referred for ILD had an underlying CTD, 33% had interstitial pneumonia with autoimmune feature, and 52% had ILD without detectable CTD. Furthermore, we demonstrated that the adoption of a standardized strategy consisting of a screening questionnaire, specific laboratory tests, and nailfold videocapillaroscopy in all incident ILD proved useful in making the right diagnosis.

Interstitial pneumonia with autoimmune features: A single center prospective follow-up study

BACKGROUND AND OBJECTIVE

Recently the term "interstitial pneumonia with autoimmune features" (IPAF) has been proposed to identify patients with interstitial lung disease and autoimmune characteristics, not fulfilling the criteria for specific connective tissue diseases (CTD). Only few data are available about the clinical and serological features of IPAF patients, their survival and the possible evolution in a CTD. The aims of the study were to investigate the demographic and clinico-serologic features of patients with IPAF, their relationship to survival, and the possible evolution in a definite CTD.

PATIENTS AND METHODS

Fifty-two patients were consecutively enrolled and prospectively followed for 45 ± 31.6 months. Data about disease onset, serological, clinical and therapeutic features, pulmonary function tests and high-resolution computed tomography were periodically repeated. The survival of patients with IPAF was compared with that of 104 patients with idiopathic pulmonary fibrosis (IPF).

RESULTS

The clinical domain for IPAF was satisfied in 44 patients, serological domain in 49 and the morphological domain in 29 patients. During the follow-up, a definite CTD was diagnosed in 7 patients, in particular Sjogren's syndrome in 4 patients, rheumatoid arthritis in 2, and polymyositis in the last. The estimated 5-year survival of IPAF patients 69.5 ± 7.8%, significantly higher than survival observed in IPF patients, and the baseline value of FVC and DLCO were the only factors associated to death.

CONCLUSIONS

IPAF seems to a distinct entity, with a low tendency to evolve in a definite CTD. Nevertheless, further studies are needed to better define the clinical evolution and the outcome of IPAF.

Possible value of antifibrotic drugs in patients with progressive fibrosing non-IPF interstitial lung diseases

BACKGROUND

Fibrosing, non-idiopathic pulmonary fibrosis (non-IPF) interstitial lung diseases (fILDs) are a heterogeneous group of diseases characterized by a different amount of inflammation and fibrosis. Therapy is currently based on corticosteroids and/or immunomodulators. However, response to these therapies is highly variable, sometimes without meaningful improvement, especially in more fibrosing forms. Pirfenidone and nintedanib have recently demonstrated to reduce functional decline in patients with IPF. However, their antifibrotic mechanism makes these two drugs an interesting approach for treatment of fibrosing ILDs other than IPF.

OBJECTIVES

We here report our experience with antifibrotic drugs in fibrosing non-IPF ILDs patients having a progressive phenotype during immunosuppressive therapy.

METHODS

Patients with a multidisciplinary team diagnosis of fibrosing non-IPF ILDs experiencing a progressive phenotype during treatment with corticosteroids and/or immunomodulators between October-2014 and January-2018 at our tertiary referral Center for ILDs were retrospectively analyzed. Antifibrotic therapy was administered after application with the respective health insurance company and after consent by the patient. Pulmonary-function-tests and follow-up visits were performed every 6 ± 1 months.

RESULTS

Eleven patients were treated with antifibrotic drugs (8 males, mean age 62 ± 12.8 years, mean FVC% 62.8 ± 22.3, mean DLCO% 35.5 ± 10.7, median follow-up under antifibrotic treatment 11.1 months). Patients had a diagnosis of unclassifiable ILD in 6 cases, pleuroparenchymal fibroelastosis in 2 cases, idiopathic-NSIP in 1 case, asbestos-related ILD in 1 case and Hermansky-Pudlak syndrome in 1 case. Treatment before antifibrotics consisted of corticosteroids in all patients: 5 combined with Azathioprin, 1 with either methotrexate or cyclophosphamide (i.v.). Ten patients were treated with pirfenidone (2403 mg/die) and 1 with nintedanib (300 mg/die). Median FVC was 56, 56, 50%, at time points - 24, - 12, - 6 before initiation, 44% at time of initiation and 46.5% at 6 months after initiation of antifibrotic treatment. Antifibrotic treatment was generally well tolerated with a need of dose reduction in 2 cases (rash and nausea) and early termination in 3 cases.

CONCLUSIONS

Antifibrotic treatment may be a valuable treatment option in patients with progressive fibrosing non-IPF ILD if currently no other treatment options exist. However, prospective, randomized clinical trials are urgently needed to assess the real impact of antifibrotic therapy in these patients.

Interstitial Pneumonia With Autoimmune Features (IPAF)

A significant proportion of patients with interstitial lung disease (ILD) manifest autoimmune features, but do not fulfill the diagnostic criteria for a definite connective tissue disease (CTD). In 2015, the European Respiratory Society (ERS) and American Thoracic Society (ATS) “Task Force on undifferentiated Forms of connective tissue disease-associated interstitial lung disease” proposed classification criteria for a so-called research category of Interstitial Pneumonia with Autoimmune Features (IPAF). These classification criteria were based on a combination of features from three domains: a clinical domain consisting of extra-thoracic features; a serologic domain with specific autoantibodies; and a morphologic domain with imaging patterns, histopathological findings or multi-compartment involvement. Patients meeting IPAF criteria tend to have a history of smoking similar to patients with idiopathic pulmonary fibrosis. The most frequent clinical and serological markers of autoimmune features are Raynaud' phenomenon and positive antinuclear antibodies, respectively. Non-specific interstitial pneumonia is the predominant radiologic and histopathologic pattern, although patients meeting IPAF criteria through the clinical and serologic domains may also have a usual interstitial pneumonia pattern. Management should be carefully individualized on a case-by-case basis in keeping with the wide heterogeneity of IPAF and lack of evidence in this particular subgroup of patients. Prognosis is generally intermediate between that of idiopathic pulmonary fibrosis and connective tissue disease-associated interstitial lung disease, but substantially variable according to the predominant histologic and radiologic patterns. As acknowledged by the Task Force, the proposed classification scheme of IPAF is a research concept that will need revision and refinement based on data to better inform prognostication and patient care.

Evaluation of the Diagnostic Efficacies of Serological Markers KL-6, SP-A, SP-D, CCL2, and CXCL13 in Idiopathic Interstitial Pneumonia

<b><i>Background:</i></b> The objective of this study was to evaluate the diagnostic value of serological markers Krebs von den Lungen-6 (KL-6), surfactant protein-A (SP-A), SP-D, chemokine ligand 2 (CCL2), and chemokine 13 (CXCL13) in idiopathic interstitial pneumonia (IIP). <b><i>Methods:</i></b> Patients with IIP aged 18–80 years from the First Affiliated Hospital of Guangzhou Medical University were enrolled in this retrospective case-control study. Data on the general patient characteristics, laboratory test results, chest high-resolution CT, and pulmonary function test results were collected. The diagnosis of idiopathic pulmonary fibrosis (IPF) was based on the international practice guidelines for the diagnosis and treatment of IPF, a collaborative effort published by the American Thoracic Society (ATS)/European Respiratory Association (ERS), Japanese Respiratory Society, and Latin American Thoracic Society. The diagnostic criteria of non-IPF (N-IPF) followed the consensus classification of the IIPs, which was jointly issued by the ATS and ERS in 2002. The diagnosis of interstitial pneumonia with autoimmune features (IPAF) was based on the official research statement on IPAF, which was jointly issued by the ATS and ERS in 2015. Serum levels of KL-6, SP-A, SP-D, CCL2, and CXCL13 were measured. The differences in the expression of these biomarkers and their correlation with the severity of the disease were analyzed. The sensitivity, specificity, cutoff value, and area under the curve (AUC) value for each of the indices were determined using the receiver operating characteristic (ROC) curve analysis. <b><i>Findings:</i></b> Between September 2015 and October 2017, 69 patients with IIP. Of these patients, 19 had IPF, 23 had N-IPF, and 27 had IPAF. We also enrolled 20 age- and gender-matched patients with pneumonia and 15 uninfected individuals as normal control. The serum levels of KL-6, SP-A, ­SP-D, CCL2, and CXCL13 were significantly higher in patients with IIP than in patients with pneumonia and the normal controls. The detection of these markers was found to have better diagnostic efficacy in patients with IIP than in those with pneumonia. Of these markers above, KL-6 had the highest diagnostic value (AUC 0.96, 95% CI 0.93–0.99). Based on a logistics regression analysis, the combination of KL-6, CCL2, and CXCL13 had an improved diagnostic efficacy for IIP. In patients with IIP, the serum levels of KL-6, SP-A, CCL2, and CXCL13 all showed a significant negative correlation with the diffusing capacity of the lungs for carbon monoxide (DLCO; <i>r</i> = –0.36, –0.37, –0.36, –0.30, respectively; all <i>p</i> &#x3c; 0.05). Although their expression levels along with that of SP-D were elevated in patients with IPF, N-IPF, and IPAF, it was difficult to distinguish between these 3 conditions by detecting the 5 serum biomarkers together. Our findings indicate that the serum levels of KL-6, SP-A, SP-D, CCL2, and CXCL13 are notably elevated in patients with IIP and show significant correlation with the severity of interstitial lung lesions. Additionally, we further explore the diagnostic efficacy of 5 biomarkers in different types of IIP. It is the first time that the level of serum marker CXCL13 of N-IPF and IPAF patients was higher than IPF patients, which further enriched the study on serum markers for IIPs. Between September 2015 and October 2017, 69 patients with IIP. Of these patients, 19 had IPF, 23 had N-IPF, and 27 had IPAF. We also enrolled 20 age- and gender-matched patients with pneumonia and 15 uninfected individuals as normal control. The serum levels of KL-6, SP-A, SP-D, CCL2, and CXCL13 were significantly higher in patients with IIP than in patients with pneumonia and the normal controls. Of these markers above, KL-6 had the highest diagnostic value (AUC 0.96, 95% CI 0.93–0.99). Based on a logistics regression analysis, the combination of KL-6, CCL2, and CXCL13 had an improved diagnostic efficacy for IIP. In patients with IIP, the serum levels of KL-6, SP-A, CCL2, and CXCL13 all showed a significant negative correlation with the DLCO (<i>r</i> = –0.36, –0.37, –0.36, –0.30, respectively; all <i>p</i> &#x3c; 0.05). Our findings indicate that the serum levels of KL-6, ­SP-A, SP-D, CCL2, and CXCL13 are notably elevated in patients with IIP and show significant correlation with the severity of interstitial lung lesions. Additionally, we further explore the diagnostic efficacy of 5 biomarkers in different types of IIP. It is the first time that the level of serum marker CXCL13 of N-IPF and IPAF patients was higher than IPF patients, which further enrich the study on serum markers in IIPs. <b><i>Interpretation:</i></b> Although the combined detection of KL-6, CCL3, and CXCL13 significantly improves the diagnosis of IIP, detection of all the 5 markers together is unable to distinguish between IPF, N-IPF, and IPAF.