Clinical Features of Idiopathic Interstitial Pneumonia with Systemic Sclerosis-Related Autoantibody in Comparison with Interstitial Pneumonia with Systemic Sclerosis

Significance of Systemic Scleroderma-Specific Autoantibodies in Idiopathic Interstitial Pneumonia

Objective Patients with idiopathic interstitial pneumonia (IIP) often test positive for systemic scleroderma-specific autoantibodies (SSc-Ab), even if they do not meet the diagnostic criteria for systemic scleroderma (SSc). However, the significance of SSc-Ab in IIP is unknown. Methods We retrospectively studied the medical records of all patients suspected of interstitial lung disease (ILD) who visited our center between January 2016 and December 2021. We evaluated the association between SSc-Ab subtypes and clinical characteristics, prognosis, and incidence of acute exacerbation (AE) of IIP. Among 571 patients suspected of having IIP and SSc-Ab measured, we excluded cases with clear causes of ILD or those diagnosed with other diseases and analyzed 386 cases diagnosed as IIP. Results Among 386 IIP patients, 48 were SSc-Ab positive (platelet-derived growth factor receptor (PDGFR) in 0, Th/To in 10, anti-nucleolar organizer region 90 antibodies (NOR90) in 12, fibrillarin in five, RP155 in 14, RP11 in three, CENP A in seven, CENP B in 10, and Scl-70 in six). There was no significant difference in survival rate or incidence of AE between patients with or without SSc-Ab. Multivariate logistic regression analysis showed that age and malignancy were significant risk factors for death, whereas age, male sex, and anti-fibrillarin antibodies were significant risk factors for AE of IIP. Conclusion None of the SSc-Abs were associated with the risk of mortality, and anti-fibrillarin antibodies, along with age and male sex may contribute to the risk of AE of IIP, predicting severe lung involvement and warranting multidisciplinary treatment and careful follow-up.

Prevalence of the limited vs. extensive scleroderma-related interstitial lung disease at the time of diagnosis of SSc-ILD based on Goh et al. criteria. Systematic review and meta-analysis

INTRODUCTION

Goh et al. proposed in 2008 a classificatory algorithm of limited or extensive SSc-ILD. The prevalence of both at the time of diagnosis of SSc-ILD is not known with exactitude.

METHODS

The review was undertaken by means of MEDLINE and SCOPUS from 2008 to 2023 and using the terms: "systemic", "scleroderma" or "interstitial lung disease" [MesH]. The Newcastle-Ottawa Scale was used for the qualifying assessment for observational studies and the Jadad scale for clinical trials. The inverse variance-weighted method was performed.

RESULTS

Twenty-seven studies were initially included in the systematic review and meta-analysis (SRMA). Of these, 17 studies had no overlapping data. They reported data from 2,149 patients, 1,369 (81.2%) were female. The mean age was 52.4 (SD 6.6) years. 45.2% of the patients had the diffuse subtype and 54.8% had the limited or sine scleroderma subtype. A total of 38.7% of the patients showed positive antitopoisomerase antibodies (ATA) and 14.2% positive anticentromere antibodies (ACA). The mean percentage of forced vital capacity (FVC) at baseline was 80.5% (SD 6.9) and of diffusing capacity of the lungs for carbon monoxide (DLco) was 59.1% (SD 9.6). Twelve studies presented SSc-ILD extension data adjusted for PFTs and were included in the meta-analysis. The 10 observational cohort studies were analyzed separately. The overall percentage of limited extension was estimated at 63.5% (95%CI 55.3-73; p < 0.001) using the random-effects model. Heterogeneity between studies (I2) was 9.8% (95%CI 0-68.2%) with the random-effects model. Extensive pulmonary involvement was estimated at 34.3% (95%CI 26-45.4; p < 0.001). Heterogeneity between studies (I2) was 0% (95%CI 0-61.6%) with the random-effects model.

CONCLUSION

The overall percentage of limited SSc-ILD at the time of diagnosis of SSc-ILD was estimated at 63.5% and extensive at 34.3%.

The role of lung biopsy for diagnosis and prognosis of interstitial lung disease in systemic sclerosis: a systematic literature review

BACKGROUND

The prognostic and theragnostic role of histopathological subsets in systemic sclerosis interstitial lung disease (SSc-ILD) have been largely neglected due to the paucity of treatment options and the risks associated with surgical lung biopsy. The novel drugs for the treatment of ILDs and the availability of transbronchial cryobiopsy provide a new clinical scenario making lung biopsy more feasible and a pivotal guide for treatment. The aim of our study was to investigate the usefulness of lung biopsy in SSc ILD with a systematic literature review (SLR).

METHODS

PubMed, Embase and Cochrane databases were searched up to June 30, 2023. Search terms included both database-specific controlled vocabulary terms and free-text terms relating to lung biopsy and SSc-ILD diagnostic and prognosis. The SLR was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA). Studies were selected according to the PEO (population, exposure, and outcomes) framework and Quality assessment of diagnostic accuracy studies (QUADAS) were reported.

RESULTS

We selected 14 articles (comprising 364 SSc-ILD patients). The paucity and heterogeneity of the studies prevented a systematic analysis. Diffuse cutaneous SSc was present in 30-100% of cases. Female predominance was observed in all studies (ranging from 64 to 100%). Mean age ranged from 42 to 64 years. Mean FVC was 73.98 (+/-17.3), mean DLCO was 59.49 (+/-16.1). Anti-Scl70 antibodies positivity was detected in 33% of cases (range: 0-69.6). All patients underwent surgical lung biopsies, and multiple lobes were biopsied in a minority of studies (4/14). Poor HRCT-pathologic correlation was reported with HRCT-NSIP showing histopathologic UIP in up to 1/3 of cases. Limited data suggest that SSc-UIP patients may have a worse prognosis and response to immunosuppressive treatment compared to other histopathologic patterns.

CONCLUSIONS

The data from this SLR clearly show the paucity and heterogeneity of the studies reporting lung biopsy in SSc ILD. Moreover, they highlight the need for further research to address whether the lung biopsy can be helpful to refine prognostic prediction and guide therapeutic choices.

Heterogeneity of determining disease severity, clinical course and outcomes in systemic sclerosis-associated interstitial lung disease: a systematic literature review

Objective The course of systemic sclerosis-associated interstitial lung disease (SSc-ILD) is highly variable and different from continuously progressive idiopathic pulmonary fibrosis (IPF). Most proposed definitions of progressive pulmonary fibrosis or SSc-ILD severity are based on the research data from patients with IPF and are not validated for patients with SSc-ILD. Our study aimed to gather the current evidence for severity, progression and outcomes of SSc-ILD.Methods A systematic literature review to search for definitions of severity, progression and outcomes recorded for SSc-ILD was performed according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines in Medline, Embase, Web of Science and Cochrane Library up to 1 August 2023.Results A total of 9054 papers were reviewed and 342 were finally included. The most frequent tools used for the definition of SSc-ILD progression and severity were combined changes of carbon monoxide diffusing capacity (DLCO) and forced vital capacity (FVC), isolated FVC or DLCO changes, high-resolution CT (HRCT) extension and composite algorithms including pulmonary function test, clinical signs and HRCT data. Mortality was the most frequently reported long-term event, both from all causes or ILD related.Conclusions The studies presenting definitions of SSc-ILD 'progression', 'severity' and 'outcome' show a large heterogeneity. These results emphasise the need for developing a standardised, consensus definition of severe SSc-ILD, to link a disease specific definition of progression as a surrogate outcome for clinical trials and clinical practice.PROSPERO registration number CRD42022379254.Cite Now.

Combined Pulmonary Fibrosis and Emphysema: When Scylla and Charybdis Ally

Combined pulmonary fibrosis and emphysema (CPFE) is a recently recognized syndrome that, as its name indicates, involves the existence of both interstitial lung fibrosis and emphysema in one individual, and is often accompanied by pulmonary hypertension. This debilitating, progressive condition is most often encountered in males with an extensive smoking history, and is presented by dyspnea, preserved lung volumes, and contrastingly impaired gas exchange capacity. The diagnosis of the disease is based on computed tomography imaging, demonstrating the coexistence of emphysema and interstitial fibrosis in the lungs, which might be of various types and extents, in different areas of the lung and several relative positions to each other. CPFE bears high mortality and to date, specific and efficient treatment options do not exist. In this review, we will summarize current knowledge about the clinical attributes and manifestations of CPFE. Moreover, we will focus on pathophysiological and pathohistological lung phenomena and suspected etiological factors of this disease. Finally, since there is a paucity of preclinical research performed for this particular lung pathology, we will review existing animal studies and provide suggestions for the development of additional in vivo models of CPFE syndrome.

Viewpoint: a multidisciplinary approach to the assessment of patients with systemic sclerosis-associated interstitial lung disease

Systemic sclerosis (SSc) is a rare and heterogeneous disease affecting the skin and internal organs. SSc-associated ILD (SSc-ILD) is a common and often early manifestation of SSc. This article discusses the rationale for a multidisciplinary approach (MDA) to the early identification and assessment of patients with SSc-ILD. Diagnosis of SSc-ILD is often challenging as patients with early disease can be asymptomatic, and SSc-ILD symptoms, such as exertional dyspnea and cough, are non-specific. High-resolution computed tomography (HRCT) of the lungs is the gold standard for diagnosis of SSc-ILD since pulmonary function tests lack sensitivity and specificity, especially in early disease. On HRCT, most patients with SSc-ILD have a non-specific interstitial pneumonia (NSIP) pattern. In addition, findings of pulmonary hypertension and esophageal dysmotility may be present. The multi-organ involvement of SSc and the diverse spectrum of symptoms support an MDA for the diagnosis and assessment of patients with SSc-ILD, with input from rheumatologists, pulmonologists, gastroenterologists, radiologists, and other specialists. Key Points • Interstitial lung disease (ILD) is a common manifestation of systemic sclerosis (SSc). • Early diagnosis is key to reducing the morbidity and mortality associated with SSc-ILD and other manifestations of SSc. • The multi-organ involvement of SSc supports a multidisciplinary approach to the diagnosis and assessment of patients with SSc-ILD, with input from rheumatologists, pulmonologists, gastroenterologists, radiologists, and other specialists.

Identification of diagnostic gene biomarkers related to immune infiltration in patients with idiopathic pulmonary fibrosis based on bioinformatics strategies

Objective

The study aims to identify potential diagnostic markers of idiopathic pulmonary fibrosis (IPF) and analyze the significance of immune cell infiltration in this pathology.

Materials and methods

Download two publicly available gene expression profiles (GSE10667 and GSE24206 datasets) from the GEO database including 48 Idiopathic pulmonary fibrosis (IPF) samples and 21 human control samples and select for distinctly expressed genes (DEG) from them. Lasso regression model and support vector machine recursive feature elimination S,V,R,F analysis were used to check candidate biomarkers. The area under the subject's work characteristic curve (AUC) value is used to evaluate its recognition ability. The GSE53845 dataset (40 IPF patients and 8 controls) continue to validate the expression level and diagnostic value of biomarkers in IPF. Comprehensive analysis of immune infiltrated cells of IPF was performed using R software and immune cell infiltration estimation analysis tool- deconvolution algorithm (CIBERSORT).

Results

43 DEGs were identified in total. The identified DEGs mostly involve pneumonia, lung disease, collagen disease, obstructive pulmonary disease and other diseases. The activation of IL-17 signaling pathways, amoebic disease, interaction of viral proteins with cytokines and cytokine receptors, protein digestion and absorption, and flaccid hormone signaling pathways in IPF were different from the control group. The expression degree of CRTAC1, COL10A1, COMP, RPS4Y1, IGFL2, NECAB1, SCG5, SLC6A4, and SPP1 in IPF tissue were prominently higher than the normal group. Immune cell infiltration analysis showed that CRTAC1, COL10A1, COMP, IGFL2, NECAB1, SCG5, SLC6A4, and SPP1 were associated with monocytes, plasma cells, neutrophils, and regulatory (treg) T cells.

Conclusion

CRTAC1, COL10A1, COMP, IGFL2, NECAB1, SCG5, SLC6A4, and SPP1 can be used as diagnostic markers for IPF, providing new ideas for the future study of IPF occurrence and molecular mechanisms.

Interstitial Lung Disease in Connective Tissue Disease: A Common Lesion With Heterogeneous Mechanisms and Treatment Considerations

Connective tissue disease (CTD) related interstitial lung disease (CTD-ILD) is one of the leading causes of morbidity and mortality of CTD. Clinically, CTD-ILD is highly heterogenous and involves rheumatic immunity and multiple manifestations of respiratory complications affecting the airways, vessels, lung parenchyma, pleura, and respiratory muscles. The major pathological features of CTD are chronic inflammation of blood vessels and connective tissues, which can affect any organ leading to multi-system damage. The human lung is particularly vulnerable to such damage because anatomically it is abundant with collagen and blood vessels. The complex etiology of CTD-ILD includes genetic risks, epigenetic changes, and dysregulated immunity, which interact leading to disease under various ill-defined environmental triggers. CTD-ILD exhibits a broad spectra of clinical manifestations: from asymptomatic to severe dyspnea; from single-organ respiratory system involvement to multi-organ involvement. The disease course is also featured by remissions and relapses. It can range from stability or slow progression over several years to rapid deterioration. It can also present clinically as highly progressive from the initial onset of disease. Currently, the diagnosis of CTD-ILD is primarily based on distinct pathology subtype(s), imaging, as well as related CTD and autoantibodies profiles. Meticulous comprehensive clinical and laboratory assessment to improve the diagnostic process and management strategies are much needed. In this review, we focus on examining the pathogenesis of CTD-ILD with respect to genetics, environmental factors, and immunological factors. We also discuss the current state of knowledge and elaborate on the clinical characteristics of CTD-ILD, distinct pathohistological subtypes, imaging features, and related autoantibodies. Furthermore, we comment on the identification of high-risk patients and address how to stratify patients for precision medicine management approaches.

Ability of the COPD Assessment Test to evaluate the lung‐specific quality of life in systemic sclerosis‐associated interstitial lung disease

Introduction

The COPD Assessment Test (CAT) is utilised to evaluate the treatment outcome regarding the health status in idiopathic interstitial pneumonia (IIP). However, the ability of the CAT to evaluate the lung‐specific quality of life in systemic sclerosis‐associated interstitial lung disease (SSc‐ILD) is not established. Therefore, we investigated whether CAT scores can be used to evaluate SSc‐ILD as they are for IIP.

Methods

A total of 150 patients with IIP or SSc‐ILD who were evaluated by the CAT were retrospectively assigned to this study. Clinical data at the visit for the CAT were analysed.

Results

The forced vital capacity and distance walked during the 6‐minute walk test (6MWD) were significantly correlated with the CAT score for SSc‐ILD and IIP, and the CAT scores were similarly distributed in SSc‐ILD and IIP. The CAT score of SSc‐ILD patients was negatively affected by pulmonary arterial hypertension, but not by corticosteroids, which affected it in IIP patients. CAT scores of patients with either disease receiving home oxygen therapy were poor. In multiple regression analysis, pulmonary arterial hypertension and 6MWD were independent predictors for the CAT score in patients with SSc‐ILD, while corticosteroid administration was selected as an independent factor in patients with IIP.

Conclusions

Our study suggests that the CAT can be applied to evaluate the lung‐specific quality of life in SSc‐ILD similar to IIP regarding the pulmonary function, but it should be noted that pulmonary arterial hypertension in SSc‐ILD influences the CAT score.

The value of serum Krebs von den lungen-6 as a diagnostic marker in connective tissue disease associated with interstitial lung disease

Objectives

The purpose of this study was to evaluate the value of serum krebs von den lungen-6 (KL-6) level as a diagnostic indicator for connective tissue disease associated with interstitial lung disease (CTD-ILD).

Methods

One hundred fifty five patients with newly diagnosed CTD in our hospital were enrolled and divided into two groups by their ILD manifestations, the CTD-ILD group and the CTD group. In parallel, 61 patients with pulmonary infection and 60 cases of healthy subjects were also enrolled into the study. The difference of serum KL-6 level among the four groups were compared. In CTD-ILD group, carbon monoxide diffusing capacity (DLCo) and high-resolution computed tomography (HRCT) of lung were also tested. The serum KL-6 level of 32 patients from the CTD-ILD group who received cyclophosphamide (CTX) pulse therapy were sampled and measured, by enzyme linked immunosorbent assay (ELISA), at three time points: before treatment, 3 months after treatment and 6 months after treatment.

Results

The serum KL-6 level in the CTD-ILD group (1004.9 (676.41738.1) IU/ml) is significantly higher than three other groups (χ² = 72.29, P < 0.001). In the CTD-ILD group the level of serum KL-6 was positively correlated with disease severity on HRCT (r = 0.75, P <  0.001), while was negatively correlated with DLCo (r = − 0.50, P <  0.001). In 32 patients who received CTX pulse therapy, the level of serum KL-6 was gradually decreased in 20 cases whose lesions were absorbed within 6 months (F = 13.67, P <  0.001), whereas it remained unchanged in the rest of 12 patients (Z = -1.328, P = 0.198).

Conclusions

Serum KL-6 level can potentially serve as a diagnostic marker for CTD-ILD and be utilized to evaluate the effectiveness of CTX pulse therapy.

Interstitial lung disease associated with anti-citrullinated peptide/protein antibody-positive anti-synthetase syndrome

Little has been reported on the characteristics of interstitial lung disease (ILD) associated with anti-citrullinated peptide/protein antibody (ACPA)-positive anti-synthetase syndrome (ASS). We sought to investigate the clinical, radiologic, and pathologic features of patients with ILD associated with ACPA-positive ASS. Medical records of seven ILD patients with positive results of both ACPA and anti-aminoacyl-tRNA synthetase antibody were retrospectively reviewed. Five patients had clinical symptoms associated with ASS other than ILD. On high-resolution computed tomography (HRCT) analysis, a nonspecific interstitial pneumonia (NSIP) pattern was shown in 3 patients and NSIP with organizing pneumonia (OP) overlap in 2 patients. Coronal slices of these 5 patients showed lower lung disease predominance with traction caudally on major fissures due to lower lobe volume loss. These were features that could commonly be observed in ASS-associated ILD. Pathological findings available for 3 patients showed NSIP. The characteristics of ILD associated with ACPA-positive ASS appear to be similar to those of ILD associated with ASS, but not to rheumatoid arthritis (RA) or ACPA, especially in terms of the radiological findings.

Emphysematous change with scleroderma-associated interstitial lung disease: the potential contribution of vasculopathy?

Background

Pulmonary emphysema combined with systemic sclerosis (SSc)-associated interstitial lung disease (ILD) occurs more often in smokers but also in never-smokers. This study aimed to describe a new finding characterized by peculiar emphysematous change with SSc-associated ILD (SSc-ILD).

Methods

We conducted a retrospective review of 21 consecutive patients with SSc-ILD diagnosed by surgical lung biopsy and focused on the radio-pathological correlation of the emphysematous change.

Results

Pathological pulmonary emphysema (p-PE) with SSc-ILD was the predominant complication in 16 patients (76.2%) with/without a smoking history, of whom 62.5% were never-smokers. A low attenuation area (LAA) within interstitial abnormality on high-resolution computed tomography (HRCT) was present in 31.3%. Diffusing capacity of the lung for carbon monoxide (D_LCO) was lower, disease extent on HRCT higher, and intimal/medial thickening in muscular pulmonary arteries more common in the patients with p-PE with SSc-ILD. However, forced vital capacity (FVC) was well preserved regardless of whether p-PE was observed. Most SSc-ILD patients had pulmonary microvasculature changes in arterioles (90.5%), venules (85.7%), and interlobular veins (81.0%).

Conclusions

Pulmonary emphysematous changes (LAA within interstitial abnormalities on HRCT and destruction of fibrously thickened alveolar walls) are specific and novel radio-pathological features of SSc-ILD. Peripheral vasculopathy may help to destroy the fibrously thickened alveolar walls, resulting in emphysematous change in SSc-ILD.

Role of Autoantibodies in the Diagnosis of Connective-Tissue Disease ILD (CTD-ILD) and Interstitial Pneumonia with Autoimmune Features (IPAF)

The diagnosis of interstitial lung disease (ILD) requires meticulous evaluation for an underlying connective tissue disease (CTD), with major implications for prognosis and management. CTD associated ILD (CTD-ILD) occurs most commonly in the context of an established CTD, but can be the first and/or only manifestation of an occult CTD or occur in patients who have features suggestive of an autoimmune process, but not meeting diagnostic criteria for a defined CTD-recently defined as "interstitial pneumonia with autoimmune features" (IPAF). The detection of specific autoantibodies serves a critical role in the diagnosis of CTD-ILD, but there remains a lack of data to guide clinical practice including which autoantibodies should be tested on initial assessment and when or in whom serial testing should be performed. The implications of detecting autoantibodies in patients with IPAF on disease behaviour and management remain unknown. The evaluation of CTD-ILD is challenging due to the heterogeneity of presentations and types of CTD and ILD that may be encountered, and thus it is imperative that immunologic tests are interpreted in conjunction with a detailed rheumatologic history and examination and multidisciplinary collaboration between respiratory physicians, rheumatologists, immunologists, radiologists and pathologists.

Serum KL-6 and surfactant protein-D as monitoring and predictive markers of interstitial lung disease in patients with systemic sclerosis and mixed connective tissue disease

BACKGROUND

Interstitial lung disease (ILD) is frequent complication of systemic sclerosis (SSc) and mixed connective tissue disease (MCTD). The disease is heterogeneous, and its outcome is unpredictable. Some patients have severe and progressive deterioration of ILD, which is the leading cause of mortality. We aimed to determine whether serum levels of Krebs von den Lungen-6 (KL-6) and surfactant protein-D (SP-D) correlate with SSc/MCTD-associated ILD activity.

METHODS

We retrospectively analyzed the medical records of 40 patients with SSc/MCTD-associated ILD: 29 patients with SSc and 11 patients with MCTD. Measurement of serum KL-6 and SP-D levels, pulmonary function tests, and high-resolution computed tomography (HRCT) performed in parallel were reviewed.

RESULTS

Serum KL-6 correlated positively with diffusing capacity of the lung for carbon monoxide (DLCO) (% predicted) and disease extent on HRCT, and the changes in serum levels of KL-6 were significantly related to the changes in forced vital capacity (FVC) in SSc/MCTD-associated ILD. On the other hand, multivariate logistic regression analyses with calculation of the area under the curve of the receiver-operating characteristic curve suggested that a higher serum level of SP-D was a significant predictor of FVC decline in SSc/MCTD-associated ILD.

CONCLUSIONS

Our study suggests that serum KL-6 can be a useful monitoring tool of SSc/MCTD-associated ILD activity. In contrast, serum SP-D may be a significant predictor of potential FVC decline in the short term.