The multifaceted aspects of interstitial lung disease in rheumatoid arthritis

The Burden of Interstitial Lung Involvement in Rheumatoid Arthritis: Could Lung Ultrasound Have a Role in Its Detection? A Literature Review

Lung involvement represents a fearful complication in rheumatoid arthritis (RA), potentially involving all compartments of the pulmonary system. Regarding interstitial lung disease (ILD), the HRCT represents the gold standard technique for its diagnosis; however, the examination is burdened by radiation exposure and high costs. In addition, although some risk factors for ILD are known, no algorithms exist to know which patients to submit to HRCT and when. In this context, lung ultrasound (LUS) showed promising results for at least 10 years, demonstrating correlation with high resolution computed tomography (HRCT) findings in other rheumatic diseases. Here, LUS may represent a screening test providing additional information to clinical examination and pulmonary function tests. The data deriving from LUS experience in other rheumatic diseases could steer the future towards the use of this technique also in RA patients, and in this review, we report the most relevant literature regarding LUS in RA-ILD.

Identification of potential hub genes and biological mechanism in rheumatoid arthritis and non-small cell lung cancer via integrated bioinformatics analysis

BACKGROUND

Although there is evidence of the association between RA and NSCLC, little is known about their interaction mechanisms. The aim of this study is to identify potential hub genes and biological mechanism in RA and NSCLC via integrated bioinformatics analysis.

METHODS

The gene expression datasets of RA and NSCLC were downloaded to discover and validate hub genes. After identifying DEGs, we performed enrichment analysis, PPI network construction and module analysis, selection and validation of hub genes. Moreover, we selected the hub gene PTPRC for expression and prognosis analysis, immune analysis, mutation and methylation analysis in NSCLC. Finally, we performed real-time PCR, colony formation assay, wound healing assay, transwell invasion assay, sphere formation assay and western blotting to validate the role of PTPRC in A549 cells.

RESULTS

We obtained 320 DEGs for subsequent analysis. Enrichment results showed that the DEGs were mainly involved in Th1, Th2 and Th17 cell differentiation. In addition, four hub genes, BIRC5, PTPRC, PLEK, and FYN, were identified after selection and validation. These hub genes were subsequently shown to be closely associated with immune cells and related pathways. In NSCLC, PTPRC was downregulated, positively correlated with immune infiltration and immune cells. Experiments showed that PTPRC could promote the proliferation, migration and invasion, and the ability to form spheroids of A549 cells. In addition, PTPRC could regulate the increased expression of CD45, β-catenin, c-Myc and LEF1 proteins.

CONCLUSIONS

This study explored the hub genes and related mechanisms of RA and NSCLC, demonstrated the central role of the inflammatory response and the adaptive immune system, and identified PTPRC as an immune-related biomarker and potential therapeutic target for RA and NSCLC patients. In addition, PTPRC can significantly promote the proliferation, migration and invasion of A549 cells, and its mechanism may be to promote the EMT process by regulating the Wnt signaling pathway and promote cell stemness, which in turn has a promoting effect on A549 cells.

The Lung in Rheumatoid Arthritis-Friend or Enemy?

Rheumatoid arthritis (RA) is a chronic autoimmune condition frequently found in rheumatological patients that sometimes raises diagnosis and management problems. The pathogenesis of the disease is complex and involves the activation of many cells and intracellular signaling pathways, ultimately leading to the activation of the innate and acquired immune system and producing extensive tissue damage. Along with joint involvement, RA can have numerous extra-articular manifestations (EAMs), among which lung damage, especially interstitial lung disease (ILD), negatively influences the evolution and survival of these patients. Although there are more and more RA-ILD cases, the pathogenesis is incompletely understood. In terms of genetic predisposition, external environmental factors act and subsequently determine the activation of immune system cells such as macrophages, neutrophils, B and T lymphocytes, fibroblasts, and dendritic cells. These, in turn, show the ability to secrete molecules with a proinflammatory role (cytokines, chemokines, growth factors) that will produce important visceral injuries, including pulmonary changes. Currently, there is new evidence that supports the initiation of the systemic immune response at the level of pulmonary mucosa where the citrullination process occurs, whereby the autoantibodies subsequently migrate from the lung to the synovial membrane. The aim of this paper is to provide current data regarding the pathogenesis of RA-associated ILD, starting from environmental triggers and reaching the cellular, humoral, and molecular changes involved in the onset of the disease.

Overview of Rheumatoid Arthritis-Associated Interstitial Lung Disease and Its Treatment

Interstitial lung disease (ILD) is a common pulmonary complication of rheumatoid arthritis (RA), causing significant morbidity and mortality. Optimal treatment for RA-ILD is not yet well defined. Reliable prognostic indicators are largely byproducts of prior ILD progression, including low or decreasing forced vital capacity and extensive or worsening fibrosis on imaging. In the absence of validated tools to predict treatment response, decisions about whether to initiate or augment treatment are instead based on clinical judgment. In general, treatment should be initiated in patients who are symptomatic, progressing, or at high risk of poor outcomes. Retrospective data suggest that mycophenolate mofetil, azathioprine, and rituximab are likely effective therapies for RA-ILD. Abatacept is also emerging as a potential first-line treatment option for patients with RA-ILD. Further, recent data demonstrate that immunosuppression may be beneficial even in patients with a usual interstitial pneumonia (UIP) pattern on imaging, suggesting that immunosuppression should be considered irrespective of imaging pattern. Recent randomized controlled trials have shown that antifibrotic medications, such as nintedanib and likely pirfenidone, slow forced vital capacity decline in RA-ILD. Consideration can be given to antifibrotic initiation in patients progressing despite immunosuppression, particularly in patients with a UIP pattern. Future research directions include developing tools to predict which patients will remain stable from patients who will progress, discriminating patients who will respond to treatment from nonresponders, and developing algorithms for starting immunosuppression, antifibrotics, or both as first-line therapies.

Identification and validation of mutual hub genes in idiopathic pulmonary fibrosis and rheumatoid arthritis-associated usual interstitial pneumonia

Objectives

The study aims at exploring common hub genes and pathways in idiopathic pulmonary fibrosis (IPF) and rheumatoid arthritis-associated usual interstitial pneumonia (RA-UIP) through integrated bioinformatics analyses.

Methods

The GSE199152 dataset containing lung tissue samples from IPF and RA-UIP patients was acquired from the Gene Expression Omnibus (GEO) database. The identification of overlapping differentially expressed genes (DEGs) in IPF and RA-UIP was carried out through R language. Protein-protein interaction (PPI) network analysis and module analysis were applied to filter mutual hub genes in the two diseases. Enrichment analyses were also conducted to analyze the possible biological functions and pathways of the overlapped DEGs and hub genes. The diagnostic value of key genes was assessed with R language, and the expressions of these genes in pulmonary cells of IPF and rheumatoid arthritis-associated interstitial lung disease (RA-ILD) patients were analyzed with single cell RNA-sequencing (scRNA-seq) datasets. The expression levels of hub genes were validated in blood samples from patients, specimens of human lung fibroblasts, lung tissue samples from mice, as well as external GEO datasets.

Results

Four common hub genes (THBS2, TIMP1, POSTN, and CD19) were screened. Enrichment analyses showed that the abnormal expressions of DEGs and hub genes may be connected with the onset of IPF and RA-UIP by regulating the progression of fibrosis. ScRNA-seq analyses illustrated that for both IPF and RA-ILD patients, THBS2, TIMP1, and POSTN were mainly expressed in lung fibroblasts, while CD19 was uniquely high-expressed in B cells. The qRT-PCR and immunohistochemistry (IHC) results verified that the expression levels of hub genes were mostly in accordance with the findings obtained from the bioinformatics analyses.

Conclusion

Though IPF and RA-UIP are distinct diseases, they may to some extent have mutual pathogenesis in the development of fibrosis. THBS2, TIMP1, POSTN, and CD19 may be the potential biomarkers of IPF and RA-UIP, and intervention on related pathways of these genes could offer new strategies for the precision treatment of IPF and RA-UIP.

Interstitial Lung Disease in Rheumatoid Arthritis: A Review

Rheumatoid arthritis (RA) is a chronic inflammatory autoimmune disorder. Although the joints are typically the first area affected in RA, it can also involve extra-articular regions. This article provides an overview on rheumatoid arthritis-associated interstitial lung disease (RA-ILD), a component of the disease manifestations leading to significant morbidity and mortality. Managing these pulmonary symptoms in people with RA poses a number of difficulties for medical professionals. In this review article, we shed light on the prevalence of RA-ILD and the common pulmonary manifestations of RA, while focusing on the evolving pathogenesis concepts that link them to RA's autoimmune cascade. We also address the diagnostic challenges and the available screening modalities that aid in the early recognition and effective management of these pulmonary complications. Furthermore, glucocorticoids, disease-modifying antirheumatic medications, immunosuppressive medications, and biological agents are among the pharmacological approaches that have been explored in this review study.

Janus Kinase Inhibitors and Interstitial Lung Disease Associated With Pediatric Rheumatic Diseases: An Unexplored Field

Rheumatic diseases are often complicated by lung disease, commonly presenting as interstitial lung disease (ILD), with potentially detrimental consequences for patient survival. Although less frequent in pediatric patients, pulmonary involvement may be observed in almost all childhood-onset rheumatic conditions. The development of biological disease-modifying anti-rheumatic drugs has significantly improved clinical outcomes. However, disease remission is not always complete or long-lasting, and treatment may need to be discontinued due to adverse effects. A novel class of drugs, namely Janus kinase inhibitors (JAKis), has been proposed to provide a significant survival benefit for patients with rheumatic diseases. Despite the ample literature on the efficacy and safety of JAKis in rheumatic disease, only a few studies have investigated the effectiveness of these drugs in patients with pulmonary involvement, and only two case reports have presented results in pediatric patients. We provide an overview of the rationale for using JAKis in ILDs associated with rheumatic disease and summarize the main studies evaluating their efficacy in both adult and pediatric patients. The present review highlights the need for controlled long-term studies to assess the efficacy and safety of JAKis in pediatric rheumatic disease complicated by lung disease.

Etiology and Pathogenesis of Rheumatoid Arthritis-Interstitial Lung Disease

Interstitial lung disease (ILD) is one of the most serious extra-articular complications of rheumatoid arthritis (RA), which increases the mortality of RA. Because the pathogenesis of RA-ILD remains poorly understood, appropriate therapeutic strategies and biomarkers have not yet been identified. Thus, the goal of this review was to summarize and analyze the reported data on the etiology and pathogenesis of RA-ILD. The incidence of RA-ILD increases with age, and is also generally higher in men than in women and in patients with specific genetic variations and ethnicity. Lifestyle factors associated with an increased risk of RA-ILD include smoking and exposure to pollutants. The presence of an anti-cyclic citrullinated peptide antibody, high RA disease activity, and rheumatoid factor positivity also increase the risk of RA-ILD. We also explored the roles of biological processes (e.g., fibroblast-myofibroblast transition, epithelial-mesenchymal transition, and immunological processes), signaling pathways (e.g., JAK/STAT and PI3K/Akt), and the histopathology of RA involved in RA-ILD pathogenesis based on published preclinical and clinical models of RA-ILD in animal and human studies.

Integrating bioinformatic resources to identify characteristics of rheumatoid arthritis-related usual interstitial pneumonia

BACKGROUND

Rheumatoid arthritis (RA) is often accompanied by a common extra-articular manifestation known as RA-related usual interstitial pneumonia (RA-UIP), which is associated with a poor prognosis. However, the mechanism remains unclear. To identify potential mechanisms, we conducted bioinformatics analysis based on high-throughput sequencing of the Gene Expression Omnibus (GEO) database.

RESULTS

Weighted gene co-expression network analysis (WGCNA) analysis identified 2 RA-positive related modules and 4 idiopathic pulmonary fibrosis (IPF)-positive related modules. A total of 553 overlapped differentially expressed genes (DEG) were obtained, of which 144 in the above modules were further analyzed. The biological process of "oxidative phosphorylation" was found to be the most relevant with both RA and IPF. Additionally, 498 up-regulated genes in lung tissues of RA-UIP were screened out and enriched by 7 clusters, of which 3 were closely related to immune regulation. The analysis of immune infiltration showed a characteristic distribution of peripheral immune cells in RA-UIP, compared with IPF-UIP in lung tissues.

CONCLUSIONS

These results describe the complex molecular and functional landscape of RA-UIP, which will help illustrate the molecular pathological mechanism of RA-UIP and identify new biomarkers and therapeutic targets for RA-UIP in the future.

Better Safe than Sorry: Rheumatoid Arthritis, Interstitial Lung Disease, and Medication-A Narrative Review

It is well known that rheumatoid arthritis (RA) patients are at an increased risk of developing non-infectious pulmonary complications, especially interstitial lung disease (ILD); however, the clinician must keep in mind that lung disease could not only be a manifestation of the underlying condition, but also a consequence of using disease-modifying therapies. New-onset ILD or ILD worsening has also been reported as a possible consequence of both conventional disease-modifying antirheumatic drugs (DMARDs) and biologic agents. This study is a narrative review of the current literature regarding the potential risk of developing interstitial lung disease along with the administration of specific drugs used in controlling rheumatoid arthritis. Its purpose is to fill knowledge gaps related to this challenging patient cohort by addressing various aspects of the disease, including prevalence, disease features, treatment strategies, and patient outcomes.

Glucocorticoid use in rheumatoid arthritis patients and the onset of pneumonia: a systematic review and meta-analysis

CONTEXT

Rheumatoid arthritis (RA) is a systemic autoimmune disease that commonly affects joints. Although many treatment options exist, the most common, disease-modifying antirheumatic drugs (DMARDs), have been associated with pulmonary infections. These types of infections (specifically pneumonia) can be detrimental to RA patients. This leads providers to utilize other treatment modalities such as glucocorticoids (GCs). GCs are commonly utilized to treat RA; however, the role of GCs in the onset of pneumonia in RA patients is not fully understood.

OBJECTIVES

The goal of this study was to systematically review and statistically analyze pooled data documenting pneumonia as an adverse event in RA patients on DMARDs as a monotherapy vs RA patients on DMARDs and GCs as combination therapy utilizing the Population, Intervention, Comparison, and Outcomes (PICO) framework.

METHODS

On August 1, 2021, a search was conducted and completed on six databases: Embase, MEDLINE, Cochrane Central Register of Controlled Trials (CENTRAL), Web of Science, International Pharmaceutical Abstracts (IPA), and ClinicalTrials.gov. A total of 12 researchers were involved with the search and screening of articles (K.E., P.R.; V.A., D.P.C.; C.B., D.C.; T.A., E.S.; S.H., L.B.; K.S., C.S.). Search terms were identified utilizing Medical Subject Headings (MeSH) and Emtree and included "glucocorticoids," "rheumatoid arthritis," "pneumonia," and "respiratory tract infections," Inclusion criteria included human subjects over the age of 18 with seropositive RA, on a combination of GC (prednisone, methylprednisolone, or prednisolone) with DMARD (methotrexate [MTX], hydroxychloroquine [HCQ], or sulfasalazine [SSZ]) and developed pneumonia of bacterial, viral, or fungal origin. The control groups were on a DMARD monotherapy regimen. Articles were excluded if they were not in English, had less than 20 participants, were case reports or literature reviews, included animal subjects, and did not adhere to the established PICO framework. Five teams of two researchers individually sorted through abstracts of articles based on the inclusion and exclusion criteria. The same teams individually sorted through full-text articles of selected abstracts based on the same criteria. Conflicts between each team were resolved by a separate researcher. Odds ratios were utilized to quantify the effect sizes of combined studies from a random effects model. Chi-square tests and I2 statistics were utilized to analyze heterogeneity.

RESULTS

A total of 3360 articles were identified from all databases, and 416 duplicate articles were removed. Thus, a total of 2944 articles abstracts were screened, of which 2819 articles either did not meet the inclusion criteria or did meet the exclusion criteria. A total of 125 articles were retrieved and assessed for full-text eligibility, of which only three observational articles were included for meta-analysis. Statistical results revealed that patients treated with DMARDs monotherapy are 95% (95% CI: 0.65-0.99) less likely to develop pneumonia compared to patients treated with a DMARD and GCs (p=0.002).

CONCLUSIONS

Our data suggest that RA patients have a higher probability of developing pneumonia on combination therapy with GCs, compared to monotherapy with DMARDs. To our knowledge, our findings are the first to systematically review and statistically evaluate the relationship between the use of GCs and show an increased chance of developing pneumonia.

Progressive fibrosing interstitial lung disease in rheumatoid arthritis: A retrospective study

BACKGROUND AND OBJECTIVE

Rheumatoid arthritis associated-interstitial lung disease (RA-ILD) is the most common pulmonary manifestation of rheumatoid arthritis (RA) and an important cause of mortality. In patients suffering from interstitial lung diseases (ILD) from different etiologies (including RA-ILD), a significant proportion is exhibiting a fibrotic progression despite immunosuppressive therapies, defined as progressive fibrosing interstitial lung disease (PF-ILD). Here, we report the frequency of RA-ILD and PF-ILD in all RA patients' cohort at University Hospital of Liège and compare their characteristics and outcomes.

METHODS

Patients were retrospectively recruited from 2010 to 2020. PF-ILD was defined based on functional, clinical and/or iconographic progression criteria within 24 months despite specific anti-RA treatment.

RESULTS

Out of 1,500 RA patients, about one third had high-resolution computed tomography (HRCT) performed, 89 showed RA-ILD and 48 PF-ILD. RA-ILD patients were significantly older than other RA patients (71 old of median age vs. 65, p < 0.0001), with a greater proportion of men (46.1 vs. 27.7%, p < 0.0001) and of smoking history. Non-specific interstitial pneumonia pattern was more frequent than usual interstitial pneumonia among RA-ILD (60.7 vs. 27.0%) and PF-ILD groups (60.4 vs. 31.2%). The risk of death was 2 times higher in RA-ILD patients [hazard ratio 2.03 (95% confidence interval 1.15-3.57), p < 0.01] compared to RA.

CONCLUSION

We identified a prevalence of PF-ILD of 3% in a general RA population. The PF-ILD cohort did not seem to be different in terms of demographic characteristics and mortality compared to RA-ILD patients who did not exhibit the progressive phenotype yet.

Automated quantification system predicts survival in rheumatoid arthritis-associated interstitial lung disease

OBJECTIVE

The prognosis of RA-associated interstitial lung disease (RA-ILD) is difficult to predict because of the variable clinical course. This study aimed to determine the prognostic value of an automated quantification system (AQS) in RA-ILD.

METHODS

We retrospectively analysed the clinical data and high-resolution CT (HRCT) images of 144 patients with RA-ILD. Quantitative lung fibrosis (QLF, sum of reticulation and traction bronchiectasis) and ILD [QILD; sum of QLF, honeycombing (QHC), and ground-glass opacity (QGG)] scores were measured using the AQS.

RESULTS

The mean age was 61.2 years, 43.8% of the patients were male, and the 5-year mortality rate was 30.5% (median follow-up, 52.2 months). Non-survivors showed older age, higher ESR and greater AQS scores than survivors. In multivariable Cox analysis, higher QLF, QHC and QILD scores were independent prognostic factors along with older age and higher ESR. In receiver-operating characteristic curve analysis, the QLF score showed better performance in predicting 5-year mortality than the QHC and QGG scores but was similar to the QILD score. Patients with high QLF scores (≥12% of total lung volume) showed higher 5-year mortality (50% vs 17.4%, P < 0.001) than those with low QLF scores and similar survival outcome to patients with idiopathic pulmonary fibrosis (IPF). Combining with clinical variables (age, ESR) further improved the performance of QLF score in predicting 5-year mortality.

CONCLUSION

QLF scores might be useful for predicting prognosis in patients with RA-ILD. High QLF scores differentiate a poor prognostic phenotype similar to IPF.

A Retrospective Study of the Clinical, Radiological, and Pathological Characteristics of Patients with Interstitial Pneumonia Preceding Rheumatoid Arthritis

Objective Interstitial lung disease (ILD) is the most critical manifestation in patients with rheumatoid arthritis (RA). In some cases, ILD may appear before the RA onset. Some patients with an initial diagnosis of idiopathic interstitial pneumonia (IIPs) develop RA; however, few studies have reported on its features, and the details remain unknown. In the present study, the clinical, radiological, and pathological features were evaluated in patients with ILD preceding RA. Methods The clinical, radiological, and pathological features of patients with ILD preceding RA were retrospectively reviewed using the medical records. Patients Ten patients with ILD preceding RA out of 883 IIP patients who underwent a surgical lung biopsy at our hospital from 2004 to 2018 were retrospectively examined. Results The median patient age was 59 (range 50-76) years old, and 7 of the patients were women. The median time from the ILD diagnosis to the RA onset was 50 (range 33-65) months. Regarding the high-resolution computed tomography pattern, the "indeterminate for UIP" pattern was the most popular, and cysts were seen in all cases. Attenuation around the cyst was prominent. Pathological findings showed plasma cell infiltration, bronchus-associated lymphoid tissue (BALT), and bronchiolitis in the lobules. Cellular and destructive bronchiolitis was noticeable in many patients with ILD preceding RA and contributed to the destruction and dilation of the bronchiole. Conclusion In ILD patients with IIP, radiological and pathological findings with increased attenuation around the cysts, prominent inflammatory cell infiltration (especially in plasma cells), an increase in the BALT number, and cellular and destructive bronchiolitis might serve as helpful RA development indicators.

CTLA-4-Ig internalizes CD80 in fibroblast-like synoviocytes from chronic inflammatory arthritis mouse model

CD80 interact with CD28 and CTLA-4 on antigen-presenting cells, and function in the co-stimulatory signaling that regulates T cell activity. CTLA-4-Ig is used to treat RA by blocking co-stimulatory signaling. Chronic inflammatory arthritis was induced in D1BC mice using low-dose arthritogenic antigens and treated with CTLA-4-Ig. We performed histopathology of the joints and lymph nodes, serological examination for rheumatoid factors, and flow cytometric analysis of isolated synovial cells, including CD45- FLSs and CD45+ synovial macrophages. CTLA-4-Ig treatment ameliorated the chronic inflammatory polyarthritis. There was a decrease in the number of infiltrating lymphoid cells in the joints as well as in the levels of RF-IgG associated with a decrease in the number of B cells in the lymph nodes; more than 15% of CD45- FLSs expressed CD80, and a small number of them expressed PD-L1, indicating the presence of PD-L1/CD80 cis-heterodimers in these cells. CTLA-4-Ig internalized CD80, but not PD-L1, in isolated synovial cells. Gene ontology analysis revealed that CTLA-4-Ig internalization did not significantly alter the expression of inflammation-related genes. The therapeutic effect of CTLA-4-Ig appears to extend beyond the lymph nodes into the inflamed synovial compartment through the synergistic inactivation of T cells by the CD80 and PD-L1 axes.

Analysis of risk factors of mortality in rheumatoid arthritis patients with interstitial lung disease: a nationwide, population-based cohort study in Taiwan

Objective

To examine the risk and risk factors of mortality in patients with rheumatoid arthritis (RA) with interstitial lung disease (ILD).

Methods

Using the 1997–2013 Taiwanese National Health Insurance Research Database, we identified 32 289 incident patients with RA by using International Classification of Diseases, Ninth Revision codes from 2001 to 2013, and 214 patients developed ILD subsequently. We matched (1:10) RA-ILD with controls for sex, age, time of ILD diagnosis and disease duration. In addition, we conducted propensity score matching (PSM) (1:1) for selected comorbidities to choose RA-ILD patients and controls. Using the Cox proportional hazard model, we estimated the association of mortality with ILD for the two matched populations and assessed factors associated with mortality among 214 RA-ILD patients, shown as adjusted HRs (aHRs) with 95% CIs.

Results

In the populations selected before and after PSM, we included 164 and 155 patients with RA-ILD and 1640 and 155 controls, respectively. ILD was associated with mortality in the population before PSM (aHR, 1.73; 95% CI 1.19 to 2.52) and in the PSM population (HR 4.38; 95% CI 2.03 to 9.43). Among 214 patients with RA-ILD, age (aHR 1.04; 95% CI 1.03 to 1.08), chronic obstructive pulmonary disease (COPD) (aHR 2.12; 95% CI 1.25 to 3.58), diabetes mellitus (DM) with end-organ damage and corticosteroid dose (prednisolone equivalent, mg/day) (aHR 1.09; 95% CI 1.07 to 1.11) were associated with mortality in RA-ILD.

Conclusion

This population-based cohort study showed that ILD was associated with risk of mortality in patients with RA, and risk factors associated with mortality in patients with RA-ILD included age, COPD, DM with end-organ damage and average daily prednisolone dose.

Novel Biomarkers, Diagnostic and Therapeutic Approach in Rheumatoid Arthritis Interstitial Lung Disease-A Narrative Review

Rheumatoid arthritis (RA) is considered a systemic inflammatory disease marked by polyarthritis which affects the joints symmetrically, leading to progressive damage of the bone structure and eventually joint deformity. Lung involvement is the most prevalent extra-articular feature of RA, affecting 10-60% of patients with this disease. In this review, we aim to discuss the patterns of RA interstitial lung disease (ILD), the molecular mechanisms involved in the pathogenesis of ILD in RA, and also the therapeutic challenges in this particular extra-articular manifestation. The pathophysiology of RA-ILD has been linked to biomarkers such as anti-citrullinated protein antibodies (ACPAs), MUC5B mutation, Krebs von den Lungen 6 (KL-6), and other environmental factors such as smoking. Patients at the highest risk for RA-ILD and those most likely to advance will be identified using biomarkers. The hope is that finding biomarkers with good performance characteristics would help researchers better understand the pathophysiology of RA-ILD and, in turn, lead to the development of tailored therapeutics for this severe RA manifestation.

Predictors of long-term prognosis in rheumatoid arthritis-related interstitial lung disease

The aim of the study was to identify specific clinical and serum protein biomarkers that are associated with longitudinal outcome of RA-associated interstitial lung disease (RA-ILD). 60 RA patients with clinical and serological profiles were assessed by HRCT and pulmonary function tests (PFTs) at baseline (Year 0) and 5 years post enrollment (Year 5). Progression versus non-progression was defined based on changes in Quantitative Modified HRCT scores and PFTs over time. Specific serum protein biomarkers were assessed in serum samples at baseline and Year 5 by Multiplex enzyme-linked immunosorbent assays (ELISAs). At Year 5, 32% of patients demonstrated progressive RA-ILD, 35% were stable, and 33% improved. Baseline age and rheumatoid factor (RF) were significantly different between RA-ILD outcomes of progression vs. no-progression (p < 0.05). Changes in levels of CXCL11/I-TAC and MMP13 over 5 years also distinguished pulmonary outcomes (p < 0.05). A final binary logistic regression model revealed that baseline age and changes in serum MMP13 as well as CXCL11/I-TAC were associated with RA-ILD progression at Year 5 (p < 0.01), with an AUC of 0.7772. Collectively, these analyses demonstrated that baseline clinical variables (age, RF) and shifts in levels of selected serum proteins (CXCL11/I-TAC, MMP13) were strongly linked to RA-ILD outcome over time.

Recent Advances in Basic and Clinical Aspects of Rheumatoid Arthritis-associated Interstitial Lung Diseases

Rheumatoid arthritis (RA) is a common autoimmune disease that mainly affects the joints and systemic organs, such as the skin, eyes, heart, gastrointestinal tract, and lungs. In particular, among various pulmonary involvements, interstitial lung disease (ILD) is closely related to the selection of anti-rheumatic drugs and the long-term prognosis of patients with RA. Although the exact pathogenesis of RA-ILD is not well defined, several mechanistic pathways, similar to those of idiopathic pulmonary fibrosis, have been elucidated recently. Conversely, RA-related autoantibodies, including anti-cyclic citrullinated peptide antibody, are detectable in circulation and in the lungs, even in the absence of articular symptoms. RA-ILD can also predate years before the occurrence of joint symptoms. This evidence supports the fact that local dysregulated mucosal immunity in the lung causes systemic autoimmunity, resulting in clinically evident polyarthritis of RA. Because the early diagnosis of RA-ILD is important, imaging tests, such as computed tomography and pulmonary function tests, are being used for early diagnosis, but there is no clear guideline for the early diagnosis of RA-ILD and selection of optimal disease-modifying anti-rheumatic drugs for the treatment of patients with RA with ILD. In addition, the efficacy of nintedanib, a new anti-fibrotic agent, for RA-ILD treatment, has been investigated recently. This review collectively discusses the basic and clinical aspects, such as pathogenesis, animal models, diagnosis, and treatment, of RA-ILD.

Syndecan-2 regulates PAD2 to exert antifibrotic effects on RA-ILD fibroblasts

Rheumatoid arthritis (RA)-associated interstitial lung disease (RA-ILD) is the most common pulmonary complication of RA, increasing morbidity and mortality. Anti-citrullinated protein antibodies have been associated with the development and progression of both RA and fibrotic lung disease; however, the role of protein citrullination in RA-ILD remains unclear. Here, we demonstrate that the expression of peptidylarginine deiminase 2 (PAD2), an enzyme that catalyzes protein citrullination, is increased in lung homogenates from subjects with RA-ILD and their lung fibroblasts. Chemical inhibition or genetic knockdown of PAD2 in RA-ILD fibroblasts attenuated their activation, marked by decreased myofibroblast differentiation, gel contraction, and extracellular matrix gene expression. Treatment of RA-ILD fibroblasts with the proteoglycan syndecan-2 (SDC2) yielded similar antifibrotic effects through regulation of PAD2 expression, phosphoinositide 3-kinase/Akt signaling, and Sp1 activation in a CD148-dependent manner. Furthermore, SDC2-transgenic mice exposed to bleomycin-induced lung injury in an inflammatory arthritis model expressed lower levels of PAD2 and were protected from the development of pulmonary fibrosis. Together, our results support a SDC2-sensitive profibrotic role for PAD2 in RA-ILD fibroblasts and identify PAD2 as a promising therapeutic target of RA-ILD.

Discrimination between NSIP- and IPF-Derived Fibroblasts Based on Multi-Parameter Characterization of Their Growth, Morphology and Physic-Chemical Properties

Background: The aim of the research presented here was to find a set of parameters enabling discrimination between three types of fibroblasts, i.e., healthy ones and those derived from two disorders mimicking each other: idiopathic pulmonary fibrosis (IPF), and nonspecific interstitial pneumonia (NSIP). Methods: The morphology and growth of cells were traced using fluorescence microscopy and analyzed quantitatively using cell proliferation and substrate cytotoxicity indices. The viability of cells was recorded using MTS assays, and their stiffness was examined using atomic force microscopy (AFM) working in force spectroscopy (FS) mode. To enhance any possible difference in the examined parameters, experiments were performed with cells cultured on substrates of different elasticities. Moreover, the chemical composition of cells was determined using time-of-flight secondary ion mass spectrometry (ToF-SIMS), combined with sophisticated analytical tools, i.e., Multivariate Curve Resolution (MCR) and Principal Component Analysis (PCA). Results: The obtained results demonstrate that discrimination between cell lines derived from healthy and diseased patients is possible based on the analysis of the growth of cells, as well as their physical and chemical properties. In turn, the comparative analysis of the cellular response to altered stiffness of the substrates enables the identification of each cell line, including distinguishing between IPF- and NSIP-derived fibroblasts.

Interstitial Lung Disease and its Associations in Rheumatoid Arthritis: Data from a District General Hospital in Sri Lanka

Context:

Interstitial lung disease (ILD) is a frequent pulmonary manifestation of rheumatoid arthritis (RA). No Sri Lankan studies have determined the prevalence of lung disease in RA and its associations.

Aims:

To find the prevalence of ILD in RA and its association with rheumatoid factor (RF), erosions, Disease activity score in 28 joints (DAS 28), disease duration, Body mass index(BMI), erythrocyte sedimentation rate (ESR), smoking, and also to determine the prevalence of lung disease with demographic factors like age, sex, and income.

Settings and Design:

Questionnaire based retrospective study at a District General Hospital in Sri Lanka.

Materials and Methods:

Diagnosed RA patients included through convenient sampling as it was a simple method that could facilitate data collection in a short duration. Since all patients with a diagnosis of RA were eligible, all consecutive patients with a diagnosis of RA at the rheumatology clinics were included in the study. To reduce the bias a large sample of patients were used as well as patients attending different rheumatology clinics were included and also patients who were referred to the hospital from peripheries were included in the study. The calculated sample size was 384 and according to patient numbers attending clinics, a period of 6 months was decided to select the study sample.

Statistical Analysis Used:

Chi-Square calculation and logistic regression analysis using Minitab 17 software.

Results:

From 384 patients, the prevalence of ILD was 14.58%, been 5.4% in early RA (<2 years disease duration). Mean age of ILD group was 52.94 years (95% CI 64.66-41.22). Mean RA duration was 7.69 years (95% CI, 2.38-12.99). Male to female sex ratio of RA was 1:7, and that of ILD was 2:9. DAS 28 was 4.58 (95% CI, 3.48-5.68). Statistically significant associations were noted with ILD and DAS 28 (P = .0006), ESR (P = .005), RF (P = .03), erosions (P < .00001), and smoking (P < .05). Mean BMI was 22.67 kg and 75.78% had low income (<50 000 rupees/month = 327 US $).

Conclusions:

ILD significantly associates RA severity indices like DAS 28, ESR, erosions, RF, and also with smoking. No significant association was found with BMI or gender difference. Therefore, disease severity indices could be used to predict progression to ILD in RA.

Rheumatoid arthritis-interstitial lung disease: manifestations and current concepts in pathogenesis and management

Rheumatoid arthritis (RA) is a systemic inflammatory disorder, with the most common extra-articular manifestation of RA being lung involvement. While essentially any of the lung compartments can be affected and manifest as interstitial lung disease (ILD), pleural effusion, cricoarytenoiditis, constrictive or follicular bronchiolitis, bronchiectasis, pulmonary vasculitis, and pulmonary hypertension, RA-ILD is a leading cause of death in patients with RA and is associated with significant morbidity and mortality. In this review, we focus on the common pulmonary manifestations of RA, RA-ILD and airway disease, and discuss evolving concepts in the pathogenesis of RA-associated pulmonary fibrosis, as well as therapeutic strategies, and have revised our previous review on the topic. A rational clinical approach for the diagnosis and management of RA-ILD, as well as an approach to patients with clinical worsening in the setting of treatment with disease-modifying agents, is included. Future directions for research and areas of unmet need in the realm of RA-associated lung disease are raised.

Rheumatoid arthritis (RA) is a systemic inflammatory disorder, with the most common extra-articular manifestation of RA being lung involvement. RA-ILD is a leading cause of death in RA patients and is associated with significant morbidity and mortality.https://bit.ly/3w6oY4i

Two sides of the same coin? A review of the similarities and differences between idiopathic pulmonary fibrosis and rheumatoid arthritis-associated interstitial lung disease

Rheumatoid arthritis associated interstitial lung disease (RA-ILD) and idiopathic pulmonary fibrosis (IPF) are distinct diseases; however, they share several clinical, radiographic and genetic features. For instance, usual interstitial pneumonia (UIP), which is an ILD pattern required for a diagnosis of IPF, is also the most common ILD pattern in RA-ILD. The presence of UIP in RA-ILD is a poor prognostic sign with outcomes similar to those seen in IPF. The recent finding of a shared genetic susceptibility between IPF and RA-ILD has sparked additional interest in this relationship. This review outlines these similarities and differences in clinical presentation, appearance and outcomes in RA-ILD and IPF.In addition, this review highlights previous research in molecular biomarkers in both conditions, exploring areas of overlap and distinction. This focus on biomarkers in IPF and RA-ILD aims to highlight potential areas of discovery and clues to a potential shared pathobiology through investigation of novel molecular markers or the repurposing of biomarkers from one condition to the other.The drive to better understand RA-ILD by leveraging our knowledge of IPF is underscored by our divergent treatment paradigms for these conditions and the concern for potential harm. As a result of advancing our understanding of the links between IPF and RA-ILD, current strategies for diagnosis, screening and treatment of ILD may fundamentally change in the coming years. Until then, clinicians face difficult clinical questions regarding the co-management of the articular disease and the ILD in RA.

Rheumatoid arthritis related interstitial lung disease

INTRODUCTION

Interstitial lung disease (ILD) represents a frequent extra-articular manifestation of rheumatoid arthritis (RA) deeply impacting both quality of life and overall prognosis. Areas covered: A literature search was performed including PubMed, Embase, Scopus, and Web of Science. Many retrospective studies investigated the possible risk factors for RA-related ILD (RA-ILD), aiming to identify patients at risk. Among them, males, smokers, positivity of anti-citrullinated peptide antibodies have been associated with RA-ILD, such as some genetic haplotypes. Usual interstitial pneumonia is the histologic and radiologic pattern most frequently observed, followed by nonspecific interstitial pneumonia. Since lung involvement can represent the RA onset, an early differential diagnosis with idiopathic interstitial pneumonia can be difficult or sometimes impossible. High-resolution computed tomography represents the gold standard for ILD diagnosis, while multidisciplinary discussion should be required to assess disease staging, severity and progression.  Expert opinion: Management of RA-ILD patients is challenging due to the lack of evidence-based data regarding both assessment and treatment. Moreover, the high variability of clinical presentation and evolution makes it difficult to establish the correct therapeutic strategy. Currently, multidisciplinary approach, including at least rheumatologists, pulmonologists, and radiologists, is desirable to define therapy and follow-up strategies.

Efficacy and safety of abatacept in interstitial lung disease of rheumatoid arthritis: A systematic literature review

BACKGROUND

Interstitial lung disease (ILD) is a serious complication that represents the second leading cause of death in patients with rheumatoid arthritis (RA). Treatment of RA-ILD remains controversial. The absence of randomized clinical trials and specific ACR or EULAR therapeutic guidelines makes it difficult to establish solid therapeutic recommendations on this issue. In this scenario, real-world data is especially valuable.

OBJECTIVE

To review the literature evidence on the efficacy and safety of abatacept (ABA) for the treatment of rheumatoid arthritis (RA) with associated interstitial lung disease (ILD), given its clinical relevance and the lack of consensus on its therapeutic management.

METHODS

PUBMED and EMBASE were searched from the date of approval of ABA to the end of 2020 using a combination of RA, ILD and ABA terms following PRISMA guidelines. Identified studies were evaluated by two independent investigators.

RESULTS

Nine original studies (1 case series and 8 observational studies) were selected for inclusion in the systematic review. No randomized trial or meta-analysis were identified. The mean age of patients ranged from 61.2 to 75 years and the mean RA duration varied from 7.4 to 18 years. Subcutaneous ABA (74.5%-91%) predominated in combination with conventional synthetic DMARDs (csDMARDs) (58%-75%), and it was used as first-line biologic agent in 22.8%-64.9% of the patients. The mean course of ILD ranged from 1 to 6.7 years, being usual and nonspecific interstitial pneumonia the most frequent patterns. Improvement or stabilization of ILD imaging (76.6%-92.7%) and FVC or DLCO (>85%) was described after a mean follow-up of 17.4-47.8 months, regardless of the pattern of lung involvement, being more remarkable in patients with shorter evolution of ILD. ABA led to significantly lower ILD worsening rates than TNF inhibitors (TNFi) and was associated with a 90% reduction in the relative risk of deterioration of ILD at 24 months of follow-up compared to TNFi and csDMARDs. Combination with methotrexate may have a corticoid-sparing effect. No unexpected adverse events were identified.

CONCLUSIONS

Current evidence suggests that ABA may be a plausible alternative to treat RA patients with ILD. It would be highly desirable to develop prospective randomized controlled studies to confirm these findings.

Systematic review and meta-analysis of the risk of rheumatoid arthritis-associated interstitial lung disease related to anti-cyclic citrullinated peptide (CCP) antibody

OBJECTIVE

To clarify the risk of rheumatoid arthritis-associated interstitial lung disease (RA-ILD) related to anti-cyclic citrullinated peptide (CCP) antibody.

ELIGIBILITY CRITERIA

Patients with RA with and without ILD were eligible. The primary outcome was the prevalence or incidence of ILD. Primary studies of any design aside from a case report were eligible.

INFORMATION SOURCES

Medline, EMBASE, Science Citation Index Expanded and Cochrane Central Register of Controlled Trials were searched from the inception through 12 November 2019.

DATA EXTRACTION AND RISK OF BIAS

Two reviewers independently selected eligible reports, extracted relevant data and assessed risk of bias using a modified Quality in Prognostic Studies tool.

DATA SYNTHESIS

Meta-analysis was conducted using a random-effects model.

QUALITY OF EVIDENCE

The Grades of Recommendation, Assessment, Development and Evaluation system was applied.

RESULTS

Among 29 out of 827 records retrieved through electronic databases and four additional reports identified from other sources, 29 studies were focused for the review. A total of 10158 subjects were included and the mean age at inclusion was between 45.8 and 63.9 years. The mean RA duration was between 4.3 and 14.9 years. The positivity of anti-CCP antibody ranged from 50.7% to 95.8%. All studies except for two were deemed as high risk of bias. A pooled analysis of univariate results demonstrated that the presence of anti-CCP antibody was significantly associated with RA-ILD with an OR of 2.10 (95% CI: 1.59 to 2.78). Similarly, the titre of anti-CCP antibody was significantly higher for RA-ILD with a standardised mean difference of 0.42 (95% CI: 0.20 to 0.65). These results were confirmed by multivariate analysis in the majority of studies and consistent by any subgroup and sensitivity analyses.

CONCLUSION

The presence and higher titres of anti-CCP antibody were suggested to be significantly associated with an increased risk of RA-ILD. However, the quality of evidence was rated as low or very low.

Methotrexate and rheumatoid arthritis associated interstitial lung disease

QUESTION ADDRESSED BY THE STUDY

Methotrexate (MTX) is a key anchor drug for rheumatoid arthritis (RA) management. Fibrotic interstitial lung disease (ILD) is a common complication of RA. Whether MTX exposure increases the risk of ILD in patients with RA is disputed. We aimed to evaluate the association of prior MTX use with development of RA-ILD.

METHODS

Through a case-control study design with discovery and international replication samples, we examined the association of MTX exposure with ILD in 410 patients with chronic fibrotic ILD associated with RA (RA-ILD) and 673 patients with RA without ILD. Estimates were pooled over the different samples using meta-analysis techniques.

RESULTS

Analysis of the discovery sample revealed an inverse relationship between MTX exposure and RA-ILD (adjusted OR 0.46, 95% CI 0.24-0.90; p=0.022), which was confirmed in the replication samples (pooled adjusted OR 0.39, 95% CI 0.19-0.79; p=0.009). The combined estimate using both the derivation and validation samples revealed an adjusted OR of 0.43 (95% CI 0.26-0.69; p=0.0006). MTX ever-users were less frequent among patients with RA-ILD compared to those without ILD, irrespective of chest high-resolution computed tomography pattern. In patients with RA-ILD, ILD detection was significantly delayed in MTX ever-users compared to never-users (11.4±10.4 years and 4.0±7.4 years, respectively; p<0.001).

ANSWER TO THE QUESTION

Our results suggest that MTX use is not associated with an increased risk of RA-ILD in patients with RA, and that ILD was detected later in MTX-treated patients.

Imaging Biomarkers in Animal Models of Drug-Induced Lung Injury: A Systematic Review

For drug-induced interstitial lung disease (DIILD) translational imaging biomarkers are needed to improve detection and management of lung injury and drug-toxicity. Literature was reviewed on animal models in which in vivo imaging was used to detect and assess lung lesions that resembled pathological changes found in DIILD, such as inflammation and fibrosis. A systematic search was carried out using three databases with key words “Animal models”, “Imaging”, “Lung disease”, and “Drugs”. A total of 5749 articles were found, and, based on inclusion criteria, 284 papers were selected for final data extraction, resulting in 182 out of the 284 papers, based on eligibility. Twelve different animal species occurred and nine various imaging modalities were used, with two-thirds of the studies being longitudinal. The inducing agents and exposure (dose and duration) differed from non-physiological to clinically relevant doses. The majority of studies reported other biomarkers and/or histological confirmation of the imaging results. Summary of radiotracers and examples of imaging biomarkers were summarized, and the types of animal models and the most used imaging modalities and applications are discussed in this review. Pathologies resembling DIILD, such as inflammation and fibrosis, were described in many papers, but only a few explicitly addressed drug-induced toxicity experiments.

Beyond the joints, the extra-articular manifestations in rheumatoid arthritis

Rheumatoid arthritis (RA) is an inflammatory disease typically affecting the joints, but the systemic inflammatory process may involve other tissues and organs. Many extra-articular manifestations are recognized, which are related to worse long outcomes. Rheumatoid nodules are the most common extra-articular feature, found in about 30% of patients. Secondary Sjögren's syndrome and pulmonary manifestations are observed in almost 10% of patients, also in the early disease. Active RA with high disease activity has been associated with an increased risk of such features. Male gender, smoking habit, severe joint disease, worse function, high pro-inflammatory markers levels, high titer of rheumatoid factor, and HLA-related shared epitope have been reported as clinical predictors of occurrence of these rheumatoid complications. In addition, there is a little evidence deriving from randomized controlled trials in this field, thus the therapeutic strategy is mainly empiric and based on small case series and retrospective studies. However, considering that these extra-articular manifestations are usually related to the more active and severe RA, an aggressive therapeutic strategy is usually employed in view of the poor outcomes of these patients. The extra-articular features of RA remain, despite the improvement of joint damage, a major diagnostic and therapeutic challenge, since these are associated with a poor prognosis and need to be early recognized and promptly managed.

Rheumatoid arthritis-associated lung disease in black Africans: Descriptive study of 28 cases in Lomé

Background

Several studies have shown that lung disease is a common extra-articular manifestation of rheumatoid arthritis (RA).

Objectives

To describe the lung manifestations in the RA population in Lomé, Togo.

Methods

The study was conducted from October 2018 to July 2019 at the pulmonology unit of the Sylvanus Olympio University teaching hospital, in collaboration with rheumatology centres in Lomé, Togo. Patients meeting the American College of Rheumatology criteria for RA were prospectively enrolled. They underwent clinical examination, spirometry, a 6-minute walk test (6MWT) and a chest X-ray (CXR). All information collected and surveys gathered were subjected to statistical analysis.

Results

Twenty-four out of 28 patients were women (85.7%). The mean (standard deviation (SD)) duration of illness was 4.1 (2.8) years. Thirteen patients out of 28 (46.4%) had respiratory symptoms. On CXR, interstitial lung disease was the only pleuropulmonary lesion (17.8%). Spirometry was abnormal in 25% of cases, with a predominance of restrictive ventilatory disorder (21.4%). The 6MWT was abnormal in 25% of patients. A total of 20 patients (71.4%) had at least one lung manifestation. We noted that there were significantly more patients with respiratory symptoms and no radiographical abnormalities than those with both respiratory symptoms and radiographical abnormalities (p=0.013).

Conclusion

Lung changes affect a significant proportion of RA patients in Lomé. Studies conducted with appropriate respiratory investigations and combining cardiovascular explorations will bring us closer to an understanding of the effects of RA-associated lung disease.

Recent advances in rheumatoid arthritis-associated interstitial lung disease

PURPOSE OF REVIEW

To provide an overview of recent studies that could be helpful in a better understanding of rheumatoid arthritis-associated interstitial lung disease (RA-ILD) and to facilitate the clinical management of this severe complication of RA.

RECENT FINDINGS

The advances in deciphering the genetic architecture of RA-ILD support the hypothesis of RA-ILD as a complex disease with a complex phenotype encompassing at least the usual interstitial pneumonia (UIP) high-resolution CT pattern and non-UIP. Genetics studies have provided evidence for a shared genetic background in idiopathic pulmonary fibrosis (IPF) and RA-ILD, and more specifically RA-UIP, a disease with high morbidity and mortality. These findings support the rationale for common pathogenic pathways opening new avenues for future intervention in RA-ILD, notably with - drugs that proved active in IPF. In agreement, a recent controlled trial suggests efficacy of nintedanib, an antifibrotic drug, in patients with progressive lung fibrosis, including RA-ILD. However, there is a substantial gap in RA-ILD treatment, notably evaluating the effect of the RA treatments on the ILD course because of no controlled trial yet.

SUMMARY

The phenotypical, environmental, and genetic similarities between IPF and RA-ILD have led to a better understanding of the underlying pathogenesis of RA-ILD. Despite the identification of several biomarkers and useful screening tools, several questions remain unanswered regarding the identification of patients with RA at increased risk of ILD and risk of progression. Other substantial gaps are the lack of recommendations for how high-risk patients should be screened and which specific therapeutic strategy should be initiated. International collaborative efforts are needed to address these issues and develop specific recommendations for RA-ILD.

The lung in a cohort of rheumatoid arthritis patients-an overview of different types of involvement and treatment

OBJECTIVES

Lung involvement in RA has several manifestations and is a major cause of morbidity and mortality. The aim of this study was to characterize the different types of lung disease and response to treatment in a UK cohort of RA patients.

METHODS

RA patients who had undergone high resolution CT scans of the lung were identified and scans reviewed. Demographic data, RA features, complementary exams and treatments were recorded for those with radiological evidence of lung involvement. Descriptive analysis was performed, and Mann-Whitney U and χ2 tests were used for comparison between different radiological subtypes.

RESULTS

Lung disease was reported in 87 (7.7%) of 1129 RA patients, usually (97.7%) post-dating articular symptoms. Most patients had positive RF (74/84; 88.1%) and ACPA (72/82; 87.7%). Interstitial lung disease (ILD) was the most common pattern, reported in 45 (51.7%) patients. Drug-induced lung disease was reported in 2 of 64 (3.1%) patients treated with MTX. Rituximab was used in 26 (57.8%) patients with ILD, with evidence of disease improvement or stabilization in patients with non-specific interstitial pneumonia and organizing pneumonia. During lung disease follow-up (6.7 ± 4.1 years), 22 (25.3%) patients were admitted to hospital with respiratory infections, with 14 (63.6%) of them having underlying bronchiectasis. Lung disease-related mortality was estimated at 8%.

CONCLUSION

ILD was the most prevalent manifestation of lung involvement in RA and was associated with higher mortality. Immunosuppressive drugs used in RA were rarely associated with lung toxicity, and rituximab demonstrated promising results for the treatment of RA-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.

Mechanisms of lung disease development in rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic autoimmune disorder that causes joint inflammation and damage. Extra-articular manifestations occur in many patients and can include lung involvement in the form of airway or parenchymal inflammation and fibrosis. Although the pathophysiology of articular RA has been extensively investigated, the mechanisms causing airway and parenchymal lung disease are not well defined. Infections, cigarette-smoking, mucosal dysbiosis, host genetics and premature senescence are all potentially important contributors to the development of lung disease in patients with RA. RA-associated lung disease (which can predate the onset of articular disease by many years) probably originates from chronic airway and alveolar epithelial injury that occurs in an individual with a genetic background that permits the development of autoimmunity, leading to chronic inflammation and subsequent airway and lung parenchymal remodelling and fibrosis. Further investigations into the specific mechanisms by which lung disease develops in RA will be crucial for the development of effective therapies. Identifying mechanisms by which environmental and host factors cooperate in the induction of autoimmunity in the lung might also help to establish the order of early events in RA.

Value of immune factors for monitoring risk of lung cancer in patients with interstitial lung disease

Objective

Patients with interstitial lung disease (ILD) are at increased risk of developing lung cancer. We aimed to investigate the clinical significance of serum immune factors in this progression.

Methods

We retrospectively screened a hospital database from January 2012 to December 2016 for patients with lung cancer and ILD. We measured serum levels of C3, C4, IgA, IgG, IgM, C-reactive protein (CRP), ceruloplasmin (CER), and rheumatoid factor in these patients and in healthy controls.

Results

We analyzed data for 262 patients with lung cancer, 220 with ILD, and 57 healthy controls. CER levels were significantly higher in patients with lung cancer (0.35 ± 0.10 g/L) compared with both ILD patients (0.31 ± 0.25 g/L) and healthy individuals (0.25 ± 0.04 g/L). C3 and C4 levels were both significantly higher in healthy individuals compared with patients with lung cancer (C3: 1.70 ± 0.29 vs 1.04 ± 0.26 g/L, C4: 0.27 ± 0.24 vs 0.24 ± 0.09 g/L) and ILD (C3: 1.70 ± 0.29 vs 0.97 ± 0.25 g/L, C4: 0.27 ± 0.24 vs 0.21 ± 0.09 g/L). Optimal scaling analysis demonstrated that lung cancer was closely associated with CRP, CER, C3, and C4.

Conclusions

Increased levels of CRP and CER and decreased levels of C3 and C4 may identify patients with ILD at high risk of developing lung cancer.

Korean Guidelines for Diagnosis and Management of Interstitial Lung Diseases: Part 5. Connective Tissue Disease Associated Interstitial Lung Disease

Connective tissue disease (CTD) is a collection of disorders characterized by various signs and symptoms such as circulation of autoantibodies in the entire system causing damage to internal organs. Interstitial lung disease (ILD) which is associated with CTD is referred to as CTD-ILD. Patients diagnosed with ILD should be thoroughly examined for the co-occurrence of CTD, since the treatment procedures and prognosis of CTD-ILD are vary from those of idiopathic interstitial pneumonia. The representative types of CTD which may accompany ILD include rheumatoid arthritis, systemic sclerosis (SSc), Sjögren's syndrome, mixed CTD, idiopathic inflammatory myopathies, and systemic lupus erythematous. Of these, ILD most frequently co-exists with SSc. If an ILD is observed in the chest, high resolution computed tomography and specific diagnostic criteria for any type of CTD are met, then a diagnosis of CTD-ILD is made. It is challenging to conduct a properly designed randomized study on CTD-ILD, due to low incidence. Therefore, CTD-ILD treatment approach is yet to been established in absence of randomized controlled clinical trials, with the exception of SSc-ILD. When a patient is presented with acute CTD-ILD or if symptoms occur due to progression of the disease, steroid and immunosuppressive therapy are generally considered.

Systemic treatment with resveratrol alleviates adjuvant arthritis-interstitial lung disease in rats via modulation of JAK/STAT/RANKL signaling pathway

Interstitial lung disease (ILD) is the most common pulmonary manifestation of Rheumatoid arthritis (RA) lung disease. The mechanism of RA-ILD remains obscure and more effective treatments are still needed. Resveratrol (RSV) a phytoalexin found with anti-inflammation and antioxidant activity. RSV has been reported to protect against RA. In current study, we evaluated the effects of RSV on RA-ILD and further explored the underlying mechanisms. We established the RA-ILD rat model by injecting Freund's complete adjuvant (FCA). After administration of RSV into RA-ILD rats, the disease parameters were assessed, inflammatory cytokines productions were analyzed, and the effects of RSV on JAK/STAT/RANKL were evaluated. Injection of FCA caused RA-ILD in rats, which had clear lung damage, fibrosis, and elevated pro-inflammatory cytokines in both serum and lung. RSV treatment significantly ameliorated the lung disease and prevented pro-inflammatory cytokines production. In addition, RSV inhibited JAK/STAT/RANKL signaling pathway in RA-ILD rats. RSV treatment alleviates RA-ILD in rats by inhibiting JAK/STAT/RANKL signaling pathway.

Rheumatoid Arthritis-Interstitial Lung Disease in the United States: Prevalence, Incidence, and Healthcare Costs and Mortality

OBJECTIVE

Interstitial lung disease (ILD) is commonly associated with rheumatoid arthritis (RA) and can have significant morbidity and mortality. The objective of this study was to calculate the prevalence, incidence, healthcare costs, and mortality of RA-related ILD (RA-ILD) in the United States.

METHODS

This retrospective cohort analysis used the Truven Health MarketScan Commercial and Medicare Supplemental health insurance databases from 2003 to 2014 and the Social Security Administration death database. Patients with RA-ILD were selected based on diagnoses on medical claims. Outcomes were 1-year prevalence and incidence of RA-ILD among the general enrollee population, all-cause and respiratory-related healthcare costs (2014 US$), and all-cause survival for a subset of newly diagnosed patients with vital status information. This analysis was descriptive. No statistical testing was conducted.

RESULTS

Prevalence of RA-ILD ranged from 3.2 to 6.0 cases per 100,000 people across the 10-year period and incidence ranged from 2.7 to 3.8 cases per 100,000 people. There were 750 incident patients with 5 years of followup data. Over that time, 72% had an inpatient admission and 76% had an emergency room visit. Mean total 5-year costs were US$173,405 per patient (SD $158,837). Annual per-patient costs were highest in years 1 and 5. At 5 years after first diagnosis in the data, 35.9% of patients had died.

CONCLUSION

Prevalence of RA-ILD increased over time. For patients who could be followed over a 5-year period, healthcare use and costs were somewhat stable over time, but were substantial. RA-ILD is associated with decreased survival.

Interstitial pneumonia with autoimmune features: a new classification still on the move

In the past decade, the attention has been focused on the relationship between interstitial lung disease (ILD) and connective tissue diseases (CTDs). The clinical impact, as well as the therapeutic approach, classification and diagnosis have been addressed. These two latter items represent an area of great interest because the underlying conditions leading to ILD and the most appropriate treatment still needs to be defined. Recently, the European Respiratory Society/American Thoracic Society proposed the interstitial pneumonia with autoimmune features (IPAF) criteria which represents the effort of pulmonologists to classify patients that may remain clinically undefined [1]. The analysis of these criteria shows that IPAF, similarly to pulmonary arterial hypertension classification [2], may cluster conditions referring to a wide spectrum of rheumatic conditions such as systemic sclerosis, myositis, rheumatoid arthritis and overlap syndromes. These diseases are characterised by highly different characteristics, evolution and therapeutic approaches. Furthermore, IPAF criteria have an intrinsically changing structure, related to the regular update of existing CTD classification criteria and to the even more common identification of new biomarkers in CTDs. By far the most important effect of these criteria is the identification of a grey zone of not well-defined rheumatology conditions, e.g. anti-synthetase syndrome (ASSD) [3]. In this issue of the European Respiratory Review, Sambataroet al. [4] address the need to identify specific clinical characteristics and potential areas of improvement in IPAF patients. The starting point of the review is interesting because of the exclusion of papers that included patients diagnosed with ASSD, because no ASSD established classification criteria still exist. The authors' choice is related to the unique characteristics of ASSD, in which it is not unusual to observe the occurrence during follow-up of findings lacking at disease onset. [5]. However, as reported previously [6], in the case of anti-synthetase antibody positivity, the diagnostic scenario may vary with the same patient diagnosed with ASSD if referred to a rheumatologist, or IPAF if referred to a pulmonologist. In fact, a high prevalence of anti-synthetase antibody positivity is reported in the majority of papers evaluated by Sambataroet al. [4], thus confirming the fact that despite the presence of this antibody (identifying ASSD) patients may frequently end up being classified as having IPAF. However, some IPAF patients could not be tested for the entire spectrum of antibodies, probably due to the local unavailability of these tests, or because initial anti-Ro antibody positivity might have prompted the clinicians to evaluate further non-anti-Jo-1 myositis specific auto-antibodies. In fact, it is established that anti-Ro antibodies and anti-synthetase antibodies may co-occur in about 50% of cases, even when patients could be classified as IPAF [7]. Furthermore, we should also consider that if eight anti-synthetase antibodies have been identified to date, at least another 12 aminoacyl-tRNA synthetase enzymes exist, and that the entire spectrum of anti-synthetase antibodies is not covered by any of the existing commercially available tests. All these points clearly indicate the risk that anti-synthetase antibody positivity could be underestimated and that it could be clustered in IPAF. This evidence clearly suggests that well-established and clinically based ASSD classification criteria are needed to reduce the risk of stratifying patients across specialties, in areas that may contribute to real-time incorrectly diagnosed primary disease. Recently, the CLASS (classification criteria of anti-synthetase syndrome) project has been funded by the American College of Rheumatology and the European League against Rheumatism. The aim of the project is to define clinically based criteria of ASSD involving a large number of rheumatology, pulmonology, dermatology, immunology and internal medicine centres expert in the management of rheumatoid arthritis, systemic sclerosis, Sjogren's syndrome and other lung fibrosing conditions. From a scientific point of view, by putting together different specialists we hope to solve the daily discussions about “anti-synthetase antibody positive patient classification” that may delay the correct approach and treatment of affected patients.

IPAF classification criteria include several autoimmune conditions with different evolution. The progression into established CTD is common and a continuous up-to-date process of classification criteria of both IPAF and CTD is mandatory.http://ow.ly/pXNW30knUzl

Nintedanib reduces pulmonary fibrosis in a model of rheumatoid arthritis-associated interstitial lung disease

Rheumatoid arthritis (RA)-associated interstitial lung disease (RA-ILD) develops in ~20% of patients with RA. SKG mice, which are genetically prone to development of autoimmune arthritis, develop a pulmonary interstitial pneumonia that resembles human cellular and fibrotic nonspecific interstitial pneumonia. Nintedanib, a tyrosine kinase inhibitor approved for treatment of idiopathic pulmonary fibrosis, has been shown to reduce the decline in lung function. Therefore, we investigated the effect of nintedanib on development of pulmonary fibrosis and joint disease in female SKG mice with arthritis induced by intraperitoneal injection of zymosan (5 mg). Nintedanib (60 mg·kg-1·day-1 via oral gavage) was started 5 or 10 wk after injection of zymosan. Arthritis and lung fibrosis outcome measures were assessed after 6 wk of treatment with nintedanib. A significant reduction in lung collagen levels, determined by measuring hydroxyproline levels and staining for collagen, was observed after 6 wk in nintedanib-treated mice with established arthritis and lung disease. Early intervention with nintedanib significantly reduced development of arthritis based on joint assessment and high-resolution μ-CT. This study impacts the RA and ILD fields by facilitating identification of a therapeutic treatment that may improve both diseases. As this model replicates the characteristics of RA-ILD, the results may be translatable to the human disease.