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

Organizing Pneumonia as First Manifestation of Seronegative Rheumatoid Arthritis

Rheumatoid arthritis is a multisystem autoimmune inflammatory disease that typically presents as a case of arthritis that can later progress to involve multiple organs. Interstitial lung disease is one of the many extra-articular manifestations of rheumatoid arthritis. We discuss a case of rheumatoid arthritis that presented with interstitial lung disease prior to the development of arthritis along with the discussion of novel anti-carbamylated protein antibody as a serological marker for the diagnosis of seronegative rheumatoid arthritis. 

Current perspective of progressive-fibrosing interstitial lung disease

Interstitial lung disease (ILD) is a parenchymal lung disease and restrictive disorder that presents as diffuse infiltrative shadows. The initial diagnosis of ILD is important because management strategies depend on the disease pathogenesis. Connective-tissue disease (CTD)-associated ILD including rheumatoid arthritis (RA), systemic sclerosis (SSc) requires a thorough evaluation of chronic respiratory symptoms such as non-productive cough and exertional dyspnea, as well as physical findings. Moreover, myeloperoxidase-positive anti-neutrophilic cytoplasmic antibody (MPO-ANCA)-associated vasculitis with ILD also shows disease progression. In CTD-associated ILD, the first-line treatment is anti-inflammatory drugs such as prednisolone or immunosuppressants. In hypersensitivity pneumonitis (HP), detailed environmental history-taking is crucial. Therefore, systematic standardized questionnaires are needed. However, the causative antigens are often not identified in daily clinical practice. When an antigen is identified or suspected, the first action is avoidance. If antigen avoidance does not contribute to clinical improvement, anti-inflammatory drugs such as prednisolone might be introduced. Regarding sarcoidosis, while most patients do not require treatment for lung involvement, some need anti-inflammatory drugs or immunosuppressants. Additionally, steroid treatment should be considered for the critical status of extrapulmonary sarcoidosis including cardiac, neurogenic and ocular sarcoidosis. Once starting treatment for ILD, multi-dimensional approaches are applied, including symptom tracking, chest imaging, pulmonary function test (PFT), and 6-min walking test. Recently, the concept of progressive-fibrosing interstitial lung disease (PF-ILD) has been proposed as a new disease entity. The definition of PF-ILD includes symptom progression, PFT decline, and extension of chest high-resolution computed tomography (HRCT) findings. This mini-review describes the background, definition, clinical characteristics, management, and challenges of PF-ILD.

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.

Clinical relevance of rheumatoid factor and anti-citrullinated peptides in fibrotic interstitial lung disease

BACKGROUND AND OBJECTIVE

Rheumatoid arthritis (RA) is a frequent cause of interstitial lung disease (ILD); however, the impact of rheumatoid factor and anti-citrullinated peptide antibody seropositivity in ILD without connective tissue disease (CTD) is unclear. We examined the association of seropositivity with ILD progression, mortality and response to immunosuppression in non-CTD ILD.

METHODS

A total of 1570 non-CTD patients (with idiopathic pulmonary fibrosis, hypersensitivity pneumonitis, interstitial pneumonia with autoimmune features or unclassifiable ILD) and 181 RA-ILD patients were included from a prospective registry. Longitudinal forced vital capacity (FVC), transplant-free survival and incidence of progressive fibrosing-ILD (PF-ILD) were compared between seronegative non-CTD ILD (reference group), seropositive non-CTD ILD and RA-ILD using linear mixed-effect and Cox proportional hazards models adjusted for age, sex, smoking pack-years and baseline FVC. Interaction between seropositivity and immunosuppression on FVC decline was assessed in patients with ≥6 months of follow-up before and after the treatment.

RESULTS

Two hundred and seventeen (13.8%) patients with seropositive non-CTD ILD had similar rates of FVC decline and transplant-free survival compared to seronegative non-CTD ILD, but more frequently met the criteria for PF-ILD (hazard ratio [HR] = 1.35, p = 0.004). RA-ILD had slower FVC decline (p = 0.03), less PF-ILD (HR = 0.75, p = 0.03) and lower likelihood of lung transplant or death (HR = 0.66, p = 0.01) compared to seronegative non-CTD ILD. No interaction was found between seropositivity and treatment on FVC decline in non-CTD ILD.

CONCLUSION

Seropositivity in non-CTD ILD was not associated with improved outcomes or treatment response, highlighting the importance of other disease features in determining prognosis and predicting response to immunosuppression.

Predictors of progression in rheumatoid arthritis-associated interstitial lung disease: A single-center retrospective study from China

AIM

Interstitial lung disease (ILD) is a common extra-articular manifestation of rheumatoid arthritis (RA) and is associated with high mortality, especially in progressive ILD. We aimed to identify predictors of disease progression in the early stages of ILD in a large sample of patients with RA.

METHOD

The medical records of 201 RA-ILD patients were retrospectively analyzed. According to changes in their pulmonary function tests, patients were divided into progressive disease and stable disease groups. Data were collected on clinical characteristics, laboratory findings, chest high-resolution computed tomography, and therapeutic agents. Univariate and multivariate analyses were performed to identify predictors of ILD progression.

RESULTS

During a median follow up of 38 months, 105 (52.5%) patients were diagnosed with progressive ILD. These patients were mostly male, past or present smokers (P = 0.028, P = 0.021, respectively). Higher Health Assessment Questionnaire-Disability Index score and higher Disease Activity Score in 28 joints with erythrocyte sedimentation rate (DAS28-ESR) were observed in the ILD progression group (P = 0.003, P < 0.001, respectively). There were no significant differences in baseline respiratory symptoms, pulmonary function, or laboratory features. Multivariate analysis indicated that high DAS28-ESR, definite usual interstitial pneumonia pattern, fibrosis score, and less use of cyclophosphamide were independent risk factors for RA-ILD progression. Fifteen (7.46%) patients died during the follow up, and the most frequent cause of death was lung infection.

CONCLUSION

Our results suggested that high disease activity, definite usual interstitial pneumonia pattern, fibrosis score, and less use of cyclophosphamide at the onset of ILD may indicate the progression of ILD in RA patients.

Sphingosine 1-phosphate receptor-targeted therapeutics in rheumatic diseases

Sphingosine 1-phosphate (S1P), which acts via G protein-coupled S1P receptors (S1PRs), is a bioactive lipid essential for vascular integrity and lymphocyte trafficking. The S1P-S1PR signalling axis is a key component of the inflammatory response in autoimmune rheumatic diseases. Several drugs that target S1PRs have been approved for the treatment of multiple sclerosis and inflammatory bowel disease and are under clinical testing for patients with systemic lupus erythematosus (SLE). Preclinical studies support the hypothesis that targeting the S1P-S1PR axis would be beneficial to patients with SLE, rheumatoid arthritis (RA) and systemic sclerosis (SSc) by reducing pathological inflammation. Whereas most preclinical research and development efforts are focused on reducing lymphocyte trafficking, protective effects of circulating S1P on endothelial S1PRs, which maintain the vascular barrier and enable blood circulation while dampening leukocyte extravasation, have been largely overlooked. In this Review, we take a holistic view of S1P-S1PR signalling in lymphocyte and vascular pathobiology. We focus on the potential of S1PR modulators for the treatment of SLE, RA and SSc and summarize the rationale, pathobiology and evidence from preclinical models and clinical studies. Improved understanding of S1P pathobiology in autoimmune rheumatic diseases and S1PR therapeutic modulation is anticipated to lead to efficacious and safer management of these diseases.

Usual interstitial pneumonia: a clinically significant pattern, but not the final word

Usual interstitial pneumonia (UIP) is a concept that is deeply entrenched in clinical practice and the prognostic significance of UIP is well established, but the field continues to suffer from the lack of a true gold standard for diagnosing fibrotic interstitial lung disease (ILD). The meaning and usage of UIP have shifted over time and this term is prone to misinterpretation and poor diagnostic agreement. For pathologists, it is worth reflecting on the limitations of UIP and our true role in the care of patients with ILD, a controversial topic explored in two point-counterpoint editorials published simultaneously in this journal. Current diagnostic guidelines are ambiguous and difficult to apply in clinical practice. Further complicating matters for the pathologist is the paradigm shift that occurred with the advent of anti-fibrotic agents, necessitating increased focus on the most likely etiology of fibrosis rather than simply the pattern of fibrosis when pulmonologists select appropriate therapy. Despite the wealth of information locked in tissue samples that could provide novel insights into fibrotic ILDs, pulmonologists increasingly shy away from obtaining biopsies, likely because pathologists no longer provide sufficient value to offset the risks of a biopsy procedure, and pathologic assessment is insufficiently reliable to meaningfully inform therapeutic decisionmaking. To increase the value of biopsies, pathologists must first recognize the problems with UIP as a diagnostic term. Second, pathologists must realize that the primary goal of a biopsy is to determine the most likely etiology to target with therapy, requiring a shift in diagnostic focus. Third, pathologists must devise and validate new classifications and criteria that are evidence-based, biologically relevant, easy to use, and predictive of outcome and treatment response. Only after the limitations of UIP are understood will pathologists provide maximum diagnostic value from biopsies to clinicians today and advance the field forward.

Disease activity as a risk factor for venous thromboembolism in rheumatoid arthritis analysed using time-averaged DAS28CRP: a nested case-control study

The objective of this study is to clarify the clinical features and risk factors of venous thromboembolism (VTE) in patients with rheumatoid arthritis (RA). We retrospectively reviewed the prevalence of VTE in RA patients who visited Hokkaido University Hospital from 2010 to 2019 and had more than 2 years of follow-up. To explore the risk to develop VTE, we selected 260 RA patients without VTE (non-VTE) via density sampling and identified the risk factors for VTE by multivariate logistic regression analysis. Univariate conditional logistic regression analysis showed older age (p < 0.0001, Odds Ratio [OR] 1.08, 95% Confidence Interval [CI] 1.04-1.14), increase of the body mass index (BMI) (p = 0.001, OR 1.17, 95% CI 1.06-1.31), higher prevalence of RA-associated lung disease (p = 0.002, OR 2.10, 95% CI 1.33-3.30) and more frequent glucocorticoid usage (p = 0.001, OR 2.09, 95% CI 1.34-3.51) in RA patients was associated with the development of VTE significantly. Furthermore, patients with higher time-averaged disease activity score 28 (DAS28) CRP were at elevated risk (p < 0.0001, OR 3.25, 95% CI 1.94-6.12). In conditional multivariate logistic regression analysis, time averaged DAS28CRP was significantly associated with the development of VTE (p = 0.0001, adjusted OR 3.40, 95% CI 1.77-7.85). Disease activity was identified as a major risk factor of VTE in patients with RA, suggesting that sustained clinical remission could be beneficial for decrease the risk of VTE.

Acute exacerbation of rheumatoid arthritis-associated interstitial lung disease: mortality and its prediction model

Background

Patients with rheumatoid arthritis-associated interstitial lung disease (RA-ILD), like those with idiopathic pulmonary fibrosis (IPF), might develop an unexpected acute exacerbation (AE)—a rapidly progressing and deadly respiratory decline. Although AE incidence and risk factors in RA-ILD patients are known, their post-AE clinical course remains unknown owing to the rarity of AE-RA-ILD. This multicentre retrospective study evaluated post-AE mortality and prognostic variables in AE-RA-ILD patients and created a mortality prediction model for AE-RA-ILD.

Methods

This research comprised 58 patients with AE-RA-ILD and 96 with AE-IPF (a control disease). Multivariate Cox regression analysis was performed to identify prognostic variables. A prediction model was created with recursive partitioning (decision tree).

Results

The post-AE 90-day mortality rate in the overall AE-RA-ILD group was 48.3%; percent predicted forced vital capacity within 12 months before AE onset (baseline %FVC) and PaO₂/FiO₂ ratio at AE onset (P/F at AE) were independent predictors of mortality. Post-AE 90-day mortality rates were 40.6% and 43.8%, respectively, in AE-RA-ILD and AE-IPF patients propensity score-matched for age, sex, baseline %FVC and P/F at AE (P = 1.0000). In AE-RA-ILD patients, C-indices of baseline %FVC and P/F at AE to predict post-AE 90-day mortality were 0.604 and 0.623, respectively. A decision tree model based on these prognostic factors classified AE-RA-ILD patients into mild, moderate and severe groups (post-AE 90-day mortality rates: 20.8%, 64.0% and 88.9%, respectively; P = 0.0002); the C-index improved to 0.775.

Conclusions

Post-AE mortality was high in AE-RA-ILD patients similar to AE-IPF patients. The discovered prognostic factors and our mortality prediction model may aid in the management of AE-RA-ILD patients.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12931-022-01978-y.

Rheumatoid Arthritis and Associated Lung Diseases: A Comprehensive Review

Rheumatoid arthritis (RA) is a prevalent autoimmune disorder affecting 0.5-1% of the population in North America and Europe. Pulmonary manifestations in rheumatoid arthritis patients result in significant morbidity and mortality. Management of these pulmonary manifestations in RA patients causes various challenges for the physicians. This review article has discussed the current state of knowledge of these pulmonary manifestations, including interstitial lung diseases, airway-related diseases, pulmonary vasculature, and pleural involvement in RA patients. This review article has also explored various pharmacological options, including steroids, disease-modifying antirheumatic drugs (DMARDs), immunosuppressive drugs, and biologic agents. Non-pharmacological options include conservative treatment, supplemental oxygen, pulmonary rehabilitation, smoking cessation, and lung transplantation.

Citrullination in the pathology of inflammatory and autoimmune disorders: recent advances and future perspectives

Numerous post-translational modifications (PTMs) govern the collective metabolism of a cell through altering the structure and functions of proteins. The action of the most prevalent PTMs, encompassing phosphorylation, methylation, acylations, ubiquitination and glycosylation is well documented. A less explored protein PTM, conversion of peptidylarginine to citrulline, is the subject of this review. The process of citrullination is catalysed by peptidylarginine deiminases (PADs), a family of conserved enzymes expressed in a variety of human tissues. Accumulating evidence suggest that citrullination plays a significant role in regulating cellular metabolism and gene expression by affecting a multitude of pathways and modulating the chromatin status. Here, we will discuss the biochemical nature of arginine citrullination, the enzymatic machinery behind it and also provide information on the pathological consequences of citrullination in the development of inflammatory diseases (rheumatoid arthritis, multiple sclerosis, psoriasis, systemic lupus erythematosus, periodontitis and COVID-19), cancer and thromboembolism. Finally, developments on inhibitors against protein citrullination and recent clinical trials providing a promising therapeutic approach to inflammatory disease by targeting citrullination are discussed.

Advances with pharmacotherapy for the treatment of interstitial lung disease

INTRODUCTION

In recent decades, the primary focus of pharmaceutical research in interstitial lung diseases (ILD) has been on idiopathic pulmonary fibrosis (IPF). Recently, pharmaceutical development has also focused on other forms of ILDs, including connective tissue diseases associated ILD, fibrotic hypersensitivity pneumonitis, and sarcoidosis.

AREAS COVERED

The authors summarize the advances in pharmacotherapy for the treatment of ILD. Specifically, the authors review the most recent studies and discuss the most recent research findings and future prospects.

EXPERT OPINION

Data collected over the past years have confirmed the efficacy of antifibrotic drugs on slowing disease progression in IPF. The usual strategy for CTD-ILD management is represented by the combined use of corticosteroids and immunosuppressive agents. There is an urgent need for new target therapies. The concept of progressive fibrosing ILD has emerged in the ILD community in recent years, which has led to grouping several diseases with a common disease behavior to find an effective treatment . At present, selecting the best therapy in ILDs should be reasonably performed on a case-by-case basis through a multidisciplinary team discussion in tertiary ILD centers, taking into consideration patients' symptoms, lung functional trends, and radiological changes.

High-titer rheumatoid factor seropositivity predicts mediastinal lymphadenopathy and mortality in rheumatoid arthritis-related interstitial lung disease

Rheumatoid arthritis-related interstitial lung disease (RA-ILD) is a common connective tissue disease-related ILD (CTD-ILD) associated with high morbidity and mortality. Although rheumatoid factor (RF) seropositivity is a risk factor for developing RA-ILD, the relationship between RF seropositivity, mediastinal lymph node (MLN) features, and disease progression is unknown. We aimed to determine if high-titer RF seropositivity predicted MLN features, lung function impairment, and mortality in RA-ILD. In this retrospective cohort study, we identified patients in the University of Chicago ILD registry with RA-ILD. We compared demographic characteristics, serologic data, MLN size, count and location, and pulmonary function over 36 months among patients who had high-titer RF seropositivity (≥ 60 IU/ml) and those who did not. Survival analysis was performed using Cox regression modeling. Amongst 294 patients with CTD-ILD, available chest computed tomography (CT) imaging and serologic data, we identified 70 patients with RA-ILD. Compared to RA-ILD patients with low-titer RF, RA-ILD patients with high-titer RF had lower baseline forced vital capacity (71% vs. 63%; P = 0.045), elevated anti-cyclic citrullinated peptide titer (122 vs. 201; P = 0.001), CT honeycombing (50% vs. 80%; P = 0.008), and higher number of MLN ≥ 10 mm (36% vs. 76%; P = 0.005). Lung function decline over 36 months did not differ between groups. Primary outcomes of death or lung transplant occurred more frequently in the high-titer RF group (HR 2.8; 95% CI 1.1-6.8; P = 0.028). High-titer RF seropositivity was associated with MLN enlargement, CT honeycombing, and decreased transplant-free survival. RF titer may be a useful prognostic marker for stratifying patients by pulmonary disease activity and mortality risk.

Interstitial Lung Disease Associated With Autoimmune Rheumatic Diseases: Checklists for Clinical Practice

Background: Interstitial lung diseases (ILDs) are often associated with rheumatic diseases. Their early diagnosis and management are not only difficult, but also crucial, because they are associated with major morbidity and mortality and can be the first cause of death in autoimmune rheumatic diseases (ARDs). Objectives: By using methodologies, such as Nominal Group Technique (NGT) and Delphi Survey, the aims of this study were (1) to measure consensus between pulmonologists, radiologists, and rheumatologists experienced in the management of ARD-ILD; (2) to highlight the importance of a multidisciplinary approach; and (3) to provide clinicians with a practical tool aimed at improving the prompt recognition and follow-up of ILD associated with ARDs and of any possible rheumatic conditions underlying ILD. Results: During the NGT round, the Steering Committee defined 57 statements to be used in the Delphi survey. A total of 78 experts participated in the Delphi survey, namely 28 pulmonologists, 33 rheumatologists, and 17 radiologists. During this round, consensus on agreement was reached in 47 statements, while disagreement was not reached in any statements. A secondary questionnaire was drafted by the Steering Committee to obtain clearer indications on ILD-ARD "red-flags" and follow-up. Delphi Panelists took part also in the second-questionnaire survey. Answers from both surveys were used to draft two checklists of "red flags" sign or symptom suggestive of ILD and ARD, respectively, and two checklists on identification and monitoring of rheumatoid arthritis (RA) and systemic sclerosis (SSc) ILD. Limitations: This study is a consensus work, which cannot produce empiric data, and is limited to the Italian scenario. Conclusions: This work showed a high level of agreement, but also shows some divergent opinions between different experts. This underlines the importance of a multidisciplinary approach. Eventually, we believe the drafted checklists can help clinicians in the diagnosis and follow-up of ILD-ARD.