Prevalence, imaging patterns and risk factors of interstitial lung disease in connective tissue disease: a systematic review and meta-analysis

Artificial intelligence-based quantification of pulmonary HRCT (AIqpHRCT) for the evaluation of interstitial lung disease in patients with inflammatory rheumatic diseases

High-resolution computed tomography (HRCT) is important for diagnosing interstitial lung disease (ILD) in inflammatory rheumatic disease (IRD) patients. However, visual ILD assessment via HRCT often has high inter-reader variability. Artificial intelligence (AI)-based techniques for quantitative image analysis promise more accurate diagnostic and prognostic information. This study evaluated the reliability of artificial intelligence-based quantification of pulmonary HRCT (AIqpHRCT) in IRD-ILD patients and verified IRD-ILD quantification using AIqpHRCT in the clinical setting. Reproducibility of AIqpHRCT was verified for each typical HRCT pattern (ground-glass opacity [GGO], non-specific interstitial pneumonia [NSIP], usual interstitial pneumonia [UIP], granuloma). Additional, 50 HRCT datasets from 50 IRD-ILD patients using AIqpHRCT were analysed and correlated with clinical data and pulmonary lung function parameters. AIqpHRCT presented 100% agreement (coefficient of variation = 0.00%, intraclass correlation coefficient = 1.000) regarding the detection of the different HRCT pattern. Furthermore, AIqpHRCT data showed an increase of ILD from 10.7 ± 28.3% (median = 1.3%) in GGO to 18.9 ± 12.4% (median = 18.0%) in UIP pattern. The extent of fibrosis negatively correlated with FVC (ρ=-0.501), TLC (ρ=-0.622), and DLCO (ρ=-0.693) (p < 0.001). GGO measured by AIqpHRCT also significant negatively correlated with DLCO (ρ=-0.699), TLC (ρ=-0.580) and FVC (ρ=-0.423). For the first time, the study demonstrates that AIpqHRCT provides a highly reliable method for quantifying lung parenchymal changes in HRCT images of IRD-ILD patients. Further, the AIqpHRCT method revealed significant correlations between the extent of ILD and lung function parameters. This highlights the potential of AIpqHRCT in enhancing the accuracy of ILD diagnosis and prognosis in clinical settings, ultimately improving patient management and outcomes.

Risk profiles for rheumatoid arthritis-associated interstitial lung disease in a cohort of patients with five-year follow-up

OBJECTIVES

Early identification of interstitial lung disease (ILD) among patients with rheumatoid arthritis (RA) is a challenge for clinicians. The aim of this study was to evaluate screening algorithms for ILD by comparing the proportion of patients assigned a high-risk profile by three recently proposed models.

METHOD

We used the four-factor risk score, categorizing patients into high and low risk; the ILD screening criteria, categorizing patients into high, intermediate, and low risk; and the risk score for detection of subclinical RA-ILD, with four different risk categories, on patients with RA followed for 5 years after the RA diagnosis with pulmonary function tests, dyspnoea score, and pulmonary imaging.

RESULTS

The four-factor risk score identified 22% of the cohort (25/115) as eligible for further ILD investigations, while the ILD screening criteria identified 37% as high risk (43/115) and 34% as intermediate risk (39/115). The risk score for detection of subclinical RA-ILD identified 44% of the cohort as being at increased risk, with 7% in the highest risk group. The agreement between high-risk groups in the two clinical ILD screening models was moderate (kappa 0.43). Three patients in the cohort had clinical or subclinical ILD, and they were identified as high risk in the two clinical models.

CONCLUSION

The three algorithms identified approximately one-third of the cohort as being at increased risk of ILD. Further development and validation of these algorithms are needed to reduce false positives and balance the potential benefit of earlier ILD diagnosis and healthcare resources used for respiratory assessment.

Implications of the 2022 lung function update and GLI global reference equations among patients with interstitial lung disease

BACKGROUND

Lung function testing remains a cornerstone in the assessment and management of interstitial lung disease (ILD) patients. The clinical implications of the Global Lung function Initiative (GLI) reference equations and the updated interpretation strategies remain uncertain.

METHODS

Adult patients with ILD with baseline forced vital capacity (FVC) were included from the Australasian ILD registry and the National Healthcare Group ILD registry, Singapore.The European Coal and Steel Community and Miller reference equations were compared with the GLI reference equations to assess (a) differences in lung function percent predicted values; (b) ILD risk prediction models and (c) eligibility for ILD clinical trial enrolment.

RESULTS

Among 2219 patients with ILD, 1712 (77.2%) were white individuals. Idiopathic pulmonary fibrosis (IPF), connective tissue disease-associated ILD and unclassifiable ILD predominated.Median FVC was 2.60 (2.01-3.36) L, forced expiratory volume in 1 s was 2.09 (1.67-2.66) L and diffusing capacity of the lungs for carbon monoxide (DLCO) was 13.60 (10.16-17.60) mL/min/mm Hg. When applying the GLI reference equations, the mean FVC percentage predicted was 8.8% lower (87.7% vs 78.9%, p<0.01) while the mean DLCO percentage predicted was 4.9% higher (58.5% vs 63.4%, p<0.01). There was a decrease in 19 IPF and 119 non-IPF patients who qualified for the nintedanib clinical trials when the GLI reference equations were applied. Risk prediction models performed similarly in predicting mortality using both reference equations.

CONCLUSION

Applying the GLI reference equations in patients with ILD leads to higher DLCO percentage predicted values and smaller lung volume percentage predicted values. While applying the GLI reference equations did not impact on prognostication, fewer patients met the clinical trial criteria for antifibrotic agents.

The causal relationship between rheumatoid arthritis and interstitial lung disease in East Asian population: A two-sample Mendelian randomization study

To investigate the causal relationship between rheumatoid arthritis (RA) and interstitial lung disease (ILD) in the East Asian population, we utilized Mendelian randomization (MR). Publicly available summarized data from genome-wide association studies on RA (4199 cases and 208,254 controls), and the data on ILD (1046 cases and 176,974 controls) were obtained from BioBank Japan. Eligible single nucleotide polymorphisms from East Asian populations were obtained from genome-wide association studies as instrumental variables, and 11 RA-related single nucleotide polymorphisms (P < 5 × 10-8) were selected as instrumental variables. MR analysis was performed using inverse variance weighted, MR-Egger regression, weighted median, and MR-PRESSO with RA as the exposure data and ILD as the outcome data. Reliability was evaluated using Cochran Q test, MR-Egger intercept, leave-one-out analysis, and funnel plot. Inverse variance weighted results showed an odds ratio (95% confidence interval) of 1.29 (1.18-1.41), P = 3.99 × 10-8, indicating a positive association between RA and ILD. The reliability evaluation could adopt the fixed-effect model, and the absolute value of the MR-Egger regression intercept was 0.021, P > 0.05, and P value of Global Test in MR-PRESSO was 0.573. The test results of the leave-one-out showed that the results are robust, and the funnel plot indicated that the instrumental variables were not affected by potential factors. In conclusion, this study demonstrates that RA is a risk factor for ILD in the East Asian population.

Clinical utility of lung ultrasound for the detection of interstitial lung disease in patients with rheumatoid arthritis

OBJECTIVE

To establish the diagnostic value of lung ultrasound (LUS) in patients with rheumatoid arthritis (RA) for the detection of interstitial lung disease (ILD).

METHODS

A cross-sectional study was performed. Consecutive patients with RA (American College of Rheumatology/European League Against Rheumatism 2010 criteria) who had a chest high-resolution computed tomography (HRCT) performed within 12 months before inclusion, regardless of symptomatology, were included. Demographic, clinical, laboratory, and pharmacological data were recorded. Each patient underwent a LUS with assessment of B-lines (BL) and pleural irregularities (PI). HRCT was considered the gold standard for the confirmatory diagnosis of ILD. Receiver operating characteristic (ROC) curves were calculated to test the ability of LUS findings (BL and PI) in discriminating patients with ILD.

RESULTS

A total of 104 RA patients were included, of which 21.8% had ILD. Patients with ILD had more BL (median 26 versus 1, p<0.001) and PI (median 16 versus 5, p<0.001) than patients without ILD. The diagnostic accuracy in ROC curves was: area under the curve (AUC) 0.88 and 95% confidence interval (CI) 0.78-0.93 for BL and AUC 0.82 and 95% CI 0.74-0.89 for PI. The best cut-off points for (ILD detection) discriminating the presence of significant interstitial lung abnormalities were 8 BL and 7 PI.

CONCLUSIONS

The presence of 8 BL and/or 7 PI in the LUS showed an adequate cut-off value for discriminating the presence of significant interstitial lung abnormalities, evocative of ILD.

Pulmonary hypertension associated with lung diseases

Pulmonary hypertension (PH) associated with chronic lung disease (CLD) is both common and underrecognised. The presence of PH in the setting of lung disease has been consistently shown to be associated with worse outcomes. Recent epidemiological studies have advanced understanding of the heterogeneity of this patient population and shown that defining both the specific type of CLD as well as the severity of PH (i.e. deeper phenotyping) is necessary to inform natural history and prognosis. A systematic diagnostic approach to screening and confirmation of suspected PH in CLD is recommended. Numerous uncontrolled studies and one phase 3 randomised, controlled trial have suggested a benefit in treating PH in some patients with CLD, specifically those with fibrotic interstitial lung disease (ILD). However, other studies in diseases such as COPD-PH showed adverse outcomes with some therapies. Given the expanding list of approved pharmacological treatments for pulmonary arterial hypertension, developing a treatment algorithm for specific phenotypes of CLD-PH is required. This article will summarise existing data in COPD, ILD and other chronic lung diseases, and provide recommendations for classification of CLD-PH and approach to the diagnosis and management of these challenging patients.

Lung imaging patterns in connective tissue disease-associated interstitial lung disease impact prognosis and immunosuppression response

OBJECTIVES

Interstitial lung disease (ILD) in CTDs has highly variable morphology. We aimed to identify imaging features and their impact on ILD progression, mortality, and immunosuppression response.

METHODS

Patients with CTD-ILD had high-resolution chest CT (HRCT) reviewed by expert radiologists blinded to clinical data for overall imaging pattern [usual interstitial pneumonia (UIP); non-specific interstitial pneumonia (NSIP); organizing pneumonia (OP); fibrotic hypersensitivity pneumonitis (fHP); and other]. Transplant-free survival and change in percent-predicted forced vital capacity (FVC) were compared using Cox and linear mixed-effects models adjusted for age, sex, smoking, and baseline FVC. FVC decline after immunosuppression was compared with pre-treatment.

RESULTS

Among 645 CTD-ILD patients, the most frequent CTDs were SSc (n = 215), RA (n = 127), and inflammatory myopathies (n = 100). NSIP was the most common pattern (54%), followed by UIP (20%), fHP (9%), and OP (5%). Compared with the case for patients with UIP, FVC decline was slower in patients with NSIP (by 1.1%/year, 95% CI 0.2, 1.9) or OP (by 3.5%/year, 95% CI 2.0, 4.9), and mortality was lower in patients with NSIP [hazard ratio (HR) 0.65, 95% CI 0.45, 0.93] or OP (HR 0.18, 95% CI 0.05, 0.57), but higher in fHP (HR 1.58, 95% CI 1.01, 2.40). The extent of fibrosis also predicted FVC decline and mortality. After immunosuppression, FVC decline was slower compared with pre-treatment in NSIP (by 2.1%/year, 95% CI 1.4, 2.8), with no change for UIP or fHP.

CONCLUSION

Multiple radiologic patterns are possible in CTD-ILD, including a fHP pattern. NSIP and OP were associated with better outcomes and response to immunosuppression, while fHP had worse survival compared with UIP.

The role of immune cells in the pathogenesis of connective tissue diseases-associated pulmonary arterial hypertension

Connective tissue diseases-related pulmonary arterial hypertension (CTD-PAH) is a disease characterized by an elevated pulmonary artery pressure that arises as a complication of connective tissue diseases. The number of patients with CTD-PAH accounts for 25.3% of all PAH patients. The main pathological features of CTD-PAH are thickening of intima, media and adventitia of pulmonary arterioles, increased pulmonary vascular resistance, autoimmune activation and inflammatory reaction. It is worth noting that abnormal immune activation will produce autoantibodies and release cytokines, and abnormal immune cell recruitment will promote inflammatory environment and vascular remodeling. Therefore, almost all forms of connective tissue diseases are related to PAH. In addition to general therapy and targeted drug therapy for PAH, high-dose glucocorticoid combined with immunosuppressant can quickly alleviate and stabilize the basic CTD-PAH disease. Given this, the development of therapeutic approaches targeting immune dysregulation and heightened inflammation is recognized as a promising strategy to prevent or reverse the progression of CTD-PAH. This review explores the potential mechanisms by which immune cells contribute to the development of CTD-PAH and examines the clinical application of immunosuppressive therapies in managing CTD-PAH.

Clinical Course of Interstitial Lung Disease in Patients With Rheumatoid Arthritis

Interstitial lung disease (ILD) is a frequent manifestation of rheumatoid arthritis (RA) that is associated with high mortality. RA-ILD may initially be asymptomatic, and lung function may be markedly impaired by the time it is diagnosed. The course of RA-ILD is highly variable, with some patients experiencing no discernable progression or a slow decline, whereas others experience more rapid deterioration. Some patients develop progressive pulmonary fibrosis, which is associated with high mortality. Although risk factors for the progression of RA-ILD have been identified, including older age, worse lung function, and a usual interstitial pneumonia pattern on high-resolution computed tomography, it is not possible to predict the course of RA-ILD in an individual patient. The association between RA disease activity and progression of RA-ILD remains unclear. Regular monitoring is important to enable the prompt identification of progression and early intervention to preserve lung function. The management of RA-ILD requires a multidisciplinary and individualized approach, taking account of the severity and progression of articular and lung disease, risk factors for the progression of RA-ILD, and the patient's preferences, and may include immunosuppression, antifibrotic therapy, and supportive care.

Serum KL-6 and the mortality of patients with connective tissue disease-associated interstitial lung disease: A meta-analysis

Connective tissue disease-associated interstitial lung disease (CTD-ILD) is an important underlying cause of morbidity and mortality in patients with CTD. Serum Krebs von den Lungen-6 (KL-6) is an immune factor which has been related to the severity of ILD. This systematic review and meta-analysis aimed to evaluate the association between serum KL-6 and mortality of patients with CTD-ILD. Longitudinal studies relevant to the aim of the meta-analysis were retrieved by search of electronic databases including PubMed, Web of Science, and Embase. A random-effects model was used to combine the data by incorporating the influence of between-study heterogeneity. Fifteen cohorts involving 1737 patients with CTD-ILD were included. During a mean follow-up of 35.3 months, 430 (24.8%) patients died. Compared to those with a lower KL-6 at admission, patients with a higher KL-6 were associated with a higher mortality risk during follow-up (risk ratio: 2.18, 95% confidence interval: 1.66 to 2.87, P < 0.001; I2 = 20%). Subgroup analysis showed a significant association in studies from Asian countries, but not in those from non-Asian countries; in studies with cutoff of KL-6 derived in receiver operating characteristic (ROC) curve analysis, but not in those derived from other methods; in studies with multivariate analysis, but not in those with univariate analysis (P for subgroup difference all < 0.05). The association was not significantly affected by different CTDs or methods for measuring serum KL-6. In conclusion, a high serum KL-6 may be a risk factor of increased mortality in patients with CTD-ILD.

Epidemiological Insights into Autoimmune Bullous Diseases in China: A Comprehensive Analysis

OBJECTIVE

This study aims to conduct an extensive analysis of autoimmune bullous diseases, particularly pemphigus vulgaris and bullous pemphigoid, in Shanghai, China, from 2016 to 2023. It seeks to understand the demographic profiles, comorbidities, mortality rates, risk factors, and socioeconomic impacts associated with autoimmune bullous disease.

METHODS

A cross-sectional study design was employed, enrolling 1,072 patients. Diagnostic measures included clinical manifestations, histopathology, direct immunofluorescence, and serologic tests. The study also involved a detailed socioeconomic analysis and evaluation of occupational risks.

RESULTS

The findings highlight a significant occupational risk in industries requiring enhanced safety measures, with a notable prevalence of autoimmune bullous disease among workers in these sectors. A considerable portion of the patients were from low-income backgrounds with limited literacy, indicating the economic burden of autoimmune bullous disease. A key discovery of the study is the potential pathological link between autoimmune bullous disease and interstitial lung disease.

CONCLUSION

This research, one of the first comprehensive studies on autoimmune bullous disease in China, underscores the need for targeted healthcare strategies and further investigation into autoimmune bullous disease, particularly its relationship with interstitial lung disease.

French protocol for the diagnosis and management of systemic lupus erythematosus

Because Systemic Lupus Erythematosus (SLE) is a rare disease, and due to the significant prognostic impact of early management, a diagnosis confirmed by a physician with experience in SLE is recommended, for example from an expert center. Once the diagnosis is confirmed, existing manifestations should be identified in particular, renal involvement by an assessment of proteinuria, disease activity and severity should be determined, potential complications anticipated, associated diseases searched for, and the patient's socioprofessional and family context noted. Therapeutic management of SLE includes patient education on recognizing symptoms, understanding disease progression as well as when they should seek medical advice. Patients are informed about routine checkups, treatment side effects, and the need for regular vaccinations, especially if they are receiving immunosuppressive treatment. They are also advised on lifestyle factors such as the risks of smoking, sun exposure, and dietary adjustments, especially when they are receiving corticosteroids. The importance of contraception, particularly when teratogenic medications are being used, and regular cancer screening are emphasized. Support networks can help relieve a patient's isolation. The first-line medical treatment of SLE is hydroxychloroquine (HCQ), possibly combined with an immunosuppressant and/or low-dose corticosteroid therapy. The treatment of flares depends on their severity, and typically involves HCQ and NSAIDs, but may be escalated to corticosteroid therapy with immunosuppressants or biologic therapies in moderate to severe cases. Because there is no curative treatment, the goals of therapy are patient comfort, preventing progression and flares, and preserving overall long-term health and fertility. The frequency of follow-up visits depends on disease severity and any new symptoms. Regular specialized assessments are necessary, especially when treatment changes, but a frequency of every 3 to 6 months is recommended during periods of remission and monthly during active or severe disease, especially in children. These assessments include both clinical and laboratory tests to monitor complications and disease activity, with specific attention to proteinuria.

The clinical value of KL-6 for predicting the occurrence and severity of connective tissue disease-associated interstitial lung disease is not affected by CTD type or treatment

Objective

The aim of this study was to explore the potential values of Krebs von den Lungen-6 (KL-6), neutrophil to lymphocyte ratio (NLR), systemic immune inflammation (SII), platelet to lymphocyte ratio (PLR), monocyte to lymphocyte ratio (MLR) and red blood cell distribution width (RDW) in the diagnosis and evaluation of the severity of connective tissue disease-associated interstitial lung disease (CTD-ILD).

Methods

A total of 140 connective tissue disease (CTD) patients and 85 CTD-ILD patients were recruited for this study at Shanxi Provincial People's Hospital from May 2022 to May 2023. Patients were divided into subgroups based on medication history and CTD subtypes to compare and analyze the clinical data and laboratory parameters of CTD-ILD patients and CTD patients. The receiver operating characteristic curve (ROC) was used to evaluate the diagnostic efficacy of KL-6, NLR, SII, PLR, MLR, and RDW in identifying CTD-ILD patients from CTD patients. A Spearman correlation analysis was conducted to elucidate the correlations between these markers and the lung function parameters of forced vital capacity (FVC, %), forced expired volume in one second (FEV1, %), and diffusing capacity of carbon monoxide (DLCO, %). Finally, binary logistic regression analysis was applied to discern the independent risk factors for CTD-ILD.

Results

NLR, SII, MLR, RDW, and KL-6 displayed significant statistical differences in the experimental groups. In both untreated and treated subgroups, KL-6 displayed higher values for CTD-ILD than CTD among all CTD subtypes. In untreated subgroups, there were significant differences in MLR levels between rheumatoid arthritis (RA) and RA-ILD patients and in NLR levels between Sjögren syndrome (SjS) and SjS-ILD patients. There were also significant differences in RDW-SD between the "other CTD" and "other CTD-ILD" groups. In treated subgroups, there were significant differences in both RDW-SD and RDW-CV between RA and RA-ILD patients and in NLR, SII, MLR, PLR, and RDW-SD between "other CTD" and "other CTD-ILD" groups. ROC revealed that KL-6 emerged as the most effective predictor for CTD-ILD in both treated and untreated groups. The multivariate logistic regression analysis results showed that both KL-6 and age were independent risk factors for CTD-ILD. NLR, SII, and PLR were negatively correlated with DLCO (%) in the untreated CTD-ILD group, and KL-6 was negatively correlated with various lung function parameters in both treated and untreated CTD-ILD groups.

Conclusion

KL-6 emerged as the most promising biomarker for diagnosing CTD-ILD and assessing its severity. The diagnostic value of KL-6 was unaffected by medication interference and surpassed the value of other parameters, such as NLR, SII, MLR, and RDW. The diagnostic value of RDW-SD was higher than that of RDW-CV in CTD-ILD patients. NLR, SII, MLR, and PLR have potential value in diagnosing the different types of CTD-ILD.

Chronic interstitial lung disease associated with systemic lupus erythematosus: A multicentric study of 89 cases

BACKGROUND AND OBJECTIVE

Chronic interstitial lung disease (ILD) occurs rarely with systemic lupus erythematosus (SLE) as compared with other connective tissue diseases. This multicentric retrospective study of patients with SLE-ILD from the OrphaLung and French SLE networks during 2005-2020 aimed to describe the characteristics of patients with SLE-ILD and analyse factors associated with prognosis.

METHODS

We analysed data for 89 patients with SLE-ILD (82 women, 92.1%) (median age at SLE diagnosis: 35 years [interquartile range 27-47]). All patients met the 2019 EULAR/ACR criteria for the diagnosis of SLE.

RESULTS

Forty two (47.2%) patients were positive for anti-ribonuclear protein antibodies and 45 (50.6%) for anti SSA/Ro antibodies. A total of 58 (65.2%) patients had another connective tissue disease: Sjögren's syndrome (n = 33, 37.1%), systemic sclerosis (n = 14, 15.7%), inflammatory myopathy (n = 6, 6.7%), or rheumatoid arthritis (n = 6, 6.7%). ILD was diagnosed along with SLE in 25 (28.1%) patients and at a median of 6 (0-14) years after the SLE diagnosis. The most frequent CT pattern was suggestive of non-specific interstitial pneumonia (n = 41, 46.0%) with or without superimposed organizing pneumonia. After a median follow-up of 86.5 [39.5-161.2] months, 18 (20.2%) patients had died and 6 (6.7%) underwent lung transplantation. The median 5-year and 10-year transplantation-free survival were 96% (92-100) and 87% (78-97). In total, 44 (49.4%) patients showed ILD progression. Cutaneous manifestations and Raynaud's phenomenon were associated with better survival. Only forced vital capacity was significantly associated with survival and ILD progression.

CONCLUSION

ILD is a rare manifestation of SLE with good overall prognosis but with possible risk of ILD progression. Patients with SLE-ILD frequently have another connective tissue disease.

Interdisciplinary Diagnosis and Management of Patients With Interstitial Lung Disease and Connective Tissue Disease

A diagnosis of interstitial lung diseases (ILD) can be challenging, and the identification of an associated connective tissue disease (CTD) is crucial to estimate prognosis and to establish the optimal treatment approach. Diagnostic delay, limited expertise, and fragmented care are barriers that impede the delivery of comprehensive health care for patients with rare, complex, and multiorgan diseases such as CTD and ILD. In this article, we present our perspective on the interdisciplinary diagnosis and interprofessional treatment of patients with ILD and suspected CTD or CTD at risk of ILD. We outline the structure of our service, delineating the roles and responsibilities of the team members. Additionally, we provide an overview of our patient population, including diagnostic approaches and specific treatments, and illustrate a patient case. Furthermore, we focus on specific benefits and challenges of joint interdisciplinary and interprofessional patient consultations. The importance of rheumatology and pulmonology assessments in specific patient populations is emphasized. Finally, we explore future directions and discuss potential strategies to improve care delivery for patients with CTD-associated ILD.

Systemic lupus erythematosus: Adding another piece to the connective tissue disease-associated interstitial lung disease puzzle

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Immune mechanisms in fibrotic interstitial lung disease

Fibrotic interstitial lung diseases (fILDs) have poor survival rates and lack effective therapies. Despite evidence for immune mechanisms in lung fibrosis, immunotherapies have been unsuccessful for major types of fILD. Here, we review immunological mechanisms in lung fibrosis that have the potential to impact clinical practice. We first examine innate immunity, which is broadly involved across fILD subtypes. We illustrate how innate immunity in fILD involves a complex interplay of multiple cell subpopulations and molecular pathways. We then review the growing evidence for adaptive immunity in lung fibrosis to provoke a re-examination of its role in clinical fILD. We close with future directions to address key knowledge gaps in fILD pathobiology: (1) longitudinal studies emphasizing early-stage clinical disease, (2) immune mechanisms of acute exacerbations, and (3) next-generation immunophenotyping integrating spatial, genetic, and single-cell approaches. Advances in these areas are essential for the future of precision medicine and immunotherapy in fILD.

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.

The interplay between rheumatic diseases and pulmonary health

Patients with rheumatic diseases (RDs) are prone to a number of comorbidities, particularly those affecting the respiratory system due to inflammatory and autoimmune mechanisms. Rheumatoid arthritis (RA), systemic sclerosis (SSc), and inflammatory idiopathic myopathies (IIMs) often present with progressive interstitial lung disease (ILD). The prevalence of ILD varies among patients with RDs, with 11% in RA, 47% in SSc, and 41% in IIMs. Some diagnostic markers, including KL-6, cytokines TNF-α and IL-6, and autoantibodies (anti-CCP), play a crucial role in assessing and predicting the course of pulmonary involvement in RDs. Lung fibrosis is a progressive disorder in SSc and RA, limiting the effiency of therapeutic interventions. Re-evaluating treatment approaches with disease-modifying anti-rheumatic drugs (DMARDs) is crucial for understanding their impact on the risk of lung affections. Despite initial concerns surrounding methotrexate, recent evidence points to its benefits in RA-associated interstitial lung disease (RA-ILD). Recognizing the intricate relationship between autoimmune RDs and lung affections is crucial for formulating effective treatment strategies. Emphasis is placed on collaborative efforts of rheumatologists and pulmonologists for early diagnosis, comprehensive care, and optimal patient outcomes in RA-ILD.

Characterization of the immune suppressive functions of eosinophils

Eosinophils account for a significant portion of immune cells in the body. It is well known that eosinophils play a role in the pathogenesis of many diseases. In which the interaction between eosinophils and other immune cells is incompletely understood. The aim of this study is to characterize the immune suppressive functions of eosinophils. In this study, an irway allergy mouse model was established. Eosinophils were isolated from the airway tissues using flow cytometry cell sorting. The RAW264.7 cell line was used to test the immune suppressive functions of eosinophils. We observed that eosinophils had immune suppressive functions manifesting inhibiting immune cell proliferation and cytokine release from other immune cells. The eosinophil's immune suppressive functions were mediated by eosinophil-derived molecules, such as eosinophil peroxidase (EPX) and major basic protein (MBP). The expression of Ras-like protein in the brain 27a (Rab27a) was detected in eosinophils, which controlled the release of MBP and EPX by eosinophils. Eosinophil mediators had two contrast effects on inducing inflammatory responses or rendering immune suppressive effects, depending on the released amounts. Administration of an inhibitor of Rab27a at proper dosage could alleviate experimental airway allergy. To sum up, eosinophils have immune suppressive functions and are also inflammation inducers. Rab27a governs the release of EPX and MBP from eosinophils, which leads to immune suppression or inflammation. Modulation of Rab27a can alleviate airway allergy responses by modulating eosinophil's immune suppressive functions, which has the translational potential for the management of eosinophil-related diseases.

Real-World Clinical Profile and Safety of Nintedanib in Systemic Sclerosis-Associated Interstitial Lung Disease: A Subgroup Analysis of Interstitial Lung Disease Data From an Interstitial Lung Disease (ILD) Specialty Clinic in India

INTRODUCTION

 Systemic sclerosis (SSc) is a multisystem autoimmune disorder characterized by dysregulated innate and adaptive immunity. Interstitial lung disease (ILD) is a common and serious complication of SSc, often leading to significant morbidity and mortality. Consistent demographic characteristics that aid in the early diagnosis of ILD in SSc are lacking. This study aims to identify clinical and demographic parameters associated with ILD in SSc patients and assess the safety and tolerability of nintedanib with other immunosuppressants.

MATERIALS AND METHODS

This study is a subgroup analysis of data from the ILD clinic at All India Institute of Medical Sciences Raipur, collected between January 2022 and January 2024. We assessed the clinical and demographic profiles, high-resolution computed tomography thorax patterns, autoantibody profiles, lung function, and treatments used in the patients.

RESULTS

We enrolled 57 patients with SSc-associated ILD. The mean age of the participants was 39.0 ± 11.1 years, with 53 (92.9%) being women. The mean body mass index was 20.4 ± 4.32 kg/m². Dyspnea was the most common symptom, followed by skin tightening and cough. Antinuclear antibody tests were positive in 92.9% of patients, and anti-Scl-70 antibodies were positive in 57.9%. Rheumatoid arthritis-SSc overlap was observed in 15.8% of patients. The mean predicted forced vital capacity was 46.5 ± 19.9%, the mean predicted total lung capacity was 64.5 ± 20.4%, and the mean predicted diffusing capacity for carbon monoxide was 46.2 ± 15.7%. The mean six-minute walk distance was 360.3 ± 81.2 meters, and the mean King's Brief Interstitial Lung Disease score was 63.9 ± 10.7. Common radiological abnormalities included ground-glass opacities in 57.8%, traction bronchiectasis in 43.8%, and honeycombing in 28.07%. The predominant ILD pattern was nonspecific interstitial pneumonia. Patients received a combination of prednisolone (5 mg/day) with mycophenolate mofetil (63.2%), hydroxychloroquine (17.5%), cyclophosphamide (12.3%), and methotrexate (7.02%). Nintedanib, the only antifibrotic used, was administered to 17 (29.8%) patients.

CONCLUSIONS

ILD is relatively common in SSc, particularly in patients with diffuse cutaneous SSc and those with anti-topoisomerase antibodies. Female patients comprised the predominant population in this study. Patients tolerated mycophenolate mofetil and cyclophosphamide well. Nintedanib was the only antifibrotic used, and all patients tolerated the combination of antifibrotics and immunosuppressants well. Early diagnosis is crucial to slow disease progression and preserve lung function. Our results highlight the need for vigilant screening in high-risk groups and suggest that MMF, cyclophosphamide, and nintedanib can be safely incorporated into treatment regimens, offering a potential strategy to improve patient outcomes.

Novel Therapeutic Approaches in Connective Tissue Disease-Associated Interstitial Lung Disease

Connective tissue diseases (CTD) comprise a group of autoimmune diseases that can affect multiple organs in the body including the lungs. The most common form of pulmonary involvement is interstitial lung disease (ILD). CTD-associated ILD (CTD-ILD) can take one of several courses including nonprogressive, chronically progressive, or rapidly progressive. Chronically and rapidly progressive patterns are associated with increased mortality. Limited randomized controlled trial data are available for treatment of CTD-ILD, with most data coming from systemic sclerosis-related ILD. The current first-line treatment for all CTD-ILD is immunosuppression with consideration of antifibrotics, stem cell transplant, and lung transplant in progressive disease. In this article, we review data for ILD treatment options in systemic sclerosis, rheumatoid arthritis, myositis, and primary Sjögren's syndrome-related ILDs.

Untreated Obstructive Sleep Apnea in Interstitial Lung Disease and Impact on Interstitial Lung Disease Outcomes

Subjects with interstitial lung disease (ILD) often suffer from nocturnal cough, insomnia, and poor sleep quality. Subjects with ILD and obstructive sleep apnea (OSA) seem to have relatively mild symptoms from sleep fragmentation compared to subjects with only ILD. The overlap of ILD, OSA, and sleeping hypoxemia may be associated with poor outcome, even though there is no agreement on which sleep parameter is mostly associated with worsening ILD prognosis. Randomized controlled trials are needed to understand when positive airway pressure (PAP) treatment is required in subjects with ILD and OSA and the impact of PAP treatment on ILD progression.

Approach to interstitial lung disease associated with systemic sclerosis-A survey to pulmonologists and rheumatologists in Colombia

INTRODUCTION

Interstitial lung disease is a leading cause of mortality in patients with systemic sclerosis. Currently, there is a lack of consensus regarding screening, rescreening, diagnosis, and follow-up practices in interstitial lung disease associated with systemic sclerosis (SSc-ILD) in Colombia.

METHODS

A structured survey focused on clinical practices in patients with SSc-ILD was conducted. Members of the Asociación Colombiana de Neumología y Cirugía de Tórax (Asoneumocito) and the Asociación Colombiana de Reumatología (Asoreuma) were invited to participate from March 2023 to May 2023.

RESULTS

We surveyed 51 pulmonologists and 44 rheumatologists. Overall, 51.6% reported having access to multidisciplinary team discussion in ILD. Among the 95 participants, 78.9% would routinely perform a high-resolution computed tomography scan of the chest once a diagnosis of systemic sclerosis was established. This practice is more frequent among rheumatologists (84.1%) than among pulmonologists (74.5%). Approximately half of the participants would rescreen patients annually with computed tomography scan (56.8%) if baseline images were negative. Spirometry (81.1%), diffusing capacity of the lung for carbon monoxide (80.0%), and 6-min walk test (55.8%) were the most frequently performed tests upon diagnosis of systemic sclerosis. During follow-up, participants would consider repeating pulmonary function tests mostly every 6 months.

CONCLUSIONS

Screening of SSc-ILD is high among pulmonologists and rheumatologists. Decision-making on diagnosis and follow-up is similar between specialties, but there are variations in their frequency and indications. Further research is needed to evaluate how to adapt recommendations for assessing SSc-ILD in different settings.

Clinical features and risk factors of primary Sjögren's syndrome complicated with severe pneumonia: a case-control study

OBJECTIVES

To analyze clinical characteristics, risk factors, pathogen distribution, and prognostic markers in primary Sjögren's syndrome (pSS) patients with severe pneumonia (SP) compared to those without severe pneumonia (NSP).

METHODS

This case-control study included 24 hospitalized pSS patients with SP and 96 NSP at the first affiliated hospital of Soochow university from June 2014 to May 2023. Data encompassing demographics, comorbidities, treatments, and laboratory results were retrospectively collected. Univariate and multivariate regression analyses, ROC curves, and statistical analyses using SPSS 23.0 assessed risk factors. The study retrospectively analyzed clinical features and risk factors, highlighting distinct parameters between pSS patients with and without SP.

RESULTS

Marked differences were observed in several parameters: pSS activity(P < 0.001), white blood cell (P = 0.043), lymphocyte (P < 0.001), neutrophils (P = 0.042), C-reactive protein (P = 0.042), and CD8+ T cell (P = 0.017). Notably, lymphocyte count and SS activity demonstrated robust discrimination ability (AUC > 0.85). C-reactive protein (CRP), procalcitonin, CD4+ T cell, and IgA showed significant associations with SP; higher CRP levels correlated with increased risk, while lower CD4+ T cell and IgA levels associated with increased risk. SS activity significantly impacted outcomes. Various biomarkers exhibited diverse discriminatory abilities but lacked strong predictive associations with outcomes.

CONCLUSION

pSS patients with SP exhibited higher disease activity and altered immune profiles compared to those NSP. Lymphocyte count and SS activity emerged as robust discriminators. Higher CRP levels correlated with increased risk of SP, while lower CD4+T cell and IgA levels associated with increased risk. SS activity significantly impacted patient outcomes. Key Points • pSS patients with SP exhibited higher disease activity and altered immune profiles compared to those NSP. • Lymphocyte count and SS activity emerged as robust discriminators. • Higher CRP levels correlated with increased risk of SP, while lower CD4+ T cell and IgA levels associated with decreased risk. • SS activity significantly impacted patient outcomes.

Potential therapeutic targets of fibrosis in inflammatory rheumatic diseases

Fibrosis is commonly associated with chronic rheumatic diseases, and causes substantial morbidity and mortality. Treatment of fibrosis is extremely challenging but is badly needed, as approved antifibrotic therapies fibrosis do not halt its progression, which will be discussed with a focus on pulmonary fibrosis. Findings from recent studies indicate several therapeutic targets for treating fibrosis. Interleukin-11 is emerging as a fibrogenic cytokine whose activity can be blocked with neutralizing monoclonal antibodies. Fibroblast activation protein (FAP) is highly expressed by activated fibroblasts in inflammatory and fibrotic tissues. Targeting FAP with different modalities has been extensively explored as adjunct treatment for cancer, which can also apply to treating fibrosis in rheumatic diseases.

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

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

Progressive Pulmonary Fibrosis and Interstitial Lung Abnormalities: AJR Expert Panel Narrative Review

Progressive pulmonary fibrosis (PPF) and interstitial lung abnormalities (ILA) are relatively new concepts in interstitial lung disease (ILD) imaging and clinical management. Recognition of signs of PPF, as well as identification and classification of ILA, are important tasks during chest high-resolution CT interpretation, to optimize management of patients with ILD and those at risk of developing ILD. However, following professional society guidance, the role of imaging surveillance remains unclear in stable patients with ILD, asymptomatic patients with ILA who are at risk of progression, and asymptomatic patients at risk of developing ILD without imaging abnormalities. In this AJR Expert Panel Narrative Review, we summarize the current knowledge regarding PPF and ILA and describe the range of clinical practice with respect to imaging patients with ILD, those with ILA, and those at risk of developing ILD. In addition, we offer suggestions to help guide surveillance imaging in areas with an absence of published guidelines, where such decisions are currently driven primarily by local pulmonologists' preference.

The diagnosis and management of systemic autoimmune rheumatic disease-related interstitial lung disease: British Society for Rheumatology guideline scope

Interstitial lung disease (ILD) is a significant complication of many systemic autoimmune rheumatic diseases (SARDs), although the clinical presentation, severity and outlook may vary widely between individuals. Despite the prevalence, there are no specific guidelines addressing the issue of screening, diagnosis and management of ILD across this diverse group. Guidelines from the ACR and EULAR are expected, but there is a need for UK-specific guidelines that consider the framework of the UK National Health Service, local licensing and funding strategies. This article outlines the intended scope for the British Society for Rheumatology guideline on the diagnosis and management of SARD-ILD developed by the guideline working group. It specifically identifies the SARDs for consideration, alongside the overarching principles for which systematic review will be conducted. Expert consensus will be produced based on the most up-to-date available evidence for inclusion within the final guideline. Key issues to be addressed include recommendations for screening of ILD, identifying the methodology and frequency of monitoring and pharmacological and non-pharmacological management. The guideline will be developed according to methods and processes outlined in Creating Clinical Guidelines: British Society for Rheumatology Protocol version 5.1.

Lung adenocarcinoma discovered during the follow-up of lung-dominant connective tissue disease: a case report and literature review

Interstitial lung disease (ILD) can lead to lung cancer, which brings great challenges to differential diagnosis and comprehensive treatment. However, the clinical features of lung-dominant connective tissue disease (LD-CTD) related ILD combined with lung cancer has not been validated. We report the case of an 80-year-old woman with LD-CTD treated regularly with nintedanib who presented progressive dyspnoea and hypoxemia after recurrent viral infections. Her chest computed tomography (CT) showed aggravated interstitial fibrosis in both lower lungs with moderate right pleural effusion. Clinicians should be alert to lung cancer in patients who are experiencing poor responsiveness to treatment or acute progression of ILD. The available literatures about the differential diagnosis of clinical manifestations, imaging, treatment and prognosis of LD-CTD are reviewed and discussed in this study.

Systemic Sclerosis in Individuals With Exposure to World Trade Center Ground Zero Rescue and Recovery Efforts: A Case Series

OBJECTIVE

The World Trade Center (WTC) attack in New York resulted in a dust plume containing silica, hydrocarbons, and asbestos. Autoimmune disorders have been reported among those with WTC site exposure. The characteristics of individuals developing systemic sclerosis (SSc) have not been previously described. The purpose of this study was to describe the features of patients with SSc with WTC exposure.

METHODS

Data were collected from 11 patients with SSc or SSc spectrum conditions who reported exposure to the WTC site. Seven patients completed an exposure assessment.

RESULTS

Of the 11 patients, the majority (n = 8) were female. The median (range) for age at diagnosis was 46 (36-75) years, time between exposure and first non-Raynaud phenomenon SSc symptom was 8 (1-19) years, and time between exposure and diagnosis was 11 (2-18) years. Fifty-five percent had SSc onset > 5 years from WTC exposure. Five patients had limited cutaneous SSc, 3 patients had diffuse cutaneous SSc, 1 patient with SSc features met criteria for mixed connective tissue disease (CTD), and 2 patients had undifferentiated CTD with features of SSc. Four patients had overlapping features with other CTDs. Interstitial lung disease (ILD) was present in 10 patients. Five of 11 patients had a history of tobacco use. Seven of 7 patients who completed the questionnaire reported other hazardous exposures outside of WTC. Of these, only 2 patients reported personal protective equipment use.

CONCLUSION

A high frequency of ILD and overlap features were observed among patients with SSc with WTC exposure. Future studies are needed to characterize this association.

Screening, diagnosis, and monitoring of interstitial lung disease in autoimmune rheumatic diseases: A narrative review

Interstitial lung disease (ILD) is a common and serious manifestation of autoimmune rheumatic diseases. While the prevalence of ILD differs among the individual autoimmune rheumatic diseases, ILD remains an important cause of morbidity and mortality in systemic sclerosis, systemic lupus erythematosus, mixed connective tissue disease, primary Sjögren's disease, rheumatoid arthritis, and idiopathic inflammatory myositis. The present review summarizes recent literature on autoimmune-associated ILD with a focus on screening and monitoring for ILD progression. Reflecting on the currently available evidence, the authors propose a guideline for monitoring for progression in patients with newly diagnosed autoimmune-associated ILD. This review also highlights clinical and biological predictors of progressive pulmonary fibrosis and describes opportunity for further study in the rapidly evolving area of rheumatology and pulmonology.

Interstitial Pneumonia with Autoimmune Features: Aiming to Define, Refine, and Treat

Interstitial pneumonia with autoimmune features (IPAF) was defined for research purposes as interstitial lung disease (ILD) associated with features of autoimmunity without diagnosed rheumatic disease. Since publication of the IPAF criteria in 2015, there have been multiple studies of IPAF. However, much remains unknown regarding pathogenesis, prognosis, and treatment in IPAF. This narrative review details the history and classification of IPAF, lists challenges associated with classifying patients as IPAF, and explores the prevalence, epidemiology and presentation of IPAF. We also examine prognosis and important features determining IPAF clinical course, outline pathogenesis, and review treatment strategies.

Respiratory involvement in connective tissue diseases

Pulmonary involvement is doubtless one the most fatal organ manifestations of the autoimmune rheumatic diseases (ARD) and involves the parenchyma, the vessels, the respiratory system itself, but also the muscles and the pleura. Close and regular screening assessments, identification of risk factors, clinical signs associated with the existence of lung disease should alarm the involved physicians treating these patients. The accurate classification is essential, as different treatment options are nowadays available. Pulmonary manifestations of ARD will be analyzed in this review article with special emphasis on interstitial lung disease and pulmonary hypertension.

Lung regeneration: diverse cell types and the therapeutic potential

Lung tissue has a certain regenerative ability and triggers repair procedures after injury. Under controllable conditions, lung tissue can restore normal structure and function. Disruptions in this process can lead to respiratory system failure and even death, causing substantial medical burden. The main types of respiratory diseases are chronic obstructive pulmonary disease (COPD), idiopathic pulmonary fibrosis (IPF), and acute respiratory distress syndrome (ARDS). Multiple cells, such as lung epithelial cells, endothelial cells, fibroblasts, and immune cells, are involved in regulating the repair process after lung injury. Although the mechanism that regulates the process of lung repair has not been fully elucidated, clinical trials targeting different cells and signaling pathways have achieved some therapeutic effects in different respiratory diseases. In this review, we provide an overview of the cell type involved in the process of lung regeneration and repair, research models, and summarize molecular mechanisms involved in the regulation of lung regeneration and fibrosis. Moreover, we discuss the current clinical trials of stem cell therapy and pharmacological strategies for COPD, IPF, and ARDS treatment. This review provides a reference for further research on the molecular and cellular mechanisms of lung regeneration, drug development, and clinical trials.

Clinical effect of progressive pulmonary fibrosis on patients with connective tissue disease-associated interstitial lung disease: a single center retrospective cohort study

The concept of progressive pulmonary fibrosis (PPF) has been introduced to predict the diverse prognosis of interstitial lung disease (ILD). However, the incidence and effect of PPF on outcomes in patients with connective tissue disease-associated interstitial lung disease (CTD-ILD) need to be elucidated. This study reviewed 197 patients with CTD-ILD. Symptomatic worsening, pulmonary function decline, and radiological deterioration were investigated to assess the fulfillment of PPF diagnostic criteria. Clinical outcomes, including mortality, were compared based on the presence or absence of PPF. The median follow-up duration was 17.4 months. The mean age of the patients was 64.0 years, and 60.9% were female. Among the underlying CTDs, rheumatoid arthritis (42.1%), inflammatory myositis (19.8%), and systemic sclerosis (13.2%) were the most common. Of the 197 patients, 37 (18.8%) met the diagnostic criteria for PPF during the follow-up period. Even after adjusting for other significant risk factors, PPF was independently associated with mortality [hazard ratio (HR) 3.856; 95% confidence interval (CI) 1.387-10.715; P = 0.010] and baseline albumin was marginally significantly associated with mortality (HR 0.549; CI 0.298-1.010; P = 0.054). The median survival was also significantly shorter in the PPF group than in the non-PPF group (72.3 ± 12.9 vs. 126.8 ± 15.5 months, P < 0.001). Baseline KL-6 ≥ 1000 (U/mL) was a significant risk factor for PPF (HR 2.885; CI 1.165-7.144; P = 0.022). In addition to increased mortality, the PPF group had significantly higher rates of respiratory-related hospitalizations, pneumonia, acute exacerbations, and weight loss than the non-PPF group. PPF is a significant prognostic indicator in patients with CTD-ILD. Thus, healthcare professionals should know that patients with CTD-ILD are at risk of PPF.

Imaging Features of Autoimmune Disease-Related Interstitial Lung Diseases

Interstitial lung diseases (ILDs) associated with autoimmune diseases show characteristic signs of imaging. Radiologic signs are also used in the identification of ILDs with features suggestive of autoimmune disease that do not meet the criteria for a specific autoimmune disease. Radiologists play a key role in identifying these signs and assessing their relevance as part of multidisciplinary team discussions. A radiologist may be the first health care professional to pick up signs of autoimmune disease in a patient referred for assessment of ILD or with suspicion for ILD. Multidisciplinary team discussion of imaging findings observed during follow-up may inform a change in diagnosis or identify progression, with implications for a patient's treatment regimen. This article describes the imaging features of autoimmune disease-related ILDs and the role of radiologists in assessing their relevance.

Overlapping Autoimmune Diseases: A Case Report and Review of Eosinophilic Granulomatosis With Polyangiitis and Mixed Connective Tissue Disease

We describe a rare case of concurrent eosinophilic granulomatosis with polyangiitis and mixed connective tissue disease in a 27-year-old man who presented with pulmonary, renal, cardiac, and skin manifestations. We confirmed the diagnosis based on clinical, histopathological, and serological criteria. We treated the patient with corticosteroids, methotrexate, cyclophosphamide, and hydroxychloroquine, achieving early remission. The coexistence of both conditions in the same patient is extremely rare and has only been reported in a few cases worldwide. We also review the literature on these two rare autoimmune diseases' coexistence, pathogenesis, diagnosis, and management. Our case emphasizes recognizing overlapping autoimmune conditions in patients with complex clinical features and employing a comprehensive diagnostic approach and tailored treatment strategies. Further research is needed to understand these patients' epidemiology, prognosis, and optimal therapy. Early diagnosis and aggressive immunosuppression are crucial for achieving remission and preventing organ damage. We also identified the knowledge gaps and research needs in this field.