Radiological images of interstitial pneumonia in mixed connective tissue disease compared with scleroderma and polymyositis/dermatomyositis

Imaging of Pulmonary Manifestations of Connective Tissue Disease

The majority of connective tissue diseases (CTDs) are multisystem disorders that are often heterogeneous in their presentation and do not have a single laboratory, histologic, or radiologic feature that is defined as the gold standard to support a specific diagnosis. Given this challenging situation, the diagnosis of CTD is a process that requires the synthesis of multidisciplinary data which may include patient clinical symptoms, serologic evaluation, laboratory testing, and imaging. Pulmonary manifestations of connective tissue disease include interstitial lung disease as well as multicompartmental manifestations. These CT imaging patterns and features of specific diseases will be discussed in this article.

Expression and diagnostic value of interleukin-22 in rheumatoid arthritis-associated interstitial lung disease

Rheumatoid arthritis-associated interstitial lung disease (RA-ILD) is characterized by a high incidence and mortality rate, highlighting the need for biomarkers to detect ILD early in RA patients. Previous studies have shown the protective effects of Interleukin-22 (IL-22) in pulmonary fibrosis using mouse models. This study aims to assess IL-22 expression in RA-ILD to validate foundational experiments and explore its diagnostic value. The study included 66 newly diagnosed RA patients (33 with ILD, 33 without ILD) and 14 healthy controls (HC). ELISA was utilized to measure IL-22 levels and perform intergroup comparisons. The correlation between IL-22 levels and the severity of RA-ILD was examined. Logistic regression analysis was employed to screen potential predictive factors for RA-ILD risk and establish a predictive nomogram. The diagnostic value of IL-22 in RA-ILD was assessed using ROC. Subsequently, the data were subjected to 30-fold cross-validation. IL-22 levels in the RA-ILD group were lower than in the RA-No-ILD group and were inversely correlated with the severity of RA-ILD. Logistic regression analysis identified IL-22, age, smoking history, anti-mutated citrullinated vimentin antibody (MCV-Ab), and mean corpuscular hemoglobin concentration (MCHC) as independent factors for distinguishing between the groups. The diagnostic value of IL-22 in RA-ILD was moderate (AUC = 0.75) and improved when combined with age, smoking history, MCV-Ab and MCHC (AUC = 0.97). After 30-fold cross-validation, the average AUC was 0.886. IL-22 expression is dysregulated in the pathogenesis of RA-ILD. This study highlights the potential of IL-22, along with other factors, as a valuable biomarker for assessing RA-ILD occurrence and progression.

Connective tissue disease-associated lung disease in children

Connective tissue diseases are a heterogeneous group of autoimmune diseases that can affect a variety of organ systems. Lung parenchymal involvement is an important contributor to morbidity and mortality in children with connective tissue disease. Connective tissue disease-associated lung disease in children often manifests as one of several radiologic-pathologic patterns of disease, with certain patterns having a propensity to occur in association with certain connective tissue diseases. In this article, key clinical, histopathologic, and computed tomography (CT) features of typical patterns of connective tissue disease-associated lung disease in children are reviewed, with an emphasis on radiologic-pathologic correlation, to improve recognition of these patterns of lung disease at CT and to empower the pediatric radiologist to more fully contribute to the care of pediatric patients with these conditions.

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.

18F-FDG PET/CT and HRCT: a combined tool for risk stratification in idiopathic inflammatory myopathy-associated interstitial lung disease

OBJECTIVES

Rapidly progressive interstitial lung disease (RP-ILD) is a life-threatening form of idiopathic inflammatory myopathy (IIM)-associated interstitial lung disease (ILD). We aimed to assess the combination of ¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography-computed tomography (PET/CT) and high-resolution computed tomography (HRCT) for the quantification of IIM-ILD activity and risk stratification for RP-ILD.

METHOD

Patients with IIM and undergoing ¹⁸F-FDG PET/CT were included in this retrospective study. Pulmonary FDG uptake was assessed using the maximum standardized uptake value (SUV_lung) and visual score (PET score). HRCT was evaluated using visual analysis (HRCT score). Multivariable logistic regression was used to identify risk factors for RP-ILD.

RESULTS

Seventy-three patients with IIM (17 with RP-ILD, 38 with non-RP-ILD, and 18 without ILD) were included. SUV_lung, PET score, and HRCT score were significantly higher in RP-ILD than in non-RP-ILD. Strong positive correlations were observed between SUV_lung, PET score, and the HRCT parameters. The area under the curve (AUC) of the PET score to differentiate between RP-ILD and non-RP-ILD (AUC = 0.860) was higher than that of the SUV_lung (AUC = 0.802) and HRCT scores (AUC = 0.806). We developed a risk score based on the number of positive risk factors (PET score > 18, HRCT score > 140, and positive anti-melanoma differentiation-associated gene 5 (MDA5) antibody) to differentiate between RP-ILD and non-RP-ILD (AUC = 0.955). Patients with higher risk scores had significantly worse prognoses.

CONCLUSIONS

¹⁸F-FDG PET/CT is useful for assessing disease activity in patients with IIM-ILD. The combination of PET score, HRCT score, and anti-MDA5 antibody can be used to identify patients at increased risk of RP-ILD and with poor prognoses.

Interstitial Lung Disease in Polymyositis and Dermatomyositis

The idiopathic inflammatory myopathies (IIMs), including polymyositis (PM) and dermatomyositis (DM), are autoimmune connective tissue diseases with variable degrees of muscle inflammation and systemic involvement. Interstitial lung disease (ILD) is a common complication of the IIMs and is associated with increased mortality. Many patients with PM/DM have myositis-specific and myositis-associated antibodies (MSA/MAAs) that result in distinct clinical phenotypes. Among these MSAs, anti-aminoacyl-tRNA antibodies and anti-melanoma differentiation factor 5 antibodies have high rates of ILD. Corticosteroids are the mainstay of treatment, although the addition of other immunosuppressive therapy is typically necessary to achieve disease control.

Imaging of the Thoracic Manifestations of Connective Tissue Disease

Imaging, specifically computed tomography (CT), is a key component in the characterization, management, and follow-up of patients with connective tissue disease (CTD)-related diffuse lung disease. The main role of CT is to help direct treatment by determining the primary pattern of lung injury present. Other roles include follow-up of lung disease over time, evaluation of acute symptoms, and monitoring for treatment complications. Although diagnosis is typically made using clinical and serologic criteria, CT plays an important role when lung disease is the dominant presenting feature. This article delineates the roles of CT in patients with CTD-related lung disease.

Pulmonary Manifestations of Systemic Sclerosis and Mixed Connective Tissue Disease

Systemic sclerosis (SSc) is a rare disease characterized by widespread collagen deposition resulting in fibrosis. Although skin involvement is the most common manifestation and also the one that determines the classification of disease, mortality in SSc is usually a result of respiratory compromise in the form of interstitial lung disease (ILD) or pulmonary hypertension (PH). Clinically significant ILD is seen in up to 40% of patients and PH in up to 20%. Treatment with either cyclophosphamide or mycophenolate has been shown to delay disease progression, whereas rituximab and lung transplantation are reserved for refractory cases.