Marked increase in serum KL-6 and surfactant protein D levels during the first 4 weeks after treatment predicts poor prognosis in patients with active interstitial pneumonia associated with polymyositis/dermatomyositis

Identifying two pathways to poor prognosis in patients with anti-MDA5 antibodies: insights from prognostic factor and cytokines analysis

OBJECTIVE

To identify pathways linking cytokine abnormalities to mortality via prognostic factors in patients with anti-melanoma differentiation-associated protein 5 antibodies (anti-MDA5 Ab).

METHODS

This study included patients with anti-MDA5 Ab whose serum was available. Serum cytokine levels were measured using a multiplex bead assay. Prognostic factors were identified using Cox regression and log-rank test. Prognostic factor groups were identified using principal component analysis (PCA) and factor and cluster analyses. The association between cytokine levels and prognostic factors (groups) was examined using PCA and correlation and path analyses. A prognosis-prediction model was developed using prognostic factors from the different groups.

RESULTS

Thirty-five patients were included in this study, of whom 31 had rapidly progressive interstitial lung disease (RP-ILD), and 14 died. We identified white blood cell (WBC), gamma-glutamyl transpeptidase (γ-GTP), lactate dehydrogenase (LDH), C-reactive protein (CRP), ferritin, and ILD-related factors (Krebs von den Lungen-6 [KL-6], surfactant protein D [SP-D], and CT score) as prognostic factors, in addition to von Willebrand factor and thrombomodulin. Two prognostic factor groups were found: Group 1 included WBC, CRP, and ILD-related factors, and Group 2 included ferritin, LDH, and γ-GTP. Both groups contributed to mortality. Group 1 was associated with IL-6, and Group 2 was related to IL-6, IL-10, and IP-10, and indirectly with TNF-α. A model using CRP (Group1) and γ-GTP (Group2) achieved an area under the curve of 0.84, which was not inferior to previously reported models.

CONCLUSIONS

Two pathways leading to poor prognosis were identified in anti-MDA5-Ab-positive patients, each marked by specific cytokine abnormalities.

Pulmonary and serum cytokine profiles of patients with anti-ARS and anti-MDA5 antibodies

The present study aimed to determine the pulmonary cytokine profiles of patients with anti-RNA synthetase (ARS) and anti-melanoma differentiation-associated protein 5 (MDA5) antibodies. The study included patients with ARS and MDA5 whose serum or bronchoalveolar fluid (BALF) was available. Sandwich enzyme-linked immunoassay microarray multiplex assay was used to measure 18 cytokine levels in serum and BALF. The cytokine patterns were investigated using factor and cluster analyses. Pulmonary cytokine production was examined using the BALF/Seum cytokine ratio. Forty participants were enrolled in the study: 19 with ARS and 21 with MDA5. All patients had interstitial lung disease (ILD). BALF was collected from 10 patients with ARS and 6 with MDA5. Serum type 1 IFN, IP-10, MCP-1, and TNF-α were elevated in both ARS and MDA5. IL-6, IL-10, and IL-15 were elevated in MDA5. Serum cytokine patterns differed between ARS and MDA5. In BALF, IFN-α, IP-10, MCP-1, and ferritin were increased in both ARS and MDA5. Higher levels of IFN-α, IL-6, and ferritin were observed in MDA5. One patient with severe MDA5-ILD showed higher levels of multiple cytokines, including IL-6 and IFN-α. BALF cytokine patterns were similar in ARS and MDA5 cases except the one with severe MDA5-ILD. IL-6, IP-10, IL-15, MCP-1, and ferritin were produced in the lungs in ARS and MDA5 and IFN-α in MDA5. In conclusion, IFN-α and pulmonary macrophage activation play important roles in ILD development in both ARS and MDA5-ILD. MDA5-ILD could be characterized by higher production of multiple cytokines and macrophage activation, particularly in severe cases.

Serum KL-6 and SP-D: Markers of Lung Function in Autoimmune-Related Interstitial Lung Diseases

This study evaluates the usefulness of serum KL-6, SP-D and TGF-β1 levels in assessing lung impairment and predicting interstitial lung disease (ILD) short-term progression in patients with interstitial pneumonia with autoimmune features (IPAF). A total of 24 patients with IPAF, 21 with connective tissue disease-associated ILD (CTD-ILD) and 23 with CTD without ILD were followed for 1 year. Serum levels of KL-6, SP-D and TGF-β1 were measured and their associations with disease severity and progression were analysed. KL-6, SP-D and TGF-β1 levels were significantly higher in IPAF and CTD-ILD patients compared to CTD without ILD (p < 0.0001, p = 0.0005 and p = 0.0001, respectively). KL-6 (r = 0.45, p = 0.002) and SP-D (r = 0.35, p = 0.02) levels correlated with lung involvement in HRCT in the ILD group. In IPAF, KL-6 levels correlated with pulmonary function tests (FVC%, TLCO%, and 6MWD) and SpO2, while SP-D correlated with 6MWD and SpO2. In CTD-ILD, KL-6 and SP-D levels were positively correlated with BAL cell count (KL-6: r = 0.58, p = 0.04; SP-D: r = 0.63, and p = 0.02). KL-6 also showed a negative correlation with the time since symptom onset (r = -0.51, p = 0.02). No significant associations were found between the baseline biomarker levels and ILD progression risk. KL-6 and SP-D may serve as potential biomarkers for assessing lung impairment in IPAF, though their predictive value for short-term prognosis remains uncertain.

Clinically Relevant Biomarkers in Connective Tissue Disease-Associated Interstitial Lung Disease

Interstitial lung disease (ILD) complicates connective tissue disease (CTD) with variable incidence and is a leading cause of death in these patients. To improve CTD-ILD outcomes, early recognition and management of ILD is critical. Blood-based and radiologic biomarkers that assist in the diagnosis CTD-ILD have long been studied. Recent studies, including -omic investigations, have also begun to identify biomarkers that may help prognosticate such patients. This review provides an overview of clinically relevant biomarkers in patients with CTD-ILD, highlighting recent advances to assist in the diagnosis and prognostication of CTD-ILD.

Pretreatment mortality risk prediction model in patients with polymyositis/dermatomyositis-associated interstitial lung disease

OBJECTIVES

Risk prediction for patients with polymyositis/dermatomyositis-associated interstitial lung disease (PM/DM-ILD) is challenging due to heterogeneity in the disease course. We aimed to develop a mortality risk prediction model for PM/DM-ILD.

METHODS

This prognostic study analysed patients with PM/DM-ILD admitted to Nanjing Drum Hospital from 2016 to 2021. The primary outcome was mortality within 1 year. We used a least absolute shrinkage and selection operator (LASSO) logistic regression model to identify predictive laboratory indicators. These indicators were used to create a laboratory risk score, and we developed a mortality risk prediction model by incorporating clinical factors. The evaluation of model performance encompassed discrimination, calibration, clinical utility and practical application for risk prediction and prognosis.

RESULTS

Overall, 418 patients with PM/DM-ILD were enrolled and randomly divided into development (n=282) and validation (n=136) cohorts. LASSO logistic regression identified four optimal features in the development cohort, forming a laboratory risk score: C reactive protein, lactate dehydrogenase, CD3+CD4+ T cell counts and PO2/FiO2. The final prediction model integrated age, arthralgia, anti-melanoma differentiation-associated gene 5 antibody status, high-resolution CT pattern and the laboratory risk score. The prediction model exhibited robust discrimination (area under the receiver operating characteristic: 0.869, 95% CI 0.811 to 0.910), excellent calibration and valuable clinical utility. Patients were categorised into three risk groups with distinct mortality rates. The internal validation, sensitivity analyses and comparative assessments against previous models further confirmed the robustness of the prediction model.

CONCLUSIONS

We developed and validated an evidence-based mortality risk prediction model with simple, readily accessible clinical variables in patients with PM/DM-ILD, which may inform clinical decision-making.

Clinically Relevant Biomarkers in Connective Tissue Disease-Associated Interstitial Lung Disease

Interstitial lung disease (ILD) complicates connective tissue disease (CTD) with variable incidence and is a leading cause of death in these patients. To improve CTD-ILD outcomes, early recognition and management of ILD is critical. Blood-based and radiologic biomarkers that assist in the diagnosis CTD-ILD have long been studied. Recent studies, including -omic investigations, have also begun to identify biomarkers that may help prognosticate such patients. This review provides an overview of clinically relevant biomarkers in patients with CTD-ILD, highlighting recent advances to assist in the diagnosis and prognostication of CTD-ILD.

Roles of biomarkers in anti-MDA5-positive dermatomyositis, associated interstitial lung disease, and rapidly progressive interstitial lung disease

BACKGROUND

Anti-melanoma differentiation-associated gene 5 (MDA5)-positive dermatomyositis (MDA5⁺ DM) is significantly associated with interstitial lung disease (ILD), especially rapidly progressive ILD (RPILD) due to poor prognosis, resulting in high mortality rates. However, the pathogenic mechanism of MDA5⁺ DM-RPILD is unclear. Although some MDA5⁺ DM patients have a chronic course of ILD, many do not develop RPILD. Therefore, the related biomarkers for the early diagnosis, disease activity monitoring, and prediction of the outcome of RPILD in MDA5⁺ DM patients should be identified. Blood-based biomarkers are minimally invasive and can be easily detected.

METHODS

Recent relative studies related to blood biomarkers in PubMed were reviewed.

RESULTS

An increasing number of studies have demonstrated that dysregulated expression of blood biomarkers related to ILD such as ferritin, Krebs von den Lungen-6 (KL-6), surfactant protein-D (SP-D), and cytokines, and some tumor markers in MDA5⁺ DM may provide information in disease presence, activity, treatment response, and prognosis. These studies have highlighted the great potentials of blood biomarker values for MDA5⁺ DM-ILD and MDA5⁺ DM-RPILD. This review provides an overview of recent studies related to blood biomarkers, besides highlighted protein biomarkers, including antibody (anti-MDA5 IgG subclasses and anti-Ro52 antibody), genetic (exosomal microRNAs and neutrophil extracellular traps related to cell-free DNA), and immune cellular biomarkers in MDA5⁺ DM, MDA5⁺ DM-ILD, and MDA5⁺ DM-RPILD patients, hopefully elucidating the pathogenesis of MDA5⁺ DM-ILD and providing information on the early diagnosis, disease activity monitoring, and prediction of the outcome of the ILD, especially RPILD.

CONCLUSIONS

Therefore, this review may provide insight to guide treatment decisions for MDA5⁺ DM-RPILD patients and improve outcomes.

Role of serum surfactant protein-D as a prognostic predictor in fibrotic hypersensitivity pneumonitis

BACKGROUND

Serum Krebs von den Lungen-6 (KL-6) and surfactant protein-D (SP-D) are candidate diagnostic and activity markers for fibrotic hypersensitivity pneumonitis (HP), although their correlation with prognosis remains unclear. We aimed to evaluate the prognostic usefulness of serum KL-6 and SP-D in patients with fibrotic HP.

METHODS

This was a retrospective medical record review of 185 patients with fibrotic HP at a single center from 2005 to 2019. The baseline and minimum serum KL-6 and SP-D levels over two years were recorded. The contribution of KL-6 and SP-D levels to the incidence of progressive fibrosing interstitial lung disease (PF-ILD) and mortality were evaluated using multivariate analysis.

RESULTS

The respective baseline and minimum levels were 1441 and 808 U/ml for KL-6 and 254 and 132 ng/mL for SP-D. A high minimum SP-D level was significantly associated with a high incidence of PF-ILD by logistic regression, independent of baseline forced vital capacity and honeycombing. Similarly, a high minimum SP-D level was significantly associated with high mortality by Cox proportional hazard model analysis. The stratified minimum SP-D levels of <100, 100-200, and >200 revealed significantly distinct groups in the entire cohort, with PF-ILD incidence rates of 28%, 48%, and 74% and median survival times of 120, 74, and 45 months, respectively.

CONCLUSIONS

High minimum SP-D levels over two years were correlated with an unfavorable prognosis in our cohort. Patient with consistently high SP-D levels during the clinical course may have a poor prognosis and be a candidate for early treatment intensification.

The Prognostic Value of Krebs von den Lungen-6 and Surfactant Protein-A Levels in the Patients with Interstitial Lung Disease

Background and Objectives

The highly variable clinical course of interstitial lung disease (ILD) makes it difficult to predict patient prognosis. Serum surfactant protein-A (SP-A) and Krebs von den Lungen-6 (KL-6) are known prognostic biomarkers. However, the clinical or pathophysiological differences in patients with these biomarkers have not been well evaluated. We investigated the clinical and pathophysiological differences through the comparison of SP-A and KL-6 levels before and after treatment.

Methods

This study included retrospective data from 91 patients who were treated for ILD between August 2015 and September 2019. Serum SP-A and KL-6 levels were measured before and after treatment. The patients were followed up for 3 months.

Results

Changes in the serum biomarkers (Delta SP-A and Delta KL-6) were found to be significantly correlated (rs = 0.523, P < 0.001); Delta SP-A and Delta KL-6 were inversely correlated with changes in pulmonary function (% predicted values of diffusing capacity for carbon monoxide [DLCO], forced vital capacity [FVC], and forced expiratory volume in 1 s [FEV1]). Patients were divided into four groups based on their Delta SP-A and Delta KL-6 levels in a cluster analysis (G1, G2, G3, and G4). Both SP-A and KL-6 were elevated in the G1 group, with all the patients enrolled classified as progressive or unchanged, and 86.4% of patients showed improved disease activity in the G4 group, where both SP-A and KL-6 levels were reduced. In the G2 group, only SP-A levels decreased post-treatment, indicating an improvement in respiratory function; the patients were not at the end stage of the disease. Only the SP-A levels increased in the G3 group with immunosuppressive treatment.

Conclusions

Reduced serum SP-A and/or KL-6 levels are associated with improved lung function in patients with ILD. Some patients only showed a decrease in SP-A levels could prognosis an improvement in respiratory function. When only SP-A is increased, it may imply that the patients are at an early stage of disease progression. As a result, for proper disease monitoring, measuring both markers is important.

Bronchoalveolar lavage and lung biopsy in connective tissue diseases, to do or not to do?

Bronchoalveolar lavage and lung biopsy (LBx) are helpful in patients with connective tissue diseases (CTD) and interstitial lung diseases (ILD) regardless of cause, including infectious, noninfectious, immunologic, or malignant. The decision whether to perform only bronchoalveolar lavage (BAL), and eventually a subsequent LBx in case of a nondiagnostic lavage, or one single bronchoscopy combining both sampling methods depends on the clinical suspicion, on patient’s characteristics (e.g. increased biopsy risk) and preferences, and on the resources and biopsy techniques available locally (e.g. regular forceps versus cryobiopsy). In CTD-ILD, BAL has major clinical utility in excluding infections and in the diagnosis of specific patterns of acute lung damage (e.g. alveolar hemorrhage, diffuse alveolar damage, and organizing pneumonia). LBx is indicated to exclude neoplasm or diagnose lymphoproliferative lung disorders that in CTD patients are more common than in the general population. Defining BAL cellularity and characterizing the CTD-ILD histopathologic pattern by LBx can be helpful in the differential diagnosis of cases without established CTD [e.g. ILD preceding full-blown CTD, interstitial pneumonia with autoimmune features (IPAF)], but the prognostic and theragnostic role of those findings remains unclear. Few studies in the pretranscriptomics era have investigated the diagnostic and prognostic role of BAL and LBx in CTD-ILD, and it is reasonable to hypothesize that future studies conducted applying innovative techniques on BAL and LBx might open new and unexpected avenues in pathogenesis, diagnosis, and treatment approach to CTD-ILD. This is particularly desirable now that a new drug treatment era is emerging, in which we have more than one therapeutic choice (immunosuppressive agents, antifibrotic drugs, and biological agents). We hope that future research will pave the path toward precision medicine providing data for a more accurate ILD-CTD endotyping that will guide the physicians through targeted therapeutic choices, rather than to the approximative approach ‘one drug fits them all’.

Clinical Relevance of the Serial Measurement of Krebs von den Lungen-6 Levels in Patients with Systemic Sclerosis-Associated Interstitial Lung Disease

Krebs von den Lungen-6 (KL-6) levels measured at baseline have been reported as a circulating biomarker useful for the detection, evaluation of severity and assessment of risk of the progression of interstitial lung disease (ILD) in patients with systemic sclerosis (SSc). In this retrospective study, longitudinal changes in serum KL-6 levels over 2 years were examined in 110 patients with SSc using prospectively collected cohort data. Serum KL-6 levels fluctuated in a significant proportion of the patients but remained stable in the remaining patients. A wide range of variability of longitudinal KL-6 levels was associated with the presence of ILD, diffuse cutaneous SSc, positive anti-topoisomerase I antibodies, negative anticentromere antibodies, increased ILD extent on high-resolution computed tomography, extensive disease, low pulmonary function parameters, high KL-6 levels at baseline and immunomodulatory treatment. Extensive disease was consistently identified as an independent factor associated with variability in KL-6 levels in different models of multiple regression analysis. We failed to demonstrate correlations between trends for KL-6 level changes during the 6 months after SSc diagnosis and ILD progression over 2 years in patients with SSc-ILD. Serum KL-6 levels fluctuate in SSc patients with ILD, especially in those with extensive disease, but the clinical utility of a serial KL-6 level measurement remains uncertain.

2020 guide for the diagnosis and treatment of interstitial lung disease associated with connective tissue disease

The prognosis of patients with connective tissue disease (CTD) has improved significantly in recent years, but interstitial lung disease (ILD) associated with connective tissue disease (CTD-ILD) remains a refractory condition, which is a leading cause of mortality. Because it is an important prognostic factor, many observational and interventional studies have been conducted to date. However, CTD is a heterogeneous group of conditions, which makes the clinical course, treatment responses, and prognosis of CTD-ILD extremely diverse. To summarize the current understanding and unsolved questions, the Japanese Respiratory Society and the Japan College of Rheumatology collaborated to publish the world's first guide focusing on CTD-ILD, based on the evidence and expert consensus of pulmonologists and rheumatologists, along with radiologists, pathologists, and dermatologists. The task force members proposed a total of 27 items, including 7 for general topics, 9 for disease-specific topics, 3 for complications, 4 for pharmacologic treatments, and 4 for non-pharmacologic therapies, with teams of 2-4 authors and reviewers for each item to prepare a consensus statement based on a systematic literature review. Subsequently, public opinions were collected from members of both societies, and a critical review was conducted by external reviewers. Finally, the task force finalized the guide upon discussion and consensus generation. This guide is expected to contribute to the standardization of CTD-ILD medical care and is also useful as a tool for promoting future research by clarifying unresolved issues.

Serum Amphiregulin and Heparin-Binding Epidermal Growth Factor as Biomarkers in Patients with Idiopathic Inflammatory Myopathy

Background. The epidermal growth factors amphiregulin (AREG) and heparin-binding epidermal growth factor (HB-EGF) are implicated in the pathogenesis of several autoimmune diseases, but their clinical and pathological roles in idiopathic inflammatory myopathy (IIM) are unclear. Methods. Serum AREG and HB-EGF levels were measured by ELISA in patients with IIM (n = 37), systemic sclerosis (n = 17), and rheumatoid arthritis (n = 10), and for seven age- and sex-matched healthy controls (HCs). Associations between serum AREG or HB-EGF levels and the clinical parameters were analyzed. Results. Serum AREG levels in IIM patients were significantly elevated compared to those in HCs (median, 20.7 and 10.7 pg/mL, respectively; p = 0.025). In particular, serum AREG levels in IIM patients with interstitial lung disease (ILD) were higher than those of HCs (22.4 pg/mL, p = 0.027). The disease duration in patients with elevated serum AREG levels was significantly shorter compared to those who had normal serum AREG levels (7 and 21 months, respectively; p = 0.0012). Serum HB-EGF levels were significantly increased in IIM patients with elevated CK levels (136.2 pg/mL; p = 0.020) and patients with anti-Mi-2 antibody (183.7 pg/mL; p = 0.045) compared to those in HCs (74.9 pg/mL). Conclusion. These results suggested that AREG could be a promising biomarker associated with early-phase IIM-related ILD, and that HB-EGF expression was associated with muscle injury and regeneration in IIM.

Risk Prediction Modeling Based on a Combination of Initial Serum Biomarker Levels in Polymyositis/Dermatomyositis-Associated Interstitial Lung Disease

OBJECTIVE

To establish predictive models for mortality in patients with polymyositis/dermatomyositis-associated interstitial lung disease (PM/DM-ILD) using a combination of initial serum biomarker levels.

METHODS

The Multicenter Retrospective Cohort of Japanese Patients with Myositis-Associated ILD (JAMI) database of 497 incident cases of PM/DM-ILD was used as a derivation cohort, and 111 cases were additionally collected as a validation cohort. Risk factors predictive of all-cause mortality were identified by univariate and multivariable Cox regression analyses using candidate serum biomarkers as explanatory variables. The predictive models for mortality were generated in patients with and those without anti-melanoma differentiation-associated gene 5 (MDA-5) antibody, using a combination of risk factors. Cumulative survival rates were assessed using Kaplan-Meier analysis, and were compared between subgroups using the Breslow test.

RESULTS

In the derivation cohort, C-reactive protein (CRP) and Krebs von den Lungen 6 (KL-6) levels were identified as independent risk factors for mortality in both anti-MDA-5-positive and anti-MDA-5-negative patients. We then developed a prediction model based on anti-MDA-5 antibody status, CRP level, and KL-6 level, termed the "MCK model," to identify patients at low (<15%), moderate (15-50%), or high (≥50%) risk of mortality, based on the number of risk factors. The MCK model successfully differentiated cumulative survival rates in anti-MDA-5-positive patients (P < 0.01 for low versus moderate risk and P = 0.03 for moderate versus high risk) and in anti-MDA-5-negative patients (P < 0.001 for low versus moderate risk). The utility of the MCK model was replicated in the validation cohort.

CONCLUSION

Our findings indicate that an evidence-based risk prediction model using CRP and KL-6 levels combined with anti-MDA-5 antibody status might be useful for predicting prognosis in patients with PM/DM-ILD.

Initial predictors for short-term prognosis in anti-melanoma differentiation-associated protein-5 positive patients

Background

Anti-melanoma differentiation-associated protein-5 (anti-MDA5) positive patients are characterized by the high mortality rate caused by interstitial lung disease (ILD). We conducted a retrospective study to summarize the clinical features and identify the initial predictors for death in anti-MDA5 positive patients.

Methods

We designed a retrospective cohort of anti-MDA5 positive patients. The demographic and clinical data recorded on first admission, as well as the outcomes during the first six months follow-up, were collected. Predictors of rapidly progressive ILD (RPILD) and poor outcomes were calculated using logistic regression models and Cox proportional hazard regression models, respectively.

Results

A total of 90 anti-MDA5 positive patients were included in this study. Eighty-one (90%) patients presented ILD on admission and 35 (38.9%) patients developed RPILD subsequently. During the first six months of follow-up, 22 (24.4%) patients died of respiratory failure at an average time of 6.6 ± 5.9 weeks. Factors including disease duration < 2 months (OR 6.1, 95% CI 1.7–22.4, P = 0.007), serum ferritin ≥ 1500 ng/ml (OR 12.3, 95% CI 3.1–49.6, P < 0.001), CRP ≥ 13 mg/L (OR 4.6, 95% CI 1.3–16.9, P = 0.021) and total GGO score ≥ 4 (OR 6.3, 95% CI 1.8–21.9, P = 0.003), were identified as independent predictors for RPILD. Cox regression model showed that total CT GGO score ≥ 4 (HR 4.8, 95% CI 1.3–17.9, P = 0.020), KL-6 > 1600 U/ml (HR 3.7, 95% CI 1.5–9.1, P = 0.004) and CRP > 5.8 mg/L (HR 3.7, 95% CI 1.0–12.8, P = 0.044) were poor prognostic risk factors, however initial combined treatment (HR 0.3, 95% CI 0.1–0.8, P = 0.019) predicted good prognosis in anti-MDA5 positive patients.

Conclusion

Anti-MDA5 positive patients demonstrated a high prevalence of ILD on admission, leading to a high short-term mortality rate. Higher total GGO score, higher levels of initial KL-6 and CRP predict poor outcome in anti-MDA5 positive patients. However, initial intensive treatment may improve the prognosis.

Predictive Factors for Pneumomediastinum During Management of Connective Tissue Disease-related Interstitial Lung Disease: A Retrospective Study

Objective To identify factors associated with pneumomediastinum during management of connective tissue disease (CTD)-related interstitial lung disease (ILD). Methods Patients diagnosed with pneumomediastinum after the initiation of corticosteroid therapy for their CTD-ILD were enrolled. The baseline characteristics of patients who developed pneumomediastinum after the initiation of corticosteroid therapy (n=13, all occurring within 120 days) were compared to those of patients who did not develop pneumomediastinum (n=49). A multivariate logistic regression analysis was performed to identify factors associated with pneumomediastinum. A receiver operating characteristic (ROC) curve analysis was also performed to assess the predictive performance. Results The body mass index (BMI) [odds ratio (OR) (95% confidence interval (CI)) 0.482 (0.272-0.853)] and serum lactate dehydrogenase (LDH) [OR (95% CI) 1.013 (1-1.025)] levels at baseline were identified as independent factors associated with pneumomediastinum after corticosteroid initiation. The optimal cut-off points of the BMI and LDH levels for predicting pneumomediastinum development, as estimated by the Youden index, were 20.2 kg/m² and 378 U/L, respectively. LDH showed a sensitivity of 61.5% and the highest specificity of 87.8%. Importantly, combining these markers resulted in the highest sensitivity of 100% and a specificity of 71.4%. Conclusion A low BMI and high serum LDH levels at baseline are useful predictive factors for pneumomediastinum development in CTD-ILD patients.

Serum SP-A and KL-6 levels can predict the improvement and deterioration of patients with interstitial pneumonia with autoimmune features

BACKGROUND

Some patients with interstitial pneumonia with autoimmune features (IPAF) showed a progressive course despite therapy. This study aimed to evaluate whether serial changes in the serum levels of surfactant protein-A (SP-A) and Krebs von den Lungen-6 (KL-6) can predict disease progression.

METHODS

Sixty-four patients with IPAF and 41 patients with non-fibrotic lung disease (non-FLD) were examined. Based on long-term changes in lung function, 36 IPAF patients who were followed up for more than 3 months were divided into a progressive group (n = 9), an improvement group (n = 13), and a stable group (n = 14). Serum KL-6 and SP-A levels were measured. The sensitivity, specificity, cut-off value, and area under the curve (AUC) value for each of the indices were determined using receiver operating characteristic (ROC) curve analysis. The expression differences in these biomarkers and their correlation with disease severity were analyzed.

RESULTS

Compared with non-FLD patients, serum SP-A and KL-6 levels in IPAF patients were increased significantly [SP-A: (p < 0.001); KL-6: (p < 0.001)] and negatively correlated with DLCO (SP-A: r_S = - 0.323, p = 0.018; KL-6: r_S = - 0.348, p = 0.0011). In patients with progressive disease, the posttreatment serum SP-A and KL-6 levels were increased significantly compared with pretreatment levels [SP-A: (p = 0.021); KL-6: (p = 0.008)]. In patients showing improvement, the levels were decreased significantly [SP-A (p = 0.007) and KL-6 (p = 0.002)]. Changes in serum biomarkers (Delta SP-A and Delta KL-6) were significantly negatively correlated with changes in lung function (Delta FVC, Delta DLCO and Delta FEV1) (r_S = 0.482, p < 0.05). A significant positive correlation was found between Delta SP-A and Delta KL-6 (r_S = 0.482, p < 0.001).

CONCLUSIONS

Serum SP-A and KL-6 offer high sensitivity and specificity for the diagnosis of IPAF. The decrease in serum SP-A and/or KL-6 levels in patients with IPAF is related to the improvement in pulmonary function. SP-A and KL-6 may be important biomarkers for predicting disease progression in patients with IPAF.

Lung ultrasound B-lines and serum KL-6 correlate with the severity of idiopathic inflammatory myositis-associated interstitial lung disease

OBJECTIVE

Idiopathic inflammatory myositis-associated interstitial lung disease (IIM-ILD) significantly increases morbidity and mortality. Lung ultrasound B-lines and Krebs von den Lungen-6 (KL-6) are identified as new sonographic and serum markers of ILD, respectively. The aim of our work was to assess the role of B-lines and KL-6 as markers of the severity of IIM-ILD. For this purpose, the correlation among B-lines score, serum KL-6 levels, high-resolution CT (HRCT) score, and pulmonary function tests were investigated in IIM-ILD patients.

METHODS

Thirty-eight patients with IIM-ILD underwent chest HRCT scans, lung ultrasound and pulmonary function tests (independently performed within 1 week) examination. To assess severity and extent of ILD at HRCT, the Warrick score was used. The B-lines score denoting the extension of ILD was calculated by summing the number of B-lines on a total of 50 scanning sites. Serum KL-6 levels (U/ml) was measured by chemiluminescent enzyme immunoassay.

RESULTS

A significant correlation was found between the B-lines score and serum KL-6 levels (r = 0.43, P < 0.01), and between the Warrick score and serum KL-6 levels (r = 0.45, P < 0.01). A positive correlation between B-lines score and the Warrick score (r = 0.87, P < 0.0001) was also confirmed. Both B-lines score and KL-6 levels inversely correlated to diffusion capacity for carbon monoxide (r = -0.77, P < 0.0001 and r = -0.42, P < 0.05, respectively) and total lung capacity (r = -0.73, P < 0.0001 and r = -0.36, P < 0.05, respectively). Moreover, B-lines correlated inversely with forced vital capacity (r = -0.73, P < 0.0001), forced expiratory volume in 1 s (r = -0.69, P < 0.0001).

CONCLUSION

B-lines score and serum KL-6 levels correlate with HRCT findings and pulmonary function tests, supporting their use as measures of IIM-ILD severity.

Evaluation of usefulness in surfactant protein D as a predictor of mortality in myositis-associated interstitial lung disease

Objective

Surfactant protein D (SP-D) is considered a serum biomarker of various forms of interstitial lung disease (ILD). In this study, we examined the utility of SP-D as a predictive biomarker for mortality in patients with ILD associated with polymyositis/dermatomyositis (PM/DM) using large-scale multicentre cohort data.

Methods

We enrolled 381 patients with incident PM/DM-associated ILD in a multicentre retrospective cohort based on the availability of serum SP-D at the baseline. Demographic and clinical characteristics as well as the presence of autoantibodies to melanoma differentiation-associated gene 5 (MDA5) and aminoacyl tRNA synthetase were measured at the time of diagnosis, and follow-up survival data were collected prospectively.

Results

Seventy-eight patients died during the median observation period of 18 months, and the majority of patients died of ILD. The SP-D levels at baseline were significantly lower (P = 0.02) in a non-survivor subset than in a survivor subset among the entire enrolled patients. However, the SP-D levels were higher in the non-survivor subset than in the survivor subset based on the stratification by anti-MDA5-positive, anti-ARS-positive and, double-negativity, although there was an only statistically significant difference (P = 0.01) in the double-negative group. Surprisingly, the SP-D levels were within the upper limit of normal, 110 ng/mL, in 54 (87%) of 62 anti-MDA5-positive patients who died. In the double-negative group, the mortality rates were significantly higher (P = 0.002) in a subset with SP-D ≥127.6 ng/mL, the cut-off value for mortality calculated by the receiver operating characteristic curve, than the other subset. All of patients with SP-D <127.6 ng/mL survived.

Conclusion

Serum SP-D levels behave differently among patients with stratified by anti-MDA5 antibody, anti-ARS antibody and both negativity in PM/DM-associated ILD. Its use in clinical practice should be applied with caution on the basis of the presence or absence of anti-MDA5 antibody or anti-ARS antibody.

Evaluation of changes in the serum levels of Krebs von den Lungen-6 and surfactant protein-D over time as important biomarkers in idiopathic fibrotic nonspecific interstitial pneumonia

BACKGROUND

Some cases of idiopathic fibrotic nonspecific interstitial pneumonia (f-NSIP) show a progressive course that is similar to that of idiopathic pulmonary fibrosis. However, it is difficult to predict poor patient outcomes. This study aimed to evaluate whether serial changes in serum levels of Krebs von den Lungen-6 (KL-6) and surfactant protein-D (SP-D) can predict disease progression.

METHODS

We retrospectively analyzed the medical records of 75 patients with idiopathic f-NSIP. Disease behavior was categorized into two groups depending on long-term change of pulmonary function: progressive type (≥5%/year relative decline in the slope of forced vital capacity [FVC] and/or ≥7.5%/year relative decline in the slope of %diffusing capacity of the lung for carbon monoxide [%D_LCO]) and stable type. Levels of KL-6 and SP-D and results of pulmonary function tests, which were performed parallelly, were reviewed and analyzed using a linear mixed-effects model.

RESULTS

The study subjects comprised 62 patients with stable type and 13 patients with progressive type disease behavior. Among these subjects, 50 patients fulfilled the diagnostic criteria of interstitial pneumonia with autoimmune features (IPAF). Serum levels of both KL-6 and SP-D at baseline showed a negative correlation with %D_LCO, but not with FVC, and these biomarkers were not related to disease progression. Persistently high levels of KL-6 and SP-D correlated with progressive type disease behavior in idiopathic (non-IPAF) f-NSIP.

CONCLUSIONS

Changes in serum KL-6 and SP-D levels over time may provide useful predictive information on disease behavior during treatment in patients with idiopathic f-NSIP and especially in those with non-IPAF f-NSIP.

Clinical Significance of Serum Chitotriosidase Level in Anti-MDA5 Antibody–positive Dermatomyositis-associated Interstitial Lung Disease

Objective.

To assess prognostic factors of antimelanoma differentiation-associated gene 5 antibody (anti-MDA5)–positive dermatomyositis/clinically amyopathic DM–associated interstitial lung disease (DM/CADM-ILD) and evaluate the use of serum chitotriosidase, a marker for macrophage activation, as a potential biomarker in anti-MDA5-positive DM/CADM-ILD.

Methods.

This retrospective study included 30 patients with anti-MDA5–positive DM/CADM-ILD. The clinical characteristics and laboratory findings at the time of diagnosis were analyzed. Serum chitotriosidase levels were measured in the 30 patients, in 21 healthy controls, and in 25 patients with anti-aminoacyl-tRNA synthetase antibody–positive (anti-ARS)-polymyositis (PM)/DM/CADM-ILD, and the potential of serum chitotriosidase as a prognostic biomarker in anti-MDA5–positive DM/CADM-ILD was assessed.

Results.

The median serum chitotriosidase level in patients with anti-MDA5–positive DM/CADM-ILD was 17.3 ng/ml, which was higher than that in healthy controls and anti-ARS–PM/DM/CADM-ILD (2.0 and 8.9 ng/ml, respectively). Of the 30 patients, 10 died of respiratory failure associated with DM/CADM-ILD deterioration. Cox hazard analysis demonstrated that higher serum chitotriosidase level and lower PaO2 value were significant predictors of a poor outcome. Using optimal cutoff levels according to receiver-operating characteristic curve analyses, chitotriosidase ≥ 23.5 ng/ml, ferritin ≥ 800 ng/ml, and Krebs von den Lungen–6 ≥ 720 U/ml were significantly associated with a poor prognosis. Serum chitotriosidase levels were negatively correlated with PaO2 and percentage predicted forced vital capacity. The survival rate was significantly poorer in patients with high chitotriosidase levels (≥ 23.5 ng/ml) than in those with low chitotriosidase levels (< 23.5 ng/ml).

Conclusion.

Serum chitotriosidase may be a potential biomarker for predicting a poor prognosis in patients with anti-MDA5–positive DM/CADM-ILD.

Biomarkers in Adult Dermatomyositis: Tools to Help the Diagnosis and Predict the Clinical Outcome

Dermatomyositis pathophysiology is complex. In recent years, medical research has identified molecules associated with disease activity. Besides providing insights into the driving mechanisms of dermatomyositis, these findings could provide potential biomarkers. Activity markers can be used to monitor disease activity in clinical trials and may also be useful in daily practice. This article reviews molecules that could be used as biomarkers for diagnosis and monitoring dermatomyositis disease activity.

Treatment consensus for management of polymyositis and dermatomyositis among rheumatologists, neurologists and dermatologists

Although rheumatologists, neurologists and dermatologists see patients with polymyositis (PM) and dermatomyositis (DM), their management appears to vary depending on the physician's specialty. The aim of the present study was to establish the treatment consensus among specialists of the three fields to standardize the patient care. We formed a research team supported by a grant from the Ministry of Health, Labor and Welfare, Japan. Clinical questions (CQ) on the management of PM and DM were raised. A published work search on CQ was performed primarily using PubMed. Using the nominal group technique, qualified studies and results in the published work were evaluated and discussed to reach consensus recommendations. They were sent out to the Japan College of Rheumatology, Japanese Society of Neurology and Japanese Dermatological Association for their approval. We reached a consensus in 23 CQ and made recommendations and a decision tree for management was proposed. They were officially approved by the three scientific societies. In conclusion, a multidisciplinary treatment consensus for the management of PM and DM was established for the first time.

Evaluation of clinical prognostic factors for interstitial pneumonia in anti-MDA5 antibody-positive dermatomyositis patients

OBJECTIVES

We retrospectively investigated clinical prognostic factors for interstitial pneumonia (IP) in anti-melanoma differentiation-associated gene 5 (MDA5) antibody (Ab)-positive dermatomyositis (DM) patients.

METHODS

Subjects comprised 18 patients with anti-MDA5 Ab-positive DM-IP (9 survivors; 9 deaths).

RESULTS

Initial serum albumin levels, ferritin levels, and ground-glass opacity (GGO) scores in the right middle lobes were significantly higher in the death group than in the survivor group (p = .033, .013, and .005, respectively). Initial alveolar-arterial oxygen gradient (P[A-a]O₂) was also higher in the death group than in the survivor group (p = .064). Initial serum ferritin, P[A-a]O₂, and right middle lobe GGO score were found to significantly relate to death. Survival rates after 24 weeks were significantly lower among patients with an initial ferritin level of ≥450 ng/mL (25%), P[A-a]O₂ of ≥30 mmHg (31%), and a right middle lobe GGO score of ≥2 (11%) than each of the others (p = .006, .020, and .002, respectively).

CONCLUSIONS

An initial serum ferritin level of ≥450 ng/mL, P[A-a]O₂ of ≥30 mmHg, and right middle lobe GGO score of ≥2 (GGO ≥5% of the lobe) were identified as poor prognostic factors for anti-MDA5 Ab-positive DM-IP patients.

Chemokine profiles of interstitial pneumonia in patients with dermatomyositis: a case control study

Chemokines play an important role in the pathophysiology of dermatomyositis (DM) with interstitial pneumonia (IP). However, the relation between chemokines and the disease activity or prognosis of DM-IP has not been elucidated. We evaluated the serum C-C motif chemokine ligand (CCL) 2, Th1 chemokines (C-X-C motif chemokine ligand [CXCL] 9, CXCL10, CXCL11), and Th2 chemokine (CCL17) profiles of 30 patients, and examined the relation between these chemokines and the disease activity or prognosis of DM-IP. Initial serum CCL2 level was higher in the death group (P = 0.007). To determine the cut-off points effective as poor prognostic factors of DM-IP, ROC curve analysis was carried out on initial serum CCL2 level. The value that maximized the area under the ROC curve was 894 pg/mL (sensitivity: 100%, specificity: 70.8%). Serum CCL2, CXCL9, CXCL10, and CXCL11 levels were lower at 2 weeks after treatment initiation than before treatment. Serum CCL2, CXCL10, and CXCL11 levels at 2 weeks after treatment initiation were higher in the death group. Serum levels of chemokines such as CCL2, CXCL10, and CXCL11 may be possible biomarkers of disease activity and prognosis in DM-IP, and serum CCL2 level may be useful when deciding initial treatment.

Connective tissue disease-related interstitial lung disease

Interstitial lung disease (ILD) is commonly present in patients with an underlying connective tissue disease (CTD), particularly those with systemic sclerosis, rheumatoid arthritis, and inflammatory myositis. The clinical spectrum can range from asymptomatic findings on imaging to respiratory failure and death. Distinguishing features in the clinical, radiographic, and histopathologic characteristics of CTD-ILD subsets can predict prognosis and treatment response. Treatment often consists of combinations of immunosuppressive medications, but there is a paucity of guidance in the literature to help clinicians determine appropriate screening and management of CTD-ILD. As such, there is a critical need for studies that can elucidate the natural history of the CTD-ILD, as well as clarify optimal therapies for CTD patients with ILD.

Increased Serum B Cell Activating Factor and a Proliferation-inducing Ligand Are Associated with Interstitial Lung Disease in Patients with Juvenile Dermatomyositis

OBJECTIVE

Rapidly progressive interstitial lung disease (RP-ILD) is an intractable and fatal complication of juvenile dermatomyositis (JDM). This study evaluated serum levels of B cell activating factor (BAFF) and a proliferation-inducing ligand (APRIL) in JDM patients with complicating ILD, and their association with ILD phenotypes, clinical variables, and anti-melanoma differentiation-associated gene 5 (MDA5).

METHODS

We measured the levels of BAFF, APRIL, and anti-MDA5 in the sera of 23 JDM patients with ILD [8 in the RP-ILD group and 15 in the chronic ILD (C-ILD) group], 17 JDM patients without ILD (non-ILD group), and 10 age-matched controls, using the ELISA method. ILD was identified by high-resolution computed tomography.

RESULTS

Serum BAFF titers were significantly higher in the JDM patients with RP-ILD versus those with C-ILD (p = 0.011) and in healthy controls (p = 0.0004). The C-ILD group had significantly higher levels of BAFF versus controls (p ≤ 0.0001). Serum APRIL was markedly elevated in the RP-ILD group as compared with the C-ILD group (p = 0.003) and controls (p = 0.006). In patients with ILD, both BAFF and APRIL levels were correlated with serum Krebs von den Lungen-6 and interleukin 18. Subjects with high titer anti-MDA5 (> 200 U) had higher levels of BAFF and APRIL than those with low titer anti-MDA5 (< 100 U; p = 0.019 and p = 0.0029, respectively), which may have been due to a relationship between RP-ILD and high anti-MDA5 titer.

CONCLUSION

Our findings of markedly elevated levels of BAFF and APRIL in patients with RP-ILD JDM suggest the potential importance of these cytokines in the diagnosis and treatment of RP-ILD accompanying JDM.

Increased Serum LIGHT Levels Correlate with Disease Progression and Severity of Interstitial Pneumonia in Patients with Dermatomyositis: A Case Control Study

BACKGROUND

Activated CD8+ T cells play an important role in the pathogenesis of dermatomyositis (DM) with interstitial pneumonia (IP). Serum CD8+ T-cell activator, LIGHT, and Th1/Th2/Th17 cytokines were measured in DM-IP patients and compared with clinical parameters to investigate their usefulness.

METHODS

The correlations between the clinical findings and serum LIGHT and Th1/Th2/Th17 cytokine levels were investigated in 21 patients with DM-IP (14 with rapidly progressive IP [RPIP] and 7 with chronic IP [CIP], including 4 fatal cases of IP).

RESULTS

The median serum LIGHT level was 119 (16-335.4) pg/ml, which was higher than that in healthy control subjects and DM patients without IP. The median serum IL-6 level was 14.7 (2.4-154.5) pg/ml (n = 13). The other cytokines were detected in only a few patients. The median serum LIGHT level in DM-RPIP patients (156 [49.6-335.4] pg/ml) was significantly higher than that in DM-CIP patients (94.3 [16-164.2] pg/ml) (P = 0.02). The serum IL-6 level did not correlate with either progression or outcome of DM-IP. ROC curve analysis determined a serum LIGHT level of ≥120 pg/ml to be the cut-off value for the rapid progression of DM-IP. Serum LIGHT levels correlated significantly with %DLco (R = 0.55, P = 0.04) and total ground-glass opacity scores (R = 0.72, P = 0.0002). The serum LIGHT level significantly decreased to 100.5 (12.4-259.3) pg/ml 4 weeks after treatment initiation (P = 0.04).

CONCLUSIONS

The serum LIGHT level may be a promising marker of disease progression and severity in patients with DM-IP.

Changes in pulmonary tissue structure and KL-6/MUC1 expression in a newborn rat model of hyperoxia-induced bronchopulmonary dysplasia

Following preterm birth, levels of Krebs von den Lungen-6/mucin 1 (KL-6/MUC1) in serum correlate closely with the development of advanced bronchopulmonary dysplasia (BPD), but the role of KL-6/MUC1 in the development of BPD is unclear. To explore whether a relationship exists between KL-6/MUC1 and pathological changes in BPD and verify such a clinical finding, we established a newborn rat model of 95% oxygen-induced BPD. The development of pulmonary alveoli was evaluated by determining the radial alveolar count (RAC) and examining the location, distribution, and expression of KL-6/MUC1 in pulmonary tissues using a fluorescent immunoassay, Western blot, and reverse transcription polymerase chain reaction. The synchronic expression levels of KL-6/MUC1 in serum, bronchoalveolar lavage fluid (BALF) and pulmonary tissues were examined using an enzyme-linked immunosorbent assay. The mean RAC in the hyperoxia group was significantly lower than in normoxia controls, whereas the expression levels of KL-6/MUC1 were higher. On days 1, 3, 7, and 14, the mean RACs in hyperoxic rats were 15.00, 12.67, 12.00, and 11.33, respectively. The expression levels of KL-6/MUC1 peaked in the experimental group on day 1, and began to decrease slightly after day 3. The expression levels of KL-6/MUC1 in serum and BALF were associated with KL-6/MUC1 expression in pulmonary tissues. We suggest that increased lung KL-6/MUC1 expression appears to be closely associated with impairment of alveolarization in a newborn rat model of hyperoxia-induced BPD. Changes in lung KL-6/MUC1 expression can be evaluated effectively and less invasively by monitoring KL-6/MUC1 in serum and BALF.

Pre-treatment ferritin level and alveolar-arterial oxygen gradient can predict mortality rate due to acute/subacute interstitial pneumonia in dermatomyositis treated by cyclosporine a/glucocorticosteroid combination therapy: a case control study [corrected]

BACKGROUND

Acute/subacute interstitial pneumonia in dermatomyositis (DM-A/SIP) is a disease associated with a poor prognosis that resists treatment with glucocorticosteroids (GC) and progresses rapidly in a period of weeks to months to death. We retrospectively studied outcomes, prognostic factors, and their relations with survival rate in patients with DM-A/SIP treated with early cyclosporine A (CSA)/GC combination therapy and 2-hour postdose blood concentration monitoring.

METHODS

This study comprised 32 DM-A/SIP patients who were simultaneously treated with CSA and prednisolone. Clinical and laboratory findings were compared between those who died due to DM-A/SIP and those surviving 24 weeks after beginning of therapy. Prognostic factors were extracted, and their relations with the survival rate were evaluated.

RESULTS

Of the 32 DM-A/SIP patients, 25 survived, 5 died of DM-A/SIP, and 2 died of infections. In those who died due to DM-A/SIP, ferritin level and the alveolar-arterial oxygen gradient were significantly increased compared with the survivors (P<0.001 and P = 0.002, respectively). Multivariate analyses showed that ferritin and alveolar-arterial oxygen gradient were independent prognostic factors of poor outcome. The survival rate 24 weeks after beginning of treatment was significantly lower in those with a ferritin level of ≥ 600 ng/ml and alveolar-arterial oxygen gradient of ≥ 45 Torr (P<0.001 and P<0.001, respectively). All patients with both prognostic factors died, and the outcome was significantly poorer in these patients than in those with one or neither of the prognostic factors (P<0.001).

CONCLUSIONS

We identified pre-treatment high serum ferritin level and high alveolar-arterial oxygen gradient as poor prognostic factors in DM-A/SIP patients undergoing early CSA/GC combination therapy and showed that the outcomes were poor in patients with both factors.