Serum KL-6 level is a prognostic marker in patients with anti-MDA5 antibody-positive dermatomyositis associated with interstitial lung disease

Soluble CXCL16 is a prognostic biomarker associated with rapidly progressive interstitial lung disease complicated with dermatomyositis

OBJECTIVES

Rapidly progressive interstitial lung disease (RPILD) in patients with dermatomyositis (DM) significantly impacts prognosis, leading to high mortality rates. Although several indicators have been demonstrated to strongly correlate with the risk of developing RPILD, their clinical utility still needs to be investigated. The objective of this study was to investigate the clinical significance of soluble CXCL16 (sCXCL16) in DM patients complicated with RPILD.

METHODS

Serum sCXCL16 was measured by enzyme-linked immunosorbent assay in 96 patients with DM and 55 matching healthy donors. Correlations between sCXCL16 levels and clinical features, laboratory examinations and the predictive value of baseline sCXCL16 level for RPILD were analysed.

RESULTS

The serum sCXCL16 levels were significantly higher in patients with DM (n = 96, 3.264 ± 1.516 ng/mL) compared with healthy donors (n = 55, 1.781 ± 0.318 ng/mL), especially in DM complicated with RPILD (n = 31, 4.441 ± 1.706 ng/mL). The sCXCL16 levels were positively correlated with levels of serum ferritin, C reactive protein, erythrocyte sedimentation rate, lactate dehydrogenase, hydroxybutyrate dehydrogenase, and negatively correlated with peripheral lymphocytes percentage, but showed no correlation with levels of anti-melanoma differentiation-associated gene 5 antibody, Krebs von den Lungen-6 or creatine kinase. Multivariable analysis showed that elevated sCXCL16 was an independent prognostic factor for poor prognosis of RPILD in patients with DM. The 2-year survival rate was significantly lower in patients with high sCXCL16 level than in those with low sCXCL16 level.

CONCLUSION

A higher serum sCXCL16 level was identified as a predictive biomarker of RPILD in patients with DM, and closely associated with poor prognosis.

The central helicase domain holds the major conformational epitopes of melanoma differentiation-associated gene 5 autoantibodies

OBJECTIVE

Autoantibodies against MDA5 (melanoma differentiation-associated protein 5) serve as a biomarker for DM (dermatomyositis) and indicate a risk factor for interstitial lung disease (ILD). MDA5 is a protein responsible for sensing RNA virus infection and activating signalling pathways against it. However, little is known about the antigen epitopes on MDA5 autoantibodies. We aimed to determine the interaction of the MDA5 autoantibody-antigen epitope.

METHODS

Cell-based assays (CBAs), immunoprecipitation-immunoblot assays, and various immunoblotting techniques were used in the study.

RESULTS

We demonstrated that DM patient autoantibodies recognize MDA5 epitopes in a native conformation-dependent manner. Furthermore, we identified the central helicase domain （3Hel） formed by Hel1, Hel2i, Hel2, and pincer as the major epitopes. As proof of principle, the purified 3Hel efficiently absorbed MDA5 autoantibodies from patient sera through immunoprecipitation-immunoblot assay.

CONCLUSION

Our study uncovered the nature of the antigen epitopes on MDA5 and can provide guidance for diagnosis and a targeted therapeutic approach development.

Predicting the death of patients with anti-melanoma differentiation-associated protein-5-positive dermatomyositis-associated interstitial lung disease: A systematic review and meta-analysis

OBJECTIVES

To investigate the risk factors for death in anti-melanoma differentiation-associated protein-5-positive dermatomyositis-associated interstitial lung disease (ILD).

METHODS

Studies were identified by searching PubMed, Embase, Web of Science, and Cochrane Library. We calculated pooled risk ratios (RRs) or standardized mean differences (SMDs) and 95% confidence intervals (CIs) using random-effects models.

RESULTS

Twenty studies were selected. Factors that may increase death risk included older age (SMD: 0.62, 95% CI: 0.42-0.81), elevated Krebs von den Lungen-6 (SMD: 0.66, 95% CI: 0.47-0.86), lactate dehydrogenase (SMD: 0.87, 95% CI: 0.72-1.02), C-reactive protein (SMD: 0.62, 95% CI: 0.44-0.80), ferritin (SMD: 0.93, 95% CI: 0.71-1.15), creatine kinase (SMD: 0.28, 95% CI: 0.13-0.44), neutrophil (SMD: 0.34, 95% CI: 0.04-0.64), neutrophil-to-lymphocyte ratio (SMD: 0.52, 95% CI: 0.24-0.79), aspartate aminotransferase (SMD: 0.70, 95% CI: 0.45-0.94), shorter disease duration (SMD: -0.44, 95% CI: -0.67 to -0.21), rapidly progressive ILD (RR: 4.08, 95% CI: 3.01-5.54), fever (RR: 1.98, 95% CI: 1.46-2.69), dyspnoea (RR: 1.63, 95% CI: 1.32-2.02), and anti-Ro52 antibody positive (RR: 1.28, 95% CI: 1.11-1.49). Female (RR: 0.86, 95% CI: 0.78-0.94), increased albumin (SMD: -1.20, 95% CI: -1.76 to -0.64), lymphocyte (SMD: -0.49, 95% CI: -0.67 to -0.30), and arthralgia (RR: 0.53, 95% CI: 0.37-0.78) were protective factors.

CONCLUSION

Older age, shorter disease duration, rapidly progressive ILD, fever, dyspnoea, anti-Ro52 antibody positive, and some inflammatory markers were risk factors for death in patients with anti-melanoma differentiation-associated protein-5-positive dermatomyositis-associated ILD.

Anti-MDA5 antibody-positive dermatomyositis: pathogenesis and clinical progress

Anti-melanoma differentiation-associated protein 5 (MDA5) antibody-positive dermatomyositis (MDA5-DM) is a subtype of dermatomyositis. Although the aetiology and pathology remain unclear, increasing evidence suggests that viral infection is a potential trigger of MDA5-DM. Multiple factors, including T cells, B cells, neutrophils and macrophages, are implicated in the pathophysiology of MDA5-DM. Distinctive skin rashes, rapidly progressive interstitial lung disease, peripheral lymphopenia and elevated serum ferritin levels are the most prominent clinical and laboratory features of MDA5-DM. Concomitant infection is a common complication of MDA5-DM. The proper evaluation of patients with MDA5-DM requires knowledge of the disease heterogeneity and clinical course variability. Several biomarkers, including serum levels of anti-MDA5 antibodies and biomarkers related to macrophage activation, have been identified as useful tools for monitoring disease activity and prognosis. MDA5-DM shows a poor response to conventional glucocorticoid and immunosuppressant therapy and has a poor overall prognosis. Therefore, there is an urgent need to explore the key pathogenic mechanisms of MDA5-DM and develop novel therapeutic options for patients. This Review discusses recent clinical progress and pathogenic findings of MDA5-DM.

Risk factors for mortality in patients with anti-MDA5 antibody-positive dermatomyositis: A meta-analysis and systematic review

OBJECTIVES

To determine the prognostic factors of dermatomyositis with anti-melanoma differentiation-associated gene 5 (MDA5) antibody, a rare disease and often complicated by life-threatening, rapidly progressive interstitial lung disease.

METHODS

Herein, we searched the Medline, Embase, and Cochrane Library databases and extracted studies published before August 23, 2022. Pooled analysis of hazard ratios (HRs) or odds ratios was used to identify prognostic factors for mortality among patients with anti-MDA5 antibody-positive dermatomyositis (MDA5+ DM).

RESULTS

Twenty-nine cohorts with 2,645 patients were included in this meta-analysis. Factors related to poor prognosis included old age (HR 1.54, 95% confidence interval (CI) 1.41-1.69, p < 0.01), male sex (HR 2.07, 95% CI 1.34-3.18, p < 0.01), rapidly progressive interstitial lung disease (RP-ILD) (HR 9.34, 95% CI 6.39-13.6, p < 0.01), high levels of ferritin (HR 1.05, 95% CI 1.01-1.08, p < 0.01), C-reactive protein (CRP) (HR 1.12, 95% CI 1.06-1.19, p < 0.01), creatine kinase (HR 1.05, 95% CI 1.03-1.07, p < 0.01), and lactate dehydrogenase (LDH) (HR 1.27, 95% CI 1.12-1.45, p < 0.01), whereas oxygen index (HR 0.990, 95% CI 0.988-0.992, p < 0.01), partial pressure of oxygen (HR 0.933, 95% CI 0.906-0.961, p < 0.01), forced vital capacity (HR 0.962, 95% CI 0.928-0.998, p = 0.038), and lymphocyte count (HR 0.421, 95% CI 0.282-0.629, p < 0.01) were associated with better outcomes.

CONCLUSIONS

Old age, male sex, hypoxemia, low forced vital capacity, lymphocytopenia, and high levels of ferritin, CRP, creatine kinase, and LDH are risk factors for mortality in patients with MDA5+ DM. However, a cautious interpretation of these results and further quality investigation are warranted.

Changes in anti-MDA5 antibody titres and serum cytokine levels before and after diagnosis of anti-MDA5 antibody-positive dermatomyositis

OBJECTIVES

Anti-melanoma differentiation-associated gene 5 (MDA5) antibody-positive DM is characterized by rapidly progressive interstitial lung disease and has a poor prognosis. We aimed to investigate whether anti-MDA5 antibody titres and cytokine levels predict clinical course, and evaluate changes in both parameters before and after diagnosis.

METHODS

This was a retrospective, single-centre study in 38 patients with anti-MDA5 antibody-positive DM. We compared clinical characteristics and laboratory data at diagnosis between patients in the treatment response (n = 23) and non-response (n = 15) groups, and between those in the relapse (n = 5) and non-relapse (n = 24) groups. We also measured serum anti-MDA5 antibody titres and cytokine levels before and after diagnosis.

RESULTS

The non-response group was older, had a higher ground-glass opacity score, lower PaO2/FiO2, higher CRP level, and higher anti-MDA5 antibody titre than the response group. No cytokines significantly differed between groups at diagnosis. The relapse group had a significantly higher anti-MDA5 antibody titre than the non-relapse group. In the survivor group, the anti-MDA5 antibody titre and levels of IFN-α, IFN-γ, monocyte chemotactic protein-1 (MCP-1), IL-6, IL-33, CRP, and ferritin were significantly lower 6 months post-treatment than at diagnosis. Macrophage-associated cytokines such as IL-6, IL-8, IL-18 and MCP-1 increased after anti-MDA5 antibody positivity in three patients who were anti-MDA5 antibody-positive before diagnosis.

CONCLUSION

The anti-MDA5 antibody titre at diagnosis may predict the clinical course. Levels of macrophage-associated cytokines significantly declined at 6 months post-treatment, and they may have increased after anti-MDA5 antibody titre positivity.

Clinical features and prognostic factors of anti-melanoma differentiation-associated gene 5 antibody-positive dermatomyositis with rapidly progressive interstitial lung disease in Chinese patients

OBJECTIVE

The objective of this study is to investigate clinical features and prognostic factors of antimelanoma differentiation-associated gene 5 (anti-MDA5)-positive dermatomyositis with rapidly progressive interstitial lung disease (RP-ILD) in Chinese patients.

METHODS

Clinical features and prognostic factors of patients with newly diagnosed or recurrent dermatomyositis patients were retrospectively analyzed. All patients were divided into the anti-MDA5-positive or negative dermatomyositis, and with or without RP-ILD groups. Clinical features and prognostic factors were statistically compared among different groups.

RESULTS

The serum ferritin (SF) levels (1500.0 [658.80, 1844.0]) and γ-glutamyl transpeptidase (γ-GT) (125.5 [61.0, 232.0] vs. 28 [16.0, 41.0], Z = 5.528; p < .001) were markedly higher, and phosphocreatine myoenzyme (CK) (73.0 [42.0, 201.0] vs. 1333.0 [79.0, 8000.0], Z = -2.739, p = .006), serum albumin level (32.51 ± 5.23 vs. 35.81 ± 5.88, t = -2.542, p = .013), and lymphocyte count (0.80 ± 0.36 vs. 1.45 ± 0.77, t = -4.717, p < .001) were lower than those in anti-MDA5-negative counterparts. Among patients with anti-MDA5 antibody (Ab) with RP-ILD, the SF level (1531.0 [1163.8, 2016.5] vs. 584.9 [564.8, 1042.5], Z = 2.664, p = .008), γ-GT (134.0 [81.0, 204.5] vs. 123.0 [76.0, 189.0], Z = 3.136, p = .002) and positive rate of anti-RO-52 Ab (90.9% vs. 50.0%, χ²  = 7.222, p = .013) were higher and lymphocyte count (0.79 ± 0.38 vs. 1.32 ± 0.74, t = -3.025, p = .029) was lower than those in their counterparts without RP-ILD. The SF level of anti-MDA5 nonsurvivors (1544 [1447.32, 2089.0] vs. 584.9 [515.7, 1500.0], Z = 2.096, p = .030), anti-RO-52 Ab-positive rate ([16/18, 88.9%] vs. [9/16, 56.2%], χ²  = 4.636, p = .031) were higher than those in survivors. Lymphocytopenia was a risk factor for RP-ILD and death of patients with anti-MDA5-positive dermatomyositis. The area under receiver operating characteristic curve was 0.888 (95% confidence interval: 0.756, 1.000; p < .001), the sensitivity was 85.7%, the specificity was 93.8%, and Youden's index was 0.795.

CONCLUSIONS

Anti-MDA5-positive dermatomyositis patients are prone to developing RP-ILD. Declined lymphocyte count is a critical risk factor for RP-ILD, probably acting as a simple and effective predictor for Chinese patients with anti-MDA5-positive dermatomyositis.

Peripheral lymphocyte count defines the clinical phenotypes and prognosis in patients with anti-MDA5-positive dermatomyositis

OBJECTIVE

To explore the role of peripheral lymphocyte count in phenotyping and prognosis prediction in dermatomyositis (DM) patients with anti-MDA5 antibodies.

METHODS

In total, 1669 patients with idiopathic inflammatory myopathy (IIM) were retrospectively enrolled. Clinical characteristics and prognosis of patients with anti-MDA5+ DM were analyzed in association with peripheral lymphocyte counts and clusters determined by unsupervised machine learning.

RESULTS

The peripheral lymphocyte count was significantly lower in the anti-MDA5+ DM group (N = 421) than in the other IIM serotype groups. The anti-MDA5+ DM patients were divided into three groups; the severe lymphopenia group had skin ulcers and rapidly progressive interstitial lung disease (RP-ILD); patients with a normal lymphocyte count had a younger age of onset, more frequent arthritis, and normal serum ferritin levels, whereas mild lymphopenia group showed a moderate increase of serum ferritin and intermediate incidence of RP-ILD. Survival analysis revealed that the 3- and 6-month mortality rates were significantly higher in the severe lymphopenia group (29.0% and 42.1%, respectively) than in the mild lymphopenia group and normal lymphocyte count group (p value <0.001). Consistently, unsupervised machine learning identified three similar groups; the arthritis cluster shows the highest lymphocyte counts and best prognosis; the RP-ILD cluster presents the lowest peripheral lymphocyte, high incidence of RP-ILD, and poor prognosis; the typical DM rash cluster had a moderate peripheral lymphocyte count and an intermediate prognosis.

CONCLUSIONS

Lymphopenia is a unique manifestation of anti-MDA5+ DM. Peripheral lymphocyte count can define clinical phenotypes and predict prognosis in anti-MDA5+ DM.

Anti-MDA5-positive dermatomyositis and remission in a single referral centre population

OBJECTIVES

To describe a single-centre North American adult cohort of anti-MDA5-positive dermatomyositis patients, with emphasis on drug-free long-term remission.

METHODS

We conducted an observational retrospective cohort study of anti-MDA5-positive DM patients. All consented patients seen in the Johns Hopkins Myositis Centre from 2003-2020 with suspected muscle disease were routinely screened for myositis-specific autoantibodies. All sera were screened for anti-MDA5 autoantibodies by line blot; positives were verified by enzyme-linked immunoassay. Patients whose sera were anti-MDA5 positive by both assays (n=52) were followed longitudinally. If clinical status was unavailable, structured telephone interviews were conducted. Clinical remission was defined as being off all immunosuppression >1 year while remaining asymptomatic.

RESULTS

38/52 (73%) of the patients were women with a median age at disease-onset of 47 (IQR 40-54). Twenty-five of the patients (48%) were White, 16 (30%) were Black and 3 (6%) were Asian. Most patients (42/52, 80%) had interstitial lung disease, defined by inflammatory or fibrotic changes on high resolution computed tomography (HRCT). 18/52 (35%) of patients required pulse-dose methylprednisolone, 4/52 (8%) experienced spontaneous pneumothorax/pneumomediastinum, 6/52 (12%) required intubation, and 5/52 (10%) died. Over longitudinal follow-up (median 3.5 years), 9 (18%) patients achieved clinical remission. The median time from symptom onset to clinical remission was 4 years, and the median duration of sustained remission was 3.5 years (range 1.4-7.8). No demographic or disease characteristics were significantly associated with remission.

CONCLUSIONS

In this single centre, tertiary referral population of anti-MDA5-positive dermatomyositis, ~20% of patients experienced long-term drug-free remission after a median disease duration of 4 years. No clinical or biologic factors were associated with clinical remission.

Evaluating the value of superoxide dismutase in anti-MDA5-positive dermatomyositis associated with interstitial lung disease

OBJECTIVE

This study aimed to investigate the relationship between serum superoxide dismutase (SOD) and interstitial lung disease (ILD) among patients with anti-melanoma differentiation-associated gene 5 antibody (MDA5)-positive DM.

METHOD

In this retrospective study, serum SOD of 90 health check-ups were tested in our hospital. A total of 94 hospitalized patients with anti-MDA5-positive DM had ILD. Their serum SOD, serum ferritin and autoantibody levels were determined and lung high-resolution CT was performed.

RESULTS

The serum SOD level was significantly lower in the anti-MDA5-positive DM group compared with the control group. The SOD level was significantly lower in patients positive for both anti-MDA5 antibodies and anti-Ro-52 antibodies than in those positive for only anti-MDA5 antibodies before treatment. The SOD level was significantly lower in the higher serum ferritin group compared with the lower serum ferritin group before treatment. After treatment, the serum SOD level decreased in patients with exacerbation of ILD, while it increased in those with alleviated ILD. The SOD level was significantly lower in the death group than in the survival group before treatment.

CONCLUSIONS

In patients with anti-MDA5-positive DM, the low SOD level before treatment indicated the presence of oxidative stress in the disease; the serum SOD level was affected by anti-Ro-52 antibodies and ferritin; there is a close relationship between serum SOD level and ILD among patients with anti-MDA5-positive DM, suggesting that SOD might serve as an effective indicator to evaluate the changes in ILD in these patients; and the low SOD level is an important indicator of poor prognosis in these patients, which deserves attention from rheumatologists.

Differences in the Clinical Characteristics and 1-Year Mortality Rates of Patients with Dermatomyositis with anti-Jo-1 and anti-MDA5 Antibodies

Objective

Patients with anti-Jo-1 antibodies (Abs) and anti-melanoma differentiation-associated protein 5 (MDA5) Abs are at a higher risk of interstitial lung disease (ILD) and have a mortality rate higher than that of patients with anti-Jo-1 Abs. This study investigated differences in the clinical characteristics and prognosis of patients with anti-Jo-1 Abs and anti-MDA5 Abs with dermatomyositis (DM).

Methods

We retrospectively reviewed the medical records of 38 patients with DM from January 2000 to December 2021. The patients were divided into anti-Jo-1 Abs and anti-MDA5 Abs groups. The basic demographic data, clinical manifestations, and 1-year mortality rates of the groups were compared.

Results

Among the 38 patients, 30 were anti-Jo-1-Abs positive and 8 patients were anti-MDA5 Aba positive. The patients with anti-MDA5 Abs presented with more apparent cutaneous symptoms and aggressive pulmonary manifestations than did those with anti-Jo-1 Abs. The mortality rate in the anti-MDA5 Abs group (1.95/person-year (PY)) was much higher than that in anti-Jo-1 Abs group (0.094/PY), and most of the mortalities occurred within the first 1-3 months of follow-up.

Conclusion

Distinct cutaneous and pulmonary manifestations were observed in the anti-Jo-1 Abs and anti-MDA5 Abs groups. The mortality rate in the anti-MDA5 Abs group was significantly higher than that in the anti-Jo-1 Abs group. Early recognition is crucial to ensuring higher chances of survival for patients with anti-MDA5 Abs.

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.

KL-6 in ARDS and COVID-19 Patients

The Acute Respiratory Distress Syndrome (ARDS) is a common, devastating clinical pattern characterized by life-threatening respiratory failure. In ARDS there is an uncontrolled inflammatory response that results in alveolar damage, with the exudation of protein-rich pulmonary-edema fluid in the alveolar space. Although severe COVID-19 lung failure (CARDS) often meets diagnostic criteria of traditional ARDS, additional features have been reported, such as delayed onset, binary pulmonary compliant states, and hypercoagulable profile. Increased levels of Krebs von den Lungen 6 (KL-6, also known as MUC1) have been reported in both ARDS and CARDS. KL-6 is a transmembrane protein expressed on the apical membrane of most mucosal epithelial cells and it plays a critical role in lining the airway lumen. Abnormalities in mucus production contribute to severe pulmonary complications and death from respiratory failure in patients with diseases such as cystic fibrosis, chronic obstructive pulmonary disease, and acute lung injury due to viral pathogens. Nevertheless, it is not clear what role KL-6 plays in ARDS/CARDS pathophysiology. KL-6 may exert anti-inflammatory effects through the intracellular segment, as proven in animal models of ARDS, while its extracellular segment will enter the blood circulation through the alveolar space when the alveolar epithelial cells are damaged. Therefore, changes in plasma KL-6 levels may be useful in ARDS and CARDS phenotyping, and KL-6 might guide future clinical trials in 'personalized medicine' settings.

Neutrophil-to-lymphocyte ratio is a predictive marker for anti-MDA5 positive dermatomyositis

Background

NLR is a systemic inflammatory marker that have been associated with overall survival in patients with some rapidly progressive disease. There are few data about the diagnostic and predictive value of NLR in autoimmune diseases, and it has not been described in anti-MDA5 positive DM. We try to correlate neutrophil-to-lymphocyte ratio (NLR) with fatality from dermatomyositis in anti-MDA5 positive patients.

Method

A retrospective study in which 195 patients were enrolled was conducted. Clinical and laboratory information was collated and ratios of neutrophil to lymphocyte counts (NLR) calculated. The primary end point was all-cause death.

Result

Of the 195 patients studied, all had interstitial lung disease, including 140 survivors and 55 non-survivors. An optimal NLR cut-off value of 4.86 for mortality prediction was identified. The NLR of non-survivors was significantly higher than that of survivors (p < 0.001). Plasma levels of lactate dehydrogenase (LDH) and C-reactive protein were significantly increased when NLR was greater than 4.86. Results of multivariate analysis established that NLR > 4.86 was an independent predictor of mortality (HR: 2.52; 95%CI: 1.33–4.78; p = 0.005). Abstinence from smoking (HR: 2.66; 95%CI: 1.33–4.78; p = 0.003), emergence of rapidly progressive interstitial lung disease (RPILD; HR: 4.38; 95%CI: 2.37–8.08; p < 0.001), low plasma LDH (HR: 3.82; 95%CI: 2.06–7.11; p < 0.001) and presentation with dyspnea (HR: 2.17; 95%CI: 1.22–3.86; p = 0.009) were all protective factors predictive of survival.

Conclusion

NLR is a cost-effective and widely accessible biomarker with utility for risk stratification in patients with anti-MDA5 + dermatomyositis.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12890-022-02106-8.

IL‑10/IL‑10 receptor 1 pathway promotes the viability and collagen synthesis of pulmonary fibroblasts originated from interstitial pneumonia tissues

Interstitial pneumonia is a pulmonary interstitial inflammatory and fibrosis disease with a variety of causes that causes respiratory disorders and threatens the lives of patients. The present study aimed to investigate the expression of interleukin (IL)-10 in peripheral blood of patients with interstitial pneumonia and its biological functions in pulmonary fibroblasts. A total of 42 patients with idiopathic pulmonary fibrosis (IPF) and 20 healthy subjects were included. ELISA was used to determine IL-10 concentration in serum from the patients and healthy subjects. Primary fibroblasts were isolated from lung tissue successfully and determined by morphology. The CCK-8 assay was performed to determine the effect of IL-10 expression on cell viability. Western blotting was used to determine COL1a1, COL1a2 and IL-10R1 protein expression. Flow cytometry was used for cell cycle analysis and to determine the number of IL-10⁺ cells. Expression of IL-10 in serum from IPF patients was higher compared to that from healthy subjects. IL-10 promoted the viability and collagen synthesis and secretion of MRC-5 cells and primary pulmonary fibroblasts. IL-10 and IL-10 receptor (R) 1 served regulatory roles in the viability and collagen synthesis of MRC-5 cells. The ratio of peripheral mononuclear lymphocytes with positive expression of IL-10 was elevated in peripheral blood from patients with IPF. The present study demonstrated that IL-10 expression in peripheral blood of patients with IPF is increased significantly compared with healthy subjects. Activation of the IL-10/IL-10R1 signaling pathway promoted the viability and collagen synthesis and secretion of pulmonary fibroblasts, leading to pulmonary fibrosis. The present study provided experimental basis for further understanding the development mechanism of pulmonary fibrosis.

Novel Usefulness of Krebs von den Lungen 6 (KL-6) with Hemoglobin and Lactate Dehydrogenase for Assessing Bone Marrow Fibrosis

Bone marrow fibrosis (BMF) is manually assessed by reticulin and trichrome stain of bone marrow (BM) biopsy and graded on a semi-quantitative scale. Krebs von den Lungen 6 (KL-6) and Mac-2 binding protein glycosylation isomer (M₂BPGi) are known to be associated with lung and liver fibrosis, respectively. We explored the usefulness of KL-6 and M₂BPGi to assess BMF. A total of 250 patients who underwent BM biopsy with hematologic or non-hematologic diseases were included, and 42 patients with lung and liver diseases were excluded. The patients’ data, including age, sex, diagnosis, white blood cell, hemoglobin (Hb), platelet, and lactate dehydrogenase (LDH) were collected. Measured KL-6 and M₂BPGi levels were compared with reticulin grade (RG) (grade 0–3). KL-6 levels were significantly elevated with an increase in RG, but M₂BPGi did not show a significant difference. Hb, LDH, or KL-6 were independent predictors for BMF (odds ratio: 1.96, 2.26, 2.91, respectively), but showed poor predictive ability (area under the curve [AUC] 0.62, 0.61, 0.60, respectively). The combination of Hb, LDH, and KL-6 showed a significantly improved predictive ability for BMF (AUC 0.73; integrated discrimination improvement 0.057; category-free net reclassification improvement 0.625). This is the first study to evaluate the usefulness of KL-6 for assessing BMF. The combination of Hb, LDH, and KL-6 would be an objective and relevant biomarker approach and be applied to risk stratification for BMF.

Tumor markers are associated with rapidly progressive interstitial lung disease in adult-dermatomyositis

OBJECTIVES

DM-associated rapidly progressive interstitial lung disease (DM-RP-ILD) has been the clinical conundrum. We assess the serum levels of tumor markers (TMs) in different types of ILD, and explore the diagnostic utility of TMs for DM/ADM-RP-ILD.

METHODS

This was a retrospective cohort study, data including clinical and laboratory records were collected from the first affiliated hospital of Zhengzhou University from December 2015, to June 2020. Tumor markers (TMs) include CEA, CA153, CA724, CA125, and CA199. Spearman analysis, ROC, and Kaplan-Meier curve were used for data analysis.

RESULTS

Total 272 patients (149 DM and 123 ADM) were enrolled, 152 (55.88%) with ILD (116 with chronic ILD, 36 with RP-ILD) and 120 (44.12%) without ILD among them. The serum levels of CEA and ferritin were significantly higher in patients with RP-ILD than in the other two groups. Serum CA125, CA199, and CA153 levels in patients with RP-ILD were higher than those without ILD. CEA levels were associated with the ferritin, KL-6 and anti-MDA5 levels, and CEA concentration was significantly negatively correlated with DLco (P = 0.016, R² =  - 0.281). CEA [AUC = 0.7, 95% CI = (0.594, 0.806)] and ferritin [AUC = 0.737, 95% CI = (0.614, 0.860)] had diagnosed value for patients developing RP-ILD. Patients with high serum CEA levels had higher mortality rate within the DM-ILD population.

CONCLUSIONS

TMs and ferritin were increased in DM/ADM-RP-ILD, and serum CEA and CA153 levels can evaluate disease severity of DM. And CEA and ferritin can be used as noninvasive diagnostic biomarkers for patients with DM-RP-ILD. Key Points • Interstitial lung disease (ILD) is a serious complication of DM, and is a leading cause of mortality, especially rapidly progressive ILD. • Tumor markers as a kind of noninvasive detection can reflect the disease severity of DM, and CEA and ferritin can be used to identify patients with RP-ILD.

Low Circulating Monocytes Is in Parallel With Lymphopenia Which Predicts Poor Outcome in Anti-melanoma Differentiation-Associated Gene 5 Antibody-Positive Dermatomyositis-Associated Interstitial Lung Disease

Anti-melanoma differentiation-associated gene 5 (MDA5) antibody-positive dermatomyositis (DM)-associated interstitial lung disease (ILD) may progress rapidly and lead to high mortality within 6 or 12 months. Except for reported prognostic factors, simple but powerful prognostic biomarkers are still in need in practice. In this study, we focused on circulating monocyte and lymphocyte counts and their variation tendency in the early stage of ILD. A total of 351 patients from two inception anti-MDA5 antibody-positive cohorts were included in this study, with various treatment choices. Lymphocyte count remained lower in the first month after admission in the non-survivor patients. Although baseline monocyte count showed no significant differences, average monocyte count in the following 4 weeks was also lower in the non-survivor group. Based on the C-index and analysis by the “survminer” R package in the discovery cohort, we chose 0.24 × 109/L as the cutoff value for Mono W0-2, 0.61 × 109/L as the cutoff value for lymph W0-2, and 0.78 × 109/L as the cutoff value for peripheral blood mononuclear cell (PBMC) W0-2, to predict the 6-month all-cause mortality. The Kaplan–Meier survival curves and adjusted hazard ratio with age, gender, and the number of immunosuppressants used all validated that patients with lower average monocyte count, lower average lymphocyte count, or lower average PBMC count in the first 2 weeks after admission had higher 6-month death risk, no matter in the validation cohort or in the pooled data. Furthermore, flow cytometry figured out that non-classical monocytes in patients with anti-MDA5 antibody-positive DM were significantly lower than healthy controls and patients with DM without anti-MDA5 antibodies. In conclusion, this study elucidated the predictive value of monocyte and lymphocyte counts in the early stage and may help rheumatologists to understand the possible pathogenesis of this challenging disease.

KL-6 as an Immunological Biomarker Predicts the Severity, Progression, Acute Exacerbation, and Poor Outcomes of Interstitial Lung Disease: A Systematic Review and Meta-Analysis

Object

Interstitial lung disease (ILD) is a specific form of chronic fibrosing interstitial pneumonia with various etiology. The severity and progression of ILD usually predict the poor outcomes of ILD. Otherwise, Krebs von den Lungen-6 (KL-6) is a potential immunological biomarker reflecting the severity and progression of ILD. This meta-analysis is to clarify the predictive value of elevated KL-6 levels in ILD.

Method

EBSCO, PubMed, and Cochrane were systematically searched for articles exploring the prognosis of ILD published between January 1980 and April 2021. The Weighted Mean Difference (WMD) and 95% Confidence Interval (CI) were computed as the effect sizes for comparisons between groups. For the relationship between adverse outcome and elevated KL-6 concentration, Hazard Ratio (HR), and its 95%CI were used to estimate the risk factor of ILD.

Result

Our result showed that ILD patients in severe and progressive groups had higher KL-6 levels, and the KL-6 level of patients in the severe ILD was 703.41 (U/ml) than in mild ILD. The KL-6 level in progressive ILD group was 325.98 (U/ml) higher than that in the non-progressive ILD group. Secondly, the KL-6 level of patients in acute exacerbation (AE) of ILD was 545.44 (U/ml) higher than stable ILD. Lastly, the higher KL-6 level in ILD patients predicted poor outcomes. The KL-6 level in death of ILD was 383.53 (U/ml) higher than in survivors of ILD. The pooled HR (95%CI) about elevated KL-6 level predicting the mortality of ILD was 2.05 (1.50–2.78), and the HR (95%CI) for progression of ILD was 1.98 (1.07–3.67).

Conclusion

The elevated KL-6 level indicated more severe, more progressive, and predicted the higher mortality and poor outcomes of ILD.

Radiological Characteristics of Patients With Anti-MDA5-Antibody-Positive Dermatomyositis in 18F-FDG PET/CT: A Pilot Study

Objective: To elucidate the ¹⁸F-fluorodeoxyglucose (FDG) PET/CT characteristics and its prognostic value in the patients with anti-melanoma differentiation associated protein 5 antibody positive (anti-MDA5+) dermatomyositis (DM). Methods: This retrospective cross-sectional study included 26 patients with anti-MDA5+ DM and 43 patients with anti-MDA5 negative (anti-MDA5-) idiopathic inflammatory myopathy (IIM) who were examined by ¹⁸F-FDG PET/CT from January 1, 2017 to December 31, 2020. The maximum standardized uptake value (SUVmax) of multiple organs and other clinical characteristics of the patients were measured and analyzed. Results: Compared with the anti-MDA5- group, the patients in the anti-MDA5+ group showed higher bilateral lung SUVmax (p = 0.029), higher SUVmax of spleen (p = 0.011), and bone marrow (p = 0.048). Significant correlations between the spleen SUVmax and serum ferritin levels (r = 0.398, p < 0.001), erythrocyte sedimentation rate (ESR) (r = 0.274, p = 0.023), platelet count (r = -0.265, p= 0.028), myositis disease activity assessment score (r = 0.332, p = 0.005), bone marrow SUVmax (r = 0.564, p < 0.001), and bilateral lung SUVmax (r = 0.393, p < 0.001) were observed. Conclusion: ¹⁸F-FDG PET/CT was found valuable in quantifying the pulmonary focal inflammation and potentially unveil the distinctive characteristics and pathophysiological mechanisms in the patients with anti-MDA5+ DM.

Role of MUC1 rs4072037 polymorphism and serum KL-6 levels in patients with antisynthetase syndrome

Mucin 1/Krebs von den Lungen-6 (KL-6) is proposed as a serum biomarker of several interstitial lung diseases (ILDs), including connective tissue disorders associated with ILD. However, it has not been studied in a large cohort of Caucasian antisynthetase syndrome (ASSD) patients. Consequently, we assessed the role of MUC1 rs4072037 and serum KL-6 levels as a potential biomarker of ASSD susceptibility and for the differential diagnosis between patients with ILD associated with ASSD (ASSD-ILD +) and idiopathic pulmonary fibrosis (IPF). 168 ASSD patients (149 ASSD-ILD +), 174 IPF patients and 523 healthy controls were genotyped for MUC1 rs4072037 T > C. Serum KL-6 levels were determined in a subgroup of individuals. A significant increase of MUC1 rs4072037 CC genotype and C allele frequencies was observed in ASSD patients compared to healthy controls. Likewise, MUC1 rs4072037 TC and CC genotypes and C allele frequencies were significantly different between ASSD-ILD+ and IPF patients. Additionally, serum KL-6 levels were significantly higher in ASSD patients compared to healthy controls. Nevertheless, no differences in serum KL-6 levels were found between ASSD-ILD+ and IPF patients. Our results suggest that the presence of MUC1 rs4072037 C allele increases the risk of ASSD and it could be a useful genetic biomarker for the differential diagnosis between ASSD-ILD+ and IPF patients.

The value of KL-6 in the diagnosis and assessment of interstitial lung disease

OBJECTIVE

To investigate the value of Krebs von den Lungen-6 (KL-6) in the diagnosis and activity assessment of interstitial lung disease (ILD).

METHODS

The data of 69 ILD patients admitted to our hospital from January 2018 to January 2020 were analyzed retrospectively, and they were included in the ILD group. In addition, 69 patients with connective tissue disease (CTD) admitted to our hospital during the same period were selected and included in the non-ILD (NILD) group. The lung function, pulmonary imaging scores, and KL-6 expression levels were compared between the two groups. The patients in the ILD group were divided into two subgroups: the inactive group and the active group. The pulmonary function, pulmonary imaging scores, and the KL-6 expression levels of the patients in the two subgroups were compared. The value of KL-6 in the diagnosis and the ILD activity evaluation were analyzed.

RESULTS

The FEV1, FVC, and DLCO levels in the LID group were lower than they were in the NLID group (P<0.05). The LUS and Warrick scores in the LID group were higher than they were in the NLID group (P<0.05). The FEV1, FVC, and DLCO levels in the active group were lower than they were in the inactive group (P<0.05). The LUS and Warrick scores in the active group were higher than they were in the NLID group (P<0.05). The patients' serum KL-6 levels in the ILD group were higher than they were in the NILD group (P<0.05), and the patients' serum KL-6 levels in the ILD group were higher than they were in the inactive group (P<0.05). The Youden's index of serum KL-6 for the diagnosis of ILD was 421.775 U/ml and the sensitivity and specificity of the serum KL-6 were 91.304% and 95.652%, respectively, showing a high diagnostic value (P<0.05). The Youden's index of the serum KL-6 levels for the evaluation of the ILD activity was den Lungen-6 (KL-, with a sensitivity of 60.976% and a specificity of 100%, showing a moderate evaluation value (P<0.05).

CONCLUSION

KL-6 has a high value in the diagnosis of interstitial lung disease, and a moderate value in the assessment of interstitial lung disease activity.

Understanding and managing anti-MDA 5 dermatomyositis, including potential COVID-19 mimicry

Anti-Melanoma Differentiation-Associated gene 5 (MDA-5) Dermatomyositis (MDA5, DM) is a recently identified subtype of myositis characteristically associated with Rapidly Progressive Interstitial Lung Disease (RP-ILD) and unique cutaneous features. We reviewed PubMed, SCOPUS and Web of Science databases and selected 87 relevant articles after screening 1485 search results, aiming to gain a better understanding of the pathophysiology, clinical features, diagnosis, and treatment approaches of anti-MDA-5 DM described in the literature. The etiopathogenesis is speculatively linked to an unidentified viral trigger on the background of genetic predisposition culminating in an acquired type I interferonopathy. The clinical phenotype is highly varied in different ethnicities, with new clinical features having been recently described, expanding the spectrum of cases that should raise the suspicion of anti-MDA-5 DM. Unfortunately, the diagnosis is frequently missed despite excessive mortality, calling for wider awareness of suspect symptoms. RP ILD is the major determinant of survival, treatment being largely based on observational studies with recent insights into aggressive combined immunosuppression at the outset.

Forced vital capacity predicts the survival of interstitial lung disease in anti-MDA5 positive dermatomyositis: a multi-centre cohort study

OBJECTIVES

Anti-melanoma differentiation-associated gene 5 (MDA5) positive dermatomyositis (DM) is a life-threatening disease often complicated with rapidly progressive interstitial lung disease (ILD). This study aimed to establish and validate a clinical prediction model for 6-month all-cause mortality in Chinese patients with anti-MDA5 positive DM-ILD.

METHODS

We conducted a retrospective observational study using a single-centre derivation cohort and a multi-centre validation cohort. Hospitalized DM patients with positive anti-MDA5 antibody and ILD course ≤3 months on admission were included. Patients' baseline characteristics were described and compared between the deceased and survivors by univariable Cox regression. Optimal cut-off values were defined by the 'survminer' R package for significant continuous variables. Independent prognostic factors were determined by the final multivariable Cox regression model chosen by backward stepwise algorithm, which could be reproduced in both cohorts. The Kaplan-Meier survival analyses based on the derived predictor were conducted.

RESULTS

A total of 184 and 81 eligible patients were included with a cumulative 40.8% and 40.7% six-month mortality in the derivation and validation cohorts, respectively. Based on multivariable Cox regression, the prognostic factor at baseline was identified and validated as three-category forced vital capacity (FVC)%: FVC% ≥ 50%, FVC% <50%, unable to perform. This significantly distinguishes three risk stages with mortalities of 15.3%, 46.8%, 97.4% in the derivation cohort, and 14.9%, 58.3%, 86.4% in the validation cohort, respectively (all p < 0.05).

CONCLUSION

The validated FVC%-based categorical predictor in anti-MDA5 positive DM-ILD is helpful for risk stratification in clinical practice and might facilitate cohort enrichment for future trials.

Juvenile Dermatomyositis: New Clues to Diagnosis and Therapy

PURPOSE OF REVIEW

To identify clues to disease activity and discuss therapy options.

RECENT FINDINGS

The diagnostic evaluation includes documenting symmetrical proximal muscle damage by exam and MRI, as well as elevated muscle enzymes-aldolase, creatine phosphokinase, LDH, and SGOT-which often normalize with a longer duration of untreated disease. Ultrasound identifies persistent, occult muscle inflammation. The myositis-specific antibodies (MSA) and myositis-associated antibodies (MAA) are associated with specific disease course variations. Anti-NXP-2 is found in younger children and is associated with calcinosis; anti-TIF-1γ+ juvenile dermatomyositis has a longer disease course. The diagnostic rash-involving the eyelids, hands, knees, face, and upper chest-is the most persistent symptom and is associated with microvascular compromise, reflected by loss of nailfold (periungual) end row capillaries. This loss is associated with decreased bioavailability of oral prednisone; the bioavailability of other orally administered medications should also be considered. At diagnosis, at least 3 days of intravenous methyl prednisolone may help control the HLA-restricted and type 1/2 interferon-driven inflammatory process. The requirement for avoidance of ultraviolet light exposure mandates vitamin D supplementation.

SUMMARY

This often chronic illness targets the cardiovascular system; mortality has decreased from 30 to 1-2% with corticosteroids. New serological biomarkers indicate occult inflammation: ↑CXCL-10 predicts a longer disease course. Some biologic therapies appear promising.

Serum KL-6 Could Represent a Reliable Indicator of Unfavourable Outcome in Patients with COVID-19 Pneumonia

KL-6 is a sialoglycoprotein antigen which proved elevated in the serum of patients with different interstitial lung diseases, especially in those with a poorer outcome. Given that interstitial pneumonia is the most common presentation of SARS-CoV2 infection, we evaluated the prognostic role of KL-6 in patients with COVID-19 pneumonia. Patients with COVID-19 pneumonia were prospectively enrolled. Blood samples were collected at the time of enrolment (TOE) and on day 7 (T1). Serum KL-6 concentrations were measured by chemiluminescence enzyme immunoassay using a KL-6 antibody kit (LUMIPULSE G1200, Fujirebio) and the cut-off value was set at >1000 U/mL. Fifteen out of 34 enrolled patients (44.1%) died. Patients with unfavourable outcome showed significantly lower P/F ratio and higher IL-6 values and plasmatic concentrations of KL-6 at TOE compared with those who survived (median KL-6: 1188 U/mL vs. 260 U/mL, p < 0.001). KL-6 > 1000 U/mL resulted independently associated with death (aOR: 11.29, p < 0.05) with a positive predictive value of 83.3%. Our results suggest that KL-6 is a reliable indicator of pulmonary function and unfavourable outcome in patients with COVID-19 pneumonia. A KL-6 value > 1000 U/mL resulted independently associated with death and showed good accuracy in predicting a poorer outcome. KL-6 may thus represent a quick, inexpensive, and sensitive parameter to stratify the risk of severe respiratory failure and death.

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.

Interstitial Lung Disease in Anti-MDA5 Positive Dermatomyositis

Anti-melanoma differentiation-associated gene 5-positive dermatomyositis (MDA5⁺ DM) is a rare autoimmune disease predominantly reported in East Asia. MDA5⁺ DM is an intractable disease with impressively high mortality due to rapid-progressive interstitial lung disease (RPILD). Other typical clinical manifestations comprise DM-specific rash (Gottron's papules, heliotrope rash) and amyopathic/hypomyopathic muscle involvement. Multiple prognostic factors have been identified. Baseline forced vital capacity (FVC) %-based staging could serve as a simplified risk stratification system. Serum biomarkers including MDA5 Ab titers, ferritin, KL-6 levels, and CD4⁺CXCR4⁺ T cell percentage could provide additional surrogate value of ILD severity and treatment response, as well as potential predictive value for survival. Spontaneous pneumomediastinum (PNM), ground-glass opacity (GGO), and consolidation were demonstrated to be the most significant features in pulmonary high-resolution computed tomography (HRCT) findings of MDA5⁺ DM-ILD. The semi-quantitative assessment of lesions in HRCT has also been demonstrated relevant to the outcome. The current treatment of this disease is still largely empirical. Immunosuppressive treatments, i.e., "triple therapy" (combination of high-dose glucocorticoids, tacrolimus, and intravenous cyclophosphamide) and JAK inhibitor-based therapy, are the mainstream regimens for MDA5⁺ DM-ILD, supported by the recently published trials. However, more efficacious regimen with favorable safety profile and high-level evidence is still urgently demanded for patients with MDA5⁺ DM-ILD, especially those at advanced-stage. We will summarize the terminology, etiology and pathogenesis, clinical features and outcome, prognostic factors, and treatment of MDA5⁺ DM-ILD in this review.

The characteristics of lymphocytes in patients positive for anti-MDA5 antibodies in interstitial lung disease

OBJECTIVE

The aim was to investigate the characteristics of blood lymphocytes in patients positive for anti-melanoma differentiation-associated gene 5 antibodies (anti-MDA5+) in interstitial lung disease.

METHODS

Thirty-eight anti-MDA5+ patients with interstitial lung disease were admitted to our hospital, and the lymphocyte count, lymphocyte subtypes and lung high-resolution CT were recorded. Some of the cases were examined by bone marrow aspiration.

RESULTS

Compared with the control group, the blood lymphocyte counts of anti-MDA5+ patients before treatment were significantly lower (P < 0.05). After treatment, lung interstitial lesions in some cases were reduced and the lymphocyte counts increased, whereas their CD4:CD8 ratio decreased (P < 0.05). In contrast, lung interstitial lesions of other cases were exacerbated after treatment and the lymphocyte counts decreased, whereas the CD4:CD8 ratio increased (P < 0.05). In cases with exacerbated lung interstitial lesions after treatment, there were fewer CD4 and CD8 T cells than before treatment, and the change in CD8 T cells was significant (P < 0.05). Bone marrow aspiration biopsy indicated that there was no abnormality in the distribution of bone marrow lymphocytes.

CONCLUSION

Anti-MDA5+ patients showed a decrease in blood lymphocyte counts. The presence of anti-MDA5+ in patients with pulmonary interstitial lesions was positively correlated with blood lymphocyte counts but negatively correlated with the CD4:CD8 ratio. The CD8 T cells decreased more significantly than CD4 T cells in patients with aggravation of interstitial lung disease. The change in blood lymphocytes in anti-MDA5+ patients might be attributable to transfer of lymphocytes to the lungs to participate in the local immune response.

Noninvasive positive pressure ventilator deteriorates the outcome of pneumomediastinum in anti-MDA5 antibody-positive clinically amyopathic dermatomyositis

BACKGROUND

Anti-melanoma differentiation-associated gene 5 (MDA5) antibody (Ab)-positive clinically amyopathic dermatomyositis (CADM) with pneumomediastinum (PNM) is a life-threatening condition. We aim to determine the prognostic factors affecting survival of patients with anti-MDA5 Ab-positive CADM complicated with PNM.

METHODS

We retrospectively established a cohort of patients with anti-MDA5 Ab-positive CADM complicated with PNM from April 2013 to July 2019. Demographic data and clinical characteristics from medical records were analyzed and variables were compared between survivors and nonsurvivors. We performed univariate and multivariate survival analyses by Cox regression. Survival curves were depicted by the Kaplan-Meier method.

RESULTS

Among 133 patients with anti-MDA5 Ab-positive CADM, 20 were diagnosed with PNM. The cumulative estimated Kaplan-Meier survival rate was 85% at 1 week, 55% at 1 month, and 40% at 1 year. Univariate analysis indicated several factors associated with survival. Worse liver function (AST, p = 0.043; LDH, p = 0.002; TBIL, p = 0.038), higher CRP level (p = 0.044), higher HRCT score (p = 0.022), and using noninvasive positive pressure ventilation (NPPV) (p < 0.01) were associated with poor prognosis. In a multivariate Cox regression model, AST level and using NPPV were indicated to be independent predictors of poor prognosis.

CONCLUSION

In this research, we found that the incidence rate of PNM in anti-MDA5 Ab-positive CADM was 15.5%, obviously higher than in classical DM. The application of noninvasive positive pressure ventilator (NPPV) and higher AST level were independent risk factors for survival.Key Points• Anti-MDA5 Ab-positive CADM complicated with PNM is a life-threatening condition with an incidence rate of 15.5%.• The application of NPPV and worse liver function were independent risk factors for survival of anti-MDA5 Ab-positive CADM patients complicated with PNM.

Serum KL-6 level is a prognostic marker in patients with anti-MDA5 antibody-positive dermatomyositis associated with interstitial lung disease

Objective

This study aimed to investigate the clinical significance of Krebs von den Lungen‐6 (KL‐6) serum levels in patients with anti‐MDA5 antibody‐positive dermatomyositis (anti‐MDA5⁺ DM) having interstitial lung disease (ILD), especially in the amyopathic DM phenotype.

Methods

The serum KL‐6 level was measured using a chemiluminescence enzyme immunoassay (CLEIA) in patients with anti‐MDA5⁺ DM, including clinically amyopathic dermatomyositis (CADM)‐ILD and classic DM‐ILD, and healthy donors. The baseline and post‐treatment serum KL‐6 levels were determined in 39 patients with CADM‐ILD who experienced remission or acute exacerbation. The association between laboratory findings, high‐resolution computed tomography (HRCT) scores, pulmonary function tests (PFTs), and the predictive value of baseline KL‐6 level for death was analyzed.

Results

The serum KL‐6 levels were significantly higher in patients with CADM‐ILD (1339 ± 1329 U/mL) compared with DM‐ILD (642.3 ± 498.4 U/mL) and healthy donors (162.4 ± 54.01 U/mL). The KL‐6 levels correlated positively with chest HRCT scores, serum lactate dehydrogenase, serum ferritin levels, and PFTs, but not with erythrocyte sedimentation rate. During follow‐up, the post‐treatment serum KL‐6 levels significantly reduced in the remission/stable group, but increased in the acute exacerbation group. Higher levels of ferritin and KL‐6 and HRCT scores were independently associated with poor prognosis. The 1‐year survival rate was significantly lower in patients with high KL‐6 level than in those with low KL‐6 level.

Conclusion

The serum KL‐6 levels may be a useful marker for predicting and monitoring ILD in Chinese patients with anti‐MDA5⁺ DM, especially amyopathic DM phenotype.