Clinical characteristics and change in the antibody titres of patients with anti-MDA5 antibody–positive inflammatory myositis

Clinicopathological features and treatment outcome of juvenile idiopathic inflammatory myopathies with anti-melanoma differentiation associated gene 5 antibodies: A case series study

To characterize the clinicopathological features and treatment outcomes of juvenile idiopathic inflammatory myopathies (JIIM) with anti-melanoma differentiation associated gene 5 (MDA5) antibodies in a Chinese cohort. Anti-MDA5 antibody was detected by immunodot assay and indirect immunofluorescence assay on HEK293 cells in a series of Chinese JIIM cohort between 2005 and 2022. The clinical features, histological findings, and treatment outcomes of these anti-MDA5-antibody-positive patients were summarized. Of 59 JIIM patients, 3 (5.08%) were found to be anti-MDA5-antibody-positive. The frequency of anti-MDA5 antibody did not show significant difference between adult idiopathic inflammatory myopathies and JIIM cohorts (P = .720). The disease duration in patients with anti-MDA5 antibody was 2.83 ± 1.04 months. All 3 patients had typical skin lesions including Gottron sign and heliotrope rash, while interstitial lung disease and arthritis was only found in 1 patient. All 3 patients showed normal creatine kinase levels. On muscle biopsy, diffuse major histocompatibility complex class-I expression was seen in 3 patients and myxovirus-resistance protein A expression was found in 2 patients. All patients received long-term follow-up (6.42 ± 4.01 years). They were all drug-free and showed favorable treatment outcome with prednisone and additional immunosuppressant. Our study indicates that anti-MDA5 antibodies may not be common in Chinese JIIM. Anti-MDA5-positive JIIMs are characterized by typical skin lesions of dermatomyositis, normal CK levels, and increased major histocompatibility complex class-I expression. JIIMs with anti-MDA5 generally have good response to immunotherapies.

Association of anti-Ro-52 antibodies with occurrence of interstitial lung disease in patients with idiopathic inflammatory myopathy

BACKGROUND

Anti-Ro-52 antibodies have been associated with interstitial lung disease (ILD) in various autoimmune diseases. However, their role in ILD among patients with idiopathic inflammatory myopathies (IIMs) is relatively underexplored. This study aimed to investigate the association between anti-Ro-52 antibodies and the occurrence of ILD in individuals with IIMs.

METHODS

This retrospective observational study included 604 patients who underwent myositis autoantibody testing between July 2018 and January 2021 at our hospital and were diagnosed with either IIMs or IIM-mimics. Comparative analyses were conducted between IIMs and IIM-mimics, as well as within the IIM group between cases with and without ILD. Logistic regression or Firth's logistic regression analyses were employed to assess the risk of ILD development in different IIM subgroups and myositis antibody categories.

RESULTS

This study included 190 patients with IIM and 414 patients with IIM-mimics. Patients with IIM demonstrated higher incidence of ILD, concurrent autoimmune disease, and a greater likelihood of various myositis autoantibodies when compared to the IIM-mimics group. Within the IIM patient cohort, those with ILD exhibited a later age of onset of IIM, an increased mortality rate, and a more frequent presence of anti-aminoacyl-tRNA synthetase (ARS) antibodies compared to those without ILD. The presence of any myositis-specific antibody (MSA) was associated with a six-fold increased risk of ILD, while dual positivity for MSA and anti-Ro-52 antibodies conferred a twenty-fold risk. Anti-ARS antibodies carried a 14-fold increased risk of ILD, which escalated to 38-fold in cases of dual positivity for anti-ARS and anti-Ro-52 antibodies. Anti-Ro-52 antibodies alone increased the risk eight-fold.

CONCLUSIONS

Among patients with IIM, the presence of ILD was linked to higher mortality. Certain autoantibodies, notably anti-ARS and anti-Ro-52 antibodies, were associated with an increased risk of ILD. The greatest risk of ILD was observed in cases of dual positivity for anti-ARS and anti-Ro-52 antibodies.

Correlation between B-cell epitope profile and clinical features of anti-MDA5 antibody-positive dermatomyositis

OBJECTIVES

Anti-melanoma differentiation-associated gene 5 (MDA5) antibody-positive (MDA5+) dermatomyositis patients exhibit a variety of clinical features. We therefore investigated whether patterns of B-cell epitope recognition are linked to the clinical course of MDA5+ dermatomyositis.

METHODS

Our cross-sectional study used ELISA-based methods to determine the relationship between antibody recognition of overlapping 155 amino acid MDA5 subfragments and clinical features of 24 MDA5+ myositis patients. Correlations between clinical features and standardized anti-MDA5 subfragment antibody titres were assessed via Spearman's rank correlation coefficients.

RESULTS

Twenty-four MDA5+ patients submitted serum samples within a median of 0 (interquartile range, 0-74) days from the initial clinic visit. In addition to typical dermatomyositis rashes, these patients exhibited muscle symptoms (n = 11), vascular dysfunction (n = 9) and interstitial lung disease (ILD) (n = 16). Female patients exhibited higher titres of antibodies recognizing fragment H (aa 905-1026) compared with male patients. Muscle involvement was associated with higher levels of anti-fragment F (aa 646-801) antibody. Conversely, patients with vascular abnormalities had higher anti-fragment B (aa 130-284) and E (aa 517-671) antibody titres than those without vascular dysfunction. Four patients died due to ILD progression and showed higher anti-fragment A (aa 1-155) antibody titres than the other 20 patients. Differences in the ratio of anti-fragment to anti-full-length MDA5 antibody titres were found for sex (H: anti-MDA5) and vascular dysfunction (anti-fragment B, E: anti-MDA5).

CONCLUSIONS

Various clinical features of MDA5+ dermatomyositis correlated with levels of antibodies targeting selected subfragments of this autoantigen, providing a link between fragment-specific immune responses and disease course.

Metabolic profiling of patients with different idiopathic inflammatory myopathy subtypes reveals potential biomarkers in plasma

Idiopathic inflammatory myopathy (IIM) are heterogeneous autoimmune diseases that primarily affect the proximal muscles. IIM subtypes include dermatomyositis (DM), polymyositis (PM), and anti-synthetase syndrome (ASS). Metabolic disturbances may cause irreversible structural damage to muscle fibers in patients with IIM. However, the metabolite profile of patients with different IIM subtypes remains elusive. To investigate metabolic alterations and identify patients with different IIM subtypes, we comprehensively profiled plasma metabolomics of 46 DM, 13 PM, 12 ASS patients, and 30 healthy controls (HCs) using UHPLC-Q Exactive HF mass spectrometer. Multiple statistical analyses and random forest were used to discover differential metabolites and potential biomarkers. We found that tryptophan metabolism, phenylalanine and tyrosine metabolism, fatty acid biosynthesis, beta-oxidation of very long chain fatty acids, alpha-linolenic acid and linoleic acid metabolism, steroidogenesis, bile acid biosynthesis, purine metabolism, and caffeine metabolism are all enriched in the DM, PM, and ASS groups. We also found that different subtypes of IIM have their unique metabolic pathways. We constructed three models (five metabolites) to identify DM, PM, ASS from HC in the discovery and validation sets. Five to seven metabolites can distinguish DM from PM, DM from ASS, and PM from ASS. A panel of seven metabolites can identify anti-melanoma differentiation-associated gene 5 positive (MDA5 +) DM with high accuracy in the discovery and validation sets. Our results provide potential biomarkers for diagnosing different subtypes of IIM and a better understanding of the underlying mechanisms of IIM.

Distinct HLA associations with autoantibody-defined subgroups in idiopathic inflammatory myopathies

BACKGROUND

In patients with idiopathic inflammatory myopathies (IIM), autoantibodies are associated with specific clinical phenotypes suggesting a pathogenic role of adaptive immunity. We explored if autoantibody profiles are associated with specific HLA genetic variants and clinical manifestations in IIM.

METHODS

We included 1348 IIM patients and determined the occurrence of 14 myositis-specific or -associated autoantibodies. We used unsupervised cluster analysis to identify autoantibody-defined subgroups and logistic regression to estimate associations with clinical manifestations, HLA-DRB1, HLA-DQA1, HLA-DQB1 alleles, and amino acids imputed from genetic information of HLA class II and I molecules.

FINDINGS

We identified eight subgroups with the following dominant autoantibodies: anti-Ro52, -U1RNP, -PM/Scl, -Mi2, -Jo1, -Jo1/Ro52, -TIF1γ or negative for all analysed autoantibodies. Associations with HLA-DRB1∗11, HLA-DRB1∗15, HLA-DQA1∗03, and HLA-DQB1∗03 were present in the anti-U1RNP-dominated subgroup. HLA-DRB1∗03, HLA-DQA1∗05, and HLA-DQB1∗02 alleles were overrepresented in the anti-PM/Scl and anti-Jo1/Ro52-dominated subgroups. HLA-DRB1∗16, HLA-DRB1∗07 alleles were most frequent in anti-Mi2 and HLA-DRB1∗01 and HLA-DRB1∗07 alleles in the anti-TIF1γ subgroup. The HLA-DRB1∗13, HLA-DQA1∗01 and HLA-DQB1∗06 alleles were overrepresented in the negative subgroup. Significant signals from variations in class I molecules were detected in the subgroups dominated by anti-Mi2, anti-Jo1/Ro52, anti-TIF1γ, and the negative subgroup.

INTERPRETATION

Distinct HLA class II and I associations were observed for almost all autoantibody-defined subgroups. The associations support autoantibody profiles use for classifying IIM which would likely reflect underlying pathogenic mechanisms better than classifications based on clinical symptoms and/or histopathological features.

FUNDING

See a detailed list of funding bodies in the Acknowledgements section at the end of the manuscript.

Magnetic resonance imaging findings of the lower limb muscles in anti-mitochondrial M2 antibody-positive myositis

Anti-mitochondrial M2 antibody (AMA-M2)-positive myositis is an idiopathic inflammatory myopathy (IIM). Of all patients with myositis, 2.5-19.5% have AMA-M2 antibodies. However, the detailed distribution of muscles affected in AMA-positive myositis is unknown. Therefore, we examined lower muscle magnetic resonance imaging (MRI) findings of patients with AMA-positive myositis. Among the 63 patients with IIM at our institute, 5 (7.9%) were positive for AMA-M2 antibodies. However, one was also positive for anti-Jo1 antibodies; therefore, four patients were finally participated in this study. All patients had high-intensity MRI signals in the proximal muscles, including the gluteus maximus and iliopsoas muscles, and in the thigh muscles, including the vastus lateralis, vastus medialis, adductor magnus, and semimembranosus muscles. Lower leg muscles were relatively spared. Fascial edema was observed in all patients and was also present in the lower leg muscles. Subcutaneous edema was observed, particularly in the proximal portion of the lower limbs. In AMA-positive myositis, proximal muscles, including the gluteus maximus, vastus lateralis, adductor magnus, and the semimembranosus, were markedly affected, while the lower leg muscles were relatively preserved. Additionally, fascial edema was evident even in lower leg muscles. Therefore, muscle MRI can be a useful diagnostic aid for AMA-positive myositis.

Association Between HLA Alleles and Autoantibodies in Dermatomyositis Defined by Sarcoplasmic Expression of Myxovirus Resistance Protein A

OBJECTIVE

The diagnosis in the studies analyzing HLA of dermatomyositis (DM) was based on a combined clinical category of polymyositis/DM. This retrospective study investigated the associations of HLA with 5 DM-specific autoantibodies in Japanese patients diagnosed by muscle pathology.

METHODS

We diagnosed Japanese patients with DM based on sarcoplasmic expression of myxovirus resistance protein A. These patients underwent investigation for 5 DM-specific autoantibodies and HLA genotyping.

RESULTS

Of 175 patients (83 males and 92 females; range 1-86 yrs; mean 46 yrs), 173 (98.9%) had 1 of the 5 autoantibodies. Seven alleles-A*02:07, B*46:01, DRB1*04:07, DRB1*07:01, DRB1*08:03, DQB1*06:01, and DPB1*02:02-were more frequently detected in the patients with DM than healthy controls, but these associations were not significant after multiple testing correction. Stratifying by DM-specific autoantibodies, we found the associations of 6 already known and 7 new alleles-B*48:01, B*52:01, C*12:02, DRB1*04:05, DRB1*15:02, DPB1*05:01, and DPB1*09:01-with subsets of DM. Moreover, significant associations of 5 alleles with antinucleosome remodeling deacetylase complex (Mi-2) remained after multiple testing correction. In particular, the DRB1*04:07 (odds ratio [OR 28.9]; corrected P = 2.7 × 10-6) and DQB1*06:01 (OR 4.0; corrected P = 1.6 × 10-4) alleles were significantly more prevalent in patients with anti-Mi-2 antibody than in controls.

CONCLUSION

This study demonstrates DM-specific autoantibodies defined immunogenetic subsets of DM.

The prevalence and effects of treatments of rapidly progressive interstitial lung disease of dermatomyositis/polymyositis adults: A systematic review and meta-analysis

Rapidly progressive interstitial lung disease (RP-ILD) clearly harms the prognoses of dermatomyositis/polymyositis (DM/PM) patients, however there is a dearth of numerical prevalence and therapy comparison in this field. Therefore, the purpose of this study was to determine the prevalence of RP-ILD in DM/PM patients and compare prognoses, including remission rate and survival data, between treatments. Studies with reports of RP-ILD in DM/PM patients and studies with definite remission and/or survival data of DM/PM-RP-ILD were included in the study. Data sources were Pubmed, Embase, and Cochrane Library without language restrictions. Two authors (WHL and WWQ) extracted independently the data. Estimates of the pooled effects were calculated using the Mantel-Haenszel technique (random effects). The prevalence meta-analysis included 18 papers with 6058 DM/PM patients, and 31 papers were analyzed for treatment effects, including remission rate, 6-month survival rate, 1-year survival rate, and 5-year survival rate. Database search yielded 1816 articles. In the DM/PM population, the combined prevalence of RP-ILD was 8.9% (95% CI, 5.8% to 12.1%). Patients with RP-ILD have a remission rate of 58.4% (95% CI, 47.3% to 69.4%), with biologic treatment with the highest remission rate, followed by triple therapy (defined as adding a third intravenous medication, including cyclophosphamide and immunoglobulin). Biologics therapy had the highest overall survival rate at six months (95% CI, 49.8% to 73.9%), followed by cDMARDs, plasma exchange, and triple therapy. The 1-year survival rate was 77.4% (95% CI, 66.7% to 88.1%), and triple therapy and cDMARDs had the best survival rates. The 5-year survival rate was 40.0% (95% CI, 10.0% to 69.9%). The prevalence of RP-ILD in DM/PM was approximately 8.9%, with a poor long-term prognosis. The use of biological agents appears to provide the best therapeutic outcomes, providing RP-ILD management with a novel evidence-based therapy. The use of strong immunosuppressive treatments may result in life-threatening side effects, thus clinicians must closely monitor the condition.

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.

Long-term risks of malignancy in myositis-specific antibody-positive idiopathic inflammatory myopathy

To identify the long-term risks of malignancy in patients with myositis-specific antibody (MSA)-positive idiopathic inflammatory myopathy (IIM). This retrospective cohort study included 216 IIM patients (aged > 18 years). Of these, 109 patients were positive for antibodies against anti-aminoacyl-tRNA synthetase (ARS), melanoma differentiation-associated gene 5 (MDA5), Mi-2, and transcriptional intermediary factor 1-γ (TIF1-γ). Age- and sex-matched standardized incidence ratios (SIRs) were calculated to compare the incidence of malignancy in IIM patients to that of the general population. The malignancy-free survival rate was estimated by Kaplan-Meier methods. Our study included 109 patients, 64 with anti-ARS, 28 with anti-MDA5, 9 with anti-Mi-2, and 8 with anti-TIF1-γ antibodies; 16 and 5 patients were diagnosed with a malignancy within 3 years before or after and within 4 to 10 years after their IIM onset, respectively. The SIRs of malignancy within 3 years of IIM onset for each MSA were calculated as follows: 2.12 (95% confidence interval [CI] 0.98-4.35) for anti-ARS, 1.87 (95% CI 0.48-4.97) for anti-MDA5, 2.11 (95% CI 0.11-13.69) for anti-Mi-2, and 9.30 (95% CI 2.98-25.58) for anti-TIF1-γ antibodies. The SIR at 4 to 10 years after IIM onset in patients with an anti-MDA5 antibody was 4.62 (95% CI 1.19-14.72); other MSAs did not have statistically significant SIRs. The long-term SIR of malignancy in patients with an anti-MDA5 antibody was 4.62 (95% CI 1.19-14.72), and the SIR among patients with an anti-TIF1-γ antibody within 3 years of IIM onset was 9.30 (95% CI 2.98-25.58). Screening for malignancies in patients with late phase of IIM and an anti-MDA5 antibody may be beneficial.

MDA5 expression is associated with TGF-β-induced fibrosis: potential mechanism of interstitial lung disease in anti-MDA5 dermatomyositis

OBJECTIVES

This study aimed to investigate the high-resolution CT (HRCT) characteristics of anti-melanoma differentiation-associated gene 5 (MDA5) antibody positive dermatomyositis-associated interstitial lung disease (anti-MDA5 DM-ILD), and to clarify the underlying mechanisms of the clinical phenomenon.

METHODS

Clinical data and HRCT patterns were compared between anti-MDA5 DM-ILD (n = 32) and antisynthetase syndrome-associated ILD (ASS-ILD) (n = 29). RNA sequencing of whole-blood samples from the two groups, and in vitro experiments using human embryonic lung fibroblasts (HELFs) were conducted to explore the potential mechanisms of the clinical findings.

RESULTS

The anti-MDA5 DM-ILD subset had a significantly higher incidence of rapidly progressive ILD (RPILD) than ASS-ILD (65.6% vs 37.9%; P = 0.031). The relative percentage of the lung fibrosis HRCT pattern was significantly lower in the anti-MDA5 DM-ILD group, especially the RPILD subgroup (P = 0.013 and 0.003, respectively). RNA sequencing detected the upregulated genes including interferon-induced helicase C domain 1 (encoding MDA5), and a trend towards downregulated expression of TGF-β signalling components in anti-MDA5 DM-ILD. In vitro culture of HELFs revealed that upregulated expression of MDA5 in HELFs was correlated with the downregulated expression of alpha smooth muscle actin, connective tissue growth factor, collagen I and collagen III by suppressing the TGF-β signalling pathway.

CONCLUSIONS

Anti-MDA5 DM-ILD patients have significantly less lung fibrosis and elevated MDA5 expression. The upregulated expression of MDA5 has relations with the suppression of the pro-fibrotic function of fibroblasts via the TGF-β signalling pathway, which may partially explain the mechanism of the clinical phenomenon.

Evaluation of the Performance of an Indirect Immunofluorescence Assay for the Detection of Anti-MDA5 Antibodies

Anti-melanoma differentiation-associated protein 5 (MDA5) antibody (Ab) positive dermatomyositis (anti-MDA5 DM) is a rare systemic autoimmune disease; further, its prognosis can be rapidly fatal due to pulmonary involvement. The identification and quantification of anti-MDA5 Abs, which serve as a highly specific biomarker of the disease, is a critical step for the establishing of both the diagnosis and monitoring of the disease's activity. The development of a simple, fast, low-cost, and specific detection system of anti-MDA5 Ab is therefore highly desirable for the purposes of routine laboratory diagnosis. Here, we developed a human cell line that stably expresses MDA5 and evaluated its analytical performance in order to detect anti-MDA5 Abs by the utilization of indirect immunofluorescence (IIF). Serum samples from 23 anti-MDA5 DM patients and 22 anti-MDA5 Abs negative myositis readings, which were obtained at time of diagnosis, were analyzed by IIF on MDA5-transfected cells. The results were compared with those obtained with specific semi-quantitative (immunodot) and quantitative (ELISA) assays. A specific cytoplasmic pattern was found solely with the sera of anti-MDA5 DM patients. The sensitivity and specificity of IIF on MDA5-transfected cells were 96% and 100%, respectively, compared with ELISA. The anti-MDA5 Abs titers that were determined by this approach were consistent with the quantitative results obtained by ELISA. Baseline concentrations of anti-MDA5 Abs, either by ELISA or IIF, were not significantly different between surviving and deceased patients; further, they did not differ significantly according to clinical phenotypes. Overall, an IIF cell-based assay constitutes a simple, fast, and low-cost approach to identify and quantify anti-MDA5 Abs; moreover, it is as efficient as ELISA.

Predictors of progression in idiopathic inflammatory myopathies with interstitial lung disease

The idiopathic inflammatory myopathies (IIMs) are a group of connective tissue diseases that afect multiple organ systems, including the lungs. Interstitial lung disease (ILD) is the most common and heterogeneous complication of IIMs, with its degree ranging from mild to fatal. Thus, it is critical to identify clinical features and validated biomarkers for predicting disease progression and prognosis, which could be beneficial for therapy adjustment. In this review, we discuss predictors for rapid progression of IIM-ILD and propose guidance for disease monitoring and implications of therapy. Systematic screening of myositis-specific antibodies, measuring serum biomarker levels, pulmonary function tests, and chest high-resolution computer tomography will be beneficial for the evaluation of disease progression and prognosis.

Single-cell profiling reveals distinct adaptive immune hallmarks in MDA5+ dermatomyositis with therapeutic implications

Anti-melanoma differentiation-associated gene 5-positive dermatomyositis (MDA5+ DM) is an autoimmune condition associated with rapidly progressive interstitial lung disease and high mortality. The aetiology and pathogenesis of MDA5+ DM are still largely unknown. Here we describe the immune signatures of MDA5+ DM via single-cell RNA sequencing, flow cytometry and multiplex immunohistochemistry in peripheral B and T cells and in affected lung tissue samples from one patient. We find strong peripheral antibody-secreting cell and CD8+ T cell responses as cellular immune hallmarks, and over-stimulated type I interferon signaling and associated metabolic reprogramming as molecular immune signature in MDA5+ DM. High frequency of circulating ISG15+ CD8+ T cells at baseline predicts poor one-year survival in MDA5+ DM patients. In affected lungs, we find profuse immune cells infiltration, which likely contributes to the pro-fibrotic response via type I interferon production. The importance of type I interferons in MDA5+ DM pathology is further emphasized by our observation in a retrospective cohort of MDA5+ DM patients that combined calcineurin and Janus kinase inhibitor therapy show superior efficacy to calcineurin inhibitor monotherapy. In summary, this study reveals key immune-pathogenic features of MDA5+ DM and provides a potential basis for future tailored therapies.

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.

Biomarkers of disease activity in dermatomyositis

PURPOSE OF REVIEW

This review provides updates regarding biomarker studies that address key clinical unmet needs, which relate to the evaluation of the disease activity in patients with dermatomyositis.

RECENT FINDINGS

Increasing evidence supports that the serum levels of dermatomyositis-specific antibodies (DM-MSAs), which include anti-Mi-2, anti-NXP2, anti-MDA5, anti-TNF1-γ, and anti-SAE, are correlated with the disease activity. Moreover, serial measurements of DM-MSA levels may help to predict the disease status. Beyond the MSA, macrophage activation-related biomarker-soluble CD163, CD206, neopterin, and galectin-3/9 are the most currently talked biomarkers for disease activity in dermatomyositis; new circulating T-cell subsets CD4+CXCR5+CCR7loPD-1hi and TIGIT+CD226+ CD4 T cells can potentially harbor biomarkers of disease activity in dermatomyositis. In addition, LDGs and NETs were also shown to be correlated with the disease activities of dermatomyositis.

SUMMARY

Promising candidate biomarkers are now available for evaluating disease activity in dermatomyositis. These biomarkers need external validation in other large cohort studies.

Friend or foe: RIG- I like receptors and diseases

Retinoic acid-inducible gene I (RIG-I)-like receptors (RLRs), which are pivotal sensors of RNA virus invasions, mediate the transcriptional induction of genes encoding type I interferons (IFNs) and proinflammatory cytokines, successfully establishing host antiviral immune response. A few excellent reviews have elaborated on the structural biology of RLRs and the antiviral mechanisms of RLR activation. In this review, we give a basic understanding of RLR biology and summarize recent findings of how RLR signaling cascade is strictly controlled by host regulatory mechanisms, which include RLR-interacting proteins, post-translational modifications and microRNAs (miRNAs). Furthermore, we pay particular attention to the relationship between RLRs and diseases, especially how RLRs participate in SARS-CoV-2, malaria or bacterial infections, how single-nucleotide polymorphisms (SNPs) or mutations in RLRs and antibodies against RLRs lead to autoinflammatory diseases and autoimmune diseases, and how RLRs are involved in anti-tumor immunity. These findings will provide insights and guidance for antiviral and immunomodulatory therapies targeting RLRs.

Pathophysiological Mechanisms and Treatment of Dermatomyositis and Immune Mediated Necrotizing Myopathies: A Focused Review

Idiopathic inflammatory myopathies (IIM), collectively known as myositis, are a composite group of rare autoimmune diseases affecting mostly skeletal muscle, although other organs or tissues may also be involved. The main clinical feature of myositis is subacute, progressive, symmetrical muscle weakness in the proximal arms and legs, whereas subtypes of myositis may also present with extramuscular features, such as skin involvement, arthritis or interstitial lung disease (ILD). Established subgroups of IIM include dermatomyositis (DM), immune-mediated necrotizing myopathy (IMNM), anti-synthetase syndrome (ASyS), overlap myositis (OM) and inclusion body myositis (IBM). Although these subgroups have overlapping clinical features, the widespread variation in the clinical manifestations of IIM suggests different pathophysiological mechanisms. Various components of the immune system are known to be important immunopathogenic pathways in IIM, although the exact pathophysiological mechanisms causing the muscle damage remain unknown. Current treatment, which consists of glucocorticoids and other immunosuppressive or immunomodulating agents, often fails to achieve a sustained beneficial response and is associated with various adverse effects. New therapeutic targets have been identified that may improve outcomes in patients with IIM. A better understanding of the overlapping and diverging pathophysiological mechanisms of the major subgroups of myositis is needed to optimize treatment. The aim of this review is to report on recent advancements regarding DM and IMNM.

A Matrix Prediction Model for the 6-Month Mortality Risk in Patients With Anti-Melanoma Differentiation-Associated Protein-5-Positive Dermatomyositis

Objectives

The purpose of this study was to investigate the baseline independent risk factors for predicting 6-month mortality of patients with anti-melanoma differentiation-associated gene 5 (anti-MDA5)-positive dermatomyositis (DM) and develop a matrix prediction model formed by these risk factors.

Methods

The hospitalized patients with DM who completed at least 6-month follow-up were recruited as a derivation cohort. The primary exposure was defined as positive anti-MDA5 at the baseline. The primary outcome was all-cause 6-month mortality after enrollment. A matrix prediction model was developed in the derivation cohort, and another published cohort was used for external validation.

Results

In derivation cohort, 82 patients with DM were enrolled (mean age of onset 50 ± 11 years and 63% women), with 40 (49%) showing positive anti-MDA5. Gottron sign/papules (OR: 5.135, 95%CI: 1.489–17.708), arthritis (OR: 5.184, 95%CI: 1.455–18.467), interstitial lung disease (OR: 7.034, 95%CI: 1.157–42.785), and higher level of C4 (OR: 1.010, 95%CI: 1.002–1.017) were the independent associators with positive anti-MDA5 in patients with DM. Patients with anti-MDA5-positive DM had significant higher 6-month all-cause mortality than those with anti-MDA5-negative (30 vs. 0%). Among the patients with anti-MDA5-positive DM, compared to the survivors, non-survivors had significantly advanced age of onset (59 ± 6 years vs. 46 ± 9 years), higher rates of fever (75 vs. 18%), positive carcinoma embryonic antigen (CEA, 75 vs. 14%), higher level of ferritin (median 2,858 ug/L vs. 619 ug/L, all p < 0.05). A stepwise multivariate Cox regression showed that ferritin ≥1,250 μg/L (HR: 10.4, 95%CI: 1.8–59.9), fever (HR: 11.2, 95%CI: 2.5–49.9), and positive CEA (HR: 5.2, 95%CI: 1.0–25.7) were the independent risk factors of 6-month mortality. A matrix prediction model was built to stratify patients with anti-MDA5-positive DM into different subgroups with various probabilities of 6-month mortality risk. In an external validation cohort, the observed 6-month all-cause mortality was 78% in high-risk group, 43% in moderate-risk group, and 25% in low-risk group, which shows good accuracy of the model.

Conclusion

Baseline characteristics such as fever, ferritin ≥1,250 μg/L, and positive CEA are the independent risk factors for 6-month all-cause mortality in patients with anti-MDA5-positive DM. A novel matrix prediction model composed of these three clinical indicators is first proposed to provide a chance for the exploration of individual treatment strategies in anti-MDA5-positive DM subgroups with various probabilities of mortality risk.

Elevated spleen FDG uptake predicts unfavorable outcome in adult idiopathic-inflammatory-myopathy patients: a crisis beyond muscles

BACKGROUND

Idiopathic inflammatory myopathy (IIM) is a group of autoimmune diseases that frequently leads to unfavorable outcome. This study aimed at identifying the clinical value of PET/CT scan in predicting the outcome of adult IIM patients.

METHODS

Adult IIM patients who were admitted to the four divisions of the First Affiliated Hospital, Zhejiang University School of Medicine (FAHZJU), from January 1, 2017, to December 31, 2020, were retrospectively reviewed. PET/CT scan and other factors of IIM patients who met the inclusion and exclusion criteria were collected and analyzed.

RESULTS

A total of 69 adult IIM patients were finally enrolled into this study. Thirty cases (43.5%) of all the patients enrolled died in follow-up, and the medium follow-up time was 11.90 (4.00, 23.80) months. In particular, 14 patients died within 3 months. The univariate Cox proportional hazards regression analyses revealed pulmonary bacterial infection (P < 0.001), rapidly progressive interstitial lung disease (RP-ILD, P = 0.018), maximum standard uptake value of spleen (spleen SUVmax, P = 0.002), and positivity of anti-MDA5 antibody (P = 0.041) were significantly related to survival in follow-up. The following multivariate Cox proportional hazards regression analysis identified pulmonary bacterial infection (P = 0.003) and spleen SUVmax (P = 0.032) as factors significantly associated with survival of IIM-ILD patients. The subsequent receiver operating characteristic curve analysis showed SUVmax was comparably effective in predicting death within 3 months.

CONCLUSION

Spleen SUVmax and complication of pulmonary bacterial infection were significantly associated with survival of IIM patients. In addition, elevated spleen SUVmax was efficient in predicting unfavorable outcome of adult IIM patients. Key Points • IIM is a group of autoimmune diseases that frequently leads to unfavorable outcome • Complications of splenic SUVmax and pulmonary bacterial infection were significantly associated with survival in IIM patients.

Clinical features and immune-related protein patterns of anti-MDA5 positive clinically amyopathic dermatomyositis Dutch patients

OBJECTIVES

The presence of melanoma differentiation-associated protein 5 (MDA5) antibodies in patients with dermatomyositis (DM) is associated with the development of a rapidly progressive interstitial lung disease (RPILD), unresponsive to conventional treatment. We characterize patients and provide more insight into potential biomarkers to identify patients with RPILD.

METHODS

Patients diagnosed with anti-MDA5 positive DM between December 2015 and November 2017 were included in this study. Clinical data were retrospectively retrieved from medical records. 180 immune-related markers were measured in sera of 16 patients and 15 healthy controls using proximity extension assay based technology.

RESULTS

Twenty patients were included, with a median time from symptoms till diagnosis of 4 months. All patients had clinically amyopathic DM. Interstitial lung disease (ILD) was present at diagnosis in 94% of the patients, 45% presented with RPILD. The mortality rate was 35% within 4 months after diagnosis and respiratory failure was the main cause of death in these patients. Furthermore, unsupervised analysis revealed that patients with RPILD show clearly different inflammatory serum profiles than healthy controls. In addition, in comparison to healthy controls, the interferon, Interleukin (IL)1, IL10 and IL18 signalling pathways are different regulated in anti-MDA5 positive patients.

CONCLUSION

In this Dutch anti-MDA5 positive CADM cohort, one third of the patients died due to RPILD soon after diagnosis, which underlines the severity of this disease. In addition, we have found several possible pathways that are differentially regulated in RPILD vs no RPILD DM and healthy controls. These markers await further validation before clinical use.

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 antifibrotics in the management of idiopathic inflammatory myopathy associated interstitial lung disease

The antifibrotic therapies nintedanib and pirfenidone were first approved by the United States for the treatment of idiopathic pulmonary fibrosis in 2014. In 2020, nintedanib received U.S. Food and Drug Administration (FDA) approval for the treatment of all progressive fibrosing interstitial lung disease (ILD). Given that a major cause of mortality and morbidity in the idiopathic inflammatory myopathies (IIM) is progressive interstitial lung disease and respiratory failure, antifibrotic therapies may be useful as adjuvant to traditional immunosuppression. However, randomized controlled trials of antifibrotic therapies in IIM are lacking. The purpose of this review is to (1) summarize the mechanism of action of nintedanib and pirfenidone in ILD with possible role in IIM-ILD, (2) review the clinical data supporting their use in interstitial lung disease in general, and more specifically in connective tissue disease associated ILD, and (3) discuss the evidence and remaining challenges for using antifibrotic therapies in IIM-ILD.

Clinical Value of 18F-FDG PET/CT Scan and Cytokine Profiles in Secondary Hemophagocytic Lymphohistiocytosis in Idiopathic Inflammatory Myopathy Patients: A Pilot Study

Background

Secondary hemophagocytic lymphohistiocytosis (sHLH) is a rare but fatal complication in idiopathic inflammatory myopathy (IIM) patients. The clinical value of radiological manifestations and serum cytokines remain unknown in this systemic crisis. This study aims to investigate the clinical value of PET/CT scan and cytokine profiles in predicting and understanding sHLH in IIM patients.

Methods

Adult IIM patients who were admitted to the four divisions of the First Affiliated Hospital, Zhejiang University School of Medicine (FAHZJU) from January 1, 2017 to December 31, 2020 were reviewed. PET/CT scan, cytokine profiles, and other factors of patients who met the inclusion and exclusion criteria were collected and analyzed.

Results

Sixty-nine out of 352 IIM patients were finally enrolled into the study. Ten patients developed sHLH and 70.0% of them died within 6 months. After false discovery rate (FDR) correction and multivariate logistic regression analysis, increased serum interferon (IFN)-γ level (p = 0.017), higher spleen mean standard uptake value (SUVmean, p = 0.035), and positivity of anti-MDA5 antibody (p = 0.049) were found to be significantly correlated with development of sHLH in IIM patients. The combination of serum IFN-γ, spleen SUVmean, and anti-MDA5 antibody found a balanced and satisfying predictor with a cutoff value of 0.047 and AUC of 0.946. A moderate correlation was identified between ferritin and spleen SUVmean (p = 0.001, r = 0.380) as well as serum IFN-γ(p = 0.001, r = 0.398). Before FDR correction, higher bilateral lung SUVmean (p = 0.034) and higher colon/rectum SUVmean (p = 0.013) were also observed in IIM patients who developed sHLH. By narrowing down to IIM patients with sHLH, anti-MDA5-antibody-positive DM patients tended to suffer from unfavorable outcome (p = 0.004) in Kaplan–Meier survival analysis.

Conclusion

Increased serum level of IFN-γ, elevated splenic FDG uptake, and positivity of anti-MDA5 antibody were significantly correlated with development of sHLH in IIM patients. Lung and lower digestive tract might also be affected due to systemic immune activation in IIM patients with sHLH. In addition, splenic FDG uptake, in combination with serum IFN-γand anti-MDA5 antibody, was found valuable in predicting development of sHLH in IIM patients. Among IIM patients with sHLH, anti-MDA5-antibody-positive DM patients showed higher tendency for unfavorable outcome.

The Risk Factors of Exacerbation in Interstitial Pneumonia With Autoimmune Features: A Single-Center Observational Cohort Study

Objectives

To investigate the long-term outcomes, including risk factors, for exacerbation between monotherapy and combination therapy in patients with interstitial pneumonia with autoimmune features (IPAF).

Methods

We assessed 672 patients between April 2009 and March 2019 who were evaluated using high-resolution computed tomography (HRCT) of the chest. We applied the IPAF criteria. Fifty-two patients who visited our department for at least 6 months were diagnosed with IPAF. Clinical, laboratory, and imaging data were collected from medical records and statistically analyzed.

Results

Among the 52 cases of IPAF, we compared the characteristics at diagnosis between treated (n = 28) and untreated patients (n = 24). The exacerbation rates were 42.9% (n = 12) and 8.3% (n = 2) (P = 0.0051), respectively. Among the treated patients, smoking history, high titer of KL-6, and the duration from diagnosis to the start of treatment were significant risk factors for exacerbation (P = 0.0062, 0.011, and 0.019, respectively). The number of risk factors was significantly and positively associated with exacerbation rate (P = 0.0053). Among the treated patients, glucocorticoid (GC) monotherapy was used in 13 cases, and GC and immunosuppressant (IS) combination therapy was used in 14 patients. There was no significant difference in the treatment methods between patients with and without risk factors (P = 0.47). When comparing the long-term outcomes between the monotherapy and combination therapy groups, the 3-year non-exacerbation rates were 72.9 and 45.9% (P = 0.020), respectively.

Conclusions

IPAF patients with risk factors had a high exacerbation rate, regardless of the type of treatment. New interventions aimed at preventing exacerbations in these patients are required.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40744-021-00371-3.

Evaluation of Prognostic Factors in Anti-MDA5 Antibody-Positive Patients in Chongqing, China: A Retrospective Study

Objective

The aim of our study was to elucidate the potential prognostic factors in anti-melanoma differentiation-associated gene 5 (anti-MDA5)-positive patients.

Methods

We divided anti-MDA5-positive patients into death and survival groups. The differences in clinical characteristics were analyzed.

Results

A total of 56 cases were included. The death group comprised 10 (17.9%) cases, and the survival group comprised 46 (82.1%) cases. Median age of the death group was greater than the survival group, 59.50 years vs 39.25 years, p<0.05. The death group had lower lymphocyte count and albumin and higher erythrocyte sedimentation rate, ferritin and lactate dehydrogenase initially (p<0.05, respectively). Ground-glass opacity on chest computed tomography was found more often in the death group (p<0.05), in which there was an absence of honey-combed shadow initially. The diagnosis of interstitial pneumonia with autoimmune features was higher in the death group than the survival group (70% vs 13%, p<0.05). The median dose of maximum daily methylprednisolone in the death group (160 mg/d) was higher than that in the survival group (48 mg/d) (p<0.05).

Conclusion

Advanced age, low lymphocyte count and albumin, and increased levels of inflammatory markers may portend poor prognosis in anti-MDA5-positive patients. Extra-large doses of glucocorticoid may have no additional benefit in these patients.

Prognostic values of anti-Ro52 antibodies in anti-MDA5-positive clinically amyopathic dermatomyositis associated with interstitial lung disease

OBJECTIVE

Anti-Ro52 antibody often co-occurs with anti-Jo1 antibody in antisynthetase syndrome and their co-occurrence correlates with a more aggressive clinical phenotype and poorer prognosis. The strong association of anti-Ro52 antibody with anti-melanoma differentiation-associated protein-5 (anti-MDA5) antibody has been indicated in juvenile myositis. The aim of this study was to assess the clinical significance of anti-Ro52 antibody in a cohort of adult patients with anti-MDA5-positive clinically amyopathic dermatomyositis with interstitial lung disease (CADM-ILD).

METHODS

We assessed a cohort of 83 consecutive patients with anti-MDA5-positive CADM-ILD. Anti-MDA5 antibodies and anti-Ro52 antibodies were detected in immunoblotting and semi-quantitatively analysed by densitometry. Clinical features and the 24 month survival were compared between anti-MDA5-positive patients with and without anti-Ro52 antibodies.

RESULTS

Anti-Ro52 antibodies were found in 74.7% of anti-MDA5-positive CADM-ILD patients and were associated with an increased frequency of rapidly progressive interstitial lung disease (RP-ILD; 54.8% vs 23.8%; P = 0.014) and cutaneous ulcerations (27.4% vs 4.8%; P = 0.033). The cumulative 24 month survival rate tended to be lower in patients with anti-Ro52 antibodies than patients without (59.9% vs 85.7%; P = 0.051). The combination of anti-Ro52 antibody status and anti-MDA5 antibody levels further stratified patients' survival rates, showing that the survival rate of patients who were dual positive for anti-MDA5 antibody and anti-Ro52 antibody was significantly lower than patients with mild positive anti-MDA5 antibody alone (59.9% vs 100%; P = 0.019).

CONCLUSION

Anti-Ro52 antibody is highly prevalent in anti-MDA5-positive CADM-ILD patients and their coexistence correlates with a subgroup of patients with more aggressive phenotypes. The combination of anti-MDA5 antibody levels and anti-Ro52 antibody status could help to predict patients' prognosis and guide risk-based therapy.

The lungs were on fire: a pilot study of 18F-FDG PET/CT in idiopathic-inflammatory-myopathy-related interstitial lung disease

Background

Interstitial lung disease (ILD) and its rapid progression (RP) are the main contributors to unfavourable outcomes of patients with idiopathic inflammatory myopathy (IIM). This study aimed to identify the clinical value of PET/CT scans in IIM-ILD patients and to construct a predictive model for RP-ILD.

Methods

Adult IIM-ILD patients who were hospitalized at four divisions of the First Affiliated Hospital, Zhejiang University School of Medicine (FAHZJU), from 1 January 2017 to 31 December 2020 were reviewed. PET/CT scans and other characteristics of patients who met the inclusion and exclusion criteria were collected and analysed.

Results

A total of 61 IIM-ILD patients were enrolled in this study. Twenty-one patients (34.4%) developed RP-ILD, and 24 patients (39.3%) died during follow-up. After false discovery rate (FDR) correction, the percent-predicted diffusing capacity of the lung for carbon monoxide (DLCO%, P = 0.014), bilateral lung mean standard uptake value (SUVmean, P = 0.014) and abnormal mediastinal lymph node (P = 0.045) were significantly different between the RP-ILD and non-RP-ILD groups. The subsequent univariate and multivariate logistic regression analyses verified our findings. A “DLM” model was established by including the above three values to predict RP-ILD with a cut-off value of ≥ 2 and an area under the curve (AUC) of 0.905. Higher bilateral lung SUVmean (P = 0.019) and spleen SUVmean (P = 0.011) were observed in IIM-ILD patients who died within 3 months, and a moderate correlation was recognized between the two values.

Conclusions

Elevated bilateral lung SUVmean, abnormal mediastinal lymph nodes and decreased DLCO% were significantly associated with RP-ILD in IIM-ILD patients. The “DLM” model was valuable in predicting RP-ILD and requires further validation.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13075-021-02578-9.

Myositis-Related Interstitial Lung Disease: A Respiratory Physician's Point of View

Idiopathic inflammatory myositis (IIM) is an umbrella term for diseases of unknown origin that cause muscle inflammation. Dermatomyositis and polymyositis are IIMs that commonly cause interstitial lung disease (ILD). When a patient presents with ILD, the evaluation of whether the case displays the characteristics of myositis should be determined by interview, physical examination, imaging findings, the measurement of myositis-related antibodies, and the determination of disease severity after diagnosis. Rapidly progressing anti-melanoma differentiation-associated gene 5 antibody-positive ILD may require rapid multi-drug therapy, while anti-aminoacyl tRNA synthetase (ARS) antibody-positive ILD can be treated with anti-inflammatory drugs. Importantly, however, anti-ARS antibody-positive ILD often recurs and sometimes develops into fibrosis. Early diagnosis is crucial for treatment, and we therefore need to clarify the features of myositis associated with ILD and suspect these pathologies early. This section reviews what clinicians need to look for and what findings are evaluated in patients when diagnosing myositis associated with ILD.

Fast-Onset Diffuse Interstitial Lung Disease in Anti-MDA5 Antibodies-Associated Amyopathic Dermatomyositis

Anti-MDA5 antibodies-associated amyopathic dermatomyositisis a rare autoimmune disease that involve polyarthritis, cutaneous and pulmonary manifestations. The development of rapidly progressing interstitial lung disease is a life-threatening complication. We report the case of a 45-year-old woman without medical history, who was addressed to the Pulmonary Department for a polyarthritis with dry cough and hypoxemic dyspnea. Initially there was neither cutaneous manifestation nor interstitial lung disease on chest CT scan. After a few days, the patient developed fatal acute respiratory failure with diffuse ground glass opacities. Identification of anti-MDA5 antibodies allowed establishing diagnosis, despite the fact that the first immunological assessment was negative. Corticosteroid bolus of 1 g for three days and immunosuppressive treatment by cyclophosphamide was only initiated at the acute respiratory distress syndrome stage. Given the rapidly unfavorable prognosis of this entity of amyopathic dermatomyositis, the testing for anti-MDA5 antibodies should be recommended in case of progressive pulmonary symptoms associated with joint signs in order to identify this disease at an early stage and to begin rapid and adequate management.

Analysis of human total antibody repertoires in TIF1γ autoantibody positive dermatomyositis

We investigate the accumulated microbial and autoantigen antibody repertoire in adult-onset dermatomyositis patients sero-positive for TIF1γ (TRIM33) autoantibodies. We use an untargeted high-throughput approach which combines immunoglobulin disease-specific epitope-enrichment and identification of microbial and human antigens. We observe antibodies recognizing a wider repertoire of microbial antigens in dermatomyositis. Antibodies recognizing viruses and Poxviridae family species are significantly enriched. The identified autoantibodies recognise a large portion of the human proteome, including interferon regulated proteins; these proteins cluster in specific biological processes. In addition to TRIM33, we identify autoantibodies against eleven further TRIM proteins, including TRIM21. Some of these TRIM proteins share epitope homology with specific viral species including poxviruses. Our data suggest antibody accumulation in dermatomyositis against an expanded diversity of microbial and human proteins and evidence of non-random targeting of specific signalling pathways. Our findings indicate that molecular mimicry and epitope spreading events may play a role in dermatomyositis pathogenesis.

Megremis, Walker at al. identify immunogenic epitopes in dermatomyositis patients. They identify antibodies recognizing a wider diversity of microbial antigens including poxviruses, and autoantibodies recognizing a large portion of the human proteome. Shared epitope homology between viral and human proteins suggests that molecular mimicry and epitope spreading events may play a role in dermatomyositis pathogenesis.

Aberrantly Expressed Galectin-9 Is Involved in the Immunopathogenesis of Anti-MDA5-Positive Dermatomyositis-Associated Interstitial Lung Disease

Background

Dermatomyositis (DM) associated rapidly progressive interstitial lung disease (RP-ILD) has high mortality rate and poor prognosis. Galectin-9 (Gal-9) plays multiple functions in immune regulation. We investigated Gal-9 expression in DM patients and its association with DM-ILD.

Methods

A total of 154 idiopathic inflammatory myopathy patients and 30 healthy controls were enrolled in the study. Cross-sectional and longitudinal studies were used to analyze the association between serum Gal-9 levels and clinical features. Enzyme-linked immunosorbent assay and qRT-PCR were used to examine Gal-9 expression in the sera and isolated peripheral blood mononuclear cells (PBMCs) from DM patients. Immunohistochemistry was performed to analyze the expression of Gal-9 and its ligand (T-cell immunoglobulin mucin (Tim)-3 and CD44) in lung tissues from anti-melanoma differentiation-associated gene 5 (MDA5)-positive patients. The effect of Gal-9 on human lung fibroblasts (MRC-5) was investigated in vitro.

Results

Serum Gal-9 levels were significantly higher in DM patients than in immune-mediated necrotizing myopathy patients and healthy controls (all p < 0.001). Higher serum Gal-9 levels were observed in anti-MDA5-positive DM patients than in anti-MDA5-negative DM patients [33.8 (21.9–44.7) vs. 16.2 (10.0–26.9) ng/mL, p < 0.001]. Among the anti-MDA5-positive DM patients, serum Gal-9 levels were associated with RP-ILD severity. Serum Gal-9 levels were significantly correlated with disease activity in anti-MDA5-positive DM patients in both cross-sectional and longitudinal studies. PBMCs isolated from anti-MDA5-positive DM patients (3.7 ± 2.3 ng/mL) produced higher levels of Gal-9 than those from immune-mediated necrotizing myopathy patients (1.1 ± 0.3 ng/mL, p = 0.022) and healthy controls (1.4 ± 1.2 ng/mL, p = 0.045). The mRNA levels of Gal-9 were positively correlated with the levels of type-I interferon-inducible genes MX1 (r = 0.659, p = 0.020) and IFIH1 (r = 0.787, p = 0.002) in PBMCs from anti-MDA5-positive DM patients. Immunohistochemistry revealed increased Gal-9 and Tim-3 expression in the lung tissues of patients with DM and RP-ILD. In vitro stimulation with Gal-9 protein increased CCL2 mRNA expression in MRC-5 fibroblasts.

Conclusions

Among anti-MDA5-positive DM patients, Gal-9 could be a promising biomarker for monitoring disease activity, particularly for RP-ILD severity. Aberrant expression of the Gal-9/Tim-3 axis may be involved in the immunopathogenesis of DM-ILD.

Dermatomyositis autoantibodies: how can we maximize utility?

The past 15 years has seen significant advances in the characterization of myositis-specific autoantibodies (MSAs) and their associated phenotypes in patients with dermatomyositis (DM). As more careful studies are performed, it is clear that unique combinations of clinical and pathological phenotypes are associated with each MSA, despite the fact that there is considerable heterogeneity within antibody classes as well as overlap across the groups. Because risk for interstitial lung disease (ILD), internal malignancy, adverse disease trajectory, and, potentially response to therapy differ by DM MSA group, a deeper understanding of MSAs and validation and standardization of assays used for detection are critical for optimizing diagnosis and treatment. Like any test, the diagnostic sensitivity and specificity of assays for various MSAs is not perfect. Currently tests for MSAs are helpful at minimum for a clinician to assess relative risk or contribute to diagnosis and perhaps counsel the appropriate patient about what to expect. With international standardization and larger studies it is likely that more antibody tests will make their way into formal schemata for diagnosis and actionable risk assessment in DM. In this review, we summarize key considerations for interpreting the clinical and pathologic associations with MSA in DM and identify critical gaps in knowledge and practice that will maximize their clinical utility and utility for understanding disease pathogenesis.

Community-Acquired Pneumonia and Hospital-Acquired Pneumonia in Adult Patients with Idiopathic Inflammatory Myopathy: Outcome and Antibiotic Therapy

INTRODUCTION

Community-acquired pneumonia (CAP) and hospital-acquired pneumonia (HAP) are common complications in idiopathic inflammatory myopathy (IIM) patients, and are frequently associated with unfavorable outcome as well as prolonged antibiotic therapy. In this study, we intended to clarify whether clinical pulmonary infection score (CPIS) and multiple serum biomarkers are valuable in predicting unfavorable outcomes and prolonged antibiotic therapy in adult IIM patients complicated with CAP or HAP.

METHODS

Data of IIM patients with CAP or HAP who were admitted to three tertiary centers from December 2010 to November 2019 were retrospectively collected. Cox proportional hazards regression analysis and logistic regression analysis were adopted to identify risk factors for unfavorable outcomes and prolonged antibiotic therapy in these patients. The predictive values of potential predictors were assessed using receiver operating characteristic analysis.

RESULTS

The mortality rate was 60.6% in 109 IIM patients complicated with CAP or HAP. Myositis Disease Activity Assessment Visual Analogue Scales (MYOACT) score, CPIS and timely adjustment to antibiotics based on drug susceptibility test (DST-based antibiotic) were significantly associated with long-term outcome in these patients. With an optimal cutoff value of 6.5 and area under the curve (AUC) of 0.813, CPIS was a more satisfying predictor compared with MYOACT score. The peak C-reactive protein (CRP) level, DST-based antibiotics, and complication of interstitial lung disease (ILD) were also significantly correlated with prolonged antibiotic therapy.

CONCLUSIONS

IIM patients complicated with CAP or HAP frequently suffer from unfavorable outcomes. Compared with IIM disease activity, CPIS worked as a better predictor of outcome in these patients. Also, the peak CRP level during hospitalization might be valuable in predicting prolonged antibiotic therapy. The existence of ILD might impede early discontinuation of antibiotics. Timely adjustment to antibiotics based on drug susceptibility testing would decrease the mortality rate and reduce the incidence of prolonged antibiotic therapy.

Efficacy and Tolerability of Nintedanib in Idiopathic-Inflammatory-Myopathy-Related Interstitial Lung Disease: A Pilot Study

Objectives: To initially clarify the efficacy and tolerability of nintedanib in patients with idiopathic-inflammatory-myopathy-related interstitial lung disease (IIM-ILD).

Methods: A retrospective, real-world analysis was conducted in IIM-ILD patients who regularly received outpatient visit or hospitalization from January 2018 to March 2020 in three centers. And the patients were divided into two groups depending on presence or absence of nintedanib therapy. Comparisons, Kaplan-Meier survival analysis and propensity score matching were made to identify difference in time to death from any cause, incidence of rapidly progressive interstitial lung disease (RP-ILD) and comorbidity of pulmonary infection between the two groups. The following logistic regression analyses and Cox proportional-hazard regression analyses were used to verify the therapeutic value of nintedanib as well as clinical significance of other factors. Adverse events were descriptively recorded.

Results: Thirty-six patients receiving nintedanib therapy and 115 patients without use of nintedanib were included. Before and after propensity score matching, the primary comparisons revealed better survival (P = 0.015, P = 0016, respectively) and lower incidence of RP-ILD (P = 0.017, P = 0.014, respectively) in patients with nintedanib therapy. Logistic regression analysis identified that disease activity (P < 0.001), percent-predicted diffusing capacity of the lung for carbon monoxide (DLCO%, P = 0.036), nintedanib therapy (P = 0.004, OR value = 0.072) and amyopathic dermatomyositis (ADM, P = 0.012) were significantly correlated with RP-ILD. Cox proportional hazards regression analysis suggested that disease activity (P < 0.001), anti-MDA5 antibody (P < 0.001) and nintedanib therapy (P = 0.013, HR value=0.268) were significantly associated with survival of IIM-ILD patients. Similar results can also be seen in analyses after propensity score matching. In the 36 patients with nintedanib therapy, diarrhea was the most common adverse event (44.4%) and hepatic insufficiency contributed to most dosage reduction (44.4% of nine patients) or therapy discontinuation (60.0% of five patients).

Conclusions: Nintedanib was found to reduce incidence of RP-ILD and improve survival in IIM-ILD patients in a real-world setting. Anti-MDA5 antibody could be taken as a risk factor for unfavorable outcome. ADM was significantly correlated with occurrence of RP-ILD. In addition to the most frequent diarrhea, hepatic insufficiency was closely related to dosage reduction or therapy discontinuation.

IL-15 is a biomarker involved in the development of rapidly progressive interstitial lung disease complicated with polymyositis/dermatomyositis

BACKGROUND

Polymyositis/dermatomyositis (PM/DM) is an autoimmune disease that is sometimes complicated with rapidly progressive interstitial lung disease (RPILD). However, serum and lung biomarkers that can predict RPILD development remain unclear.

OBJECTIVES

To determine potential serum and lung biomarkers that can predict RPILD development in patients with PM/DM-ILD.

METHODS

In total, 49 patients with PM/DM-ILD were enrolled. We measured the serum levels of 41 cytokines/chemokines, ferritin and anti-MDA5 antibody, compared them between the RPILD (n = 23) and non-RPILD (n = 26) groups, and ranked them by their importance through random forest analysis. To distinguish the two groups, we determined biomarker combinations by logistic regression analysis. We also measured the bronchoalveolar lavage fluid (BALF) levels of 41 cytokines/chemokines. Using immunohistochemistry, we examined IL-15 expression in lung tissues. The IL-15 production was also investigated using A549 and BEAS-2B cells.

RESULTS

The RPILD group had significantly higher IL-15, IL-1RA, IL-6, CXCL10, VCAM-1, anti-MDA5 antibody and ferritin serum levels than the non-RPILD group, but it had a significantly low CCL22 level. Meanwhile, anti-MDA5 antibody, IL-15, CXCL8, CCL22, IL-1RA and ferritin were the best combination to distinguish the two groups. IL-15 and CCL22 were also predictive marker for RPILD development in anti-MDA5 antibody-positive patients. Additionally, the RPILD group had significantly high IL-15 levels in BALF. The lung tissues expressed IL-15, which increased after cytokine stimulation in the A549 cells.

CONCLUSION

This study identified a combination of biomarkers predicting PM/DM-RPILD progression, and IL-15 is an important cytokine for predicting RPILD development and reflecting ILD severity.

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.

Prevalence of interstitial lung disease in polymyositis and dermatomyositis: A meta-analysis from 2000 to 2020

OBJECTIVE

Interstitial lung disease (ILD) is the most important prognostic factor for mortality in patients with polymyositis (PM) and dermatomyositis (DM), but the prevalence of ILD in PM/DM may vary between countries. The aim of this study was to determine the overall prevalence of ILD in global patients with PM/DM.

METHODS

We performed a systematic literature review of studies published from Jan 1, 2000 to April 30, 2020 on ILD and PM/DM. We extracted data and pooled the prevalence by using a random-effect model due to high heterogeneity. Heterogeneity was assessed by subgroup analysis and sensitivity analysis.

RESULTS

A total of 34 studies with 10,130 patients were included in our meta-analysis. Pooled data demonstrated that the global prevalence of ILD in patients with PM/DM was 0.41 (95% confidence interval [CI] 0.35-0.48). However, this prevalence varied with geographical locations and time trends. The prevalence of ILD in PM/DM was 0.5 (95% CI 0.42-0.57) in Asia, 0.23 (95% CI 0.15-0.31) in America, and 0.26 (95% CI 0.18-0.34) in Europe. A higher prevalence of ILD was reported in studies published in 2011-2015 (0.43, 95% CI 0.34-0.52) and 2016-2020 (0.45, 95% CI 0.35-0.54), compared with those published in 2000-2010 (0.27, 95% CI 0.16-0.39). The pooled prevalence of ILD in patients with DM, PM, and clinically amyopathic dermatomyositis subtype was 0.42 (95% CI 0.35-0.49), 0.35 (95% CI 0.27-0.42), and 0.53 (95% CI 0.32-0.74), respectively. Patients with anti-Jo-1 and anti-melanoma differentiation-associated gene 5 antibodies were more likely to develop ILD than other myositis-specific autoantibodies.

CONCLUSION

The global prevalence of ILD in patients with PM/DM was approximately 41% and the condition was predominant in Asians. This highlights potential genetic and environmental differences in the pathogenesis of ILD in patients with PM/DM. More studies are required to elucidate the specific associations.

Predictors of Poor Outcome of Anti-MDA5-Associated Rapidly Progressive Interstitial Lung Disease in a Chinese Cohort with Dermatomyositis

Objective

Antimelanoma differentiation-associated protein 5 (anti-MDA5) autoantibody has been reported in dermatomyositis (DM) to be associated with rapidly progressive interstitial lung disease (RP-ILD). Our study is aimed at determining the clinical characteristics and prognostic factors underpinning anti-MDA5-associated RP-ILD.

Methods

Patients with anti-MDA5-associated DM (aMDA5-DM) were identified at the Peking University People's Hospital. The presence of anti-MDA5 antibody was determined by immunoblotting. Kaplan-Meier, chi-square test, univariate, and multivariate data analyses were used.

Results

Out of 213 patients with DM and clinically amyopathic dermatomyositis (CADM), 20.7% (44/213) of patients were identified as aMDA5-DM. Amongst the aMDA5-DM patients, 63.6% (28/44) were identified as having anti-MDA5-associated RP-ILD. During the follow-up, 32.1% (9/28) of patients with anti-MDA5-associated RP-ILD died of respiratory failure. We identified older age and periungual erythema as two independent risk factors for RP-ILD mortality. Age ≥ 57 years at disease onset was significantly associated with poor survival (P = 0.02) in patients with anti-MDA5-associated RP-ILD, while patients with periungual erythema had a better survival rate than those without periungual erythema (P < 0.05).

Conclusions

Anti-MDA5-associated RP-ILD is significantly associated with poor survival rates in DM/CADM patients. More effective intervention should be administered to anti-MDA5-associated RP-ILD patients, especially to senior patients and those without periungual erythema.

Revisiting B cell tolerance and autoantibodies in seropositive and seronegative autoimmune rheumatic disease (AIRD)

Autoimmune rheumatic diseases (AIRD) are categorized seropositive or seronegative, dependent upon the presence or absence of specific autoreactive antibodies, including rheumatoid factor and anti-citrullinated protein antibodies. Autoantibody-based diagnostics have proved helpful in patient care, not only for diagnosis but also for monitoring of disease activity and prediction of therapy responsiveness. Recent work demonstrates that AIRD patients develop autoantibodies beyond those contained in the original categorization. In this study we discuss key mechanisms that underlie autoantibody development in AIRD: defects in early B cell development, genetic variants involved in regulating B cell and T cell tolerance, environmental triggers and antigen modification. We describe how autoantibodies can directly contribute to AIRD pathogenesis through innate and adaptive immune mechanisms, eventually culminating in systemic inflammation and localized tissue damage. We conclude by discussing recent insights that suggest distinct AIRD have incorrectly been denominated seronegative.

Interstitial pneumonia with autoimmune features in a patient with melanoma differentiation-associated gene 5 (MDA5) antibody

Melanoma differentiation-associated gene 5 (MDA5) antibody, also known as anti-CADM140 antibody is recognised to be associated with rapidly progressive interstitial lung disease, which can be fatal within 3 months. It is also known to be associated with amyopathic dermatomyositis. We report a case of MDA5 antibody-associated interstitial pneumonia with autoimmune features, without cutaneous features of dermatomyositis, in a Sudanese patient with dual positive antibodies to Ro52. The patient notably had several features associated with poor prognosis, including age, high serum ferritin level, anti-Ro52 antibodies and progressive lung infiltrates during treatment.

Efficacy and Safety of Rituximab in Korean Patients with Refractory Inflammatory Myopathies

BACKGROUND

Rituximab (RTX), a monoclonal antibody that selectively binds to CD20+ B cells, showed favorable outcomes in patients with idiopathic inflammatory myopathies (IIM) in small case series, but the evidence is still not enough. Our goal was to determine the efficacy and safety of RTX for Korean patients with refractory IIM.

METHODS

We retrospectively analyzed the medical records of 16 patients with refractory IIM treated with RTX in seven tertiary rheumatology clinics in the Korea. The efficacy of RTX was evaluated with the improvement of serum creatine phosphokinase (CPK) level and physician's global assessment (PGA), and daily corticosteroid dose reduction. A > 25% decrease in CPK level, corticosteroid dose, or PGA was considered significant. A complete response (CR) was designated by meeting three efficacy criteria and a partial response (PR) by only two criteria.

RESULTS

Sixteen patients with IIM were evaluated (13 female; median age, 51.8 years). All patients had received at least one conventional immunosuppressive agent (median, 3.6 [2.0-5.0]) and concomitant corticosteroids. The median CPK level and median dose of prednisolone was 421.0 units/L and 20.0 mg/day respectively. Eleven patients were treated with intravenous immunoglobulin. Seven patients received 2,000 mg of RTX and the others received lower dose. Twenty-four weeks after RTX treatment, 11 patients achieved a > 25% reduction in corticosteroid dose and CPK levels, and nine showed improved PGA. The overall response rate was 68.8% (11 patients). At the end of follow-up (median 24 weeks), 12 (75.0%) patients responded overall: four (25.0%) and eight (50.0%) patients achieved CR and PR, respectively. Baseline muscle enzyme levels were higher in responders than non-responders, but disease duration, RTX dose, ESR and serum CRP were not significantly different between the two groups. The rate of adverse event was 25.4/1,000 person-years.

CONCLUSION

RTX could be an effective and relatively safe therapeutic option in patients with refractory IIM.

Anti-Ro52 antibody is an independent risk factor for interstitial lung disease in dermatomyositis

AIM

Recent studies have shown that anti-Ro52 antibody is associated with both interstitial lung disease (ILD) and the degree of disease severity in juvenile patients with dermatomyositis (DM). We found that more than half of adult patients with DM were positive for anti-Ro52 antibody. In this study, we analysed the correlation between anti-Ro52 antibody and ILD in adult patients with DM.

METHOD

Serum samples were collected from 153 adult inpatients with DM, at the First Medical Centre of PLA General Hospital, Beijing, China, who met the classification criteria of idiopathic inflammatory myopathies from March 1, 2016 to September 30, 2019. The patients were followed up to May 31, 2020. Immunoblotting was used to detect 16 types of myositis-specific autoantibodies (MSAs) and myositis-associated autoantibodies (MAAs) from serum samples. High-resolution computed tomography (HRCT) was used to calculate the ILD score, and tumours were screened. Clinical data and HRCT scores were evaluated and analysed retrospectively.

RESULTS

Our results showed that anti-Ro52 antibodies were the most commonly found antibodies in patients with DM, with a positive rate of 52.9%. Anti-Ro52, anti-aminoacyl-tRNA synthetase (anti-ARS), and anti-melanoma differentiation-related gene 5 (anti-MDA5) antibodies were found to be risk factors for ILD development. Anti-Ro52 antibodies had a strong predictive effect on ILD in patients with DM.

CONCLUSION

The occurrence of ILD is highly likely in patients with DM who are positive for the anti-Ro52 antibodies. Thus, anti-Ro52 antibodies is an independent risk factor for ILD in patients with DM.

Successful treatment of anti-MDA5 antibody-positive refractory interstitial lung disease with plasma exchange therapy

OBJECTIVES

We examined the effectiveness of plasma exchange (PE) therapy to reduce the mortality of rapidly progressive interstitial lung disease (RP-ILD) in patients positive for anti-melanoma differentiation-associated gene 5 (MDA5) antibodies.

METHODS

Among 142 patients newly diagnosed with PM/DM or clinically amyopathic DM from 2008 to 2019 at our hospital, 10 were diagnosed with refractory RP-ILD and were positive for anti-MDA5 antibodies. PE was used as an adjunct to standard therapy and consisted of fresh frozen plasma as replacement solution. The primary outcome was non-disease-specific mortality.

RESULTS

Anti-MDA5 antibodies were detected in 28 patients, of whom 21 were diagnosed with RP-ILD and 10 were refractory to intensive immunosuppressive therapy. Six patients received PE (PE group) and four did not (non-PE group). The 1-year survival rate of the PE group was higher than that of the non-PE group (100% and 25%, respectively, P = 0.033). Regarding adverse events associated with PE, two patients had anaphylactic shock, one had high fever due to fresh frozen plasma allergy and one had a catheter infection. All adverse events resolved with appropriate treatment.

CONCLUSION

We evaluated the association between 1-year survival rate and PE for refractory RP-ILD in patients positive for anti-MDA5 antibodies. Intensive immunosuppressive therapy improved the survival rate in RP-ILD patients with anti-MDA5 antibodies, but 20-30% of cases were still fatal. PE could be administered to patients with active infectious disease who were immunocompromised by intensive immunosuppressive therapy. PE may be considered in refractory RP-ILD patients positive for anti-MDA5 antibodies.