Update on outcome assessment in myositis

Pain is common in myositis and associated with disease activity

BACKGROUND

Understanding pain in myositis remains challenging. This study aimed to assess patient-reported pain and its correlation with myositis core set measures (CSMs), patient-reported outcomes (PROs) and functional measures.

METHODS

Fifty subjects underwent baseline, 3-month and 6-month assessments, evaluating myositis CSMs, functional measures and PROs. Pain was measured using three methods: (i) a 10-cm visual analogue scale, (ii) the pain score from the HAQ Disability Index and (iii) the Short Form 36 survey pain questions. Correlations between disease activity measures and pain were examined at baseline, and changes in both were assessed at 6 months, along with longitudinal change of pain. The change in pain was also correlated with the published 2016 ACR/EULAR myositis response criteria, physician/patient's assessment of change.

RESULTS

Nearly half of patients (45%) reported moderate to severe pain in all three pain scales, with higher severity of pain in PM/necrotizing myopathy subset. At baseline, pain severity showed a strong correlation with most CSMs, PROs and functional outcomes in all three pain scales, and similar trends were noted for change in pain at the 6 months. On longitudinal analysis, the physical function scores and fatigue showed strong correlation with pain. Pain improved in myositis patients with improvement in disease activity over time.

CONCLUSIONS

Pain is common in myositis and is associated with multiple measures of disease activity, PROs and functional outcomes in myositis. Most importantly pain improves with improvement in disease activity. SF-36 pain questions have good psychometric properties.

Patient-reported outcome for physical function in idiopathic inflammatory myopathy

OBJECTIVES

There is an unmet need to develop patient-reported outcomes measures for idiopathic inflammatory myopathies (IIM). We aimed to investigate the feasibility, compliance and psychometric properties of the National Institutes of Health's Patient-Reported Outcomes Measurement Information System (PROMIS) physical function-20 (PF-20) in a large US IIM population.

METHODS

'Myositis Patient Centered Tele-Research' (My PACER) is a multicentre prospective observational study of IIM patients, competitively recruited through traditional in-person clinic visits [centre-based cohort (CBC)], and remotely using smartphone- and web-based technology [tele-research cohort (TRC)]. The CBC was further randomly divided (1:1 ratio) into a traditional local subcohort and a remote subcohort. Data collected included patient-reported outcomes and other patient self-assessments monthly for 6 months. Clinician-reported outcomes were obtained at baseline and 6 months.

RESULTS

A total of 120 IIM patients were enrolled (82 TRC/38 CBC, mean ± s.d. age 55 ± 13.4 years, 75% females, 81% Caucasians), with similar demographics and mean PROMIS PF-20 score between cohorts. The PROMIS PF-20 score was not associated with age, sex or race. The compliance and completion rates were similar between TRC and CBC as well as subcohorts. PROMIS PF-20 showed strong test-retest reliability at 1 month. PROMIS PF-20 was significantly associated with all core set measures except extra-muscular global and creatine kinase, as well as with most symptoms, and function and physical activity measures. PROMIS PF-20 illustrated concordant change with myositis response criteria and patient assessment, with a large effect size.

CONCLUSIONS

PROMIS PF-20 demonstrates favourable psychometric properties including reliability, validity and responsiveness in a large cohort of myositis patients, with similar adherence in local or remotely enrolled patients.

Measurement properties of the Inclusion Body Myositis Functional Rating Scale

OBJECTIVES

To evaluate the validity, reliability, responsiveness and meaningful change threshold of the Inclusion Body Myositis (IBM) Functional Rating Scale (FRS).

METHODS

Data from a large 20-month multicentre, randomised, double-blind, placebo-controlled trial in IBM were used. Convergent validity was tested using Spearman correlation with other health outcomes. Discriminant (known groups) validity was assessed using standardised effect sizes (SES). Internal consistency was tested using Cronbach's alpha. Intrarater reliability in stable patients and equivalence of face-to-face and telephone administration were tested using intraclass correlation coefficients (ICCs) and Bland-Altman plots. Responsiveness was assessed using standardised response mean (SRM). A receiver operator characteristic (ROC) curve anchor-based approach was used to determine clinically meaningful IBMFRS change.

RESULTS

Among the 150 patients, mean (SD) IBMFRS total score was 27.4 (4.6). Convergent validity was supported by medium to large correlations (rs modulus: 0.42-0.79) and discriminant validity by moderate to large group differences (SES=0.51-1.59). Internal consistency was adequate (overall Cronbach's alpha: 0.79). Test-retest reliability (ICCs=0.84-0.87) and reliability of telephone versus face-to-face administration (ICCs=0.93-0.95) were excellent, with Bland-Altman plots showing good agreement. Responsiveness in the worsened group defined by various external constructs was large at both 12 (SRM=-0.76 to -1.49) and 20 months (SRM=-1.12 to -1.57). In ROC curve analysis, a drop in at least two IBMFRS total score points was shown to represent a meaningful decline.

CONCLUSIONS

When administered by trained raters, the IBMFRS is a reliable, valid and responsive tool that can be used to evaluate the impact of IBM and its treatment on physical function, with a 2-point reduction representing meaningful decline.

TRIAL REGISTRATION NUMBER

NCT02753530.

Elucidating genetic intersections: Co-differentially expressed genes in myasthenia gravis and idiopathic inflammatory myopathies and their role in comorbid pathogenesis

Background

Myasthenia gravis (MG) and idiopathic inflammatory myopathies (IIM) are autoimmune disorders that can co-occur, complicating diagnosis and treatment. The molecular mechanisms underlying this comorbidity are not well understood.

Objective

This study aims to identify common differentially expressed genes (co-DEGs) between MG and IIM to elucidate shared pathogenic pathways and potential therapeutic targets.

Methods

Transcriptomic data from the Gene Expression Omnibus (GEO) were analyzed using the "limma" package in RStudio. Functional enrichment analyses were performed using Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways. A nomogram prediction model was developed, and receiver operating characteristic (ROC) analysis was used to evaluate its diagnostic potential.

Results

Four co-DEGs were identified between MG and IIM, associated with neurotransmitter transport and ion channel regulation. The nomogram model, incorporating three of these co-DEGs, showed high predictive accuracy for MG with IIM complications, with an area under the ROC curve of 0.94. Immune infiltration analysis revealed distinct patterns in MG and IIM, particularly involving gamma delta T cells and activated mast cells.

Conclusion

The study identifies key genetic intersections between MG and IIM, providing insights into their shared pathogenesis and highlighting potential diagnostic and therapeutic targets. Further experimental validation is required to confirm these findings.

Disease activity in patients with idiopathic inflammatory myopathy according to time since diagnosis and positivity to antisynthetase autoantibodies: data from the Myo-Spain registry

OBJECTIVE

To evaluate the main outcomes of disease activity and their association with other measures of activity, damage, and quality of life in patients with idiopathic inflammatory myopathy (IIM) according to time since diagnosis and positivity to antisynthetase autoantibodies (ASAs).

METHODS

Cross-sectional multicenter study within the Spanish Myo-Spain registry. Cases were classified as incident (≤ 12 months since diagnosis) and prevalent. The main outcomes of disease activity were the Myositis Disease Activity Assessment visual analogue scale (MYOACT), the Manual Muscle Test 8 (MMT-8), physician global activity (PhGA), and extramuscular activity. Other measures of activity, damage, and quality of life included patient global disease activity, MYOACT muscular, creatine phosphokinase, Health Assessment Questionnaire, physician and patient global damage, global damage of the Myositis Damage Index, and the 12-item Short-Form Health Survey (SF-12). We analyzed associations using a multivariate generalized linear model and a simple linear regression model.

RESULTS

A total of 554 patients with different diagnostic subgroups of IIM were included (136 incident and 418 prevalent cases), with 215 ASA-positive patients (58 incident and 157 prevalent cases). All measures of disease activity were higher in the incident cases (p < 0.05), except for MYOACT muscular and creatine phosphokinase, for which no differences were recorded in ASA-positive patients. No differences were found between incident and prevalent cases for measures of damage. Values for the physical component of the SF-12 were higher in the prevalent cases (p < 0.05). The multivariate model was initially significant overall for the main activity outcomes. Positivity to ASAs was positively and negatively associated with the MYOACT index and MMT-8, respectively (p < 0.05), although no association was recorded with PhGA and extramuscular activity. Prevalent cases were negatively associated with the main outcomes of activity, except with MMT-8, for which the association was positive (p < 0.05).

CONCLUSIONS

The main activity outcomes validated in polymyositis and dermatomyositis could also be used in other subtypes of IIM, such as antisynthetase syndrome. Recent diagnosis is associated with greater disease activity, as assessed based on these activity outcomes. PhGA and extramuscular activity are not modified by ASA positivity, thus supporting their preferred use for assessing treatment response in IIM with ASAs.

The relationship between patient-reported and clinician-assessed outcome measures in Inclusion body myositis - insights from a retrospective cohort study

Inclusion body myositis (IBM) is an inflammatory myopathy, characterised by slow progression of weakness, skeletal muscle atrophy, and heterogeneous clinical presentation. This variability in disease progression and presentation complicates tracking of clinical progress and intervention response in clinical trials, presenting challenges in identifying reliable outcome measures. We aimed to identify the most useful suite of clinician-assessed and patient-reported outcome measures (PROMs) for use in clinical practice and trials from a selection of the most commonly used outcome measures in IBM. We retrospectively analysed clinician-assessed outcome measures (manual muscle testing (MMT8, MMT12)), right- and left-handed grip strength, modified timed up and go (mTUG), two-minute walk test (2MWT); a clinician-administered patient-reported tool (IBM Functional Rating Scale (IBMFRS)); and PROMs including the eating assessment tool (EAT-10), and neuromuscular symptom score (NSS) from 20 participants attending a single specialist myositis clinic in Perth, Australia. Correlation analysis revealed significant correlations between the IBMFRS, MMT8, MMT12, mTUG and 2MWT (p < 0.05). The NSS strongly correlated with the MMT8, MMT12 and 2MWT (p < 0.05). Univariate regression analyses revealed that 2MWT, MMT12 and mTUG were significant predictors of the IBMFRS and NSS, and backward stepwise linear regression highlighted that the 2MWT was a significant positive predictor for the IBMFRS (p < 0.001). Overall, we concluded that the IBMFRS, NSS, 2MWT and mTUG models were the best predictors of patient-perceived physical function in IBM.

273rd ENMC International workshop: Clinico-Sero-morphological classification of the Antisynthetase syndrome. Amsterdam, The Netherlands, 27-29 October 2023

Among the idiopathic inflammatory myopathies, patients harbouring an Antisynthetase syndrome exhibit a unique clinical picture, with characteristic signs such as myositis, interstitial lung disease, arthritis, rash, and/or fever. Characteristic morphological features on skeletal muscle biopsies differentiate Antisynthetase syndrome from other forms of myositis. Autoantibodies typically recognizing one of the members of the aminoacyl-tRNA synthetase family of proteins can be detected in the serum of such patients, with anti-Jo1 being most frequent. Until now, an international consensus definition of the Antisynthetase syndrome is lacking, hence this workshop has undertaken the task to inform about the clinical, morphological and autoantibody profiles of Antisynthetase syndrome. The authors also expand their aims by giving management and therapeutic strategies, and finally provide precise classification criteria for Antisynthetase syndrome.

The Dermatomyositis Disease Symptom Questionnaire (DM-DSQ): A Measure to Assess the Patient Experience of Dermatomyositis Symptoms

OBJECTIVE

Dermatomyositis (DM) symptoms negatively affect the quality of life of individuals living with the disease. Disease-specific, patient-reported outcome (PRO) instruments are needed to assess symptoms important to individuals with DM. This study aimed to conceptualize patient DM experience and disease activity definition to refine the development of the Dermatomyositis Disease Symptom Questionnaire (DM-DSQ), a novel PRO instrument capturing patient-reported symptoms.

METHODS

An observational, qualitative study was conducted with 30 individuals with DM (aged ≥ 18 yrs) in the US. A 1-hour semistructured interview, including concept elicitation and cognitive debriefing, was conducted with each participant. Inductive coding was used to identify concepts; a saturation analysis was conducted to confirm sample size. Concepts from transcripts were used to refine the preliminary conceptual model and DM-DSQ items.

RESULTS

Concept elicitation analysis findings included disease symptoms (eg, muscle weakness) and functional impacts (eg, walking). The analysis achieved conceptual saturation; the first 5 interviews uncovered most of the concepts. During cognitive debriefing of the DM-DSQ, participants found the items relevant, comprehensive, and easily understood (except for "skin sensitivity in sunlight"). The revised DM-DSQ content appears preliminarily valid in the patient population surveyed, pending further additions and debriefing based on refinement of the preliminary conceptual disease model and items.

CONCLUSION

The DM-DSQ is being used in a phase II clinical trial and could become a valuable tool for studies evaluating PROs in patients with DM. Preliminary results indicate its content validity; extensive psychometric analysis using clinical trial data will determine its ability to capture symptoms for patients with DM.

Clinico-sero-pathological characteristics of anti-Ha antisynthetase syndrome

To define the clinical, serological, and muscle histopathological characteristics, as well as treatment outcomes, of patients with anti-Ha antibody. We performed a retrospective analysis of clinical, serological, and pathological data and long-term treatment outcomes of anti-Ha patients between January 2005 and July 2023 at our center. Anti-Ha antibody was identified by immunoblot and reconfirmed by immunoprecipitation. Of the 570 patients with idiopathic inflammatory myopathies, 17 (3.0%) were found to be anti-Ha positive, of whom 5 (29.4%) were also positive for another myositis-specific antibody (MSA). All patients with anti-Ha antibody as the single MSA (12/17, 70.6%) had clinical and histopathological evidence of muscle damage. Skin lesions were identified in nine of them (75%), while both interstitial lung disease and Raynaud's phenomenon were only seen in four patients. A necrotizing myopathy without a perifascicular pattern was the most common pathological manifestation (50%). Perifascicular necrosis (PFN) and myofiber major histocompatibility complex class-II expression were observed only in one and four patients, respectively. Muscle weakness relapse was reported in five patients, and skin rashes worsening were observed in one patient. Most of the anti-Ha patients (66.7%) finally achieved a favorable outcome at last follow-up. Anti-Ha antibody might not be as rare as previously thought and may coexist with other MSAs. Muscle damage is the most common manifestation in anti-Ha patients, while extra-muscular symptoms except for the cutaneous manifestations are unusual. The histopathological features varied with a predominance of necrotizing myopathy without PFN. These patients often finally had favorable outcomes, although relapses often occur.

Clinical endpoints in myositis: challenges and ways forward

PURPOSE OF REVIEW

This review addresses the challenges and advances in clinical endpoints for myositis, with a particular focus on ensuring comprehensive assessment of both muscle and skin disease activity. The relevance of this review stems from recent developments in outcome measures and their implications for clinical trial design and patient inclusivity. While quality of life (QoL) and lung involvement are also important aspects of myositis, they are beyond the scope of this review and need to be addressed in future studies.

RECENT FINDINGS

Traditional outcome measures like the Total Improvement Score (TIS) have limitations, especially for patients with skin-predominant dermatomyositis (DM). Recent studies highlight the importance of incorporating skin-specific measures such as the Cutaneous Disease Area and Severity Index (CDASI) and the novel composite measure, Dermatomyositis Outcomes for Muscle and Skin (DMOMS). These measures provide a more balanced assessment of disease activity. Clinical trial data analyzed using these measures have demonstrated significant benefits for patients with both classic and amyopathic DM, emphasizing the need for their broader adoption.

SUMMARY

Advancements in outcome measures are crucial for inclusive and effective myositis clinical trials. Incorporating comprehensive tools like the DMOMS can enhance the assessment of both muscle and skin disease activities, potentially leading to better therapeutic strategies and improved patient outcomes. This shift is essential for addressing the needs of all Idiopathic inflammatory myopathy patients, including those with skin-predominant DM.

Increased Cytokine Levels in Seronegative Myositis: Potential Th17 Immune Response Implications

Th17 cells are known for producing IL-17 and their role in the pathogenesis of various autoimmune diseases, including myositis. Likewise, the participation of the IL-23/IL-17 pathway in autoimmunity has been confirmed. In this study, we aimed to evaluate the behavior of cytokines in myositis, focusing on the autoantibodies profile and the myositis core set measures. Twenty-five myositis patients were enrolled in this cross-sectional study. An expert rheumatologist evaluated the myositis core set measures. Serum levels of cytokines and chemokines were quantified using the LEGENDplex Multi-Analyte Flow Assay Kit from BioLegend. The autoantibodies detection was carried out using the line-blot assay kit Euroline: Autoimmune Inflammatory Myopathies from EUROIMMUN. We found higher serum levels of IL-33, CXCL8, IL-6, IL-23, and IL-12p70 in seronegative patients. A multiple linear regression analysis revealed that MYOACT scores could be predicted by the increment of IL-23 and the decrement of CCL2, IL-10, and CXCL8 serum levels. These findings suggest that the immune response in seronegative myositis patients exhibits an IL-23-driven Th17 immune response. The relevance of this discovery lies in its potential therapeutic implications. Insights into the IL-23-driven Th17 immune response in seronegative patients highlight the potential for targeted therapies aimed at modulating Th17 activity.

Nuclear PCGF3 inhibits the antiviral immune response by suppressing the interferon-stimulated gene

Type I interferon (IFN-I) plays a crucial role in the antiviral immune response and inflammatory autoimmune diseases by inducing the expression of IFN-stimulated genes (ISGs). Hence, the regulation of ISG expression is fundamental for maintaining immune homeostasis. In this study, we found that PCGF3 negatively regulates the antiviral response by suppressing the expression of ISGs. The deficiency of PCGF3 in innate immune cells results in an augmented expression of ISGs in response to IFN-I stimulation. Mechanistically, PCGF3 is recruited to interferon-stimulated response elements (ISREs) region in an IFN-dependent way, precluding STAT1 from binding to the ISG promoter and diminishing ISRE activity. Additionally, we observed a negative correlation between decreased PCGF3 expression and elevated ISG expression in peripheral blood mononuclear cells (PBMCs) of patients with dermatomyositis (DM). Our findings clarified the epigenetic regulatory role of PCGF3 in inhibiting the excessive expression of ISGs induced by IFN-I under pathological circumstances.

Differences in the autoantibody phenotypes and long-term outcomes between juvenile- and adult-idiopathic inflammatory myopathies

OBJECTIVE

To investigate differences in autoantibodies, clinical features, and long-term outcomes between juvenile-idiopathic inflammatory myopathy (IIM) and adult-IIM METHODS: Autoantibodies, clinical characteristics, and drug-free conditions for a maximum of 20 years were retrospectively analyzed in 320 Japanese IIM patients (juvenile-IIM, n = 34; adult-IIM, n = 286) using the Kyoto University Registry.

RESULTS

Autoantibodies observed in juvenile-IIM were anti-TIF1-γ (15 %), anti-MDA-5 (15 %), anti-ARS (9 %), and anti-NXP-2 (6 %). Those observed in adult-IIM were anti-ARS (32 %), anti-MDA-5 (23 %), anti-TIF1-γ (8 %), anti-SRP (8 %), anti-Mi-2 (2 %), and anti-NXP-2 (1 %). The cumulative drug-free condition rate was higher in juvenile-IIM than in adult-IIM up to 20 years (juvenile-IIM vs. adult-IIM, 34 % vs. 18 %, p = 0.0016). Anti-TIF1-γ was associated with lesser muscle symptoms (60 % vs. 90 %), malignancy (0 % vs. 57 %), and glucocorticoid use (40 % vs. 86 %) in juvenile-IIM compared to adult-IIM, while juvenile-IIM more achieved drug-free conditions (60 % vs. 25 %). Both juvenile-IIM and adult-IIM with anti-MDA-5 demonstrated a high frequency of amyopathic dermatomyositis, interstitial lung disease (ILD), and multi-immunosuppressive therapy, with high drug-free conditions (50 % vs. 49 %). Both juvenile-IIM and adult-IIM with anti-ARS showed frequent skin rashes, muscle symptoms, and ILD, frequent need for multi-immunosuppressive therapy, and low drug-free condition rates (0 % vs. 3 %). Both juvenile-IIM and adult-IIM with anti-NXP-2 showed frequent skin rashes and muscle symptoms, low ILD frequency, and frequent use of methotrexate and glucocorticoids, which did not achieve drug-free conditions (0 % vs. 0 %).

CONCLUSIONS

Drug-free condition was achieved more frequently in juvenile-IIM patients than adult-IIM patients. Specific autoantibodies were associated with different clinical characteristics and outcomes between juvenile-IIM and adult-IIM.

High-intensity resistance training improves quality of life, muscle endurance and strength in patients with myositis: a randomised controlled trial

Myositis is associated with reduced quality of life, which is accompanied by significant impairments in muscle endurance and strength, altogether representing cardinal traits in patients with myositis. This randomised controlled trial aimed to investigate the effect of high-intensity resistance training on quality of life in patients with myositis. Thirty-two patients with established, stable myositis were randomised to 16 weeks of high-intensity resistance training (intervention group) or 16 weeks of usual care (control group). Primary outcome was quality of life assessed as the change in the physical component summary score (PCS) of the Short Form-36 health questionnaire from baseline to post-intervention. Secondary outcomes included functional capacity measures, such as functional index 3, and International Myositis Assessment and Clinical Studies Group (IMACS) disease activity and damage core set measures, including manual muscle testing 8 (MMT8). The primary outcome PCS showed an improvement in favour of high-intensity resistance training with a between-group difference of 5.33 (95% CI 0.61; 10.05) (p = 0.03). Additionally, functional index 3 showed a between-group difference indicating greater gains with high-intensity resistance training 11.49 (95% CI 3.37; 19.60) (p = 0.04), along with a between-group improvement in MMT8 1.30 (95% CI 0.09; 2.51) (p = 0.04). High-intensity resistance training for 16 weeks effectively improved quality of life in patients with myositis. Clinical measures of muscle endurance and muscle strength were also found to improve with high-intensity resistance training, while patients stayed in disease remission. Consequently, progressively adjusted high-intensity resistance training is feasible and causes no aggravation of the disease, while benefitting patients with myositis.Clinical trial registration: Clinicaltrials.gov ID: NCT04486261- https://clinicaltrials.gov/study/NCT04486261 .

Incidence and outcomes for children with idiopathic inflammatory myopathy in Western Australia-a long-term population-based study

AIM

To determine the incidence and health outcomes for juvenile idiopathic inflammatory myopathy (JIIM) in a long-term whole-population study.

METHODS

We included patients under 18 years hospitalized in Western Australia (WA) from 1985 and 2015 with incident JIIM as defined by pertinent diagnostic codes for dermatomyositis (JDM) polymyositis (JPM), other JIIM and overlap myositis (JOM). We compared clinical outcomes and modified Charlson comorbidity scores with age and gender matched (2:1 ratio) patients with new onset juvenile idiopathic arthritis (JIA). Trends over time for annual incidence rate per million child-population (AIR) were analyzed by least square regression and survival by Kaplan-Meier curves.

RESULTS

We included 40 patients with JIIM (63% female, median age 8.5 years) for an average AIR of 2.52 per million (CI 1.09-5.57). AIR was stable over time leading to a point prevalence of 52.61 (CI 40.57-67.06) in 2015. Most patients (80%) were classified as JDM with an AIR for JDM of 2.02 (CI 1.09-5.58) and AIR for the combined other JIIM at 0.51 (CI 0.24-1.15). There was female preponderance (62.5%) in both JIIM groups, but no evidence of seasonality. Over a median follow-up of 13 years, one- and ten-year survival was 94.1%. Compared to JIA patients, readmission (80.4 vs. 63.7, p = .02) and infection rates (15.2 vs. 9.6, p < .01) per 100 person-years were higher for JIIM, with similar frequency of interstitial lung disease, fractures, and thrombotic events. At last observation, nearly all patients in both JIIM cohorts (97.5 vs. 92.5%) had accrued some form of comorbidity.

CONCLUSIONS

The overall incidence of JIIM leading to hospitalization in WA was stable over 30 years. JIIM prognosis remains suboptimal due to early mortality and accrual of long-term comorbidity.

Association of anti-HMGCR antibodies of the IgM isotype with refractory immune-mediated necrotizing myopathy

OBJECTIVE

Anti-3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMGCR) autoantibodies are one of the myositis-specific antibodies which is associated with immune-mediated necrotizing myopathy (IMNM). However, the relationship between anti-HMGCR isotypes and prognosis has not yet been fully investigated. This study was conducted to gain insight into the association between anti-HMGCR isotypes and clinical, and prognosis in IMNM patients who were positive for anti-HMGCR antibodies.

METHODS

Levels of anti-HMGCR isotypes (IgG, IgA and IgM) were assessed by enzyme-linked immunosorbent assay (ELISA) in 123 consecutive serum samples obtained from 71 patients who were positive for anti-HMGCR IgG at baseline. Disease activity was assessed by manual muscle testing (MMT) 8, Physician's Global Assessment (PGA) visual analog scale (VAS), and muscle VAS.

RESULTS

Baseline anti-HMGCR IgG levels were correlated with PGA VAS (r = 0.24; p = 0.04), muscle VAS (r = 0.32; p < 0.01), and MMT8(r=-0.24; p = 0.04), and baseline anti-HMGCR IgM levels were positively correlated with PGA VAS (r = 0.27, p = 0.02), muscle VAS (r = 0.24, p = 0.04). Anti-HMGCR IgM positive patients had a lower age of onset [29(25,46) vs. 51(33,65), p = 0.006], and a higher proportion of neck weakness (63.5% vs. 34.6%, p = 0.031) compared with anti-HMGCR IgM negative patients. Longitudinal analysis showed that the changes in anti-HMGCR IgG levels were correlated with the changes in the PGA VAS (β = 3.830; p < 0.0001), muscle VAS (β = 2.893; p < 0.0001), MMT8 (β=-19.368; p < 0.0001), and creatine kinase (CK) levels (β = 3900.05, p < 0.0001). Anti-HMGCR IgM levels were weakly correlated with anti-HMGCR IgA levels at baseline (r = 0.33, p < 0.01), and the variations in anti-HMGCR IgA levels were correlated with the changes in anti-HMGCR IgM levels during follow-up (β = 0.885; p < 0.0001). There were more patients with anti-HMGCR IgM who showed a refractory course than those who were with anti-HMGCR IgM negative (polycyclic course: 40% vs. 25%; chronic continuous course: 46.7% vs. 20.5%, p = 0.018).

CONCLUSION

In anti-HMGCR IgG-positive IMNM patients, the levels of anti-HMGCR IgG are associated with disease activity, and anti-HMGCR IgM is associated with refractory outcome and poor prognosis.

Tacrolimus personalized therapy based on CYP3A5 genotype in Chinese patients with idiopathic inflammatory myopathies

OBJECTIVE

Idiopathic inflammatory myopathies (IIM) are a heterogeneous and life-threatening group of diseases; in particular, anti-melanoma differentiation-associated gene 5 antibody positive DM (MDA5+ DM) is reportedly strongly associated with high mortality rate. Tacrolimus (TAC) provides an excellent therapeutic option, but the trough concentration (Cmin)-outcome relationship remains unexplored. This study was undertaken to identify optimal Cmin and individualized dose based on CYP3A5 genotype for IIM patients.

METHODS

A total of 134 IIM patients with 467 Cmin were enrolled. We examined the relationship between TAC Cmin and relapses. The receiver operating characteristic analysis was used to confirm the optimal Cmin. Analyses of factors influencing Cmin were conducted. The dose requirement based on CYP3A5 genotype was confirmed.

RESULTS

TAC Cmin is strongly associated with relapses. The optimal cutoff values were 5.30, 5.85, 4.85 and 5.35 ng/ml for acute, subacute, chronic and all-phase IIM patients (P = 0.001, 0.013, 0.002 and <0.001, respectively), as well as 5.35, 5.85, 5.55 and 5.85 ng/ml for acute, subacute, chronic and all-phase MDA5+ DM patients (P = 0.007, 0.001, 0.036 and <0.001, respectively). CYP3A5 genotype was one of the significant factors influencing TAC Cmin. CYP3A5 expressers required 0.059 mg/kg/day to attain the target Cmin, while nonexpressers required 0.046 mg/kg/day (P = 0.019).

CONCLUSION

TAC treatment may elicit favorable outcome in patients with IIM and MDA5+ DM when Cmin exceeded 5.35 and 5.85 ng/ml, which is crucial to a lower relapse rate. The individualized dose based on the CYP3A5 genotype provides a reference for TAC personalized therapy in IIM.

Targeting endothelial PDGFR-β facilitates angiogenesis-associated bone formation through the PAK1/NICD axis

The intricate orchestration of osteoporosis (OP) pathogenesis remains elusive. Mounting evidence suggests that angiogenesis-driven osteogenesis serves as a crucial foundation for maintaining bone homeostasis. This study aimed to explore the potential of the endothelial platelet-derived growth factor receptor-β (PDGFR-β) in mitigating bone loss through its facilitation of H-type vessel formation. Our findings demonstrate that the expression level of endothelial PDGFR-β is reduced in samples obtained from individuals suffering from OP, as well as in ovariectomy mice. Depletion of PDGFR-β in endothelial cells ameliorates angiogenesis-mediated bone formation in mice. The regulatory influence of endothelial PDGFR-β on H-type vessels is mediated through the PDGFRβ-P21-activated kinase 1-Notch1 intracellular domain signaling cascade. In particular, the endothelium-specific enhancement of PDGFR-β facilitates H-type vessels and their associated bone formation in OP. Hence, the strategic targeting of endothelial PDGFR-β emerges as a promising therapeutic approach for the management of OP in the near future.

Current evidence for janus kinase inhibitors in adult and juvenile dermatomyositis and key comparisons

INTRODUCTION

Adult dermatomyositis (DM) and juvenile dermatomyositis (JDM) are rare autoimmune diseases with characteristic skin rashes, weakness, and other systemic features. Upregulated interferon signaling has been consistently described in both adult and juvenile DM which makes janus kinase inhibitors (jakinibs) an attractive therapeutic agent that has a targeted mechanism of action.

AREAS COVERED

Herein is a review of the growing literature of jakinib use in adult and juvenile DM, including reports on specific disease features and safety of jakinibs in this population and a comparison between adult and juvenile DM. We performed a literature review using PubMed including all English-language publications before 1 February 2024 and abstracts from key recent rheumatology conferences.

EXPERT OPINION

Jakinibs are an exciting and promising treatment in both adult and juvenile DM. Current Phase 2 and 3 randomized placebo-controlled trials of jakinibs in both adult and JDM will provide significant insights into the efficacy of this class of medication as a potentially more mechanistically targeted treatment of both skin and muscle disease. In fact, these results will likely inform the treatment paradigm of dermatomyositis in that it may even be considered as first or second line. The next five years in the therapeutic landscape of both juvenile and adult DM is an exciting time for both patients and medical providers.

Clinico-sero-pathological profiles and risk prediction model of idiopathic inflammatory myopathy (IIM) patients with different perifascicular changes

AIMS

To explore the clinico-sero-pathological characteristics and risk prediction model of idiopathic inflammatory myopathy (IIM) patients with different muscular perifascicular (PF) changes.

METHODS

IIM patients in our center were enrolled and the clinico-sero-pathological data were retrospectively analyzed. A decision tree model was established through machine learning.

RESULTS

There were 231 IIM patients enrolled, including 53 with perifascicular atrophy (PFA), 39 with perifascicular necrosis (PFN), and 26 with isolated perifascicular enhancement of MHC-I/MHC-II (PF-MHCn). Clinically, PFA patients exhibited skin rashes and dermatomyositis-specific antibodies (DM-MSAs, 74.5%) except for anti-Mi2. PFN patients showed the most severe muscle weakness, highest creatine kinase (CK), anti-Mi2 (56.8%), and anti-Jo-1 (24.3%) antibodies. PF-MHCn patients demonstrated negative MSAs (48.0%) and elevated CK. Histopathologically, MAC predominantly deposited on PF capillaries in PFA but on non-necrotic myofiber in PFN (43.4% and 36.8%, p < 0.001). MxA expression was least in PF-MHCn (36.0% vs. 83.0% vs. 63.2%, p < 0.001). The decision tree model could effectively predict different subgroups, especially PFA and PFN.

CONCLUSIONS

Three types of PF change of IIMs representing distinct clinico-serological characteristics and pathomechanism. Undiscovered MSAs should be explored especially in PF-MHCn patients. The three pathological features could be accurately predicted through the decision tree model.

Development of the Cutaneous Dermatomyositis Investigator Global Assessment (CDM-IGA): A De Novo IGA of Cutaneous Manifestations of Dermatomyositis

INTRODUCTION

Dermatomyositis (DM) is a rare systemic autoimmune disease characterized by a distinctive debilitating skin rash and skeletal muscle weakness. It is unclear if existing clinical outcome assessment (COA) measures include the concepts of priority to patients and those necessary to fully capture improvements in the active cutaneous manifestations of DM. This study aimed to develop the Cutaneous Dermatomyositis Investigator Global Assessment (CDM-IGA), a de novo IGA, for use in clinical trials of adult DM.

METHODS

Eight DM clinical experts participated in 60-min qualitative interviews consisting of concept elicitation and cognitive debriefing methodologies. Concept elicitation comprised open-ended questions with follow-up probes to explore clinicians' experiences of treating patients with DM, the impact of symptoms on patients' quality of life, and the severity levels of disease characteristics to explore DM progression. Cognitive debriefing required the clinical experts to perform a review of the CDM-IGA, designed to assess the severity of cutaneous disease activity of DM. After the interviews, a consensus meeting with three clinical experts was held to agree on any outstanding issues relating to the CDM-IGA.

RESULTS

The CDM-IGA was iteratively developed using the opinions of nine clinical experts. Feedback provided by all clinicians agreed that erythema was the main active cutaneous manifestation of DM and should be the primary characteristic on the CDM-IGA, split by erythema color and extent. To determine cutaneous disease severity, experts suggested adding a metric called secondary changes, which combined erosion/ulceration and lichenification, which could modify the patient's final score. Three clinical experts suggested that a photo-guide to support assessments of erythema across different skin tones could be beneficial.

CONCLUSIONS

A novel CDM-IGA was developed for use with adult patients with DM in clinical trials, based on an iterative development process that combined qualitative feedback from clinical experts of DM and importantly adult patients living with DM.

Updates on efficacy and safety janus kinase inhibitors in juvenile dermatomyositis

INTRODUCTION

Juvenile dermatomyositis (JDM) is a rare autoimmune disease most commonly with proximal weakness due to inflammation and characteristic skin rashes. Most patients have a chronic or polycyclic disease course on standard therapy so better treatments are needed. An interferon signature is well-established in key tissues of JDM. Janus kinase inhibitors (jakinibs), which can decrease IFN signaling, are therefore appealing as a targeted therapy.

AREAS COVERED

Herein is a review of the growing literature on JDM patients in jakinibs, including specifics of their jakinib exposure, summary of efficacy, disease features, and characteristics of patients treated, and safety parameters.

EXPERT OPINION

The vast majority of refractory JDM patients respond to jakinib therapy, though they have varied features, doses, and previous/concurrent medications, and data is largely retrospective. Jakinibs are an exciting and promising treatment in JDM. Evaluation with larger prospective controlled studies is needed to answer remaining questions about jakinibs in JDM regarding dosing, which JDM patients to treat with jakinibs, potential biomarkers to use, and how best to monitor safety risks in JDM.

Evaluating disease status in idiopathic inflammatory myopathies with quantitative muscle ultrasound

INTRODUCTION/AIMS

Muscle strength, functional status, and muscle enzymes are conventionally used to evaluate disease status in idiopathic inflammatory myopathies (IIM). This study aims to investigate the role of quantitative muscle ultrasound in evaluating disease status in IIM patients.

METHODS

Patients with IIM, excluding inclusion body myositis, were recruited along with age- and sex-matched healthy controls (HC). All participants underwent muscle ultrasound and clinical assessments. Six limb muscles were unilaterally scanned using a standardized protocol, measuring muscle thickness (MT) and echo intensity (EI). Results were compared with HC, and correlations were made with outcome measures.

RESULTS

Twenty IIM patients and 24 HC were recruited. The subtypes of IIM were dermatomyositis (6), necrotizing myositis (6), polymyositis (3), antisynthetase syndrome (3), and nonspecific myositis (2). Mean disease duration was 8.7 ± 6.9 years. There were no significant differences in demographics and anthropometrics between patients and controls. MT of rectus femoris in IIM patients was significantly lower than HC. Muscle EI of biceps brachii and vastus medialis in IIM patients were higher than HC. There were moderate correlations between MT of rectus femoris and modified Rankin Scale, Physician Global Activity Assessment, and Health Assessment Questionnaire, as well as between EI of biceps brachii and Manual Muscle Testing-8.

DISCUSSION

Muscle ultrasound can detect proximal muscle atrophy and hyperechogenicity in patients with IIM. The findings correlate with clinical outcome measures, making it a potential tool for evaluating disease activity of patients with IIM in the late phase of the disease.

A new proposal for phenotypic classification and outcome assessment of dermatomyositis based on clinical manifestations and serological testing

BACKGROUND

Dermatomyositis (DM) is an infrequent disease subgroup of idiopathic inflammatory myopathies characterized by distinct skin lesions. However, high heterogeneity makes clinical diagnosis and treatment of DM very challenging.

OBJECTIVES

Unsupervised classification in DM patients and analysis of key factors related to clinical outcomes.

METHODS

This retrospective study was conducted between 2017 and 2022 at the Department of Rheumatology, Xiangya Hospital, Central South University. 162 DM patients were enrolled for unsupervised hierarchical cluster analysis. In addition, we divided the clinical outcomes of DM patients into four subgroups: withdrawal, stabilization, aggravation, and death, and compared the clinical profiles amongst the subgroups.

RESULTS

Out of 162 DM patients, three clusters were defined. Cluster 1 (n = 40) was mainly grouped by patients with prominent muscular involvement and mild Interstitial Lung Disease (ILD). Cluster 2 (n = 72) grouped patients with skin rash, anti-Melanoma Differentiation Associated protein 5 positive (anti-MDA5+), and Rapid Progressive Interstitial Lung Disease (RP-ILD). Cluster 3 (n = 50) grouped patients with the mildest symptoms. The proportion of death increased across the three clusters (cluster 3 < cluster 1 < cluster 2).

STUDY LIMITATIONS

The number of cases was limited for the subsequent construction and validation of predictive models. We did not review all skin symptoms or pathological changes in detail.

CONCLUSIONS

We reclassified DM into three clusters with different risks for poor outcome based on diverse clinical profiles. Clinical serological testing and cluster analysis are necessary to help clinicians evaluate patients during follow-up and conduct phenotype-based personalized care in DM.

Patient-reported quality of life and working status outcomes in ambulatory patients with idiopathic inflammatory myopathy

OBJECTIVE

To investigate the health-related quality of life (HR-QoL), work productivity and activity impairment and associated factors among patients with idiopathic inflammatory myopathy (IIM).

METHODS

This was an observational, cross-sectional study. The 189 ambulatory patients with IIM were recruited from May 2019 to May 2022. HR-QoL was measured by the European Quality of Life 5-Dimension (EQ-5D) questionnaire. The Work Productivity and Activity Impairment (WPAI) questionnaire was used to evaluate work productivity and activity impairment. The IIM-related parameters were assessed by the 8-item Manual Muscle Test (MMT-8), Myositis Disease Activity Assessment visual analogue scale (MYOACT), Myositis Damage Index (MDI), Disease Activity Score (DAS) and Physician/Patient Global Assessment (PhGA/PtGA). Quantile regression and ordinal logistic regression were performed to identify the factors, considering EQ-5D or WPAI scores as dependent variables, respectively.

RESULTS

Of the 189 IIM patients enrolled, 60% had DM, 13% had PM and 27% had clinical amyopathic DM. The median EQ-5D score was 1.00 (95% CI 0.73, 1.00), 28% were employed and 45% of overall work was impaired due to health problems. EQ-5D values were positively associated with MMT-8 and negatively with MYOACT, DAS, MDI-global and PhGA/PtGA. For the WPAI, activity impairment was associated with a lower MMT-8 score, older onset age and higher PhGA only in 25th-75th percentile. Increased PtGA was associated with increased activity and overall working productivity impairment in most quantiles (P<0.05).

CONCLUSION

Multiple disease characteristics were associated with reduced HR-QoL or working productivity impairment in patients with IIM, especially for PtGA.

Idiopathic inflammatory myopathies: current insights and future frontiers

Idiopathic inflammatory myopathies are a group of autoimmune diseases with a broad spectrum of clinical presentations, primarily characterised by immune-mediated muscle injury. Until recently, there was little insight into the pathogenesis of idiopathic inflammatory myopathies, which challenged the recognition of the breadth of heterogeneity of this group of diseases as well as the development of new therapeutics. However, the landscape of idiopathic inflammatory myopathies is evolving. In the past decade, advances in diagnostic tools have facilitated an enhanced understanding of the underlying disease mechanisms in idiopathic inflammatory myopathies, enabling the expansion of therapeutic trials. The fields of transcriptomics, prot§eomics, and machine learning offer the potential to gain greater insights into the underlying pathophysiology of idiopathic inflammatory myopathies. Harnessing insights gained from these sophisticated tools could contribute to the identification of differences at a molecular level among patients, accelerating the development of targeted, tailored therapies. Bolstered by the validation and standardisation of robust outcome measures, many promising therapies are in clinical trial development. Although challenges remain, there is great optimism in the field due to the progress in innovative diagnostics, outcome measures, and therapeutic approaches. In this Review, we discuss the expanding landscape of idiopathic inflammatory myopathies as the frontier of precision medicine becomes imminent.

The longitudinal study of muscle changes with ultrasound: differential changes in idiopathic inflammatory myopathy subgroups

OBJECTIVES

We investigated shear wave elastography (SWE), B mode US and power Doppler (PDUS) as imaging biomarkers for longitudinal follow-up in idiopathic inflammatory myopathy (IIM), with a particular focus on immune-mediated necrotizing myopathy (IMNM) and DM.

METHODS

Participants had serial SWE, PDUS on the deltoid (D) and vastus lateralis (VL) muscles on four occasions at intervals of 3-6 months. Clinical assessments included manual muscle testing, and patient- and physician-reported outcome scales.

RESULTS

Thirty-three participants were included: IMNM = 17, DM = 12, overlap myositis = 3, PM = 1. Twenty were in a prevalent clinic group, and 13 were recently treated cases in an incident group. Differential changes in SWS and US domains occurred with time in both the prevalent and incident groups. In the VL-prevalent subgroup, echogenicity increased over time (P = 0.040), while in the incident cases there was a trend for reduction to normal over time (P = 0.097) with treatment. Muscle bulk reduced in the D-prevalent subgroup over time (P = 0.096), suggesting atrophy. SWS also reduced in the VL-incident subgroup over time (P = 0.096), suggesting a trend towards improvement in muscle stiffness with treatment.

CONCLUSION

SWE and US appear promising as imaging biomarkers for patient follow-up in IIM and indicate changes over time, especially with echogenicity, muscle bulk and SWS in the VL. Due to the limitations of the participant numbers, additional studies with a larger cohort are needed to help evaluate these US domains further and outline specific characteristics within the IIM subgroups.

Patient-Reported Outcome Measures in Neuromuscular Diseases: A Scoping Review

 Patient-reported outcome measures (PROMs) are valuable in comprehensively understanding patients' health experiences and informing healthcare decisions in research and clinical care without clinicians' input. Until now, no central resource containing information on all PROMS in neuromuscular diseases (NMD) is available, hindering the comparison and choice of PROMs used to monitor NMDs and appropriately reflect the patient's voice. This scoping review aimed to present a comprehensive assessment of the existing literature on using PROMs in children and adults with NMD. A scoping methodology was followed using Preferred Reporting Items for Systematic reviews and Meta-Analyses extension for Scoping Reviews (PRISMA-ScR) and COnsensus-based Standards for the selection of health Measurement INstruments (COSMIN) guidelines to assess the literature on PROMs in NMDs. Eligibility criteria encompassed articles describing psychometric development or evaluation of generic or disease-specific PROM-based instruments for adults and children with specific NMDs. The data charting process involved extracting measurement properties of included PROMs, comprising validity, reliability, responsiveness, and interpretability information. The review identified 190 PROMs evaluated across 247 studies in individuals with NMDs. The majority of PROMs were disease specific. The physical functioning domain was most assessed. Validity was the most frequently investigated measurement property, with a limited number of PROMs sufficiently evaluated for a range of psychometric characteristics. There is a strong need for further research on the responsiveness and interpretability of PROMs and the development of PROMs on social functioning in NMD.

Discordance between patient- and physician-reported disease activity in adult idiopathic inflammatory myopathy

OBJECTIVES

Patient-reported global disease activity (patient-global) is a myositis core set measure. Understanding the drivers of patient-global is important in patient assessment, and disagreements between physician and patient perception of disease activity may negatively impact shared decision making. We examined the determinants of patient-global and discordance between patient-global and physician-reported global disease activity (physician-global) in idiopathic inflammatory myopathies (IIMs).

METHODS

Adults with IIM were enrolled in a prospective observational cross-sectional study. The following myositis outcome measures were collected: patient-global, physician-global, extramuscular and muscle disease activity, manual muscle testing, HAQ, creatine kinase, fatigue, pain, Patient-Reported Outcomes Measurement Information System physical function, 36-item Short Form, sit to stand, timed up and go, 6-minute walk and Actigraph steps/min/day count. A linear regression model was used to determine the contribution of each measure to patient-global. Discordance was defined as ≥3 points difference between patient-global and physician-global.

RESULTS

Fifty patients [60% females; mean age 51.6 years (s.d. 14.9)] with probable/definite IIM (EULAR/ACR classification criteria for IIM) were enrolled. Physical function and fatigue measures contributed to patient-global the most, followed by measures of pain, physical activity, quality of life and muscle disease, while physician-global was primarily driven by muscle disease activity. Patient-global was discordant with physician-global in 30% of the patients, of which patient-global was higher than physician-global in 66%. Pain, fatigue and physical activity contributed more to patient-global than physician-global.

CONCLUSION

Fatigue, pain and physical activity are important driving factors of the differences observed in the patient vs physician assessment of myositis disease activity. Understanding the gap between patient and physician perspectives may help provide better patient-centred care.

Long Term Outcomes in Idiopathic Inflammatory Myositis: An Observational Epidemiologic Study over 15 Years

Background

We report a longitudinal observational cohort of idiopathic inflammatory myositis (IIM) focusing on the long-term clinical outcome and associated parameters.

Methods

IIM patients were classified as per Bohan and Peter criteria. In those with ≥ 24 months of follow-up; the treatment response, functional outcomes, and damage at last follow-up were recorded. Complete clinical response and clinical remission as defined by Oddis et al., was used to define outcomes at last follow-up.

Results

The cohort consists of 175 patients, mean age 40.9 (+12.6) years, M:F 1:3.3; and the major subsets were dermatomyositis (44.6%), overlap myositis (25.7%), antisynthetase syndrome (6.3%), polymyositis (14.3%), and juvenile DM/OM (8.6%). Ninety-four patients have followed up for 24 months or more, with the median (IQR) of 65(35,100.7) months. Of them, 74.1% and 11.8% had complete and partial clinical responses respectively at the last follow-up. In our cohort 40.2% were off-steroids and 13.8% were in clinical remission at the last follow-up. Complete clinical response was associated with better functional outcomes and lesser damage as determined by HAQ-DI of 0[OR10.9; 95%CI (3.3,160)], MRS [OR 3.2; 95%CI (1.4,7.3)] and lesser MDI [OR 1.7; 95% CI (1.1,2.7)] respectively as compared to partial response (unadjusted analysis). Baseline parameters and IIM subsets did not significantly influence the functional outcome and damage. The mortality rate in our cohort is 24/175 (13.7%), the disease-specific mortality rate being 9.1%. Large majority of deaths were early, associated with active disease.

Conclusion

We report good long-term outcomes in all major myositis subsets. Partial clinical response to treatment is associated with worse functional outcomes and damage accrual. Death occurs early in association with active disease.

Skeletal muscle injury in COVID infection: Frequency and patterns

INTRODUCTION/AIMS

Little is known about skeletal muscle injury with coronavirus disease 2019 (COVID-19). We estimate the frequency and explore the patterns of skeletal muscle injury in acute COVID-19.

METHODS

A cohort of COVID patients with mild to moderate symptoms were evaluated in a COVID-designated hospital between May and December 2021 and followed for 2 weeks. Skeletal muscle injury was assessed according to creatine kinase (CK) levels, Manual Muscle Test-8 (MMT-8) score, and the Health Assessment Questionnaire (HAQ) score. Injury was defined as CK >200 IU/L with an MMT-8 score < 76. The association between such injury and severity and outcomes were evaluated using cross-tabulations.

RESULTS

Two hundred fifty participants with a mean age of 50.2 years (SD: 17.2) were included. One hundred nine (43.6%) were women; 84 (34%) developed severe disease. Median CK levels were 91 IU/L (IQR 56-181). [Correction added on 17 November 2023, after first online publication: In the preceding sentence, the IQR was corrected from '56,181'.] Patients with weakness on the MMT-8 (n = 247, 98.8%) and disability on the HAQ (n = 107; 42.8%) were common. Neck flexor muscles were prominently affected. Skeletal muscle injury was seen in 22.4% (95% CI: 17.4-28.1). There was no significant association between skeletal muscle injury and maximal severity of illness or short-term outcomes. Disability increased over 14 days in most survivors (n = 172, 72.3%) and this was not seen in those with mild disease (OR: 0.4, 95% CI: 0.22-0.70).

DISCUSSION

Skeletal muscle injury appears to be common in people presenting with mild to moderate COVID infection.

Treat-to-Target in Pediatric Rheumatic Diseases

PURPOSE OF REVIEW

To summarize the current evidence on the adoption of the treat-to-target (T2T) strategy in pediatric rheumatic diseases (PRD).

RECENT FINDINGS

The recent advances in the management of PRD have markedly increased the ability to achieve disease remission. Complete disease quiescence is regarded as the ideal therapeutic goal because its attainment leads to lesser long-term damage and physical disability, and to optimization of quality of life. Studies in adult rheumatic diseases have shown that patient outcomes are improved if complete suppression of the inflammatory process is aimed for by frequent adjustments of therapy according to quantitative indices. This approach, which underlies the T2T concept, has been applied in strategic trials in rheumatoid arthritis (RA). Furthermore, recommendations for the T2T have been issued for RA and other adult rheumatic diseases. There is currently a growing interest for the introduction of T2T in PRD, and recommendations for treating juvenile idiopathic arthritis (JIA) to target were promulgated. A similar initiative has been undertaken for childhood-onset systemic lupus erythematosus. Preliminary therapeutic studies have explored the T2T design in JIA. The T2T strategy is a modern therapeutic approach that holds the promise of improving the outcomes in patients with PRD.

Inclusion body myositis-health-related quality of life and care situation during phases of the "patience journey" in Germany: results from a qualitative study

BACKGROUND

To understand the health-related quality of life (HRQoL) in inclusion body myositis (IBM) from a holistic perspective on the background of a complex care situation. The focus was on how the patient journey may be structured over the course of this rare disease.

METHODS

An exploratory qualitative study was performed via in-depth semi-structured interviews. Seven patients (males n = 5) with 2011 European Neuromuscular Centre (ENMC) IBM criteria from the German IBM patient registry were interviewed for this study. The dynamic network approach of resilience and the throughput-model of health services research were used to structure the qualitative analysis.

RESULTS

Our results suggest that IBM patients experience the holistic HRQoL and care situation typically in four phases: (1) uncertainty about physical vulnerability until diagnosis, (2) promising treatment approaches, (3) self-management and dyadic coping, (4) weak body, busy mind and caregiver burden. The homophonous in-vivo code "patience journey" describes the frequently reported emotional perspective of the patient journey. Although the overarching theme of perceived social support varied throughout these phases, a reliable patient-partner-dyad may lead to improved HRQoL in the long-term.

CONCLUSIONS

New hypotheses for future quantitative research were generated to better understand the IBM patients' burden in the long term. The identified relevance of social support emphasizes the patients' need to handle IBM as manageable in medical settings. During exhausting phases of IBM progression, more effective care elements for patients and their partners could disclose varying needs. Strengthening multi-professional healthcare services via individualised informational, practical, or emotional support could improve HRQoL, especially since there is no curative treatment available so far.

Safety and efficacy of arimoclomol for inclusion body myositis: a multicentre, randomised, double-blind, placebo-controlled trial

BACKGROUND

Inclusion body myositis is the most common progressive muscle wasting disease in people older than 50 years, with no effective drug treatment. Arimoclomol is an oral co-inducer of the cellular heat shock response that was safe and well-tolerated in a pilot study of inclusion body myositis, reduced key pathological markers of inclusion body myositis in two in-vitro models representing degenerative and inflammatory components of this disease, and improved disease pathology and muscle function in mutant valosin-containing protein mice. In the current study, we aimed to assess the safety, tolerability, and efficacy of arimoclomol in people with inclusion body myositis.

METHODS

This multicentre, randomised, double-blind, placebo-controlled study enrolled adults in specialist neuromuscular centres in the USA (11 centres) and UK (one centre). Eligible participants had a diagnosis of inclusion body myositis fulfilling the European Neuromuscular Centre research diagnostic criteria 2011. Participants were randomised (1:1) to receive either oral arimoclomol 400 mg or matching placebo three times daily (1200 mg/day) for 20 months. The randomisation sequence was computer generated centrally using a permuted block algorithm with randomisation numbers masked to participants and trial staff, including those assessing outcomes. The primary endpoint was the change from baseline to month 20 in the Inclusion Body Myositis Functional Rating Scale (IBMFRS) total score, assessed in all randomly assigned participants, except for those who were randomised in error and did not receive any study medication, and those who did not meet inclusion criteria. Safety analyses included all randomly assigned participants who received at least one dose of study medication. This trial is registered with ClinicalTrials.gov, number NCT02753530, and is completed.

FINDINGS

Between Aug 16, 2017 and May 22, 2019, 152 participants with inclusion body myositis were randomly assigned to arimoclomol (n=74) or placebo (n=78). One participant was randomised in error (to arimoclomol) but not treated, and another (assigned to placebo) did not meet inclusion criteria. 150 participants (114 [76%] male and 36 [24%] female) were included in the efficacy analyses, 73 in the arimoclomol group and 77 in the placebo group. 126 completed the trial on treatment (56 [77%] and 70 [90%], respectively) and the most common reason for treatment discontinuation was adverse events. At month 20, mean IBMFRS change from baseline was not statistically significantly different between arimoclomol and placebo (-3·26, 95% CI -4·15 to -2·36 in the arimoclomol group vs -2·26, -3·11 to -1·41 in the placebo group; mean difference -0·99 [95% CI -2·23 to 0·24]; p=0·12). Adverse events leading to discontinuation occurred in 13 (18%) of 73 participants in the arimoclomol group and four (5%) of 78 participants in the placebo group. Serious adverse events occurred in 11 (15%) participants in the arimoclomol group and 18 (23%) in the placebo group. Elevated transaminases three times or more of the upper limit of normal occurred in five (7%) participants in the arimoclomol group and one (1%) in the placebo group. Tubulointerstitial nephritis was observed in one (1%) participant in the arimoclomol group and none in the placebo group.

INTERPRETATION

Arimoclomol did not improve efficacy outcomes, relative to placebo, but had an acceptable safety profile in individuals with inclusion body myositis. This is one of the largest trials done in people with inclusion body myositis, providing data on disease progression that might be used for subsequent clinical trial design.

FUNDING

US Food and Drug Administration Office of Orphan Products Development and Orphazyme.

Therapeutic Effects of Treating COVID-19 Vaccine-Induced Anti-TIF1-γ-Positive Dermatomyositis

An increase in skin-related autoimmune disorders has been reported as an adverse effect of coronavirus disease 2019 (COVID-19) vaccines. We present the case of a 90-year-old Taiwanese female who was newly diagnosed with anti-transcription intermediary factor 1-gamma (anti-TIF1-γ)-positive dermatomyositis (DM) after receiving a second dose of the AstraZeneca COVID-19 vaccine. Under treatment with prednisolone and monoclonal antibody therapy of abatacept, her skin lesions improved, and her muscle power increased. The serum creatinine phosphokinase level decreased from 4858 to 220 U/L, and the anti-TIF1-γ antibody titer decreased from 202 to 99. Flow cytometry data showed an increase in T cells, while NK cells, B cells (CD19), and plasma blasts all decreased. These findings suggest that standard DM treatment might be beneficial to patients with COVID-19 vaccine-induced DM.

Investigating the Association Between Muscular Ultrasonographic Alterations and Clinical Symptoms in Patients With Inflammatory Myopathy

Introduction

Muscle biopsy is commonly used to diagnose inflammatory myopathies. We evaluated the ability of muscle ultrasound, a non-invasive and simple tool, to distinguish between healthy subjects and patients with inflammatory myopathy.

Methods

This study was conducted on 17 patients recently diagnosed with biopsy inflammatory myopathies (12 dermatomyositis, 5 polymyositis) compared with 17 age- and gender-matched healthy control adults. All patients underwent clinical assessments, including manual muscle testing, hand-held dynamometry, and muscle ultrasound evaluations, including thickness and echo intensity in predefined muscle groups.

Results

The disease duration was seven months (interquartile range: 3 to 11 months). Except for the biceps and gastrocnemius, patients' muscles had significantly higher echo intensity and lower thickness than the control group. The echo intensity sum-score manifested the highest area under the curve compared to the sum-scores of other variables (echo intensity vs manual muscle testing: Area under curves-difference=0.18, P<0.01; echo intensity vs dynamometry: Area under curves-difference=0.14, P=0.02; echo intensity vs thickness: Area under curves-differences-difference=0.25, P<0.01).

Conclusion

The echo intensity of muscles differed significantly between healthy individuals and patients with inflammatory myopathies and may serve as a useful diagnostic biomarker.

Urine proteomics by mass spectrometry identifies proteins involved in key pathogenic pathways in patients with juvenile dermatomyositis

OBJECTIVES

To identify and validate biomarkers in JDM patients using a multiplexing tandem mass tag urine proteome profiling approach.

METHODS

First morning void urine samples were collected from JDM patients (n = 20) and healthy control subjects (n = 21) and processed for analysis using a standardized liquid chromatography-tandem mass spectrometry approach. Biomarkers with significantly altered levels were correlated with clinical measures of myositis disease activity and damage. A subset of candidate biomarkers was validated using commercially available ELISA kits.

RESULTS

In total, 2348 proteins were detected in the samples, with 275 proteins quantified across all samples. Among the differentially altered proteins, cathepsin D and galectin-3 binding protein were significantly increased in the urine of JDM patients (adjusted P < 0.05), supporting previous findings in myositis patients. These two candidate biomarkers were confirmed with ELISAs. Cathepsin D positively correlated with Myositis Damage Index (r = 0.57, P < 0.05) and negatively correlated with the Childhood Myositis Assessment Scale (r = -0.54, P < 0.05). We also identified novel JDM candidate biomarkers involved with key features of myositis, including extracellular matrix remodelling proteins.

CONCLUSION

This study confirmed the presence of several proteins in the urine of JDM patients that were previously found to be elevated in the blood of myositis patients and identified novel candidate biomarkers that require validation. These results support the use of urine as a source for biomarker development in JDM.

Treatment with add-on IVIg in Myositis Early In the diSease course May be sUperior to Steroids alone for reaching CLinical improvEment (TIME IS MUSCLE): study protocol of a phase-2 double-blind placebo-controlled randomised trial

INTRODUCTION

For idiopathic inflammatory myopathies (IIM) ('myositis') standard initial treatment is high-dosed glucocorticoids, which results in relatively slow improvement of muscle strength. Early immunosuppression or modulation by intensive treatment ('hit-early, hit-hard') may induce faster reduction of disease activity and prevent chronic disability due to disease-induced structural muscle damage. Intravenous immunoglobulin (IVIg) in addition to standard glucocorticoid treatment may be promising in this regard as was shown in various studies: add-on IVIg improved symptoms and muscle strength in refractory myositis patients and monotherapy IVIg improved outcomes after 9 weeks, in about half of treatment-naive patients.

HYPOTHESIS

We hypothesise that early add-on IVIg leads to a greater clinical response after 12 weeks in patients with newly diagnosed myositis, in comparison to prednisone monotherapy. Second, we expect that early treatment with add-on IVIg leads to a faster time to improvement and sustained positive effects on multiple secondary outcomes.

METHODS

The Time Is Muscle trial is a phase-2 double-blind placebo-controlled randomised trial. Forty-eight patients with IIM will be treated with IVIg or placebo at baseline (within 1 week after diagnosis) and after 4 and 8 weeks, in addition to standard therapy with prednisone. The primary outcome is the Total Improvement Score (TIS) of the myositis response criteria at 12 weeks. At baseline, and after 4, 8, 12, 26 and 52 weeks, relevant secondary outcomes will be assessed, including time to moderate improvement (TIS≥40), mean daily prednisone dosage, physical activity, health-related quality of life, fatigue and MRI muscle imaging parameters.

ETHICS AND DISSEMINATION

Ethical approval was obtained from the medical ethics committee of the Academic Medical Centre, University of Amsterdam, the Netherlands (2020_180; including a first amendment approval at the 12 April 2023; A2020_180_0001). The results will be distributed through conference presentations and peer-reviewed publications.

TRIAL REGISTRATION NUMBER

EU Clinical trials register (2020-001710-37).

Currently recommended skin scores correlate highly in the assessment of patients with Juvenile Dermatomyositis (JDM)

BACKGROUND

Juvenile Dermatomyositis (JDM) is a rare, chronic, and life-threatening childhood autoimmune disease. Currently, there are recommended, reliable and validated measurement tools for assessment of skin disease activity in JDM including the Disease Activity Score (skinDAS), Cutaneous Assessment Tool (CAT), and the Cutaneous Dermatomyositis Disease Area and Severity Index (CDASI). The Physician's global assessment skin visual analog scale (Skin VAS) is also widely used for skin activity in JDM. For the purpose of comparative international studies, we wanted to compare these tools to the Physician's skin VAS (as a standard) to identify which performs better.

OBJECTIVES

We sought to compare the correlations of these scoring tools, and separately assess the responsiveness each tool demonstrates following patient treatment, in order to see if one tool may be preferred. This was determined by assessing how well these tools correlate with each other, and the Physician's skin VAS over time, as well as the responsiveness of each tool after patient treatment.

METHODS

Skin scores were recorded at a baseline (first visit after June 1^st, 2018) and all follow-up office visits at the Juvenile Dermatomyositis Clinic. Following baseline visits, patients were followed up as clinically indicated. A subset of newly diagnosed patients (inception cohort) was identified. Correlations were assessed at the baseline visit and over time for the whole cohort. The correlations over time were derived using Generalized Estimating Equations (GEEs). Standardized response means with 95% confidence intervals were calculated to test score responsiveness for the nested inception cohort.

RESULTS

The skinDAS, CAT and CDASI all correlated highly with each other and with the Physician's skin VAS. The three scoring tools accurately reflected Physician's skin VAS scores over time. In addition, all tools showed moderate to high responsiveness following treatment.

CONCLUSION

All studied skin score tools performed well in our study and appear to be useful. Since no tool far outperforms the others, arbitrary consensus will be needed to select a single standard measurement tool for the purposes of efficiency and global comparability.

Cessation of Immunomodulatory Medication Use in Dermatomyositis: A Single-Center Cohort Study

OBJECTIVE

To determine the frequency with which adults with dermatomyositis (DM) are able to discontinue systemic immunomodulatory therapy and factors associated with medication cessation.

METHODS

We studied a cohort of adult DM patients seen in a rheumatology/dermatology clinic between 2013 and 2020. All patients had exposure to at least 1 systemic immunomodulatory medication for a minimum of 3 months and were followed until medications were discontinued for at least 12 months. Survival analysis was performed using Kaplan-Meier curves with log-rank analyses, and multivariate analysis was done using Cox proportional hazards models.

RESULTS

A total of 246 DM patients were followed up for a median time of ∼7 years (47-134 months). Forty-seven patients (19%) discontinued all immunomodulatory medications with a median follow-up of ∼3 years (interquartile range 22-108 months) following DM onset. Log-rank analysis demonstrated that those with anti-MDA5 autoantibodies discontinued medications faster compared with those without autoantibodies (P = 0.03). Multivariate modeling showed that clinically amyopathic patients were 2.7-fold (95% confidence interval [95% CI] 1.34-5.59) more likely to discontinue medications than those with muscle disease. Those with anti-MDA5, anti-NXP2, and anti-SAE1 antibodies had increased likelihood of medication cessation with hazard ratios of 9.83 (95% CI 2.00-48.2), 8.92 (95% CI 1.69-47.0), and 10.8 (95% CI 2.06-56.6), respectively, when compared with the autoantibody-negative group.

CONCLUSION

Approximately 20% of adult DM patients discontinued immunomodulatory medications over a median 7-year follow-up. Those with clinically amyopathic disease, anti-MDA5, anti-NXP2, and anti-SAE1 antibodies have a higher likelihood of medication cessation.

Pruritogenic molecules in the skin of patients with dermatomyositis

Introduction

Pruritus is a common excruciating symptom in systemic autoimmune diseases such as dermatomyositis (DM) but the pathogenesis is not fully understood. We intended to investigate the targeted expression analysis of candidate molecules involved in the development of pruritus in lesional vs. non-lesional skin samples of patients affected with active DM. We looked for correlations between the investigated pruriceptive signaling molecules, disease activity, and itching sensation of DM patients.

Methods

Interleukins (IL-33 and IL-6), tumor necrosis factor α (TNF-α), peroxisome proliferator-activated receptor γ (PPAR-γ), and ion channels belonging to the transient receptor potential (TRP) family were analyzed. The expression of TNF-α, PPAR-γ, IL-33, IL-6, and TRP channels in lesional DM skin was evaluated by RT-qPCR and immunohistochemistry and was compared with non-lesional DM skin samples. Pruritus, disease activity, and damage of DM were evaluated by the 5-D itch scale and Cutaneous Dermatomyositis Disease Area and Severity Index (CDASI), respectively. Statistical analysis was performed with IBM SPSS 28 software.

Results

A total of 17 active DM patients participated in the study. We could show that the itching score was positively correlated with the CDASI activity score (Kendall's tau-b = 0.571; p = 0.003). TNF-α gene expression was significantly higher in lesional DM skin than in non-lesional DM skin (p = 0.009) and differed in the subgroups of patients with different itch intensities (p = 0.038). The mRNA expression of lesional IL-6 correlated positively with 5-D itch and CDASI activity score (Kendall's tau-b = 0.585; p = 0.008 and 0.45; p = 0.013, respectively). TRPV4 expressions were positively correlated with CDASI damage score (Kendall's tau-b = 0.626; p < 0.001), but the mRNA expressions of the TRP family, PPAR-γ, IL-6, and IL-33 were not different in lesional and non-lesional samples. Immunohistochemistry analysis did not find significant alterations in the expressions of TNF-α, PPAR-γ, IL-6, and IL-33 in lesional and non-lesional regions.

Discussion

Our results argue that cutaneous disease activity, TNF-α, and IL-6 might play a central role in DM-associated itch, while TRPV4 plays a central role in tissue regeneration.

A machine learning analysis to evaluate the outcome measures in inflammatory myopathies

OBJECTIVE

To assess the long-term outcome in patients with Inflammatory Idiopathic Myopathies (IIM), focusing on damage and activity disease indexes using artificial intelligence (AI).

BACKGROUND

IIM are a group of rare diseases characterized by involvement of different organs in addition to the musculoskeletal. Machine Learning analyses large amounts of information, using different algorithms, decision-making processes, self-learning neural networks.

METHODS

We evaluate the long-term outcome of 103 patients with IIM, diagnosed on 2017 EULAR/ACR criteria. We considered different parameters, including clinical manifestations and organ involvement, number and type of treatments, serum creatine kinase levels, muscle strength (MMT8 score), disease activity (MITAX score), disability (HAQ-DI score), disease damage (MDI score), and physician and patient global assessment (PGA). The data collected were analysed, applying, with R, supervised ML algorithms such as lasso, ridge, elastic net, classification, and regression trees (CART), random forest and support vector machines (SVM) to find the factors that best predict disease outcome.

RESULTS AND CONCLUSION

Using artificial intelligence algorithms we identified the parameters that best correlate with the disease outcome in IIM. The best result was on MMT8 at follow-up, predicted by a CART regression tree algorithm. MITAX was predicted based on clinical features such as the presence of RP-ILD and skin involvement. A good predictive capacity was also demonstrated on damage scores: MDI and HAQ-DI. In the future Machine Learning will allow us to identify the strengths or weaknesses of the composite disease activity and damage scores, to validate new criteria or to implement classification criteria.

Incidence, features, and outcome of disease relapse after COVID-19 vaccination in patients with idiopathic inflammatory myopathies

INTRODUCTION/AIMS

Vaccination against coronavirus disease 2019 (COVID-19) is relatively safe in patients with idiopathic inflammatory myopathies (IIM); however, myositis flares following vaccination have been poorly studied. We aimed to evaluate the frequency, features, and outcomes of disease relapses in patients with IIM following COVID-19 vaccination.

METHODS

A cohort of 176 IIM patients were interviewed after the third wave of the COVID-19 pandemic and followed prospectively. Relapses were determined using the disease state criteria and the outcome of the flares with myositis response criteria, calculating the total improvement score (TIS).

RESULTS

A total of 146 (82.9%) patients received a vaccination, 17/146 (11.6%) patients had a relapse within 3 mo, and 13/146 (8.9%) patients within 1 mo. The relapse rate of unvaccinated patients was 3.3%. Three months after the post-vaccination relapses, 70.6% of the patients (12/17) achieved an improvement of disease activity (average TIS score: 30 ± 15.81; seven minor, five moderate, and zero major improvements). Six months after flares improvement was detected in 15/17(88.2%) of relapsed patients (average TIS score: 43.1 ± 19.53; 3 minimal, 8 moderate, and 4 major). Forward stepwise logistic regression analysis revealed that the active state of myositis at the time of injection (p < .0001; odds ratio, 33; confidence interval, 9-120) was significantly associated with the occurrence of a relapse.

DISCUSSION

A minority of the vaccinated IIM patients had a confirmed disease flare after COVID-19 vaccination and the majority of the relapses improved after individualized treatment. An active disease state at the time of vaccination probably contributes to the increased risk of a post vaccination myositis flare.

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.

Low-dose rituximab is efficacious in refractory idiopathic inflammatory myopathies

OBJECTIVES

Rituximab (RTX) use early in the course of refractory idiopathic inflammatory myopathy (IIM) is not well studied. This study sought to determine the short-term efficacy of RTX in a registry-based cohort of refractory IIM.

METHODS

Registry-based observational data about IIM patients receiving RTX between 2018 and 2021 were included. Total improvement score was calculated from the core set measures as per International Myositis Assessment and Clinical Studies group (IMACS) at baseline, 6 months and 12 months of follow-up.

RESULTS

Forty-two patients (F:M, 29:13), with a mean (s.d.) age of 39.5 (11.5) years were studied. Majority of patients received RTX for refractory myositis, after a median (interquartile range) duration of 8 (4,18) months. Twenty-eight received RTX at a dosage of 1 g × two doses, while 14 received 500 mg × two doses with an interval of 15 days. At 6 months and 12 months post-RTX, the improvement was recorded in manual muscle testing (MMT-8) scores, physician global assessment (PGA), patient global assessment (PtGA) and median steroid dosage as compared with the baseline (P < 0.01 for all). A mean (s.d.) improvement of 44.5 (16) and 48.7 (19.2) in total improvement score was recorded at 6 and 12 months, respectively. The change in MMT-8, PGA and PtGA scores from baseline between the two dosage regimens of RTX were comparable at 6 and 12 months. Severe lower respiratory tract infections requiring hospitalization occurred in three patients of the cohort.

CONCLUSION

RTX improved IMACS core set measures and had steroid sparing efficacy at 6 and 12 months in patients with IIM in this registry-based study. Rituximab as an induction regimen of two doses of 500 mg can be as efficacious as 1 g at 6 months and 12 months of follow-up.

Myostatin in idiopathic inflammatory myopathies: Serum assessment and disease activity

AIMS

In idiopathic inflammatory myopathies (IIM), disease activity is difficult to assess, and IIM may induce severe muscle damage, especially in immune-mediated necrotising myopathies (IMNM) and inclusion body myositis (IBM). We hypothesise that myostatin, a negative regulator of muscle mass, could be a new biomarker of disease activity and/or muscle damage.

METHODS

Prospective assessment of myostatin protein level in 447 IIM serum samples (dermatomyositis [DM], n = 157; IBM, n = 72; IMNM, n = 125; and antisynthetase syndrome [ASyS], n = 93) and 59 healthy donors (HD) was performed by ELISA. A gene transcript analysis was also carried out on 18 IIM muscle biopsies and six controls to analyse myostatin and myostatin pathway-related gene expression.

RESULTS

IIM patients had lower myostatin circulating protein levels and gene expression compared to HD (2379 [1490; 3678] pg/ml vs 4281 [3169; 5787] pg/ml; p < 0.0001 and log2FC = -1.83; p = 0.0005, respectively). Myostatin-related gene expression varied accordingly. Based on the Physician Global Assessment, inactive IIM patients showed higher myostatin levels than active ones. This was the case for all IIM subgroups, except IMNM where low myostatin levels were maintained (2186 [1235; 3815] vs 2349 [1518; 3922] pg/ml; p = 0.4).

CONCLUSIONS

Myostatin protein and RNA levels are decreased in all IIM patients, and protein levels correlate with disease activity. Inactive ASyS and DM patients have higher myostatin levels than active patients. Myostatin could be a marker of disease activity in these subgroups. However, IMNM patients do not have significant increase in myostatin levels after disease remission. This may highlight a new pathological disease mechanism in IMNM patients.

Work situation, work ability and expectation of returning to work in patients with systemic autoimmune myopathies

OBJECTIVES

To document the work situation, the work ability and the expectation of returning to work among adult patients with systemic autoimmune myopathies (SAMs), and to identify the factors associated with each of these outcomes.

METHODS

Cross-sectional study. The work situation (performing paid work vs out of work) was ascertained via a structured questionnaire. For those who were working, we applied the Work Ability Index (WAI; scale 7-49); and for those who were out of work, we applied the Return-to-Work Self-Efficacy questionnaire (RTW-SE; scale 11-66).

RESULTS

Of the 75 patients with SAMs included, 33 (44%) were doing paid work and 42 (56%) were out of work. The work situation was independently associated with physical function, assessed by the Health Assessment Questionnaire-Disability Index (HAQ-DI). A 1-point increase in the HAQ-DI (scale 0-3) decreased the chance of doing paid work by 66% (95% CI: 0.16, 0.74; P = 0.007). Patients performing paid work had a mean WAI of 33.5 (6.9). The following variables were associated with a decrease in the WAI score in the regression model: female sex (-5.04), diabetes (-5.94), fibromyalgia (-6.40), fatigue (-4.51) and severe anxiety (-4.59). Among those out of work, the mean RTW-SE was 42.8 (12.4). Cutaneous manifestations and >12 years of education were associated with an average increase of 10.57 and 10.9 points, respectively, in the RTW-SE. A 1-point increase in the HAQ-DI decreased the RTW-SE by 4.69 points.

CONCLUSION

Our findings highlight the poor work participation in a well-characterized sample of working-age patients with SAMs. Strategies to improve work-related outcomes in these patients are urgently needed.

Transcriptome Profiling of Immune Cell Types in Peripheral Blood Reveals Common and Specific Pathways Involved in the Pathogenesis of Myositis-Specific Antibody-Positive Inflammatory Myopathies

OBJECTIVE

Idiopathic inflammatory myopathies (IIM) demonstrate characteristic clinical phenotypes depending on the myositis-specific antibody (MSAs) present. We aimed to identify common or MSA-specific immunological pathways in different immune cell types from peripheral blood by transcriptome analysis.

METHODS

We recruited 33 patients with IIM who were separated into the following groups: 15 patients with active disease at onset and 18 with inactive disease under treatment. All patients were positive for MSAs: anti-melanoma differentiation-associated gene 5 (MDA5) antibody (Ab) in 10 patients, anti-Mi-2 Ab in 7, and anti-aminoacyl-transfer RNA synthetase (ARS) Ab in 16. The patients were compared with 33 healthy controls. Twenty-four immune cell types sorted from peripheral blood were analyzed by flow cytometry, RNA sequencing, and differentially expressed gene analysis combined with pathway analysis.

RESULTS

The frequencies of memory B cell types were significantly decreased in active patients, and the frequency of plasmablasts was prominently increased in active patients with anti-MDA5 Ab in comparison with healthy controls. The expression of type I interferon (IFN)-stimulated genes of all immune cell types was increased in the active, but not inactive, patients. Endoplasmic reticulum stress-related genes in all IIM memory B cells and oxidative phosphorylation-related genes in inactive IIM double negative B cells were also increased, suggesting prominent B cell activation in IIM. Furthermore, active patients with anti-MDA5 Ab, anti-Mi-2 Ab, or anti-ARS Ab were distinguished by IFN-stimulated and oxidative phosphorylation-related gene expression in plasmablasts.

CONCLUSION

Unique gene expression patterns in patients with IIM with different disease activity levels and MSA types suggest different pathophysiologies. Especially, B cells may contribute to common and MSA-specific immunological pathways in IIM.

Myositis Multidisciplinary Clinic in a Tertiary Referral Center

Background

Idiopathic inflammatory myopathies (IIM) are a rare heterogeneous group of diseases characterised by chronic skeletal muscle inflammation, but other organs are also frequently involved. IMM represent a diagnostic challenge and a multidisciplinary approach is important to ensure successful diagnosis and adequate follow-up of these patients.

Objective

To describe the general functioning of our multidisciplinary myositis clinic, highlighting the benefits of multidisciplinary team management in patients with confirmed or suspected IIM and to characterise our clinical experience.

Methods

Description of the organization of a dedicated multidisciplinary myositis outpatient clinic, supported by IMM specific electronic assessment tools and protocols based on our Portuguese Register - Reuma.pt. In addition, an overview of our activity between 2017 and 2022 is provided.

Results

An IIM multidisciplinary care clinic, based on a close collaboration between Rheumatologists, Dermatologists and Physiatrist is detailed in this paper. One hundred and eighty-five patients were assessed in our myositis clinic; 138 (75%) of those were female, with a median age of 58 [45-70] years. At the last appointment, 130 patients had a confirmed IIM diagnosis, and the mean disease duration was 4 [2-6] years. The most frequent diagnosis was dermatomyositis (n = 34, 26.2%), followed by antisynthetase syndrome (n = 27, 20.8%) and clinically amyopathic/paucimyopathic dermatomyositis (n = 18, 13.8%). Twenty-four patients (18.5%) were on monotherapy and 94 (72.3%) were on combination therapy.

Conclusion

A multidisciplinary approach is important to ensure the correct diagnosis and follow-up of these patients. A myositis clinic, with a standardised practice at a tertiary hospital level, contributes to a standardization of care and opens research opportunities.