Myositis Patients Research Articles

Diagnostic measures for patients with systemic sclerosis-associated myopathy.

To evaluate the clinico-serological profile and to assess diagnostic parameters of myopathy in patients with systemic sclerosis (SSc)-associated myopathy. We explored the profiles of SSc-myopathy patients and matched non-myopathy SSc patients as well as different diagnostic measures for muscle affection. Additionally, the muscle performance of SSc-myopathy patients, assessed by the Manual Muscle Test for 8 muscle groups (MMT-8) and the Functional Index-2 (FI-2), was compared with that of patients with primary myositis. In SSc-myopathy patients, the following features occurred significantly more often even after Bonferroni correction for multiple comparisons: immunosuppressive treatment (56.0% vs. 24.1%; p=0.0003), elevated levels of creatine kinase (CK) (48.3% vs. 5.3%, p<0.0001), anti-PM-Scl antibodies (30.4% vs. 4%, p=0.00048), and absence of RNA Polymerase III antibodies (7.3% vs. 28.3%, p<0.0001). The MMT-8 showed a mild muscle weakness in SSc-myopathy as well as in primary myositis patients with similar age and sex. Muscle endurance tested by the FI-2 was generally compromised in both cohorts, yet the distribution pattern of affected muscle groups differed between the two cohorts. We confirmed previously described clinic-serological characteristics of SSc-myopathy patients. Our study suggests that autoantibody profile and CK levels may be helpful in establishing the diagnosis of SSc-myopathy. Whole-body MRI might be more accurate to capture the disease extent than MRI of selected muscle groups. Functional muscle tests validated for primary myositis did not perform well for the assessment of muscle function in patients with SSc-myopathy. Both, potential confounders such as skin, joint, and cardiovascular involvement as well as lack of sensitivity might have negatively affected the test performance in this population.

Paraneoplastic orbital myositis in a patient with natural killer/T-cell lymphoma

Paraneoplastic orbital myositis can occur in patients with natural killer/T-cell lymphoma (NKTL). A discrepancy between ocular motility examinations and imaging findings may suggest paraneoplastic orbital myositis in patients with malignancy. Extraocular muscle biopsy should be performed for definite diagnosis and appropriate treatment, especially in patients with atypical clinical manifestations.

Capillary basement membrane reduplication in myositis patients with mild clinical features of systemic sclerosis supports the concept of 'scleromyositis'.

Capillary basement membrane reduplication in myositis patients with mild clinical features of systemic sclerosis supports the concept of 'scleromyositis'.

Significance of Sjögren's syndrome and anti-cN1A antibody in myositis patients.

We recently recorded a high prevalence of inclusion body myositis (IBM) in patients with Sjögren's syndrome (SS). Whether myositis patients with SS differ from myositis patients without SS in terms of the characteristics of the myositis is currently unknown. Anti-cytosolic 5'-nucleotidase 1 A (cN1A) has recently been proposed as a biomarker for IBM but is also frequent in SS. Whether anti-cN1A is independently associated with IBM is still an open question. We aimed to assess the significance of SS and anti-cN1A in myositis patients. Cumulative data on all myositis patients (EULAR/ACR 2017 criteria) screened for SS (ACR/EULAR 2016 criteria) in a single centre were analysed. Ninety-nine patients were included, covering the whole spectrum of EULAR/ACR 2017 myositis subgroups and with a median follow-up of 6 years (range 1.0-37.5). The 34 myositis patients with SS (myositis/SS+) were compared with the 65 myositis patients without SS (myositis/SS-). . IBM was present in 24% of the myositis/SS+ patients vs 6% of the myositis/SS- group (P = 0.020). None of the IBM patients responded to treatment, whether they had SS or not. Anti-cN1A was more frequent in myositis/SS+ patients (38% vs 6%, P = 0.0005), independently of the higher prevalence of IBM in this group (multivariate P value: 0.02). Anti-cN1A antibody specificity for IBM was 0.96 (95% CI: 0.87, 0.99) in the myositis/SS- group but dropped to 0.70 (95% CI: 0.48, 0.85) in the myositis/SS+ group. In myositis patients, SS is associated with IBM and with anti-cN1A antibodies, independently of the IBM diagnosis. As a consequence, anti-cN1A has limited specificity for IBM in myositis patients with SS.

Anti-cN1A Antibodies Are Associated with More Severe Dysphagia in Sporadic Inclusion Body Myositis.

In recent years, an autoantibody directed against the 5′-citosolic nucleotidase1A (cN1A) was identified in the sera of sporadic inclusion body myositis (s-IBM) patients with widely variable sensitivity (33%–76%) and specificity (87%–100%). We assessed the sensitivity/specificity of anti-cN1A antibodies in an Italian cohort of s-IBM patients, searching for a potential correlation with clinical data. We collected clinical data and sera from 62 consecutive s-IBM patients and 62 other inflammatory myopathies patients. Testing for anti-cN1A antibodies was performed using a commercial ELISA. Anti-cN1A antibodies were detected in 23 s-IBM patients, resulting in a sensitivity of 37.1% with a specificity of 96.8%. Positive and negative predictive values were 92.0% and 60.6%, respectively. We did not find significant difference regarding demographic variables, nor quadriceps or finger flexor weakness. Nevertheless, we found that anti-cN1A-positive patients presented significantly lower scores in IBMFRS item 1 (swallowing, p = 0.045) and more frequently reported more severe swallowing problems, expressed as an IBMFRS item 1 score ≤ 2 (p < 0.001). We confirmed the low sensitivity and high specificity of anti-cN1A Ab in s-IBM patients with a high positive predictive value. The presence of anti-CN1A antibodies identified patients with a greater risk of more severe dysphagia.

Borrelia burgdorferi sensu lato seroconversion after intravenous immunoglobulin treatment: A cohort study.

ObjectiveIntravenous immunoglobulin (IVIg) consists of pooled donor immunoglobulins (IgG), possibly including anti‐Borrelia burgdorferi (Bbsl) antibodies. Apparent IVIg‐related Bbsl seroconversion could lead to incorrect diagnosis of Lyme borreliosis. This cohort study was designed to determine how often IVIg treatment leads to apparent Bbsl seroconversion and whether antibodies disappear post‐treatment.MethodsSera from chronic inflammatory demyelinating polyneuropathy (CIDP) and myositis patients were analyzed, drawn pre‐treatment and 6–12 weeks after the start of IVIg. In patients with apparent seroconversion, follow‐up samples after treatment withdrawal were analyzed, if available. Patients treated with corticosteroids were included as controls. A two‐tier protocol was used for serological testing consisting of the C6 Lyme ELISA (Oxford Immunotec) and confirmation by immunoglobulin M (IgM) and immunoglobulin G (IgG) immunoblot (Mikrogen®).ResultsWe included 61 patients: 51 patients were treated with IVIg and 10 with dexamethasone. Of the patients treated with IVIg, 42 had CIDP (82%) and were treated with Nanogam® (Sanquin Plasma Products). Nine patients had myositis (18%) and were treated with Privigen® (CSL Behring). Anti‐Bbsl IgG seroprevalence pre‐treatment was 3% (2/61). Apparent seroconversion during IVIg treatment occurred in 39% (20/51) of patients, all treated with Nanogam. Post‐treatment seroreversion occurred in 92% (12/13) of patients with available follow‐up samples; in 78% (7/9) seroreversion was observed within 3 months.ConclusionsTransient presence of anti‐Bbsl IgG antibodies after IVIg is regularly observed. This effect appears to be dependent on the IVIg brand, probably reflecting variation in Bbsl exposure of plasma donors. Lyme borreliosis serological testing during, and weeks to months after, IVIg is therefore of limited utility.

MRI and muscle imaging for idiopathic inflammatory myopathies.

Although idiopathic inflammatory myopathies (IIM) are a heterogeneous group of diseases nearly all patients display muscle inflammation. Originally, muscle biopsy was considered as the gold standard for IIM diagnosis. The development of muscle imaging led to revisiting not only the IIM diagnosis strategy but also the patients’ follow‐up. Different techniques have been tested or are in development for IIM including positron emission tomography, ultrasound imaging, ultrasound shear wave elastography, though magnetic resonance imaging (MRI) remains the most widely used technique in routine. Whereas guidelines on muscle imaging in myositis are lacking here we reviewed the relevance of muscle imaging for both diagnosis and myositis patients’ follow‐up. We propose recommendations about when and how to perform MRI on myositis patients, and we describe new techniques that are under development.

The phenotype of myositis patients with anti-Ku autoantibodies

ObjectivesTo define the clinical features of anti-Ku-positive myositis patients and to determine the reliability of the Euroline assay to detect anti-Ku autoantibodies. MethodsSerum samples were screened for anti-Ku autoantibodies by Euroline and positive samples were confirmed by ELISA. The prevalence and severity of clinical features at onset and during follow-up in patients with anti-Ku-positive myositis were compared to those with dermatomyositis, immune-mediated necrotizing myopathy (IMNM), the antisynthetase syndrome (AS), inclusion body myositis (IBM), anti-U1-RNP-positive myositis, and anti-PM/Scl-positive myositis. Results72 (2.9%) of 2475 samples were anti-Ku positive by Euroline using the manufacturer's recommended cutoff of >15. Just 17 (23.6%) of these were confirmed by ELISA and considered anti-Ku-positive for the analysis. Comparators included 169 IMNM, 168 AS, 387 IBM, 20 anti-U1-RNP-positive, and 47 anti-PM/Scl-positive patients. Muscle weakness was a presenting feature in 38% of anti-Ku-positive patients; 81% developed weakness during follow-up. Anti-Ku-positive patients had increased distal weakness compared to the non-IBM comparators. Interstitial lung disease (ILD) was present in 19% of anti-Ku-positive patients at the first visit and eventually developed in 56% of them. Throughout the course of disease, Gottron's papules and/or heliotrope rashes were less common in anti-Ku-positive patients (19%) compared to those with dermatomyositis (94%) or anti-PM/Scl-positive myositis (89%). Anti-Ku-positive patients never developed calcinosis. ConclusionsThe phenotype of anti-Ku positive myositis is distinguished by distal weakness, frequent ILD, infrequent rash, and no calcinosis. When used according to the current manufacturer's instructions, the Euroline assay has a high false-positive rate for anti-Ku autoantibodies.

P170 The validity and utility of the SLE-key® rule-out serological test when applied in a selected cohort of patients with SLE and other connective tissue diseases

Abstract Background/Aims We aimed to establish the validity of the SLE-key® rule-out test and analyse its utility in distinguishing systemic lupus erythematosus (SLE) from other autoimmune rheumatic connective tissue diseases. Methods We used data from the Lupus Extended Autoimmune Phenotype (LEAP) study, which included a representative cross-sectional sample of patients with a variety of rheumatic connective tissue diseases, including SLE, mixed connective tissue disease (MCTD), inflammatory myositis, systemic sclerosis, primary Sjögren’s syndrome and undifferentiated connective tissue disease (UCTD). The modified 1997 ACR criteria were used to classify patients with SLE. Banked serum samples were sent to Immune-Array’s CLIA- certified laboratory Veracis (Richmond, VA) for testing. Patients were assigned test scores between 0 and 1 where a score of 0 was considered a negative rule-out test (i.e. SLE cannot be excluded) whilst a score of 1 was assigned for a positive rule-out test (i.e. SLE excluded). Performance measures were used to assess the test’s validity and measures of association determined using linear regression and Spearman’s correlation. Results Our study included a total of 155 patients of whom 66 had SLE. The mean age in the SLE group was 44.2 years (SD 13.04). 146 patients (94.1%) were female. 84 (54.2%) patients from the entire cohort had ACR SLE scores of ≤ 3 whilst 71 (45.8%) had ACR SLE scores ≥ 4. The mean ACR SLE total score for the SLE patients was 4.85 (SD 1.67), ranging from 2 to 8, with mean disease duration of 12.9 years. The Sensitivity of the SLE-Key® Rule-Out test in diagnosing SLE from other connective tissue diseases was 54.5%, specificity was 44.9%, PPV 42.4% and NPV 57.1 %. 45% of the SLE patients had a positive rule-out test. SLE could not be ruled out in 73% of the MCTD patients whilst 51% of the UCTD patients had a positive Rule-Out test and &amp;gt;85% of the inflammatory myositis patients had a negative rule-out test. ROC analysis generated an AUC of 0.525 illustrating weak class separation capacity. Linear regression established a negative correlation between the SLE-key Rule-Out score and ACR SLE total scores. Spearman’s correlation was run to determine the relationship between ACR SLE total scores and SLE-key rule-out score and showed very weak negative correlation (rs = -0.0815, n = 155, p = 0.313). Conclusion Our findings demonstrate that when applied in clinical practice in a rheumatology CTD clinic setting, the SLE-key® rule-out test does not accurately distinguish SLE from other CTDs. The development of a robust test that could achieve this would be pivotal. It is however important to highlight that the test was designed to distinguish healthy subjects from SLE patients and not for the purpose of differentiating SLE from other connective tissue diseases. Disclosure S. Achieng: None. J.A. Reynolds: None. I.N. Bruce: Other; I.N.B is a National Institute for Health Research (NIHR) Senior Investigator and is funded by the NIHR Manchester Biomedical Research Centre. M. Bukhari: None.

Utility of patient-reported outcomes measurement information system (PROMIS) physical function form in inflammatory myopathy

ObjectiveIdiopathic inflammatory myopathies (IIM) are a group of diseases characterized by muscle weakness, which limit activities of daily living. Patient Reported Outcomes Measurement Information System (PROMIS) is a set of outcome measures developed using NIH funding, but has not yet been studied in adult IIM. Currently, the most commonly used PROs in IIM are Health Assessment Questionnaire (HAQ-DI) and SF-36 physical function-10 (PF10), both of which have several limitations. In this study, we investigated psychometric properties of PROMIS physical function-20 (PF-20) and compared to HAQ-DI and SF-36 PF10. MethodsPatients with IIM completed PROMIS PF-20 and six myositis core set measures [manual muscle testing (MMT), physician (MD-GDA), patient (PT-GDA) and extra-muscular global disease activity, HAQ-DI and creatine kinase], SF-36 PF10 and functional tests [six-minute walk, timed up-and-go and sit-to-stand tests] at monthly visits over 6-months. Total improvement score (TIS) using 2016 ACR/EULAR myositis response criteria was obtained as measures of change. ResultsFifty patients [mean age, 51.6; 60% females] were enrolled; 6 PM, 24 DM, 9 NM and 11 with AS. PROMIS PF-20 showed strong test-retest reliability when repeated in 1-month. PROMIS PF-20 had moderate-strong correlations with MD-GDA, PT-GDA, MMT, HAQ-DI, SF-36 PF10, and functional tests indicating good convergent validity. Change in PROMIS PF-20 strongly correlated with TIS demonstrating good responsiveness. HAQ-DI and SF-36 PF10 exhibited similar validity and responsiveness; HAQ-DI was found to have a ceiling effect. ConclusionPROMIS PF-20 demonstrates favorable psychometric properties in a large cohort of myositis patients and offers distinct advantages.

Dysphagia in Inclusion Body Myositis, A Disease of the Elderly

Inclusion body myositis is one of the most common acquired myopathies seen in the aging population. The muscle weakness is of insidious onset, frequently starting in the legs, but over time gradually progresses to eventually involve all skeletal muscles of the limbs, face, swallowing and respiratory muscles, leading to significant morbidity and mortality. Complications resulting from dysphagia are the leading cause of poor quality of life and mortality, while highly prevalent, are still underappreciated and underrecognized. This review highlights the importance of understanding the urgent need for recognizing and improving the evaluation, outcome measures and therapeutic options of dysphagia in inclusion body myositis patients.

Clinical and immunological characteristics of myositis complicated with thromboembolism

OBJECTIVE To investigate and analyse the clinical and immunological features of patients with myositis complicated with thromboembolism. METHODS We identified a cohort of 390 myositis patients diagnosed with myositis admitted to People's Hospital of Peking University from 2003 to 2019. The patients were retrospectively enrolled in this investigation. According to the outcome of the color Doppler ultrasound, CT pulmonary angiography, pulmonary ventilation and perfusion scan patients were divided into myositis with and without thromboembolism group. Demographic, clinical (heliotrope rash, Gottron's sign/papules, periungual erythema, skin ulceration, subcutaneous calcinosis, Mechanic's hands, myalgia, interstitial lung disease, pulmonary arterial hypertension), laboratory, immunological [anti-autoantibodies including melanoma differentiation associated gene 5 (anti-MDA5), anti-Mi-2, anti-transcription intermediary factor-1γ (anti-TIF-1γ, anti-nuclear matrix protein 2 (anti-NXP2), anti-small ubiquitin-like modifier activating enzyme (anti-SAE), anti-synthetase], imaging and therapeutic status data of the patients at the diagnosis of myositis with and without thromboembolism were collected and the differences in these data were analyzed. Logistic regressive analysis was used to identify the risk factors of thromboembolism. RESULTS In the retrospective study, 390 myositis patients were investigated. The mean age of onset was (49.6±13.4) years, male to female ratio was 0.31 :1. Thromboembolism was identified in 4.62% (18/390) of the myositis patients, which was lower than the published reports. Out of 18 patients with thromboembolism, 55.6% (10/18) of them were deep venous thrombosis, followed by cerebral infarction (22.2%, 4/18), pulmonary embolism (11.1%, 2/18), renal artery embolism (5.6%, 1/18) and embolism of upper extremity (5.6%, 1/18). Fifty percent of thromboembolism events occurred 6 months after the diagnosis of myositis, 38.9% of thromboembolism events occurred 6 months within the diagnosis of myositis, 11.1% of thromboembolism events occurred 6 months before the diagnosis of myositis. As compared with the myositis patients without thromboembolism, the myositis patients complicated with thromboembolism were older [(58.3±11.7) years vs. (49.3±13.4) years, P=0.006]. C-reaction protein (CRP) (12.2 mg/L vs. 4.1 mg/L, P < 0.001), ferritin (20 085.5 μg/L vs. 216.6 μg/L, P < 0.001) and D-dimer (529.0 μg/L vs. 268.0 μg/L, P=0.002) were significantly higher in thromboembolism group. Diabetes (44.4% vs. 16.4%, P=0.006), coronary heart disease (22.2% vs. 3.0%, P=0.003) and surgery (16.7% vs. 3.5%, P=0.032) were observed more common in thromboembolism group than those without thromboembolism. Activated partial thromboplastin time (APTT) (26.9 s vs. 28.7 s, P=0.049) and albumin (32.4 g/L vs. 36.5 g/L, P=0.002) was lower in thromboembolism group. The risk factors of thromboembolism in the myositis patients were low level of albumin (OR=0.831, 95%CI: 0.736-0.939, P=0.003), diabetes (OR=4.468, 95%CI: 1.382-14.448, P=0.012), and coronary heart disease (OR=22.079, 95%CI: 3.589-135.837, P=0.001) were independent significant risk factors for thromboembolism in the patients with myositis. There was no significant difference in clinical manifestations, myositis-specific antibodies or myositis-associated antibodies between the two groups. CONCLUSION Thromboembolism is a complication of myositis. Lower levels of albumin, diabetes, and coronary heart disease might be risk factors of thromboembolism in myositis patients.

Reader response: Granulomatosis-associated myositis: High prevalence of sporadic inclusion body myositis.

We read with great interest the recent article by Dr. Dieudonne et al.1 The authors reported the high prevalence of sporadic inclusion body myositis (SIBM) in patients with granulomatous myositis, and a significant proportion of these SIBM patients also had systemic features suggestive of sarcoidosis. Their observation is similar to what we previously reported.2 In addition, we found that the majority of treatment-refractory granulomatous myositis patients had sarcoplasmic congophilic deposits, including those who did not fulfill the ENMC diagnostic criteria of SIBM. Although this was not statistically significant, the presence of congophilic aggregates—regardless of the diagnosis of SIBM—could be an indicator of treatment refractoriness. Dr. Dieudonne et al. analyzed the protein accumulation using TDP43 or p62 immunoreactivity, but we are not certain whether congo red stain was performed. We would appreciate if they can share their experience with congo red stain in their cohort because this is more widely available stain in routine clinical practice when compared with TDP43 and p62 immunostains. Last but not least, given the similar results of 2 relatively large cohorts of granulomatous myositis,1,2 an epidemiologic study looking into the incidence of SIBM in sarcoidosis could be of clinical interest.

Aberrant expression of cell-free nucleosomes in dermatomyositis/polymyositis.

Nucleosomes are typically located intracellularly, and extracellular levels of nucleosomes indicated the degree of cell death. We postulated aberrant nucleosomes expression in dermatomyositis (DM) and polymyositis (PM). To assess the aberrant expression of circulating nucleosomes in DM and polymyositis. 76 consecutive DM and PM patients from 1 September 2017 to 31 October 2018 were enrolled in this study, in addition to 20 healthy controls. The levels of circulating nucleosomes, with 16 kinds of detectable myositis-specific antibodies (MSAs) were detected in IIMs patients using enzyme-linked immunosorbent assay kit (ELISA). Receiver operating characteristic (ROC) curve analysis was performed for evaluating the ability of this candidate marker for detecting DM/PM. The results showed that the levels of circulating nucleosomes in DM/PM patients were significantly higher than that in normal individuals. Specifically, elevated levels of nucleosomes were associated with MDA5 Ab, ARS, and TIF1γAb. In addition, elevated levels of circulating nucleosomes correlated with skin eruption. This study has evidenced nucleosomes as a potential new biomarker of DM/PM. Aberrant nucleosomes expression occurs in myositis patients and the difference in nucleosomes expression between patients with and without skin eruption is statistically significant. A unique expression profile of elevated serum nucleosomes was detected in DM/PM-MDA5 Ab(+), ASS, and TIF1γAb(+).

Interleukin-35 in idiopathic inflammatory myopathies

BackgroundInterleukin-35 (IL-35) is a recently described heterodimeric cytokine that belongs to the IL-12 family and consists of p35 (IL-12a) and EBI3 (IL-27b) subunits. The expression of IL-35 in humans is inducible in response to inflammatory stimuli. Increased IL-35 levels were documented in several autoimmune inflammatory diseases, suggesting a possible immunomodulatory role in their pathogenesis. ObjectivesThe aim of this study was to explore a potential role of IL-35 in the pathogenesis of idiopathic inflammatory myopathies (IIM) by studying the expression of IL-35 subunits in muscle biopsy samples and by evaluating serum levels of IL-35 and their association with disease activity in IIM patients. MethodsThe expression of IL-35 subunits was studied in serial sections of 9 muscle biopsy samples [4 polymyositis (PM), 5 dermatomyositis (DM)] and in 7 non-inflammatory control muscle biopsies. Serum levels of IL-35 were measured in 23 PM, 28 DM and 15 cancer associated myositis (CAM) patients as well as in 40 healthy controls. Disease activity was evaluated using the Myositis Disease Activity Assessment Tool (MDAAT) and by serum muscle enzymes. ResultsExpression of both IL-35 subunits was evident in the inflammatory infiltrates in IIM muscle biopsies, while no IL-35 expression was observed in control muscle samples. IL-35 serum levels were increased in all IIM patients compared to healthy controls [median 119.5 (range 32.1–1074.5) vs 36.2 (range 1.5–86.5) pg/ml, P < 0.001]. There were no differences in IL-35 serum levels between myositis subgroups (DM, PM or CAM). Serum IL-35 levels correlated significantly with physician's assessment of global (r = 0.29, p = 0.021), muscle (r = 0.30, p = 0.017) and extramuscular (r = 0.30, p = 0.016) disease activity as well as creatine kinase (r = 0.26, p = 0.044) and lactate dehydrogenase (r = 0.40, p = 0.003) levels. There was a significant correlation with pulmonary activity in patients with interstitial lung disease (r = 0.39, p = 0.037). Serum IL-35 correlated negatively with duration of treatment (r = −34, p = 0.009). ConclusionsIL-35 is overexpressed in inflammatory infiltrates in muscle tissue and serum in IIM patients and there is correlation with several disease activity parameters. These data suggest potential role of locally produced IL-35 in the pathogenesis of inflammatory myopathies.

Anti-Zo antibodies in Japanese myositis patients detected by a newly developed ELISA.

The myositis-specific autoantibodies that characterise certain forms of idiopathic inflammatory myopathy (IIM) are useful for diagnosing dermatomyositis (DM) / polymyositis (PM) and predicting its prognosis. The autoantibody to phenylalanyl-tRNA synthetase (anti-Zo) has been identified as a disease marker antibody for anti-synthetase syndrome only in a UK cohort. Here we aim to establish an ELISA for the measurement of anti-Zo and to characterise the clinical features of Japanese patients who have this autoantibody. Anti-Zo was investigated by immunoprecipitation with recombinant phenylalanyl-tRNA synthetase α/β proteins. The results were confirmed by immunoprecipitation-Western blotting with cell extract. Sera from patients with DM/PM (n=224) were screened by an ELISA with the recombinant proteins. Medical records were retrospectively reviewed to obtain detailed information on the clinical phenotypes of the anti-Zo-positive patients. Only two male patients were confirmed to have anti-Zo. Both patients had fever, myopathy, interstitial lung disease, and mechanic's hands, and these clinical features are consistent with those of anti-synthetase syndrome. Another patient's serum showed a higher level than the cut-off value for anti-phenylalanyl-tRNA synthetase α by our in-house ELISA, but was judged to be negative for anti-Zo by immunoprecipitation-Western blotting. This is the first report of anti-Zo-positive IIM patients from Asia. Although Japanese patients with anti-Zo have a clinical phenotype similar to that of Caucasian patients, further large cohort studies are necessary to confirm the frequency of anti-Zo in Japanese IIM patients. Our newly developed ELISA should be validated for sensitivity and specificity in large cohorts.

Hand-held dynamometry for assessment of muscle strength in patients with inflammatory myopathies.

Muscle weakness in idiopathic inflammatory myopathies (IIMs) is conventionally assessed using manual muscle testing (MMT). However, more objective tools must be developed to accurately and reliably quantify muscle strength in myositis patients. Hand-held dynamometry (HHD) is a quantitative, portable device with reported reliability in neuromuscular disorders. Our aim was to assess the reliability, validity and responsiveness of HHD in myositis. Myositis patients [DM, necrotizing myopathy (NM), PM and anti-synthetase syndrome] evaluated at the University of Pittsburgh myositis centre were prospectively enrolled. Each patient was assessed at 0, 3 and 6 months for validated outcome measures of myositis disease activity and physical function. At each visit, muscle strength was assessed using both MMT and HHD (Micro FET2, Hoggan Health Industries, Draper, UT, USA). The reliability, validity and responsiveness of the HHD was assessed using standard statistical methods. Fifty IIM patients (60% female; mean age 51.6 years; 6 PM, 9 NM, 24 DM and 11 anti-synthetase syndrome) were enrolled. HHD showed strong test-retest intrarater reliability (r = 0.96) and interrater reliability (r = 0.98). HHD correlated significantly with the MMT score (r = 0.48, P = 0.0006) and myositis disease activity and functional measures. Longitudinal analysis showed a significant and strong association between the HHD and MMT as well as 2016 ACR/EULAR myositis response criteria (r = 0.8, P < 0.0001) demonstrating responsiveness. The mean effect size and standardized response mean of HHD was large: 0.95 and 1.03, respectively. MMT had a high ceiling effect compared with HHD. HHD demonstrated strong reliability, construct validity and responsiveness in myositis patients. External validation studies are required to confirm these findings.

Dysphonia and dysphagia as early manifestations of autoimmune inflammatory myopathy.

While dysphagia is a recognized manifestation of autoimmune inflammatory myopathy, a relationship between myositis and dysphonia or laryngeal pathology is not well-documented. We therefore sought to describe the spectrum of laryngeal disorders present in myositis patients, evaluate whether any specific conditions are overrepresented among these patients compared to a large treatment-seeking population, and examine the clinical course and outcomes of these symptoms. This was a retrospective chart review, including all patients seen at the Johns Hopkins Voice Center between January 2016 and December 2017. Demographic data, comorbidities, and laryngeal diagnoses were extracted from the electronic medical record. The charts of patients with myositis were reviewed further to ascertain details of their laryngeal symptoms and myositis disease course. Associations between myositis and dysphonia/dysphagia were evaluated using binary regression and multinomial logistic regression models to adjust for age, sex, race, and smoking status. Of 4252 patients, sixteen had myositis. Compared to 4236 controls, these patients had significantly higher odds of presenting with muscular voice disorders (adjusted odds ratio (OR*)=4.503, p*=0.005) and dysphagia (OR*=6.823, p*<0.001). A majority (64.3%, CI:35.6-93.0%) of myositis patients had laryngeal pathology among the presenting symptoms of their myositis. Across all diagnostic categories, there was a non-significant trend towards better outcomes in patients receiving specific interventions for their laryngeal symptoms. Muscular voice disorders and dysphagia are significantly overrepresented in myositis patients presenting to a laryngology clinic, and in these patients, both are frequently among the presenting symptoms of myositis.

Quantitative MRI in myositis patients: comparison with healthy volunteers and radiological visual assessment

To assess whether magnetic resonance imaging (MRI)-based measurements of T2, fat fraction, diffusion tensor imaging, and muscle volume can detect differences between the muscles of myositis patients and healthy controls, and to identify how they compare with semi-quantitative MRI diagnosis. Sixteen myositis patients and 16 age- and gender-matched healthy controls underwent MRI of their thigh. Quantitative MRI measurements and radiologists' semi-quantitative scores were assessed. Strength was assessed using an isokinetic dynamometer. Fat fraction and T2 values were higher in myositis patients whereas muscle volume was lower compared to healthy controls. There was no difference in diffusion. Muscle strength was lower in myositis patients compared to healthy controls. In a subgroup of eight patients, scored as unaffected by radiologists, T2 values were still significantly higher in myositis patients. Quantitative MRI measurements can detect differences between myositis patients and healthy controls. Changes in the muscles of myositis patients, undetected by visual, semi-quantitative scoring, can be detected using quantitative T2 measurements. This suggests that MRI T2 values may be useful for the management of myositis patients.

Histopathologic Findings in Idiopathic Orbital Myositis

To report the histologic and clinical features of idiopathic orbital myositis (IOM) patients who underwent extraocular muscle (EOM) biopsy over 20 years, to provide the first methodical reference to the expected histopathologic findings, and to discuss the histopathologic differences from common differential diagnoses. Cohort study. All patients with a diagnosis of IOM who underwent EOM biopsy from 2000 through 2019 were included. Patients who had a different final diagnosis were excluded. Tissue samples of EOM and medical records of all participants were reviewed. Histopathologic features of muscle biopsy, including tissue morphologic features and cellular composition. Thirteen patients met both inclusion and exclusion criteria, and their tissue samples were revisited. Nine patients showed histopathologic findings that suggested a conclusive diagnosis of IOM, and the study focused on them. The average age at presentation was 49 years, and 66.7% of patients were women. The most commonly biopsied EOM was the medial rectus (44.4%). The most common indications for biopsy were nonresolving orbital disease with inadequate response to corticosteroids (44.4%) or a high suspicion of malignancy because of known pre-existing systemic malignancy or the presence of an atypical orbital mass in addition to enlarged muscles (44.4%). The histopathologic findings that suggested a diagnosis of IOM were splaying of muscle fibers by inflammatory infiltrates (n= 9) and mild fibrosis (n= 8) in the endomysium or replacing muscle fibers, with no granulomas or vasculitis. The inflammatory infiltrates identified were of chronic inflammatory cells, consisting of lymphocytes (n= 9), plasma cells (n= 6), and histiocytes (n= 6). Other less commonly identified cells were eosinophils (n= 4), polymorphonuclears (n= 1), and giant cells (n= 1). Muscle fiber degeneration or regeneration was evident in 5 patients. Four patients from the initial cohort showed inconclusive histologic findings on revision and were reassigned as suspected IOM. The histopathologic features of involved muscles in IOM resemble those seen in idiopathic orbital inflammation and differ from those seen in common differential diagnoses. Extraocular muscle biopsy should be strongly considered whenever the presentation of orbital myositis is not typical or when significant underlying conditions are a possibility.