Features Of Idiopathic Inflammatory Myopathies Research Articles

Clinical characteristics of idiopathic inflammatory myopathies patients with anti-PM/Scl antibodies

ObjectivesTo analyze the clinical features of idiopathic inflammatory myopathies (IIMs) patients with anti-PM/Scl antibodies. MethodsIn this retrospective cohort study, we compared the clinical manifestations between patients who were solely positive for anti-PM/Scl antibodies (isolated anti-PM/Scl group) and those with a coexistence of anti-PM/Scl antibodies and myositis-specific antibodies (MSAs) (double-positive group). ResultsSixty-five IIMs patients positive for anti-PM/Scl antibodies were included, among whom 51 (78.5 %) were females, with a mean age of 49.1 years. Thirty-four (52.3 %) patients coexisted with MSAs. Compared to the double-positive group, the isolated anti-PM/Scl group demonstrated a higher proportion of women (90.3 % vs 67.6 %, p = 0.026) and a higher incidence of sclerodactyly (16.1 % vs 0, p = 0.021). Although there were no differences in the incidence of muscular weakness, dysphagia, or creatine kinase levels, thigh magnetic resonance imaging (MRI) revealed less muscle edema, atrophy, and fatty replacement in the isolated anti-PM/Scl group (p < 0.05). Interstitial lung disease (ILD) occurred in 80 % of patients, more frequently in the double-positive group (90.6 % vs 67.9 %, p = 0.028). According to HRCT, non-specific interstitial pneumonia (NSIP) was the most common pattern among anti-PM/Scl antibodies positive IIMs patients. The double-positive group exhibited higher ferritin levels, and a lower peripheral lymphocyte count (p < 0.05). The mortality rate in the double-positive group was higher than that in the isolated anti-PM/Scl group (20.6 % vs 0, p = 0.034). ConclusionAmong IIMs patients who tested positive for anti-PM/Scl antibodies, ILD emerged as the predominant clinical feature, particularly when combined with MSA. Notably, patients with isolated anti-PM/Scl antibodies exhibited a favorable prognosis following immunotherapy.

Reliability and validity of PROMIS physical function, pain interference, and fatigue as patient reported outcome measures in adult idiopathic inflammatory myopathies: International study from the OMERACT myositis working group

ObjectivePain interference, fatigue, and impaired physical function are common features of idiopathic inflammatory myopathies (IIM). The objective of this study was to evaluate the construct validity and test-retest reliability of the Patient Reported Outcome Information System (PROMIS) Pain Interference 6av1.0, Fatigue 7av1.0, and Physical Function 8bv2.0 instruments. MethodsPatient-Reported Outcome Measures (PROMs) were deployed to adult IIM patients from OMERACT Myositis Working Group (MWG) international clinic sites via two online surveys (2019, 2021). Internal consistency of each PROM was analyzed by Cronbach's α. Construct validity was determined by a priori hypotheses generated by the MWG with >75% agreement for each hypothesis and calculated with Pearson correlations. Test-retest reliability was assessed using intraclass correlation coefficient with PROMIS instruments administered at time zero and 7 days. ResultsSurveys were sent to 368 participants in total; participants who completed each questionnaire varied (n=65 to 263). For construct validity, 10 out of 13 a priori hypotheses were met supporting construct validity of PROMIS instruments (Pain Interference 3/4, fatigue 4/4, and Physical Function 3/5). Test-retest reliability was strong for all PROMIS instruments. All PROMIS instruments demonstrated excellent internal consistency. None of the measures demonstrated any ceiling or floor effects except for a ceiling effect in the Pain Interference instrument. ConclusionsThis study presents test-retest reliability and construct validity evidence supporting PROMIS Pain Interference (6a v1.0), Fatigue (7a v1.0), and Physical Function (8b v2.0) using a large international cohort of patients with IIM. Internal consistency of these instruments was excellent. A ceiling effect was noted in the Pain Interference instrument.

The clinical and histopathological features of idiopathic inflammatory myopathies with asymmetric muscle involvement

The objective is to determine the frequency of idiopathic inflammatory myopathies (IIMs) with asymmetric muscle involvement (IIMs-A) as initial manifestations in total IIMs and to compare the demographic, clinical, histopathological and radiological characteristics of IIMs-A with classical IIMs (IIMs-C). We retrospectively reviewed the clinical, laboratory, muscle images, histopathological features and treatment response of patients at the Qilu hospital who were diagnosed as IIMs from April 2005 to August 2017. We found among 134 IIMs patients, 13(9.2%) patients with IIMs-A were identified, of which 7 patients were diagnosed as dermatomyositis (DM), 2 as polymyositis (PM), 4 as immune-mediated necrotizing myopathy (IMNM) using the European Neuromuscular Centre (ENMC) criteria. The mean age of our group was 59.1 years old. The duration from the initial symptoms to the first examination was less than 12 months in 12 patients (92.3%). 46.2% patients accompanied with weakness of distal limbs and bulbar symptoms. Finger flexion involvement was found in 5 patients (38.5%). There was no patient that finger flexion was weaker than shoulder abduction. The creatine kinase (CK) level in the serum ranged from 41 IU/L to 9125 IU/L (average: 3192.7 ± 2769.9 IU/L). Serum positive anti-mitochondrial antibodies (AMAs) were found in four patients (30.8%). Endomysial fibrosis and inflammatory cell infiltration were detected in 92.3%, 84.6% patients respectively. Mitochondrial abnormalities in histopathological finding of muscle biopsy were seen in 100% cases. The major histocompatibility complex class I (MHC-I) (84.6%) and class II (MHC-II) (92.3%) expressed on muscle biopsies from almost all cases of our patients. MAC antibody, however, was detected in only 20–40% patients. Eight patients (61.5%) had favorable outcomes. The conclusion was that IIMs-A presented mainly in DM, generally with mitochondrial abnormality and highly positive AMAs. The relationship between the presence of AMAs and the asymmetric muscle involvement in DM needs to be further clarified. We should also consider the diagnosis of IIMs when the patient has features of positive AMAs and asymmetric muscle involvement.

Muscle biopsy features of idiopathic inflammatory myopathies and differential diagnosis

The gold standard to characterize idiopathic inflammatory myopathies is the morphological, immunohistochemical and immunopathological analysis of muscle biopsy. Mononuclear cell infiltrates and muscle fiber necrosis are commonly shared histopathological features. Inflammatory cells that surround, invade and destroy healthy muscle fibers expressing MHC class I antigen are the typical pathological finding of polymyositis. Perifascicular atrophy and microangiopathy strongly support a diagnosis of dermatomyositis. Randomly distributed necrotic muscle fibers without mononuclear cell infiltrates represent the histopathological hallmark of immune-mediated necrotizing myopathy; meanwhile, endomysial inflammation and muscle fiber degeneration are the two main pathological features in sporadic inclusion body myositis. A correct differential diagnosis requires immunopathological analysis of the muscle biopsy and has important clinical implications for therapeutic approach. In particular, unnecessary, potentially harmful, immune-suppressive therapy should be avoided alike in dystrophic myopathies with secondary inflammation.

Polymyositis and dermatomyositis: Disease spectrum and classification

Muscle inflammation and weakness are the key features of idiopathic inflammatory myopathies (IIMs). In addition IIMs are frequently associated with cutaneous and pulmonary involvement. In clinical practice the three common inflammatory myopathies we come across are polymyositis (PM), dermatomyositis (DM) and inclusion body myositis (IBM). The Bohan and Peter criteria combine clinical, laboratory, and pathologic features to define PM and DM. They did not recognize inclusion body myositis (IBM) or other inflammatory myopathies, such as granulomatous and eosinophilic myositis. Thus the disease spectrum is wide and IIMs are a heterogeneous group of autoimmune disorders. To address these issues in this article we have discussed the currently developing newer classifications of IIMs.

Activity of certain drugs in inducing of inflammatory myopathies with cutaneous manifestations

Background: At present, the pharmacological activity of drugs in inducing of inflammatory myopathies is not a solved problem. Objective: Analysis of the adverse reaction of drugs show that in both adults and children they can cause clinical manifestations of dermatomyositis and its variants [classic, juvenile, paraneoplastic or amyopathic], polymyositis and its variants [eosinophilic myositis, overalp syndrome], or other conditions such as eosinophilia myalgia syndrome, and eosinophilic fasciitis. Methods: Literature databases were analyzed and combined with personal experience to identify drug activity associated with dermatomyositis and its variants. Conclusion: Lipid-lowering agents, anti-infectious, NSAIDs, antineoplastic medicines, other non-related drugs, vaccines, and over the counter essential amino acids such as L-tryptophan are of particular interest in the induction of myositis, or myalgia and cutaneous features of idiopathic inflammatory myopathies. Clinical manifestations and various pathogenetic mechanisms leading to injury of muscles and skin from medicines in this illness are presented and analyzed.