Inflammatory myopathies: management of steroid resistance

A rare intersection: squamous cell carcinoma of the tonsil and the anti-TIF1 syndrome masquerade

BACKGROUND

Dermatomyositis is a chronic inflammatory condition affecting muscles and skin, often associated with an increased risk of cancer. Specific autoantibodies, including anti-TIF1 (Transcription Intermediary Factor 1), have been linked to this risk. We present a case of dermatomyositis in a male patient positive for anti-TIF1 antibodies, subsequently diagnosed with squamous cell carcinoma of the tonsil, a novel association not previously documented. Early recognition of such associations is crucial for timely intervention and improved outcomes in these patients.

CASE PRESENTATION

A 53-year-old Caucasian male with hyperlipidemia presented with chronic dry, scaly skin and pruritus, diagnosed with eczematous dermatitis. Despite treatment, symptoms persisted. After two years, he reported increased redness of the rash and new eruptions on his hands and fingers. During a rheumatology visit, he reported weight loss, fatigue, muscle weakness, and trismus. Further evaluation indicated signs of dermatomyositis, and laboratory tests revealed anti-TIF1 antibodies, prompting further investigation. The patient underwent age-appropriate cancer screening, and due to a known association with malignancy, a positron emission scan was ordered, detecting increased activity in the right tonsil. Subsequent magnetic resonance imaging showed a suspicious mass in the tonsillar area. A biopsy confirmed invasive squamous cell carcinoma positive for P16+. Initial treatment included radiotherapy, with a post-treatment PET scan showing no evidence of disease. However, four months later, the cancer recurred, leading to significant symptoms and complications. Despite supportive measures, the patient succumbed to high-volume oral cavity bleeding during hospitalization.

CONCLUSIONS

TIF1 dermatomyositis is a unique subset of dermatomyositis with a strong association with malignancy, particularly squamous cell carcinoma (SCC). Mechanisms connecting TIF1 dermatomyositis and cancer involve gene expression dysregulation and chronic inflammation. Anti-TIF1 antibodies are key biomarkers, with IgG2 isotype levels highly predictive of cancer risk. Common malignancies include ovarian, breast, and lung cancers, often detected within three years of dermatomyositis onset. Distinctive features include severe skin lesions, dysphagia, and minimal interstitial lung disease. Management focuses on early cancer detection and treatment, with options for refractory disease, including IVIg, rituximab, and emerging therapies like JAK inhibitors. Our case highlights a new association between TIF1α antibodies and tonsil squamous cell carcinoma. Despite successful radiotherapy, cancer recurred. TIF1 antibody detection should prompt rigorous cancer screening, emphasizing multidisciplinary management.

Clinical Characteristics of Dermatomyositis with Interstitial Lung Disease: A Retrospective Case-Control Study

INTRODUCTION

Interstitial lung disease (ILD) is a common complication of dermatomyositis (DM) and one of the main risk factors for poor prognosis in DM patients. The aim of this study was to reveal the clinical characteristics of DM patients with ILD.

METHODS

Clinical data from the Second Affiliated Hospital of Soochow University were used to conduct a retrospective case-control study. Univariate and multivariate logistic regression analysis were performed to identify risk factors for ILD in DM.

RESULTS

A total of 78 DM patients were included in this study, including 38 DM patients with ILD and 40 DM patients without ILD. Compared with patients without ILD, patients with ILD were older (59.6 vs. 51.2 years, P = 0.004), and had higher rates of clinically amyopathic DM (CADM) (45 vs. 20%, P = 0.019), Gottron's papules (76 vs. 53%, P = 0.028), mechanic's hands (13 vs. 0%, P = 0.018), myocardial involvement (29 vs. 8%, P = 0.014), and higher positive rates of anti-SSA/Ro52 (74 vs. 20%, P < 0.001) and anti-melanoma differentiation-associated gene-5 (MDA5) (24 vs. 8%, P = 0.048) antibodies, while albumin (ALB) (34.5 vs. 38.0 g/l, P = 0.006), prognostic nutritional index (PNI) (40.3 vs. 44.7, P = 0.013), the rates of muscle weakness (45 vs. 73%, P = 0.013) and heliotrope rash (50 vs. 80%, P = 0.005) were lower. In addition, the five patients who died were all DM patients with ILD (13 vs. 0%, P = 0.018). Multivariate logistic regression showed that old age (odds ratio [OR] = 1.119, 95% confidence interval [CI] = 1.028-1.217, P = 0.009), Gottron's papules (OR = 8.302, 95% CI = 1.275-54.064, P = 0.027) and anti-SSA/Ro52 (OR = 24.320, 95% CI = 4.102-144.204, P < 0.001) were independent risk factors for ILD in DM.

CONCLUSIONS

DM patients with ILD usually present with older age, higher rates of CADM, Gottron's papules, mechanic's hands, myocardial involvement, higher positive rates of anti-MDA5 and anti-SSA/Ro52 antibodies, lower ALB, PNI, and lower rates of muscle weakness and heliotrope rash. Old age, Gottron's papules, and anti-SSA/Ro52 were independent risk factors for ILD in DM.

Dermatomyositis: An Update on Diagnosis and Treatment

Dermatomyositis is a rare inflammatory disease with characteristic cutaneous findings and varying amounts of systemic involvement. Patients may present with skin disease alone, have concomitant muscle disease, or have extracutaneous manifestations such as pulmonary disease or an associated malignancy. Given such diverse presentations, dermatomyositis is both a diagnostic and therapeutic challenge. However, a prompt diagnosis is of utmost importance to institute adequate therapy and screen patients for an associated malignancy. Dermatologists should play a crucial role in the diagnosis and management of patients with dermatomyositis as cutaneous disease tends to be chronic, negatively impact quality of life, and be more recalcitrant to therapy. In this review, we discuss diagnosis, with a focus on myositis-specific antibodies and their associated phenotypes. We also review therapies available for this often refractory skin disease.

Polymyositis and dermatomyositis - challenges in diagnosis and management

Polymyositis (PM) and dermatomyositis (DM) are different disease subtypes of idiopathic inflammatory myopathies (IIMs). The main clinical features of PM and DM include progressive symmetric, predominantly proximal muscle weakness. Laboratory findings include elevated creatine kinase (CK), autoantibodies in serum, and inflammatory infiltrates in muscle biopsy. Dermatomyositis can also involve a characteristic skin rash. Both polymyositis and dermatomyositis can present with extramuscular involvement. The causative factor is agnogenic activation of immune system, leading to immunologic attacks on muscle fibers and endomysial capillaries. The treatment of choice is immunosuppression. PM and DM can be distinguished from other IIMs and myopathies by thorough history, physical examinations and laboratory evaluation and adherence to specific and up-to-date diagnosis criteria and classification standards. Treatment is based on correct diagnosis of these conditions.

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Challenges of diagnosis and management influences the clinical research and practice of Polymyositis and dermatomyositis.

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Diagnostic criteria have been updated and novel therapies have been developed in PM/DM.

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Pathogenesis investigation and diagnosis precision improvement may help to guide future treatment strategies.

Muscle Changes During Atrophy

Muscle atrophy typically is a direct effect of protein degradation induced by a diversity of pathophysiologic states such as disuse, immobilization, denervation, aging, sepsis, cachexia, glucocorticoid treatment, hereditary muscular disorders, cancer, diabetes and obesity, kidney and heart failure, and others. Muscle atrophy is defined by changes in the muscles, consisting in shrinkage of myofibers, changes in the types of fiber and myosin isoforms, and a net loss of cytoplasm, organelles and overall a protein loss. Although in the literature there are extensive studies in a range of animal models, the paucity of human data is a reality. This chapter is focused on various aspects of muscle wasting and describes the transitions of myofiber types during the progression of muscle atrophy in several pathological states. Clinical conditions associated with muscle atrophy have been grouped based on the fast-to-slow or slow-to-fast fiber-type shifts. We have also summarized the ultrastructural and histochemical features characteristic for muscle atrophy in clinical and experimental models for aging, cancer, diabetes and obesity, and heart failure and arrhythmia.

Medical resource utilization in dermatomyositis/polymyositis patients treated with repository corticotropin injection, intravenous immunoglobulin, and/or rituximab

Background

Dermatomyositis and polymyositis (DM/PM) are rare, incurable inflammatory diseases that cause progressive muscle weakness and can be associated with increased medical resource use (MRU). When corticosteroid treatment is unsuccessful, patients may receive intravenous immunoglobulin (IVIg), rituximab, or repository corticotropin injection (RCI). This study compared real-world, non-medication MRU between patients treated with RCI and those treated with IVIg and/or rituximab for DM/PM.

Methods

Claims of DM/PM patients were analyzed from the combination of three commercial health insurance databases in the United States from July 2009 to June 2014. Patients treated with RCI were propensity score matched to those treated with IVIg, rituximab, and both (IVIg+rituximab) based on demographics, prior clinical characteristics, and prior MRU. Per-patient per-month (PPPM) MRU and costs were compared using Poisson regression and generalized linear modeling, respectively.

Results

One-hundred thirty-two RCI, 1,150 IVIg, and 562 rituximab patients had an average age of 52.6, 46.6, and 51.7 years, respectively, and roughly two-thirds were female. After matching, there were no significant differences in demographics or prior clinical characteristics. RCI patients had fewer PPPM hospitalizations (0.09 vs 0.17; P=0.049), shorter length of stay (LOS; 3.24 days vs 4.55 days; P=0.004), PPPM hospital outpatient department (HOPD) visits (0.60 vs 1.39; P<0.001), and PPPM physician office visits (2.01 vs 2.33; P=0.035) than IVIg. RCI had fewer PPPM HOPD visits (0.56 vs 0.92; P<0.001) than rituximab. Patients treated with RCI had shorter LOS (2.18 days vs 5.15; P<0.001) and less PPPM HOPD visits (0.53 vs 1.26; P<0.001) than IVIg+rituximab. Total non-medication PPPM costs were 23%–75% lower for RCI compared to IVIg ($2,126 vs $3,964; P<0.001), rituximab ($2,008 vs $2,607; P=0.018), and IVIg+rituximab ($1,234 vs $4,858; P<0.001).

Conclusion

Patients treated with RCI had less PPPM non-medication MRU and costs than those treated with IVIg and/or rituximab, particularly in the hospital setting where significant costs are incurred.

Use of intravenous immunoglobulin therapy for myositis: an audit in South Australian patients

In South Australia, between 2000 and 2014, 57 patients with idiopathic inflammatory myositis (IIM) were treated with intravenous immunoglobulin (IVIg). We reviewed disease characteristics to determine predictors of response to therapy and IVIg dosing and duration to identify opportunities to rationalise IVIg use. Patients with dermatomyositis/polymyositis had a response rate of 77% and were more likely than inclusion body myositis to respond to therapy. Consideration should be given to the use of the lowest possible dose of IVIg and to the undertaking of trials of cessation of IVIg in patients with stable IIM.

Chronic Myopathy Associated With Anti-Signal Recognition Particle Antibodies Can Be Misdiagnosed As Facioscapulohumeral Muscular Dystrophy

OBJECTIVES

To report cases of chronic autoimmune necrotizing myopathy with anti-signal recognition particle antibodies (anti-SRP myopathy) initially misdiagnosed as muscular dystrophy, in particular, facioscapulohumeral muscular dystrophy (FSHD).

METHODS

Medical records of patients with anti-SRP myopathy in our institution were retrospectively reviewed.

RESULTS

All 6 patients were initially diagnosed with muscular dystrophy because of the long-term clinical course and lack of inflammation on biopsy; 5 were diagnosed with FSHD based on a winged scapula. However, the following features suggested an alternative diagnosis, leading to anti-SRP antibody measurement: (1) lack of family history, (2) lack of facial involvement and asymmetry, (3) prominent dysphagia, and (4) profuse spontaneous activities on needle electromyography. All patients showed improvement with immunomodulating therapy.

CONCLUSIONS

Anti-SRP antibody measurement should be considered in patients diagnosed with FSHD if they present with diagnostic hallmarks of anti-SRP myopathy listed above, to avoid oversight of this potentially treatable disorder.

Current pharmacological treatment of idiopathic inflammatory myopathies

The idiopathic inflammatory myopathies are uncommon and heterogeneous disorders. Their classification is based on distinct clinicopathologic features. Although idiopathic inflammatory myopathies share some similarities, different subtypes may have variable responses to therapy, so it is very important to distinguish the correct subtype. There are few randomised, double blind placebo controlled studies to support the current treatment. High dose corticosteroids continue to be the first-line therapy and other immunosupressive drugs are used in refractory cases, as well as steroid-sparing agents. Some novel therapeutic approaches have emerged as potential treatment including tacrolimus, intravenous immunoglobulin and rituximab, following good outcomes reported in case studies. However, more randomised controlled trials are needed. This review considers the current and the potential future therapies for inflammatory myopathies.

Anti-B-Cell Therapies in Autoimmune Neurological Diseases: Rationale and Efficacy Trials

B cells have an ever-increasing role in the etiopathology of a number of autoimmune neurological disorders, acting as antibody-producing cells and, most importantly, as sensors, coordinators, and regulators of the immune response. B cells, among other functions, regulate the T-cell activation process through their participation in antigen presentation and production of cytokines. The availability of monoclonal antibodies or fusion proteins against B-cell surface molecules or B-cell trophic factors bestows a rational approach for treating autoimmune neurological disorders, even when T cells are the main effector cells. This review summarizes basic aspects of B-cell biology, discusses the role(s) of B cells in neurological autoimmunity, and presents anti-B-cell drugs that are either currently on the market or are expected to be available in the near future for treating neurological autoimmune disorders.

Innate immune-response mechanisms in dermatomyositis: an update on pathogenesis, diagnosis and treatment

Dermatomyositis (DM) is an autoimmune disease mainly affecting muscle and skin. Typical clinical and laboratory findings include muscle weakness with elevated muscle enzymes, characteristic skin lesions (e.g., Gottron papules, heliotrope erythema, Shawl sign), and specific serum autoantibodies. Recent studies have highlighted the activation of the innate immune system, including high expression of interferons (IFNs) and IFN-regulated proteins, as an important pathological hallmark of DM. These findings have changed our understanding of the disease fundamentally, since inappropriate activation of the innate immune system with secondary dysregulation of the adaptive immune response is now considered to be a central pathogenetic feature of DM. In this article, we review current guidelines and standards in diagnosis and treatment. We detail evidence-based and pathophysiology-based treatment strategies, with a focus on skin as well as on muscle lesions. Particularly, we discuss how the recent advances in the understanding of the pathomechanisms of DM have altered our conception of the mode of action of established drugs such as chloroquine and methotrexate. Finally, we outline possible future treatment strategies, with a focus on the innate immune system, e.g., targeting the IFN system with the anti-IFN-α antibody sifalimumab.

Cost-utility analysis of intravenous immunoglobulin for the treatment of steroid-refractory dermatomyositis in Thailand

INTRODUCTION

Intravenous immunoglobulin (IVIG) has been shown to be effective in treating steroid-refractory dermatomyositis (DM). There remains no evidence of its cost-effectiveness in Thailand.

OBJECTIVE

Our objective was to estimate the cost utility of IVIG as a second-line therapy in steroid-refractory DM in Thailand.

METHODS

A Markov model was developed to estimate the relevant costs and health benefits for IVIG plus corticosteroids in comparison with immunosuppressant plus corticosteroids in steroid-refractory DM from a societal perspective over a patient's lifetime. The effectiveness and utility parameters were obtained from clinical literature, meta-analyses, medical record reviews, and patient interviews, whereas cost data were obtained from an electronic hospital database and patient interviews. Costs are presented in $US, year 2012 values. All future costs and outcomes were discounted at a rate of 3% per annum. One-way and probabilistic sensitivity analyses were also performed.

RESULTS

Over a lifetime horizon, the model estimated treatment under IVIG plus corticosteroids to be cost saving compared with immunosuppressant plus corticosteroids, where the saving of costs and incremental quality-adjusted life-years (QALYs) were $US4738.92 and 1.96 QALYs, respectively. Sensitivity analyses revealed that probability of response of immunosuppressant plus corticosteroids was the most influential parameter on incremental QALYs and costs. At a societal willingness-to-pay threshold in Thailand of $US5148 per QALY gained, the probability of IVIG being cost effective was 97.6%.

CONCLUSIONS

The use of IVIG plus corticosteroids is cost saving compared with treatment with immunosuppressant plus corticosteroids in Thai patients with steroid-refractory DM. Policy makers should consider using our findings in their decision-making process for adding IVIG to corticosteroids as the second-line therapy for steroid-refractory DM patients.

Diffuse cutaneous mucinosis in dermatomyositis: a case report and review of the literature

We present the case of a patient with dermatomyositis and diffuse cutaneous mucinosis and give an up-to-date detailed review of all the published cases in the English literature describing the demographics, clinical picture, pathology management, and outcomes of this unique group of patients.

[Biological therapy in idiopathic inflammatory myopathies]

Idiopathic inflammatory myopathies are systemic, immune-mediated diseases characterized by proximal, symmetrical, progressive muscle weakness. The aim of this work is to give an overview of the biological therapy used in the treatment of idiopathic inflammatory myopathies. The authors also focus on novel results in the therapy directed against the B- and T-cells. They emphasize the importance of new trials in these diseases which may lead to the introduction of novel therapeutic options in these disorders.

A rare association of early-onset inclusion body myositis, rheumatoid arthritis and autoimmune thyroiditis: a case report and literature review

Sporadic inclusion body myositis (sIBM) is a slowly progressive, red-rimmed vacuolar myopathy leading to muscular atrophy and progressive weakness; it predominantly affects males older than fifty years, and is resistant to immunotherapy. It has been described in association with immuno-mediated thrombocytopenic purpura, multiple sclerosis, connective tissue disorders and, occasionally, rheumatoid arthritis. A 37-year-old man with longstanding rheumatoid arthritis and autoimmune thyroiditis with hypothyroidism was referred to us with slowly progressive, diffuse muscle weakness and wasting, which had initially involved the volar finger flexors, and subsequently also the ankle dorsiflexors and knee extensors. Needle electromyography showed typical myopathic motor unit potentials, fibrillation and positive sharp waves with normal nerve conduction studies. Quadriceps muscle biopsy was suggestive of sIBM. Considering data published in the literature, this case may be classified as an early-onset form. The patient was treated with long-term intravenous immunoglobulin and obtained a substantial stabilization of his muscle strength.

Cutaneous dermatomyositis: an updated review of treatment options and internal associations

Dermatomyositis is a specific type of inflammatory myopathy with characteristic cutaneous findings. Patients may have skin disease without clinically apparent muscle disease, but this disorder is best thought of as a systemic process. Therefore, all patients with dermatomyositis skin lesions need appropriate evaluation for muscle disease, esophageal dysfunction, cardiopulmonary disease, and potential internal malignancy. There are many therapies that have been used for patients with dermatomyositis, but most are based upon case series or expert opinion rather than meta-analyses or randomized, placebo-controlled trials. Even those therapies that have been subjected to randomized, blinded, placebo-controlled trials include a mixture of patients with idiopathic inflammatory myopathy and do not utilize a validated assessment tool for measuring cutaneous disease responses. In this review, we discuss the therapies available as well as the internal associations with dermatomyositis.

[Intravenous immunoglobulin treatment in idiopathic inflammatory myopathy]

Idiopathic inflammatory myopathies are chronic, systemic autoimmune diseases, characterized by symmetric and progressive weakness of proximal muscles in the upper and lower extremities. Treatment of the disease presents a complex challenge and it needs practical knowledge. In this review the authors summarize current treatment options, and discuss intravenous immunoglobulin treatment in therapy-unresponsive cases. Relevant data from the international literature is collected, too. Benefits and side effects of this treatment are also disclosed.

Statin-associated polymyositis following omeprazole treatment

Statins are an extensively used class of drugs, and myopathy is an uncommon, but well-described side effect of statin therapy. Inflammatory myopathies, including polymyositis, dermatomyositis, and necrotizing autoimmune myopathy, are even more rare, but debilitating, side effects of statin therapy that are characterized by the persistence of symptoms even after discontinuation of the drug. It is important to differentiate statin-associated inflammatory myopathies from other self-limited myopathies, as the disease often requires multiple immunosuppressive therapies. Drug interactions increase the risk of statin-associated toxic myopathy, but no risk factors for statin-associated inflammatory myopathies have been established. Here we describe the case of a man, age 59 years, who had been treated with a combination of atorvastatin and gemfibrozil for approximately 5 years and developed polymyositis after treatment with omeprazole for 7 months. Symptoms did not resolve after discontinuation of the atorvastatin, gemfibrozil, and omeprazole. The patient was treated with prednisone and methotrexate followed by intravenous immunoglobulin, which resulted in normalization of creatinine kinase levels and resolution of symptoms after 14 weeks. It is unclear if polymyositis was triggered by interaction of the statin with omeprazole and/or gemfibrozil, or if it developed secondary to long-term use of atorvastatin only.

Paraneoplastic necrotizing myopathy associated with adenocarcinoma of the lung - a rare entity with atypical onset: a case report

Introduction

Inflammatory myopathies (such as dermatomyositis and polymyositis) are well-recognized paraneoplastic syndromes. However, paraneoplastic necrotizing myopathy is a more recently defined clinical entity, characterized by rapidly progressive, symmetrical, predominantly proximal muscle weakness with severe disability, and associated with a marked increase in serum muscle enzyme levels. Paraneoplastic necrotizing myopathy requires muscle biopsy for diagnosis, which typically shows massive necrosis of muscle fibers with limited or absent inflammatory infiltrates.

Case presentation

We report the case of an 82-year-old Italian-born Caucasian man who was admitted to hospital because of heart failure and two drop attacks. Over the following days, he developed progressive severe weakness, dysphagia, and dysphonia. Testing showed increasing serum muscle enzyme levels. Electromyography showed irritative myopathy of the proximal muscles and sensorimotor polyneuropathy. Muscle biopsy (left vastus lateralis) showed massive necrosis of muscle fibers with negligible inflammatory infiltrates, complement membrane attack complex deposition on endomysial capillaries, and moderate upregulation of major histocompatibility complex-I. Computed tomography of the thorax showed a nodular mass in the apex of the right lung. The patient was diagnosed with paraneoplastic necrotizing myopathy. In spite of high-dose corticoid therapy, he died 1 month later because of his aggressive cancer. Subsequent electron microscopic examination of a muscle biopsy specimen showed thickened walls and typical pipestem changes of the endomysial capillaries, with swollen endothelial cells. Poorly differentiated adenocarcinoma of the lung was confirmed on post-mortem histological examination.

Conclusions

Paraneoplastic necrotizing myopathy is a rare syndrome with outcomes ranging from fast progression to complete recovery. Treatment with corticosteroids is often ineffective, and prognosis depends mainly on the characteristics of the underlying cancer. This case shows that paraneoplastic necrotizing myopathy may have an atypical appearance, and should be considered in elderly patients with neoplastic disease. In this case, the diagnosis was delayed by the unusual clinical picture that suggested heart disease rather than muscle disease.

Inclusion body myositis associated with Sjögren's syndrome

Inclusion body myositis (IBM) belongs to the group of idiopathic inflammatory myopathies. It is a poorly understood disease, which affects skeletal muscles. IBM usually occurs as an isolated condition, but in some cases, it may be associated with another autoimmune disorder, Sjögren’s syndrome. We report a case of a 47-year-old woman with headaches, symptoms of trigeminal neuralgia, progressive weakness in muscles of the upper and lower extremities and symptoms of dry eyes and mouth. On admission, creatine kinase level was increased to 6,956 IU/mL and lactate dehydrogenase (LDH) to 1,011 U/L in the serum. The increase in inflammatory factor (CRP, ESR) levels was not found. The diagnosis of inclusion body myositis associated with Sjögren’s syndrome was established on the basis of clinical picture and diagnostic tests. In this therapy, methotrexate and methylprednisolone were administered. The considerable improved muscle strength in the upper and lower extremities, improved speech and swallowing, disappearance of headache and reduction in CPK and LDH levels were found 8 months after establishing the diagnosis. Treatment with methotrexate and methylprednisolone improved the clinical symptoms and quality of life of this patient and may offer a therapeutic option for some patients with IBM and concomitant Sjögren’s syndrome.

Enterococcus faecalis overcomes foreign body-mediated inflammation to establish urinary tract infections

Urinary catheterization elicits major histological and immunological changes that render the bladder susceptible to microbial invasion, colonization, and dissemination. However, it is not understood how catheters induce these changes, how these changes act to promote infection, or whether they may have any protective benefit. In the present study, we examined how catheter-associated inflammation impacts infection by Enterococcus faecalis, a leading cause of catheter-associated urinary tract infection (CAUTI), a source of significant societal and clinical challenges. Using a recently optimized murine model of foreign body-associated UTI, we found that the implanted catheter itself was the primary inducer of inflammation. In the absence of the silicone tubing implant, E. faecalis induced only minimal inflammation and was rapidly cleared from the bladder. The catheter-induced inflammation was only minimally altered by subsequent enterococcal infection and was not suppressed by inhibitors of the neurogenic pathway and only partially by dexamethasone. Despite the robust inflammatory response induced by urinary implantation, E. faecalis produced biofilm and high bladder titers in these animals. Induction of inflammation in the absence of an implanted catheter failed to promote infection, suggesting that the presence of the catheter itself is essential for E. faecalis persistence in the bladder. Immunosuppression prior to urinary catheterization enhanced E. faecalis colonization, suggesting that implant-mediated inflammation contributes to the control of enterococcal infection. Thus, this study underscores the need for novel strategies against CAUTIs that seek to reduce the deleterious effects of implant-mediated inflammation on bladder homeostasis while maintaining an active immune response that effectively limits bacterial invaders.

Immune-mediated necrotizing myopathy is characterized by a specific Th1-M1 polarized immune profile

Immune-mediated necrotizing myopathy (IMNM) is considered one of the idiopathic inflammatory myopathies, comprising dermatomyositis, polymyositis, and inclusion body myositis. The heterogeneous group of necrotizing myopathies shows a varying amount of necrotic muscle fibers, myophagocytosis, and a sparse inflammatory infiltrate. The underlying immune response in necrotizing myopathy has not yet been addressed in detail. Affected muscle tissue, obtained from 16 patients with IMNM, was analyzed compared with eight non-IMNM (nIMNM) tissues. Inflammatory cells were characterized by IHC, and immune mediators were assessed by quantitative real-time PCR. We demonstrate that immune- and non-immune-mediated disease can be distinguished by a specific immune profile with significantly more prominent major histocompatibility complex class I expression and complement deposition and a conspicuous inflammatory infiltrate. In addition, patients with IMNM exhibit a strong type 1 helper T cell (T1)/classically activated macrophage M1 response, with detection of elevated interferon-γ, tumor necrosis factor-α, IL-12, and STAT1 levels in the muscle tissue, which may serve as biomarkers and aid in diagnostic decisions. Furthermore, B cells and high expression of the chemoattractant CXCL13 were identified in a subgroup of patients with defined autoantibodies. Taken together, we propose a diagnostic armamentarium that allows for clear differentiation between IMNM and nIMNM. In addition, we have characterized a Th1-driven, M1-mediated immune response in most of the autoimmune necrotizing myopathies, which may guide therapeutic options in the future.

Diagnosis and treatment of inflammatory myopathy: issues and management

The idiopathic inflammatory myopathies include polymyositis (PM), dermatomyositis (DM) and inclusion body myositis (IBM). The specific etiologies of these muscle diseases are not well known and are thought to involve components of the humoral and cellular immune system as well as other nonimmune factors. Diagnosing these myopathies involves a laboratory evaluation, imaging studies, multidisciplinary consultations, histologic examination and potentially genetic studies. Despite all that we currently know about inflammatory muscle disease with these studies, we find that our current concept of muscle disease is changing. In the cases of immune-mediated necrotizing myopathy and inclusion body myositis, the concept of inflammation needs to be rethought. Moreover, the classification schemes for these idiopathic myopathies may need updating to include current research findings that relate to pathogenesis. With ongoing discoveries, classification and appropriate treatment is becoming increasingly challenging. This paper discusses the inflammatory myopathies, the challenges to diagnosis, classification controversies and potential treatment options.

Genetics of neuromuscular disorders

Neuromuscular disorders affect the peripheral nervous system and muscle. The principle effect of neuromuscular disorders is therefore on the ability to perform voluntary movements. Neuromuscular disorders cause significant incapacity, including, at the most extreme, almost complete paralysis. Neuromuscular diseases include some of the most devastating disorders that afflict mankind, for example motor neuron disease. Neuromuscular diseases have onset any time from in utero until old age. They are most often genetic. The last 25 years has been the golden age of genetics, with the disease genes responsible for many genetic neuromuscular disorders now identified. Neuromuscular disorders may be inherited as autosomal dominant, autosomal recessive, or X-linked traits. They may also result from mutations in mitochondrial DNA or from de novo mutations not present in the peripheral blood DNA of either parent. The high incidence of de novo mutation has been one of the surprises of the recent increase in information about the genetics of neuromuscular disorders. The disease burden imposed on families is enormous including decision making in relation to presymptomatic diagnosis for late onset neurodegenerative disorders and reproductive choices. Diagnostic molecular neurogenetics laboratories have been faced with an ever-increasing range of disease genes that could be tested for and usually a finite budget with which to perform the possible testing. Neurogenetics has moved from one known disease gene, the Duchenne muscular dystrophy gene in July 1987, to hundreds of disease genes in 2011. It can be anticipated that with the advent of next generation sequencing (NGS), most, if not all, causative genes will be identified in the next few years. Any type of mutation possible in human DNA has been shown to cause genetic neuromuscular disorders, including point mutations, small insertions and deletions, large deletions and duplications, repeat expansions or contraction and somatic mosaicism. The diagnostic laboratory therefore has to be capable of a large number of techniques in order to identify the different mutation types and requires highly skilled staff. Mutations causing neuromuscular disorders affect the largest human proteins for example titin and nebulin. Successful molecular diagnosis can make invasive and expensive diagnostic procedures such as muscle biopsy unnecessary. Molecular diagnosis is currently largely based on Sanger sequencing, which at most can sequence a small number of exons in one gene at a time. NGS techniques will facilitate molecular diagnostics, but not for all types of mutations. For example, NGS is not good at identifying repeat expansions or copy number variations. Currently, diagnostic molecular neurogenetics is focused on identifying the causative mutation(s) in a patient. In the future, the focus might move to prevention, by identifying carriers of recessive diseases before they have affected children. The pathobiology of many of the diseases remains obscure, as do factors affecting disease severity. The aim of this review is to describe molecular diagnosis of genetic neuromuscular disorders in the past, the present and speculate on the future.