Myxovirus resistance protein A (MxA) expression in myositides: Sarcoplasmic expression is common in both dermatomyositis and lupus myositis

INTRODUCTION/AIMS

Myxovirus resistance protein A (MxA) is a type I interferon (IFN1) pathway activation marker and MxA sarcoplasmic expression is currently recognized as a highly specific marker for dermatomyositis (DM). However, we have frequently observed endothelial tubuloreticular inclusions (TRI), another surrogate IFN1 activation marker, in a variety of overlap myositides. The aim of this study was to examine MxA expression in those myositides.

METHODS

We retrospectively performed MxA immunostaining on a wide range of myositides.

RESULTS

MxA sarcoplasmic expression was present in DM (94.4%, 17/18), active lupus myositis (LM, 80%,16/20), inactive LM (36%, 4/11), antisynthetase syndrome (ASyS, 20%, 2/10), systemic sclerosis (13%, 2/15), Sjogren's syndrome (7.7%, 1/13), and human immunodeficiency virus (HIV) myositis (5.6%, 1/18) and was absent in immune-mediated necrotizing myopathy (IMNM, 0/16) and hydroxychloroquine myopathy (0/5). The sensitivity and specificity of MxA sarcoplasmic expression for LM and DM combined compared with all other myositides were 84.6% (95% CI: 69.5-94.1) and 92.1 (95% CI: 83.6-97.0), respectively, and superior to TRIs. MxA capillary expression was nonspecific. Histologically, 35% of LM cases demonstrated a unique panfascicular necrotizing myopathy pattern. The remainder of the LM cases had significant morphological overlap with DM/ASyS (20%), IMNM (20%), or polymyositis (15%).

DISCUSSION

MxA sarcoplasmic expression is highly prevalent in LM and DM and is a useful marker in differentiating DM and LM from other myositides. LM can manifest in various pathology patterns that need to be differentiated from DM, IMNM, ASyS, and polymyositis.

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.

[Magnetic resonance imaging T2 mapping could reflect disease status in patients with dermatomyositis or polymyositis]

This study aimed to explore the value of magnetic resonance imaging (MRI) T2 mapping in the assessment of dermatomyositis (DM) and polymyositis (PM). Thirty-three confirmed cases (myosin group) and eight healthy volunteers (healthy control group) at the Department of Rheumatology and Immunology, the First Affiliated Hospital of Kunming Medical University, from October 2016 to December 2017, were collected and analyzed. Multiple parameters of the myosin group were quantified, including creatine kinase (CK), erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), complement C3, and complement C4. Disease status was evaluated using a panel of tools: myositis disease activity assessment tool-muscle (MDAAT-muscle), myositis disease activity assessment tool-whole (MDAAT-all), health assessment questionnaire (HAQ), medical outcomes study health survey short form-36 item (SF-36), hand muscle strength test (MMT-8) score, and MRI T2 mapping of muscle (22 muscles in the pelvis and thighs) T2 values. The results showed that in the myositis group, the measurements for CK, ESR, CRP, complement C3, and complement C4 were 457.2 (165.6, 1 229.2) IU/L, 20 (10, 42) mm/1h, 3.25 (2.38, 10.07) mg/L, 0.90 (0.83, 1.06) g/L, and 0.18 (0.14, 0.23) g/L, respectively. The scores for MMT-8, MDAAT-muscle, MDAAT-all, HAQ, and SF-36 were 57.12±16.23, 5.34 (4.00, 6.00), 34.63±12.62, 1.55 (0.66, 2.59), and 44.66±7.98, respectively. T2 values were significantly higher in all 22 muscles of the pelvis and thighs of patients with DM or PM compared with the healthy controls [(54.99±11.60)ms vs. (36.62±1.66)ms, P<0.001], with the most severe lesions in the satrorius, iliopsoas, piriformis, gluteus minimus, and gluteus medius muscles. The total muscle T2 value in the myositis group was positively correlated with CK, MDAAT-muscle, MDAAT-all, and HAQ (r=0.461, 0.506, 0.347, and 0.510, respectively, all P<0.05). There was a negative correlation between complement C4, SF-36, and MMT-8 scores (r=-0.424, -0.549, and -0.686, respectively, all P<0.05). Collectively, the findings from this study suggest that MRI T2 mapping can objectively reflect the disease status of DM and PM.

Involvement of YKL-40-positive macrophages commonly identified in polymyositis and dermatomyositis in the pathogenesis of myositis: a retrospective study

YKL-40 is implicated in inflammation and tissue repair, but no reports have investigated its involvement in myositis in polymyositis (PM) and dermatomyositis (DM). Therefore, we aimed to investigate the relationship between YKL-40 and PM/DM. We retrospectively enrolled 35 patients diagnosed with PM/DM along with 26 healthy controls (HCs). Both PM and DM were diagnosed according to Bohan and Peter's criteria. Serum YKL-40 levels were measured, age-corrected to YKL-40 percentile values, and compared to HCs. Patients with myositis without interstitial lung disease were also enrolled and compared to HCs. Immunofluorescence staining was performed to identify YKL-40-positive inflammatory cells in muscle biopsy samples from two patients each with PM and DM. Age-corrected serum YKL-40 levels were significantly higher in patients with PM/DM compared to HCs with and without lung disease; however, these levels decreased significantly after treatment. Immunohistochemical analysis showed infiltration of YKL-40-positive inflammatory cells into the intramuscular sheath and perimuscular membrane. Immunofluorescence staining showed CD68 expression in YKL-40-positive inflammatory cells, suggesting that these cells were macrophages. To the best of our knowledge, this is the first study to demonstrate that YKL-40-positive macrophages are present in PM and DM, indicating that YKL-40 may be involved in PM/DM.

Pompe disease misdiagnosed as polymyositis

Late-onset Pompe disease manifests predominantly in the proximal lower limbs and may be mistaken for an inflammatory myopathy. A 46-year-old man with acromegaly had an 8-year history of progressive weakness. His myopathy was initially attributed to the acromegaly, but severe progression prompted a muscle biopsy, which suggested an inflammatory myopathy. However, his weakness progressed despite treatment for polymyositis. His muscle ultrasound scan pattern was more suggestive of Pompe disease than polymyositis, and Pompe disease was confirmed by genetic and enzymatic testing. Patients with apparent polymyositis, which persists despite treatment, require reconsideration of the diagnosis, with particular attention to treatable genetic causes.

Prominent mitochondrial pathology in a case of refractory dermatomyositis: coincidence or concause?

INTRODUCTION

Mitochondrial alterations are a common finding in muscle biopsy of sporadic inclusion body myositis (s-IBM) and polymyositis with mitochondrial pathology (PM-Mito). Both disorders generally have poor treatment response. Nevertheless, mitochondrial myopathology has been rarely reported in dermatomyositis (DM) outside areas of perifascicular atrophy and a relationship with therapeutic outcome is not established.

METHODS

We report on clinical, immunological, radiological, and myopathological findings of a case of severe, treatment-refractory anti-Mi-2-positive DM.

RESULTS

A 77-year-old woman developed anti-Mi-2 DM with severe diffuse muscle weakness associated with abundant mitochondrial abnormalities at muscle biopsy, beside the typical features of inflammatory myopathy. The patient was poorly responsive to multiple-line therapies and finally anti-JAK (anti-Janus activated kinase) was administered, leading to partial clinical improvement.

DISCUSSION

Given the usual satisfactory treatment response and favorable outcome of anti-Mi-2 DM, we suppose that mitochondrial dysfunction on muscle biopsy could represent a marker of disease severity in DM, predicting a worse response to treatment and a poor clinical outcome. JAK-inhibitors could represent a good treatment option in refractory anti-Mi-2 DM with mitochondrial abnormalities.

The Plasma Cell Infiltrate Populating the Muscle Tissue of Patients with Inclusion Body Myositis Features Distinct B Cell Receptor Repertoire Properties

Inclusion body myositis (IBM) is an autoimmune and degenerative disorder of skeletal muscle. The B cell infiltrates in IBM muscle tissue are predominantly fully differentiated Ab-secreting plasma cells, with scarce naive or memory B cells. The role of this infiltrate in the disease pathology is not well understood. To better define the humoral response in IBM, we used adaptive immune receptor repertoire sequencing, of human-derived specimens, to generate large BCR repertoire libraries from IBM muscle biopsies and compared them to those generated from dermatomyositis, polymyositis, and circulating CD27+ memory B cells, derived from healthy controls and Ab-secreting cells collected following vaccination. The repertoire properties of the IBM infiltrate included the following: clones that equaled or exceeded the highly clonal vaccine-associated Ab-secreting cell repertoire in size; reduced somatic mutation selection pressure in the CDRs and framework regions; and usage of class-switched IgG and IgA isotypes, with a minor population of IgM-expressing cells. The IBM IgM-expressing population revealed unique features, including an elevated somatic mutation frequency and distinct CDR3 physicochemical properties. These findings demonstrate that some of IBM muscle BCR repertoire characteristics are distinct from dermatomyositis and polymyositis and circulating Ag-experienced subsets, suggesting that it may form through selection by disease-specific Ags.

Evolving classification and role of muscle biopsy in diagnosis of inflammatory myopathies

Idiopathic inflammatory myopathy (IIM) is a broad term that includes dermatomyositis, polymyositis, overlap myositis, sporadic inclusion body myositis, and immune-mediated necrotizing myopathy. The understanding of the pathogenesis of IIM is ever-evolving with regular updates in the classification schema. With the recognition of autoantibodies and their detection, the diagnostic algorithms are changing in favor of non-invasive diagnoses. However, muscle biopsy has immensely contributed to our understanding of the pathogenesis of inflammatory myopathies, and the pathologic features of different subtypes are well established. The biopsy also aids in distinguishing myopathies with overlapping clinical features, particularly dystrophies, which can show inflammation on biopsy in some cases. In this article, the various classification schemes of the IIM are reviewed. Also, the pathogenesis and pathology of each type of IIM have been highlighted. This article emphasizes the role of muscle biopsy in the diagnosis of inflammatory myopathies.

Antibody Therapies in Autoimmune Inflammatory Myopathies: Promising Treatment Options

Inflammatory myopathies, including polymyositis (PM), dermatomyositis (DM), inclusion body myositis (IBM), necrotizing myopathy (NM), antisynthetase syndrome (ASS) and overlap myositis (OM), in short myositis, are rare diseases. All forms of myositis have progressive muscle weakness in common, with each subtype characterized by different autoantibody profiles, histological findings and extramuscular manifestations. Due to better understanding of the pathogenesis of the muscle inflammation in myositis, new molecular pathways for targeted therapy have been discovered. Current therapies aim at different components of the innate or the adaptive immune response. Additionally, non-inflammatory mechanisms in myositis have come into focus as possible treatment targets. The use of therapeutical antibodies in myositis has been examined in various clinical studies, several of them randomized controlled ones: Depletion of B-cells by rituximab has been established as treatment of refractory myositis. IVIG, an antibody therapy in the wider sense, has now been licensed for DM following a recent positive clinical trial. Negative study results were reported in randomized trials with infliximab, sifalimumab and bimagrumab. Studies on basiliximab and eculizumab are currently underway, and are expected to yield results in a couple of years. Despite some promising results of clinical studies with antibody therapy in myositis, further research is crucial to optimize the treatment for this debilitating disease and to find treatment alternatives for treatment-refractory patients.

Polymyositis: is there anything left? A retrospective diagnostic review from a tertiary myositis centre

OBJECTIVE

The current classification criteria for idiopathic inflammatory myopathy (IIM) retain PM as a major disease subgroup. However, evolution in the understanding of IIM has suggested that many of these patients could be better described as having an alternative diagnosis. In the present study, we apply the latest understanding of IIM subtyping to retrospectively review PM diagnoses in a large cohort of IIM patients.

METHODS

Within a previously reported cohort of 255 patients from a UK tertiary myositis clinic, 37 patients classified as PM according to both the EULAR/ACR IIM criteria and expert opinion were identified. Clinical data and complementary tests were reviewed, and consensus decisions regarding final classification were reached in each case.

RESULTS

Nine (9/37, 24.3%) patients remained classified as PM, 3.5% (9/255) of the original cohort; these PM patients were seronegative for myositis antibodies, responsive to immunosuppression, and in 4/7 (57.1%) patients where muscle biopsy was performed had HLA-1 upregulation and endomysial inflammatory infiltrates. Immune-mediated necrotizing myopathy (5/37, 13.5%) and connective tissue disease overlap myositis (7/37, 19%) were the main alternative diagnoses. The remaining patients were diagnosed as: unspecified myopathy (6/37, 16%), dermatomyositis (2/37, 5%), cancer-associated myopathy (3/37, 8.1%), and non-inflammatory myopathy (1/37, 3%, myofibrillar myopathy). Four patients (4/37, 10%) had insufficient data available to confidently reclassify.

CONCLUSION

Our study confirms that PM can now be considered a rare IIM subgroup. A thorough examination, complete myositis autoantibody panel, and careful interpretation of the biopsy results is recommended to confirm the correct IIM sub-type.

Apoptosis in idiopathic inflammatory myopathies with partial invasion; a role for CD8+ cytotoxic T cells?

Polymyositis and inclusion body myositis are idiopathic inflammatory myopathies, with a pathology characterized by partial invasion of non-necrotic muscle fibres by CD8+ cytotoxic T-cells, leading to fibre degeneration. Although the main effector pathway of CD8+ T-cells is to induce apoptosis of target cells, it has remained unclear if apoptosis occurs in these diseases, and if so, if it is mediated by CD8+ T-cells. In consecutive biopsy sections from 10 patients with partial invasion, muscle fibres and inflammatory cells were assessed by immunohistochemistry and apoptotic nuclei by the TUNEL assay. Analysis of muscle fibre morphology, staining pattern and quantification were performed on digital images, and they were compared with biopsies from 10 dermatomyositis patients and 10 controls without muscle disease. Apoptotic myonuclei were found in muscle with partial invasion, but not in the invaded fibres. Fibres with TUNEL positive nuclei were surrounded by CD8+ T-cells, granzyme B+ cells and macrophages, but lacked FAS receptor expression. In contrast, apoptotic myonuclei were rare in dermatomyositis and absent in controls. The findings confirm that apoptosis occurs in idiopathic inflammatory myopathies and support that it is mediated by CD8+ cytotoxic T- cells, acting in parallel to the process of partial invasion.

A Study Based on the Correlation Between Slit2/Robo1 Signaling Pathway Proteins and Polymyositis/Dermatomyositis

AIMS

To investigate the role of Slit2 and Robo1 during the vascular disease of Polymyositis (PM) / dermatomyositis (DM).

BACKGROUND

PM and DM are nonsuppurative inflammatory myopathies that mainly invade the skeletal muscles.

OBJECTIVE

This study attempted to explore the specific mechanism of Slit2/Robo1 signaling pathway proteins during the vascular disease of PM/DM.

METHODS

The mRNA expressions of Slit2 and Robo1 in the muscle tissue were detected by RT-qPCR between newly-diagnosed PM/DM patients and healthy controls. The number of Slit2 and Robo1 positive cells in the serial sections of muscle paraffin tissues was measured by immunohistochemistry in 10 patients with PM, 10 patients with DM and 20 healthy controls.

RESULTS

The study results revealed that the mRNA expressions of Slit2 and Robo1 in muscle tissue in the PM and DM groups were higher than that in the control group (P<0.05). The positive expression rates of Slit2 and Robo1 in muscle tissue in the PM and DM groups were 80.0%, 80.0%, 70.0% and 70.0%, respectively. The difference was statistically significant (P<0.001), when compared to the control group (the positive expression rates were 0% and 10%, respectively).

CONCLUSION

The activation of the Slit2/Robo1 signaling pathway is an important mechanism leading to the development of PM/DM.

An Anti-PM/Scl-75 Antibody-positive Japanese Woman Who Developed Inflammatory Myopathy

A 69-year-old Japanese woman presented with mild muscle weakness of the neck and symmetrical proximal parts of the upper and lower limbs. Laboratory tests, needle electromyography, and a muscle biopsy revealed inflammatory myopathy with an apparent clinical classification of polymyositis and positive findings for anti-PM/Scl-75 antibody. This antibody is rare among Japanese populations, and most Japanese patients with the antibody are not classified with the inflammatory myopathy seen in polymyositis. The muscle biopsy also showed marked necrotic and regenerative fibers. We need to collectively investigate patients with the potential to develop this disease, and to identify any unique characteristics for Asian populations, including Japanese.

Clinical significance of myositis-specific autoantibody profiles in Japanese patients with polymyositis/dermatomyositis

Myositis-specific autoantibodies, such as anti-melanoma differentiation associated gene 5 (MDA5) and anti-anti-amino acyl-tRNA synthetases (ARS) antibodies, are associated with interstitial lung diseases (ILD), which determine the prognosis of polymyositis/dermatomyositis (PM/DM) patients. However, there is a paucity of data on the clinical correlation between anti-Sjögren syndrome-related antigen A (anti-SSA)/Ro52 antibodies in PM/DM. We investigated the prevalence of myositis-specific autoantibodies including anti-SSA/Ro52 antibody and assessed the clinical significance of these antibodies in patients with PM/DM.We retrospectively reviewed demographic data and clinical outcomes in patients with PM/DM. The study population comprised 24 patients with PM and 60 patients with DM. The presence of anti-myositis-specific antibodies (MDA5, ARS, Jo-1, SSA/Ro52) was determined by immunosorbent assay (ELISA).Anti-MDA5 antibody was detected in 18 patients with DM (n = 60). Anti-ARS/anti-SSA/Ro52 antibodies were detected in 31 and 39 patients with PM/DM (n = 84). Rapidly progressive ILD patients were mainly found in the anti-MDA5 antibody-positive DM group. During the follow-up period, 9 patients died. Kaplan-Meier analysis demonstrated that survival rates seem to be lower in DM patients with anti-MDA5 antibodies compared with those without anti-MDA5 antibodies. Furthermore, dual positivity for anti-SSA/Ro52 and anti-MDA5 antibodies was significantly higher in nonsurviving DM patients compared with survivors.Although the presence of anti-ARS or anti-MDA5 antibodies is a prognostic marker in patients with PM/DM, combined presence of anti-SSA/Ro52 and anti-MDA5 antibodies represent another marker for clinical outcome in DM patients. Our results suggest that anti-SSA/Ro52 antibody positivity in DM patients with anti-MDA5 antibody reveals a subgroup of DM patients with poor prognosis.

Serum-soluble TRAIL: a potential biomarker for disease activity in myositis patients

OBJECTIVES

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is a member of the TNF super-family, which is involved in the regulation of immune response and pathogenesis of autoimmune diseases, including polymyositis (PM) and dermatomyositis (DM). In this study, we examined the level and origin of serum-soluble TRAIL (sTRAIL) in patients with PM and DM and analyzed its association with disease activity and clinical features.

METHOD

11 PM patients, 33 DM patients, and 20 healthy controls were enrolled in this study. Clinical features were recorded when admitted, and disease activity was evaluated by myositis disease activity assessment visual analogue scale (MYOACT). TRAIL expression in muscle tissues was detected by immunohistochemistry. Serum sTRAIL levels were measured by enzyme-linked immunosorbent assay. The expression of membrane TRAIL (mTRAIL) and its receptors, including DR4 and DR5, on circulating T cells was analyzed by flow cytometry.

RESULTS

TRAIL was expressed in infiltrated inflammatory cells in muscle tissues from patients. The serum sTRAIL level was markedly increased in patients and was positively correlated with the disease activity. Serum sTRAIL was decreased after therapy in patients and was specifically higher in patients with dysphagia, but lower in patients with autoantibody Jo-1 positive. The frequency of mTRAIL and its receptors on circulating T cells from patients were significantly elevated than that from healthy controls.

CONCLUSIONS

The serum sTRAIL could be a biomarker for evaluating the disease activity of PM and DM, and targeting the generation of TRAIL in T cells might be a potential approach in the treatment of PM and DM.

Triggers of inflammatory myopathy: insights into pathogenesis

The inflammatory myopathies, which include dermatomyositis, polymyositis, and the immune-mediated necrotizing myopathies, are a heterogeneous group of autoimmune diseases that manifest with muscle, skin, or lung damage. Collectively, these autoimmune diseases result from loss of tolerance to a select group of self-antigens, although the precise mechanism through which this occurs is not known. Infection, malignancy, and certain medications including statins and the immune checkpoint inhibitors used in cancer therapy have been identified as potential immunologic triggers of the inflammatory myopathies. Some of these triggers are classically associated with specific myositis-specific autoantibodies (MSAs). The strong association between certain triggers and MSAs provides insights into how an immunologic event can lead to loss of tolerance to specific self-antigens, resulting in autoimmune disease. In this review, we discuss the proposed triggers of the inflammatory myopathies and their associations with MSAs, and provide insights into how these triggers may result in the inflammatory myopathies.

Treatment of Fulminant Giant Cell Myocarditis Associated with Polymyositis Using a Left Ventricular Assist Device and Subsequent Corticosteroid and Immunosuppressive Therapy Leading to Remission

A 58-year-old man with a recent history of generalized myalgia and muscle weakness was transferred to our hospital because of acute progressive dyspnea. The patient underwent left ventricular (LV) assist device (LVAD) implantation due to cardiogenic shock with a LV ejection fraction (LVEF) of 6%. The histological findings obtained from LV apex showed the infiltration of multinucleated giant cells and severe myocardial contusion. Combining this histological finding with our experienced neurologists comments, resulted in a final diagnosis of fulminant giant cell myocarditis associated with polymyositis. A day after LVAD implantation, the patient received corticosteroid and immunosuppressive therapy, and the LVEF recovered to 68%.

Atorvastatin-induced necrotizing autoimmune myositis: An emerging dominant entity in patients with autoimmune myositis presenting with a pure polymyositis phenotype

The general aim of this study was to evaluate the disease spectrum in patients presenting with a pure polymyositis (pPM) phenotype. Specific objectives were to characterize clinical features, autoantibodies (aAbs), and membrane attack complex (MAC) in muscle biopsies of patients with treatment-responsive, statin-exposed necrotizing autoimmune myositis (NAM). Patients from the Centre hospitalier de l'Université de Montréal autoimmune myositis (AIM) Cohort with a pPM phenotype, response to immunosuppression, and follow-up ≥3 years were included. Of 17 consecutive patients with pPM, 14 patients had a NAM, of whom 12 were previously exposed to atorvastatin (mean 38.8 months). These 12 patients were therefore suspected of atorvastatin-induced AIM (atorAIM) and selected for study. All had aAbs to 3-hydroxy-3-methylglutaryl coenzyme A reductase, and none had overlap aAbs, aAbs to signal recognition particle, or cancer. Three stages of myopathy were recognized: stage 1 (isolated serum creatine kinase [CK] elevation), stage 2 (CK elevation, normal strength, and abnormal electromyogram [EMG]), and stage 3 (CK elevation, proximal weakness, and abnormal EMG). At diagnosis, 10/12 (83%) patients had stage 3 myopathy (mean CK elevation: 7247 U/L). The presenting mode was stage 1 in 6 patients (50%) (mean CK elevation: 1540 U/L), all of whom progressed to stage 3 (mean delay: 37 months) despite atorvastatin discontinuation. MAC deposition was observed in all muscle biopsies (isolated sarcolemmal deposition on non-necrotic fibers, isolated granular deposition on endomysial capillaries, or mixed pattern). Oral corticosteroids alone failed to normalize CKs and induce remission. Ten patients (83%) received intravenous immune globulin (IVIG) as part of an induction regimen. Of 10 patients with ≥1 year remission on stable maintenance therapy, IVIG was needed in 50%, either with methotrexate (MTX) monotherapy or combination immunosuppression. In the remaining patients, MTX monotherapy or combination therapy maintained remission without IVIG. AtorAIM emerged as the dominant entity in patients with a pPM phenotype and treatment-responsive myopathy. Isolated CK elevation was the mode of presentation of atorAIM. The new onset of isolated CK elevation on atorvastatin and persistent CK elevation on statin discontinuation should raise early suspicion for atorAIM. Statin-induced AIM should be included in the differential diagnosis of asymptomatic hyperCKemia. Three patterns of MAC deposition, while nonpathognomonic, were pathological clues to atorAIM. AtorAIM was uniformly corticosteroid resistant but responsive to IVIG as induction and maintenance therapy.

[Paraneoplastic myasthenia gravis and polymyositis secondary to a thymoma in a young woman]

We present the case of a 33-year-old woman who within weeks developed severe swallowing difficulties and weakness in her limbs to an extent requiring hospitalization. Workup confirmed clinically suspected diagnoses of polymyositis and autoimmune myasthenia. A suspicion of malignant thymoma based on chest computed tomography was histologically verified. Patient treatment and response are presented. The case emphasizes the importance of recognizing that thymomas, in rare instances, may present with a combination of neuromuscular disorders in the same patient.

IL-15 up-regulates the MMP-9 expression levels and induces inflammatory infiltration of macrophages in polymyositis through regulating the NF-kB pathway

This study was aimed to research the effects of IL-15 on inducing inflammatory infiltration of macrophages in polymyositis (PM) through the NF-kB pathway, and whether IL-15 was able to further regulate MMP-9 expression levels. Prepared PM cells, collected from the patients suffering from PM, were administered to SD rats. Also, a group of healthy SD rats was undergoing the same treatment as the control group. The test animals were treated with either anti-IL-15, IL-15, MMP-9 siRNA or ERK1/2 inhibitor. The blood toxicological parameters creatine kinase (CK) and CD163 were tested by using ELISA and immunohistochemistry assay. In addition, NF-kB expression in macrophages was measured by immunocytochemical assay. To measure the degree of cell infiltration the Transwell assay was performed. Lastly, western blot and zymography were carried out to compare MMP-9 and ERK expression levels between the two groups, both in vivo and in vitro. The results showed that S-CK, IL-15 and IL-15Rα levels increased rapidly after the conventional treatment was introduced to the PM infected SD rats. The PM model establishment and IL-15 treatment significantly increased the expressions of IL-15Rα, MMP-9, p-ERK and p-IKBα. However, the same effect can be suppressed by using anti-IL-15, MMP-9 siRNA or ERK1/2 inhibitor (P < 0.05). In addition, IL-15 is proved to increase cell migration and nucleus expression of NF-kB in the macrophages. IL-15 is able to significantly regulate the inflammatory infiltration of macrophages in PM patients through affecting the NF-kB pathway and MMP-9 expression levels.

Chronic Polymyositis Associated with Disseminated Sarcocystosis in a Captive-born Rhesus Macaque

A 2–year-old, captive-born, clinically healthy male, rhesus macaque, was euthanatized as part of an experimental study. At necropsy, diffuse pale streaking of the trunk, lumbar, and limb muscles were noted macroscopically. On histology, numerous elongated cysts that contained crescent-shaped basophilic spores were found in the fibers of skeletal muscles. Scattered affected myofibers were degenerate and accompanied by eosinophilic-to-granulomatous inflammation. Sarcocysts had prominent villus-like projections with the morphology of a type 11 sarcocyst wall similar to Sarcocystis neurona but possessing many more villus microtubules than is reported for S. neurona. In addition, bradyzoites were very long, up to approximately 12 um in length. The protozoa were consistent with a Sarcocystis sp., based on histology and ultrastructure, however, a definitive identification of the species was not possible. Nonspecific immunohistochemical crossreaction with Sarcocystis cruzi antisera was observed. The 18S ribosomal deoxyribonucleic acid sequence showed 91% similarity to Sarcocystis hominis, 90% similarity to Sarcocystis buffalonis, and 89% similarity to Sarcocystis hirsuta. Interestingly, the ITSI sequence showed very little homology to any sequence in GenBank, suggesting that this is possibly a unique Sarcocystis sp. Sarcocystosis is often considered an incidental finding, particularly in wild-caught animals, with little clinical significance. However, as demonstrated in this report and others, disseminated sarcocystosis can occur in captive-born rhesus macaques with or without clinical signs. In some cases interference with research results can occur; including death in fulminant cases.

Autoantibodies in adult patients with idiopathic inflammatory myopathies in Buenos Aires

The idiopathic inflammatory myopathies(IIM) are a heterogeneous group of diseases of the skeletal muscle. On the basis of clinical, serologic and histological differences, they are classified in dermatomyositis (DM), polymyositis (PM), inclusion body myositis and immunomediated necrotizing myopathy. Autoantibodies directed against nuclear and cytoplasmic antigens are present with variable frequencies among studies. Myositis-specific antibodies (MSAs) are useful in IIM because they contribute to the diagnosis, help to identify different clinical subsets, and have prognostic value. This study aimed to explore the frequency of autoantibodies, especially MSAs, and their relationship with clinical features in adult patients with DM, PM and overlap syndrome. Medical records were reviewed. Myositis-associated antibodies (non-specific) and MSAs (anti Jo-1, PL-7, PL-12, Mi-2 and SRP) were measured using commercial kits. Twelve patients had MSAs, an overall frequency similar to those of international series, but PL-12 and Mi-2 were more frequent than Jo-1, which is the most frequently observed elsewhere. All five patients with Mi-2 had classical DM with a favorable response to treatment. Interstitial pneumonia (n: 4) and/or treatment-refractory disease (n: 3) were found in the presence of anti-PL-12, alone or associated with anti-SRP and/or Jo-1. In conclusion, the coexistence of AEM, a rare finding, was found in three patients. The presence of MSAs aided to the diagnosis of IIM, in particular in those patients without available or conclusive biopsy results.

[Relapses in inflammatory myopathies]

Most studies about treatment of inflammatory myopathies consist of cross-sectional analyses that do not assess long-term efficacy. In the present study we describe the follow-up of seven patients with inflammatory myopathies, 5 polymyositis and 2 dermatomyositis. We describe their clinical features, follow-up, muscle enzyme levels, and treatment responses. We define the latter as treatment cycles, every one of which end when steroid doses need to be increased or a new immunosuppressive drug has to be added because of clinical worsening or sustained increases in muscle enzyme levels. Treatment can cause remission, partially control, or fail in achieving myositis improvement when it normalizes, stabilizes, or does not affect muscle enzymes or clinical features, respectively. We analyzed 20 cycles, in which remission was achieved in 14 cases, partial control in 5 instances, and treatment failure in one case. Remission occurred after an average of 139 ± 98 days, whereas partial control took place in 160 ± 100 days. Except in one case, all treatment cycles controlled or remitted the symptoms. However, in all patients the illness recurred with time.

The Prevalence of Individual Histopathologic Features Varies according to Autoantibody Status in Muscle Biopsies from Patients with Dermatomyositis

OBJECTIVE

Individual dermatomyositis (DM)-associated autoantibodies are associated with distinct clinical phenotypes. This study was undertaken to explore the association of these autoantibodies with specific muscle biopsy features.

METHODS

DM subjects with a muscle biopsy reviewed at Johns Hopkins had sera screened for autoantibodies recognizing Mi-2, transcriptional intermediary factor 1-γ (TIF1-γ), NXP2, MDA5, Ro52, PM-Scl, and Jo1. We also included anti-Jo1–positive patients with polymyositis (PM) who had a biopsy read at Johns Hopkins. Analyzed histological features included perifascicular atrophy, perivascular inflammation, mitochondrial dysfunction, primary inflammation, and myofiber necrosis. Duration of disease, biopsy location, and treatment at biopsy were also analyzed.

RESULTS

We studied 91 DM and 7 anti-Jo1–positive patients with PM. In univariate analyses, TIF1-γ+ patients had more mitochondrial dysfunction (47% vs 18%; p = 0.05), NXP2+ patients had less primary inflammation (0% vs 28%; p = 0.01), Mi-2+ patients had more primary inflammation (50% vs 19%; p = 0.03), and PM-Scl+ patients had more primary inflammation (67% vs 18%; p = 0.004) than those who were negative for each autoantibody. Although reliability was limited because of small sample numbers, multivariate analysis confirmed that TIF1-γ+ patients had more mitochondrial dysfunction [prevalence ratio (PR) 2.6, 95% CI 1.0–6.5, p = 0.05] and PM-Scl+ patients had more primary inflammation (PR 5.2, 95% CI 2.0–13.4; p = 0.001) independent of disease duration at biopsy, biopsy site, and treatment at biopsy. No differences in muscle biopsy features were noted between anti-Jo1–positive patients diagnosed with DM and PM.

CONCLUSION

The prevalence of different histological features varies according to autoantibody status in DM. Muscle biopsy features are similar in anti-Jo1 patients with and without a rash.

The effect of prior corticosteroid use in muscle biopsies from patients with dermatomyositis

OBJECTIVES

The aim of this study was to evaluate the effect of prior corticosteroid (CS) use on the presence of inflammatory infiltrates (InI) in muscle biopsies from dermatomyositis (DM).

METHODS

Sixty-five muscle biopsy samples were obtained at the time of DM diagnosis. The patients were divided into the following three groups according to the degree of the InI present in the muscle biopsies: (I) minimal InI present only in an interstitial area (endomysium, perimysium) or in a perivascular area; (II) moderate InI in one or two areas of the interstitium or of the perivascular area; and (III) moderate InI throughout the interstitium or intense inflammation in at least one area of the interstitium or of the perivascular area.

RESULTS

All groups (I=17, II=16 and III=32) were comparable regarding the patient age at the time of the muscle biopsy, gender, ethnicity distribution, time interval between the muscle biopsy and the symptom onset, clinical manifestations, degree of muscle weakness, autoantibodies and serum muscle enzyme measurements (p<0.05). The median (interquartile) duration of CS use [7 (0-60), 6 (0-105) and 14 (0-30) days in groups I, II and III, respectively] and the median cumulative CS dose used [560 (0-2100), 1005 (0-2850) and 875 (0-2850) mg] were similar between the groups (p>0.05).

CONCLUSIONS

Previous CS use did not influence the presence or the degree of inflammatory infiltrates found in muscle biopsies in DM with clinical and laboratory disease activity. Therefore, muscle biopsies should be performed in this population, including patients currently undergoing CS therapy.

Does previous corticosteroid treatment affect the inflammatory infiltrate found in polymyositis muscle biopsies?

OBJECTIVES

The aim of the study was to evaluate the effect of the prior use of corticosteroids (CS) on the presence of inflammatory infiltrates (InI) in muscle biopsies of polymyositis (PM).

METHODS

We retrospectively evaluated 60 muscle biopsy samples that had been obtained at the time of the diagnosis of PM. The patients were divided into three groups according to the degree of the InI present in the muscle biopsies: (a) minimal InI present only in an interstitial area of the muscle biopsy (endomysium, perimysium) or in a perivascular area; (B) moderate InI in one or two areas of the interstitium or of the perivascular area; and (C) moderate InI throughout the interstitium or intense inflammation in at least one area of the interstitium or of the perivascular area.

RESULTS

The three groups were comparable regarding the demographic, clinical and laboratory features (p>0.05). Approximately half of the patients in each group were using CS at the time of the muscle biopsy. The median (interquartile) duration of CS use [4 (0-38), 4 (0-60) and 5 (0-60) days: groups A, B and C, respectively] and the median cumulative CS dose used [70 (0-1200), 300 (0-1470) and 300 (0-1800)mg] were similar between the groups (p>0.05).

CONCLUSIONS

Previous CS use did not influence the presence or the degree of InI found in muscle biopsies in PM with clinical and laboratory disease activity. Our study showed that muscle biopsies should be performed this population, even in individuals who have already been taking CSs.

Clinical values of FDG PET in polymyositis and dermatomyositis syndromes: imaging of skeletal muscle inflammation

OBJECTIVES

[(18)F] Fluorodeoxyglucose positron emission tomography (FDG PET), a standard tool for evaluating malignancies, can also detect inflammatory lesions. However, its usefulness in evaluating muscle lesions in polymyositis and dermatomyositis syndromes (PM/DM) has not been established.

METHODS

33 patients with PM/DM who had undergone FDG PET were retrospectively analysed. FDG uptake was visually evaluated (visually identified FDG uptake, vFDG) in 16 regions of the body using mediastinum blood vessels as a positivity criterion. We also calculated the maximum standardised uptake value (SUVmax) in all four limbs of the patients with PM/DM as well as in 22 patients with amyotrophic lateral sclerosis (ALS) with similar disabilities. In 24 patients with PM/DM, MRI and FDG PET findings were compared.

RESULTS

vFDG was observed in multiple muscle lesions with varying distributions in two-thirds of the patients with PM/DM, with most lesions being symmetrical. The number of vFDG-positive regions strongly correlated with the mean SUVmax in all four limbs (p<0.0001). Histological grades of biopsied muscles correlated with both the mean SUVmax and number of vFDG-positive regions. Serum creatine kinase levels were higher in patients with more than two vFDG-positive regions than in those with two or less regions (p<0.05). While the inflamed muscles showed diffused, patchy or marginal signal abnormalities on MRI, FDG uptake was most prominent inside the muscles. Compared with ALS, the mean SUVmax was significantly higher in the patients with PM/DM (p<0.0001) and showed a striking correlation in the bilateral muscles, reflecting symmetrical muscle involvement in PM/DM.

CONCLUSIONS

The visual assessment of FDG uptake as well as calculation of SUV enabled us to comprehensively evaluate skeletal muscle. This method can improve clinical practices and provide insights into pathomechanisms of PM/DM.

[Anti-signal recognition particle autoantibody positive myopathy]

Idiopathic inflammatory myopathies are systemic, autoimmune diseases characterized by proximal symmetrical muscle weakness. We review the myositis-associated and myositis-specific autoantibodies, among them the anti-SRP autoantibody. Among those autoimmune myopathy cases, that are associated with autoantibodies, we can detect anti-SRP autoantibody positive myositis cases. We describe the role of signal recognition particle, its structure and role in protein biosynthesis. We review how necrotizing autoimmune myopathy is identified, and the differences from classical polymyositis. The anti-SRP titer correlates with disease activity. We present some cases to show how the disease appears in childhood and also some rare cases from the literature. Finally we present a case to draw attention to the importance of this disease.

Activated IL-22 pathway occurs in the muscle tissues of patients with polymyositis or dermatomyositis and is correlated with disease activity

OBJECTIVE

The aim of this study was to assess the expression of IL-22, IL-22 receptor 1 (IL-22R1), IL-22 binding protein (IL-22BP) and p-STAT3 in muscle tissue from patients with PM and DM.

METHODS

Levels of IL-22, IL-22R1, IL-22BP and STAT3 mRNA were quantified by RT-PCR. The expression of IL-22, IL-22R1, IL-22BP and p-STAT3 was also analysed using immunohistochemistry.

RESULTS

Significant modulation of the IL-22 pathway was observed in inflammatory myopathic tissues. In particular, a significant overexpression of IL-22 at the protein but not the mRNA level was observed in PM/DM tissues and was correlated with myositis activity. IL-22R1 aberrant expression was also observed among infiltrating mononuclear cells and necrotic muscle cells. IL-22BP, which inhibits IL-22 signalling, was expressed only in some muscle fibres in PM/DM patients.

CONCLUSION

Our findings indicate that the IL-22 pathway is activated in inflammatory myopathic tissues and may be involved in the induction of muscle inflammatory processes and muscle necrosis.

[A multi-center retrospective study of organ involvement in adult patients with polymyositis or dermatomyositis]

OBJECTIVE

To explore the prevalence and characteristics of main organ involvement in adult patients with polymyositis (PM) or dermatomyositis (DM) and determine their specific relative factors.

METHODS

Using unified questionnaire, we retrospectively collected the medical records of 1 387 confirmed adult PM/DM patients from 2007 to 2012 at 22 rheumatology centers in China. Statistical analyses were performed with chi-square or Fisher exact test and multivariate analyses with logistic regression.

RESULTS

A total of 1 387 patients were collected with 460 (33.2%) PM and 927 (66.8%) DM. The female:male ratio was 2.4: 1. Their onset age was ( 47 ± 14) years. A total of 1 031 (74.3%) patients had organ involvement. The prevalence of pulmonary involvement, arthritis, gastrointestinal and cardiac involvement were 44.6%, 32.3%, 21.9% and 20.3% respectively. The multivariate analysis indicated that older onset age (P < 0.01) was positively associated with pulmonary involvement while myalgia (P < 0.05) was negatively associated. Fever (P < 0.05), weight loss (P < 0.05) and Raynaud's phenomenon (P < 0.01) were positively associated with arthritis while muscle weakness (P < 0.05) negatively associated. Weight loss (P < 0.05), Raynaud's phenomenon (P < 0.01) and muscle weakness (P < 0.05) were positively associated with gastrointestinal involvement. Weight loss (P < 0.05) and swollen limbs (P < 0.05) were positively associated with cardiac involvement.

CONCLUSION

The prevalence of organ involvement is high in adult PM/DM patients. Our study may aid the diagnosis of organ damage in PM/DM patients.

[Idiopathic inflammatory myopathies: main clinical and immunological variants, difficulties of differential diagnostics and therapy]

Idiopathic inflammatory myopathies are rare autoimmune diseases with inflammatory lesions in skeletal muscles. They include polymyositis, dermatomyositis, juvenile myositis and inclusion body myositis. These are clinically and immunologically heterogeneous conditions differently responding to therapy. The authors consider the main manifestations of polymyositis/dermatomyositis and principal differences between them. Therapy is based on the prescription of glucocorticoids in combination with immunesuppressors. Better understanding immunological, genetic, and molecular mechanisms opens up new prospects for the management of idiopathic inflammatory myopathies.

[Myositis and the skin: cutaneous manifestations of dermatomyositis]

Idiopathic inflammatory myopathies include dermatomyositis, polymyositis, and inclusion body myositis. Among them, cutaneous manifestations are observed most frequently in dermatomyositis. While dermatomyositis commonly affects the skin and muscles, it can also affect the lungs and other organs. Dermatomyositis presenting clinically and histopathologically with typical cutaneous lesions, but without myositis, is called amyopathic dermatomyositis. Given that the Bohan and Peter criteria cannot distinguish amyopathic dermatomyositis, understanding the characteristic skin manifestations may be essential for diagnosing this condition. The cutaneous manifestations of dermatomyositis are thought to be the result of the Koebner phenomenon, vasculopathy, or photosensitivity; manifestations include various eruptions, such as heliotrope rush, Gottron's sign, Gottron's papules, mechanic's hand, nail-fold bleeding, skin ulcer, vasculitis, flagellate erythema, V-sign, and Shawl sign. The presence of multiple types of eruptions can help diagnose the disease. Several skin diseases, including adult Still's disease, contact dermatitis, and sarcoidosis, can mimic the cutaneous manifestations of dermatomyositis. Skin biopsy is useful for differential diagnoses. Histopathologically, dermatomyositis of the skin is characterized by liquefaction degeneration, vacuolar degeneration, edema, and mucin deposition. Dermatologists, neurologists, and rheumatologists are responsible for the diagnosis and management of dermatomyositis, in cooperation with pulmonologists, pediatricians, and pathologists. This review aims to provide clinicians with recent findings regarding skin involvement in dermatomyositis.

Cardiac metastasis and tumor embolism in a patient with adenocarcinoma of the colon presenting with paraneoplastic polymyositis

Colorectal cancer usually presents with alterations in the bowel habit. Less commonly, the presenting symptoms may be part of a paraneoplastic syndrome. Metastasis can occur by lymphatic or hematogenous spread, most frequently to the lungs and liver. We present the case of a 56-year-old man admitted with paraneoplastic polymyositis due to a poorly differentiated colon adenocarcinoma. The evolution was unfavorable with death on the 19th day following admission due to pulmonary thromboembolism and subsequent pulmonary edema. Autopsy showed micrometastases with lymphatic and venous emboli to the heart, liver, kidney, adrenal gland and lung. The case highlights the diversity of manifestation that can occur in a colon adenocarcinoma.

Primary cutaneous undifferentiated round cell tumor with concurrent polymyositis in a dog

A cutaneous poorly differentiated round cell tumor with concurrent, non-suppurative, polymyositis was diagnosed in a hovawart dog. Histochemical staining, immunohistochemistry, and transmission electron microscopy findings suggested that the tumors cells were of myeloid, or possibly natural killer cell origin. The possibility that the concurrent polymyositis may represent a pre-neoplastic or paraneoplastic process is discussed.

[Overlap syndrome]

The overlap syndromes are characterized by the occurrence in the same patient of two or more autoimmune diseases. The overlap syndrome between scleroderma and polymyositis is rare. We describe a case of a 58-year-old woman in which the clinical expression, the effect of therapy and the evolution, support the concept that this syndrome is a distinct clinical entity in the spectrum of autoimmune disease.

Polymyositis presenting with respiratory failure

Polymyositis is a systemic autoimmune disorder characterised by inflammatory myopathy of the skeletal muscles predominantly affecting the proximal muscles and associated with extra-muscular manifestations like dysphagia and skin involvement. In this case report, we describe the occurrence of diaphragmatic weakness and respiratory failure due to polymyositis with relatively well preserved power in limb muscles.

Magnetic resonance imaging of inflammatory myopathies

The following article reviews the role of magnetic resonance imaging (MRI) in patients with idiopathic inflammatory myopathies (IIMs), focusing on the 3 major types of IIM: polymyositis, dermatomyositis, and inclusion-body myositis. After a brief introduction with general information about IIM, we will discuss the reasons why MRI plays an important role in the diagnosis and management of patients with polymyositis, dermatomyositis, and inclusion-body myositis. Magnetic resonance imaging can confirm the diagnosis and can help to phenotype the disease. Moreover, the support of MRI is important in addressing the muscle biopsy site and in reducing the high false-negative rate of biopsy when performed in a blind fashion. In monitoring therapy, MRI can add important information about the activity of the muscle disease and can identify cases where continued immunosuppressive therapy is no longer warranted owing to complete fatty replacement of the muscles. Lastly, we provide an overview about some advanced MRI techniques that focus more on function than on morphology of muscle.

Immunolocalization of protein-bound 3-nitrotyrosine in inflammatory myopathies

3-nitrotyrosine (3NT) is regarded as a "footprint" of nitric oxide generation. The study aimed at documenting the presence and distribution of 3-nitrotyrosine (3NT) in muscle tissue samples from patients with idiopathic inflammatory myopathies (IIM) as well as from those with non-inflammatory myopathies to consider whether polymyositis (PM) and dermatomyositis (DM) could be distinguished based on 3NT immunohistochemistry in muscle biopsy. Cryosections prepared from muscle biopsies of 54 patients with either IIM, i.e., PM and DM, or various non-inflammatory myopathies were immunostained using monoclonal antibody against 3NT. The 3NT immunostaining was localized to endothelial cells and their close surroundings in muscle biopsies of DM and PM patients but only in those areas of tissue sections where inflammatory cell infiltrates were present. No 3NT positivity was found in tissue sections of IIM patients without inflammatory infiltrates in the studied sample as well as in muscle tissue sections of patients with non-inflammatory myopathies. However, the endothelial cells were also positive in cases of confirmed non-inflammatory myopathies with secondary lymphocytic infiltration (myodystrophies, myasthenia gravis). Despite the pathogenetic significance, the 3NT immunohistochemistry is of low diagnostic value for the differential diagnosis of IIM in muscle biopsy.

Expression of B7-homolog 1 in Polymyositis

OBJECTIVES

Costimulatory molecules are increasingly recognized as crucial for stimulation and/ or inhibition of immune responses. The present study was undertaken to examine the expression and functional relevance of B7-homolog 1 (B7-H1) attributed significant immunoregulatory functions in polymyositis in vivo.

METHODS

43 muscle biopsy specimens obtained from patients with polymyositis, 26 cases with limb girdle muscular dystrophies (LGMD) 2B and 21 normal muscle samples were analyzed by immunohistochemistry for B7-H1 expression. The clinical and histopathologic data were analyzed.

RESULTS

B7-H1 was not detectable on normal muscle fibers and rarely detectable from patients with LGMD-2B. In contrast, its expression was markedly increased on muscle fibers from patients with polymyositis, even after short-term immunosuppressive treatment. Positive staining mainly localized at the surface of the muscle tissue, rarely in the cytoplasm, focused in areas where inflammatory cells lay in close apposition to damaged, necrotic or degenerative muscle fibers. The expression of B7-H1 was correlated to the degrees of muscular necrosis and clinical muscular strength.

CONCLUSION

Our results demonstrate that human muscle cells express B7-H1 in polymyositis. The muscle-related expression of B7-H1 may be helpful in the diagnosis of polymyositis and might be an indicator of prognosis of polymyositis.

Polymyositis in African HIV-infected subjects

Polymyositis in HIV-infected subjects, clinically and pathologically resemble polymyositis in non-HIV-infected subjects. We report 14 consecutive HIV-associated polymyositis cases and compare specific features with 25 polymyositis cases seen over the same 6.5 year period. The HIV-polymyositis cases were all female and compared to the polymyositis cases were younger (median age 33 years, interquartile range (IQR) 29; 37 vs. 46 years, IQR 38; 52, p=0.002), and with 4-fold lower serum creatine kinase (CK) values (median 1158 vs. 5153IU/l; p=0.019). A definite clinical improvement on prednisone therapy was documented in eight HIV-polymyositis cases and one improved with anti-retroviral therapy alone. The recognition of HIV-polymyositis which is treatable, but may present with serum CK elevations less than twofolds above normal, is clinically relevant in sub-Saharan Africa where electromyography and muscle biopsies are not readily available.

[An autopsied case of giant cell myocarditis and myositis associated with invasive thymoma]

A 75-year-old man was given a diagnosis of invasive thymoma (WHO type B3, stage IVa) in 2004. He received 8 cycles of chemotherapy with doxorubicin, vincristin, cyclophosphamide and cisplatin from November 2004 to May 2005, combined thoracic radiotherapy (total dosage 60 Gy) in April 2006, and 2 cycles of chemotherapy with carboplatin and paclitaxel from July 2008 to August 2008. He was readmitted to our hospital complaining of fever and neck pain in September 2008. Laboratory data on admission revealed elevated serum levels of CRP, GOT, GPT, LDH, CK, and troponin-I with hypo gamma-globulinemia. Although he received immunoglobulin and antibiotic therapy, he suddenly died of cardiac shock on the 9th hospital day. On postmortem examination of the myocardium, the skeletal muscles of the neck and iliopsoas muscle showed inflammatory cell infiltration containing multinucleated giant cells with degeneration and necrosis of the muscle tissues. These findings were consistent with giant cell myocarditis with polymyositis. Autopsy findings suggested that sudden death was caused by giant cell myocarditis, probably associated with invasive thymoma.

Central and peripheral demyelination with immune polymyositis in a patient with Bardet Biedl syndrome

We report extremely rare combination of central and peripheral demyelination with immune polymyositis in a patient with Bardet-Biedl syndrome. The inciting factor postulated was mycoplasma pneumonia infection.

Malignancy is associated with dermatomyositis but not polymyositis in Northern New England, USA

OBJECTIVE

To retrospectively evaluate the association of idiopathic inflammatory myopathy (IIM) and malignancy in patients seen at 1 academic center over a 23-year period.

METHODS

Patients were identified using the International Classification of Diseases, 9th edition (ICD-9) codes and diagnoses, then confirmed by chart review. Population cancer statistics obtained from the US Centers for Disease Control for Vermont and New Hampshire were used for comparison.

RESULTS

Chart review confirmed IIM in 198 of 483 patients initially identified by ICD-9 codes. Within 5 years of diagnosis with IIM, malignancy developed in 32 patients (16.2%), 24 of whom (75%) had dermatomyositis (DM). Malignancy and DM developed within 1 year in 75%. The cancer risk associated with DM was much greater than the risk associated with other IIM. The most frequent tumor types were breast, lung, pancreas, and colon. DM patients with cancer were more frequently male and >or= 45 years of age than those without cancer. There were no cases of interstitial lung disease among patients with cancer and any form of IIM. The incidence of cancer was increased in patients with DM compared to age- and sex-matched population controls, both over a 5-year interval surrounding the diagnosis of DM and over the lifetime interval following diagnosis.

CONCLUSION

The risk of cancer in IIM is concentrated among patients with DM. The association between DM and cancer was enhanced by its temporal relationship (< 1 year) in 87.5% of these cases. Patients with malignancy-associated DM were more frequently male and over age 45 and less likely to have interstitial lung disease.

Differential immunohistological features of inflammatory myopathies and dysferlinopathy

This study was performed in order to characterize the types of the infiltrating cells, and the expression profiles of major histocompatibility complex (MHC) class I and membrane attack complex (MAC) in patients with inflammatory myopathies and dysferlinopathy. Immunohistochemical stains were performed using monoclonal antibodies against several inflammatory cell types, MHC class I, and MAC in muscles from inflammatory myopathies and dysferlinopathy. There was significant difference in the types of infiltrating cells between polymyositis (PM), dermatomyositis (DM), and dysferlinopathy, including significantly high CD4+/CD8+ T cell ratio and B/T cell ratio in DM. In dysferlinopathy, CD4+ T cells were the most abundant and the proportions of infiltrating cell types were similar to those of DM. MHC class I was expressed in muscle fibers of PM and DM regardless of the presence of inflammatory infiltrates. MAC was expressed in necrotic fibers and vessels of PM and DM. One patient with early stage DM had a MAC deposits on endomysial capillaries. In dysferlinopathy, MAC deposit was also observed on the sarcolemma of nonnecrotic fibers. The analysis of inflammatory cells, MHC class I expressions and MAC deposits may help to differentiate dysferlinopathy from idiopathic inflammatory myopathy.

[Medical case of successful therapy of polymyositis by high doses of glucocorticoid]

Questions of diagnostics and treatment of dermatomyositis-polymyositis in literature are contradictory character. They have scanty description of peculiarities of course of this pathology by men of young and certain age, and character of complications, connected with long ingestion of corticosteroid agents. Medical case, done in the article, is of great interest undoubtedly. By reason of using corticosteroid agents, the patient get a complex of specific complications, but pains in muscles, fever, arthralgia, weakness have disappeared. There was made a decision about speeded decreasing of dose of hormonal agent to 8 mg per day for the term pf 3 months in alternative session with parallel ingestion of disaggregants. On this base was marked epilosis of bioptic damage, was achieved recanalization of deep viens of left leg, was normalized carbohydrate metabolism, generalclinic analyze of blood, transaminase level, body weight was decreased. Now-days it's marked a clinical-laboratorial remission, not requiring a supplying corticosteroid therapy.

MHC class I and II expression in juvenile dermatomyositis skeletal muscle

OBJECTIVE

To assess MHC I and II expressions in muscle fibres of juvenile dermatomyositis (JDM) and compare with the expression in polymyositis (PM), dermatomyositis (DM) and dystrophy.

PATIENTS AND METHODS

Forty-eight JDM patients and 17 controls (8 PM, 5 DM and 4 dystrophy) were studied. The mean age at disease onset was 7.1+/-3.0 years and the mean duration of weakness before biopsy was 9.4+/-12.9 months. Routinehistochemistry and immunohistochemistry (StreptABComplex/HRP) for MHC I and II (Dakopatts) were performed on serial frozen muscle sections in all patients. Mann-Whitney, Kruskal Wallis, chi-square and Fisher's exact statistical methods were used.

RESULTS

MHC I expression was positive in 47 (97.9%) JDM cases. This expression was observed independent of time of disease, corticotherapy previous to muscle biopsy and to the grading of inflammation observed in clinical, laboratorial and histological parameters. The expression of MHC I was similar on JDM, PM and DM, and lower in dystrophy. On the other hand, MHC II expression was positive in just 28.2% of JDM cases and was correlated to histological features as inflammatory infiltrate, increased connective tissue and VAS for global degree of abnormality (p<0.05). MHC II expression was similar in DM/PM and lower in JDM and dystrophy, and it was based on the frequency of positive staining rather than to the degree of the MCH II expression.

CONCLUSIONS

MHC I expression in muscle fibres is a premature and late marker of JDM patient independent to corticotherapy, and MHC II expression was lower in JDM than in PM and DM.