Diagnosis Of Inclusion Body Myositis Research Articles

Syndrome de Sjögren et anticorps anti-cN1A

AbstractSince their discovery in 2013, anti-5’nucleotidase 1A (anti-cN1A) antibodies have been the subject of numerous publications to assess their sensitivity and diagnostic specificity. Currently used as an aid in the diagnosis of inclusion body myositis for which their specificity is good, they can be detected in other autoimmune diseases and in particular in Sjögren’s Syndrome. Their prevalence, which is significant during this disease, decreases diagnostic performance in patients with both myositis and Sjögren’s Syndrome. Anti-cN1A antibodies may also have a prognostic role during SGS.

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

Inclusion body myositis is the most common progressive muscle wasting disease in people older than 50 years, with no effective drug treatment. Arimoclomol is an oral co-inducer of the cellular heat shock response that was safe and well-tolerated in a pilot study of inclusion body myositis, reduced key pathological markers of inclusion body myositis in two in-vitro models representing degenerative and inflammatory components of this disease, and improved disease pathology and muscle function in mutant valosin-containing protein mice. In the current study, we aimed to assess the safety, tolerability, and efficacy of arimoclomol in people with inclusion body myositis. This multicentre, randomised, double-blind, placebo-controlled study enrolled adults in specialist neuromuscular centres in the USA (11 centres) and UK (one centre). Eligible participants had a diagnosis of inclusion body myositis fulfilling the European Neuromuscular Centre research diagnostic criteria 2011. Participants were randomised (1:1) to receive either oral arimoclomol 400 mg or matching placebo three times daily (1200 mg/day) for 20 months. The randomisation sequence was computer generated centrally using a permuted block algorithm with randomisation numbers masked to participants and trial staff, including those assessing outcomes. The primary endpoint was the change from baseline to month 20 in the Inclusion Body Myositis Functional Rating Scale (IBMFRS) total score, assessed in all randomly assigned participants, except for those who were randomised in error and did not receive any study medication, and those who did not meet inclusion criteria. Safety analyses included all randomly assigned participants who received at least one dose of study medication. This trial is registered with ClinicalTrials.gov, number NCT02753530, and is completed. Between Aug 16, 2017 and May 22, 2019, 152 participants with inclusion body myositis were randomly assigned to arimoclomol (n=74) or placebo (n=78). One participant was randomised in error (to arimoclomol) but not treated, and another (assigned to placebo) did not meet inclusion criteria. 150 participants (114 [76%] male and 36 [24%] female) were included in the efficacy analyses, 73 in the arimoclomol group and 77 in the placebo group. 126 completed the trial on treatment (56 [77%] and 70 [90%], respectively) and the most common reason for treatment discontinuation was adverse events. At month 20, mean IBMFRS change from baseline was not statistically significantly different between arimoclomol and placebo (-3·26, 95% CI -4·15 to -2·36 in the arimoclomol group vs -2·26, -3·11 to -1·41 in the placebo group; mean difference -0·99 [95% CI -2·23 to 0·24]; p=0·12). Adverse events leading to discontinuation occurred in 13 (18%) of 73 participants in the arimoclomol group and four (5%) of 78 participants in the placebo group. Serious adverse events occurred in 11 (15%) participants in the arimoclomol group and 18 (23%) in the placebo group. Elevated transaminases three times or more of the upper limit of normal occurred in five (7%) participants in the arimoclomol group and one (1%) in the placebo group. Tubulointerstitial nephritis was observed in one (1%) participant in the arimoclomol group and none in the placebo group. Arimoclomol did not improve efficacy outcomes, relative to placebo, but had an acceptable safety profile in individuals with inclusion body myositis. This is one of the largest trials done in people with inclusion body myositis, providing data on disease progression that might be used for subsequent clinical trial design. US Food and Drug Administration Office of Orphan Products Development and Orphazyme.

Anti-Cytosolic 5'-Nucleotidase 1A in the Diagnosis of Patients with Suspected Idiopathic Inflammatory Myopathies: An Italian Real-Life, Single-Centre Retrospective Study.

Anti-cytosolic 5'-nucleotidase 1A (anti-cN1A) antibodies were proposed as a biomarker for the diagnosis of inclusion body myositis (IBM), but conflicting specificity and sensitivity evidence limits its use. Our study aimed to assess the diagnostic accuracy of anti-cN1A in a cohort of patients who underwent a myositis line immunoassay for suspected idiopathic inflammatory myopathies (IIM). We also assessed the agreement between two testing procedures: line immunoassay (LIA) and enzyme-linked immunoassay (ELISA). We collected retrospective clinical and serological data for 340 patients who underwent a myositis antibody assay using LIA (EUROLINE Autoimmune Inflammatory Myopathies 16 Ag et cN-1A (IgG) line immunoassay) and verification with an anti-cN1A antibody assay using ELISA (IgG) (Euroimmun Lubeck, Germany). The serum samples of 20 (5.88%) patients (15 females, 5 males, mean age 58.76 ± 18.31) tested positive for anti-cN1A using LIA, but only two out of twenty were diagnosed with IBM. Seventeen out of twenty tested positive for anti-cN1A using ELISA (median IQR, 2.9 (1.9-4.18)). Our study suggests excellent concordance between LIA and ELISA for detecting anti-cN1A antibodies. LIA may be a rapid and useful adjunct, and it could even replace ELISA for cN1A assay. However, the high prevalence of diseases other than IBM in our cohort of anti-cN1A-positive patients did not allow us to consider anti-cN1A antibodies as a specific biomarker for IBM.

A Case of Inclusion Body Myositis with Clinical, Pathological and Serological Consideration

Inclusion body myositis is a rare condition of idiopathic inflammatory myopathy. Prior criteria for the diagnosis of inclusion body myositis essentially required pathological features of rimmed vacuoles, tubulofilamentous inclusions, and amyloid deposits. However, recently developed new diagnostic criteria emphasize clinical characteristics including weakness of finger flexors and knee extensors. In addition, a serological evaluation of anti-cN1A antibody is helpful for the diagnosis. We report a case of inclusion body myositis with clinical, pathological, and serological consideration.

Imaging beyond muscle magnetic resonance imaging in inclusion body myositis.

Diagnosis of inclusion body myositis (IBM), the most common acquired muscle disorder in adults above the age of 40, remains dependent on demonstration of the classic clinical phenotype and confirmed by muscle histopathological examination. The European Neuromuscular Centre (ENMC) 2011 diagnostic criteria for the diagnosis of IBM includes the demonstration of one or more of the muscle pathological findings - inflammation, vacuolation or protein aggregation. Muscle biopsy is an invasive procedure and patients often require more than one biopsy to establish a definitive diagnosis of IBM. Over the past few years, there has been considerable gain in knowledge regarding various imaging modalities that may complement the diagnosis of IBM, and in some cases have the potential to obviate the need for more invasive procedures, such as muscle biopsy. Positron emission tomography (PET) using different ligands may serve as a surrogate biomarker of therapeutic target engagement in IBM. This review concentrates on a critical evaluation of the literature looking at the utility of muscle ultrasound, dual energy x-ray absorptiometry (DEXA), and positron emission tomography and their role in IBM.

An Italian Multicenter Study on Anti-NXP2 Antibodies: Clinical and Serological Associations

The identification of anti-NXP2 antibodies is considered a serological marker of dermatomyositis (DM), with calcinosis, severe myositis and, in some reports, with cancer. Historically, these associations with anti-NXP2 antibodies have been detected by immunoprecipitation (IP), but in the last few years commercial immunoblotting assays have been released. The aim of this collaborative project was to analyse the clinical features associated to anti-NXP2 antibodies, both with commercial line blot (LB) and IP. Myositis-specific and myositis-associated autoantibodies were detected in single centres by commercial line blot (LB); available sera were evaluated in a single centre by protein and RNA immunoprecipitation (IP), and IP-Western blot. Sixty patients anti-NXP2+ (NXP2+) positive by LB were compared with 211 patients anti-NXP2 negative with idiopathic inflammatory myositis (IIM). NXP2+ showed a younger age at IIM onset (p = 0.0014), more frequent diagnosis of dermatomyositis (p = 0.026) and inclusion-body myositis (p = 0.009), and lower rate of anti-synthetase syndrome (p < 0.0001). As for clinical features, NXP2+ more frequently develop specific skin manifestations and less frequently features related with overlap myositis and anti-synthetase syndrome. IP confirmed NXP2 positivity in 31 of 52 available sera (62%). Most clinical associations were confirmed comparing NXP2 LB+/IP+ versus NXP2-negative myositis, with the following exceptions: inclusion-body myositis diagnosis was not detected, whilst dysphagia and myositis were found more frequently in NXP2 LB+/IP+ patients. The 21 LB+ /IP-myositis patients did not show differences in clinical features when compared with the NXP2-myositis patients and more frequently displayed multiple positivity at LB. Risk of developing cancer-associated myositis was similar between NXP2-positive and NXP2-negative myositis patients, either when detected by LB or IP. Protein-IP confirmed NXP2 antibodies in nearly 60% of sera positive for the same specificity with commercial assay. Double-positive cases rarely occurred in myositis patients with a clinical diagnosis other than dermatomyositis. Patients only positive by LB (LB+/IP−) did not display clinical features typical of NXP2. NXP2 positivity by LB should be confirmed by other methods in order to correctly diagnose and characterize patients affected by idiopathic inflammatory myositis.

Diagnostic Accuracy of Anti-CN1A on the Diagnosis of Inclusion Body Myositis. A Hierarchical Bivariate and Bayesian Meta-analysis.

Sporadic inclusion body myositis (IBM) is an acquired muscle disease and the most common idiopathic inflammatory myopathy over the age of 50. It is characterized by male predominance, with a prevalence rate between 1 and 71 cases per million, reaching 139 cases per million over the age of 50 globally. The diagnosis of IBM is based on clinical presentation and muscle biopsy findings. However, there is increasing evidence for the role of genetics and serum biomarkers in supporting a diagnosis. Antibodies against the cytosolic 5'-nucleotidase 1A (Anti-CN1A), an enzyme catalyzing the conversion of adenosine monophosphate into adenosine and phosphate and is abundant in skeletal muscle, has been reported to be present in IBM and could be of crucial significance in the diagnosis of the disease. In this study, we investigated the diagnostic accuracy of anti-CN1A antibodies for sporadic IBM in comparison with other inflammatory myopathies, autoimmune disorders, motor neurone disease, using a hierarchical bivariate approach, and a Bayesian model taking into account the variable prevalence. The results of the present analysis show that anti-CN1A antibodies have moderate sensitivity, and despite having high specificity, they are not useful biomarkers for the diagnosis of IBM, polymyositis or dermatomyositis, other autoimmune conditions, or neuromuscular disorders. Neither the hierarchical bivariate nor the Bayesian analysis showed any significant usefulness of anti-CN1A antibodies in the diagnosis of IBM.

Sirolimus for treatment of patients with inclusion body myositis: a randomised, double-blind, placebo-controlled, proof-of-concept, phase 2b trial.

Inclusion body myositis is the most frequent myositis in patients older than 50 years. Classical immunosuppressants are ineffective in treating inclusion body myositis, and to date there are no recommendations for pharmacological approaches to treatment. When used after organ transplantation, sirolimus can block the proliferation of effector T cells, while preserving T regulatory cells, and induce autophagy, all of which are processes that are impaired in inclusion body myositis. In this pilot study, we aimed to test the efficacy of sirolimus in patients with inclusion body myositis. This randomised, double-blind, placebo-controlled, proof-of-concept, phase 2b trial was done at a single hospital in Paris, France. The study included men and women (aged 45-80 years) who had a defined diagnosis of inclusion body myositis according to established criteria. Eligible participants were randomly assigned (1:1) to receive once-daily oral sirolimus 2 mg or placebo. Centralised balanced block randomisation (blocks of four) was computer generated without stratification. The study comprised a 15-day screening period (days -15 to 0) and a 52-week treatment period (day 0 to month 12). The primary endpoint was the relative percentage change from baseline to month 12 in maximal voluntary isometric knee extension strength. Secondary endpoints included the following assessments at months 6 and 12: 6-min walking distance, isometric muscle strength for hand grip (finger flexors), knee flexion and elbow flexion and extension, forced vital capacity, muscle replacement with fat measured by quantitative nuclear MRI, Inclusion Body Myositis Weakness Composite Index (IBMWCI), Inclusion Body Myositis Functional Rating Scale (IBMFRS), Health Assessment Questionnaire without Disability Index (HAQ-DI), and analyses of T-cell subpopulations by mass cytometry. The primary analysis was done on the intention-to-treat population. The trial is registered at ClinicalTrials.gov, NCT02481453. Between July 15, 2015, and May 13, 2016, we screened 285 patients, 44 of whom were randomly allocated to sirolimus (22 patients) or placebo (22 patients). We observed no difference in the primary outcome of relative percentage change from baseline to month 12 of the maximal voluntary isometric knee extension strength (median difference 3·78, 95% CI -10·61 to 17·31; p=0·85). For secondary outcomes, differences between the groups were not significant for changes in strength of other muscle groups (grip, elbow flexion and extension, or knee flexion), IBMWCI, IBMFRS, and lower limb muscle fat fraction. However, we observed significant differences in favour of sirolimus between the study groups for HAQ-DI, forced vital capacity, thigh fat fraction, and 6-min walking distance. Ten (45%) of 22 patients in the sirolimus group had a serious adverse event compared with six (27%) of 22 patients in the placebo group. Four (18%) patients in the sirolimus group stopped their treatment because of adverse events (severe mouth ulcers, aseptic pneumonia, renal insufficiency, and peripheral lower limb oedema), which resolved after treatment discontinuation. Canker sores were the most frequent side-effect and were mainly mild or moderate in ten patients. We found no evidence for efficacy of sirolimus for treating inclusion body myositis based on maximal voluntary isometric knee extension strength and other muscle strength measures, and the side-effects of treatment were substantial for some patients. However, we believe there was enough evidence of benefit in certain secondary outcomes to pursue a multicentre phase 3 trial to further assess the safety and efficacy of sirolimus. Institut national de la santé et de la recherche médicale, Direction générale de l'offre de soins, and Association Française contre les Myopathies.

Ultrasound can differentiate inclusion body myositis from disease mimics.

IntroductionThe diagnosis of inclusion body myositis (IBM) can be challenging, and its presentation can be confused with other forms of myositis or neuromuscular disorders. In this study we evaluate the ability of quantitative muscle ultrasound to differentiate between IBM and mimicking diseases.MethodsPatients 50 years of age and older were included from two specialty centers. Muscle echogenicity and muscle thickness of four characteristically involved muscles in IBM were measured and compared with polymyositis (PM)/dermatomyositis (DM), other neuromuscular disorders, and healthy controls.ResultsEchogenicity was higher and muscle thickness generally lower in all four muscles in IBM compared with PM/DM and normal controls. When comparing IBM with the comparator groups, the flexor digitorum profundus was the most discriminative muscle.DiscussionUltrasound appears to be a good test to differentiate established IBM from PM/DM and neuromuscular controls, with value as a diagnostic tool for IBM.

Difficulties in the Diagnosis of Inclusion Body Myositis-Case Report

Abstract Inclusion body myositis belongs to the group of idiopathic inflammatory myopathies. Two processes, one autoimmune and the other degenerative, appear to occur in parallel. There are two forms of inclusion body myositis, hereditary and sporadic. Case report: 47-year-old woman with muscle weakness and atrophy of the distal and proximal muscles, and involvement of quadriceps and deep finger flexors was admitted for neuromuscular evaluation. These changes have been started gradually and insidiously over three years. Electromyography findings were nonspecific and for this reason in the beginning of the disease it was misdiagnosed as demyelization peripheral neuropathy. Muscle biopsy, with the presence of characteristic structures such as rimmed vacuoles and amyloid deposits definitely confirmed the diagnosis of inclusion body myositis. Conclusion: There are several difficulties in the diagnosis of inclusion body myositis as nonspecific EMG findings and overreliance on electrophysiology and lack of the cardinal histological features in muscle biopsy. Although this disease is rare and incurable, making the correct diagnosis is crucial to directing the patient to physical therapy for weakness and occupational therapy to improve a patient’s ability in activities of daily living.

[18F]Florbetapir positron emission tomography: identification of muscle amyloid in inclusion body myositis and differentiation from polymyositis

ObjectivesWith the tools available currently, confirming the diagnosis of inclusion body myositis (IBM) can be difficult. Many patients are initially misdiagnosed with polymyositis (PM). In this observational study at a...

Usefulness of cytoplasmic 5’ - nucleotidase 1A autoantibodies for the diagnosis of inclusion body myositis

Background: Recently, autoantibodies against NT5C1A were known to be positive in some IBM patients. Diagnosing IBM is a key to avoid unnecessary long-term steroids. It is important to assess the diagnostic usefulness of anti-NT5C1A autoantibody for differentiating IBM from other myositis.

Predictors of Reduced Health-Related Quality of Life in Adult Patients With Idiopathic Inflammatory Myopathies.

Extensive studies on health-related quality of life (HRQoL) in idiopathic inflammatory myopathies (IIMs) are lacking. Our objective was to document HRQoL and to identify factors associated with a reduced HRQoL in patients with IIM. A total of 1,715 patients (median age 49.9 years, 70% female, 87% white) who met probable or definite Bohan and Peter criteria or Griggs criteria for myositis were included from the Myovision registry. HRQoL was ascertained using the Short Form 12 (SF-12) health survey questionnaire. HRQoL physical component summary (PCS) and mental component summary (MCS) scores in relation to different patient and disease characteristics were compared to scores from matched normative data from the US general population and rheumatoid arthritis (RA) patients. Bivariate and multiple linear regression analyses were performed to assess the association between HRQoL and patient and disease parameters. The mean SF-12 summary scores were significantly lower in IIM patients than in the normative and RA populations. A diagnosis of inclusion body myositis, older age, patient-reported negative effect of disease on work, presence of another co-occurring autoimmune disease, polypharmacy, and IIM-associated lung disease and joint involvement were significantly associated with lower PCS scores. Lower MCS scores were associated with joint involvement and a negative effect of disease on work. In this large study of patient-reported outcomes in IIM, an association was found between multiple disease characteristics and reduced HRQoL, mostly in the physical domain. In the US, the HRQoL of IIM patients was found to be lower than that of the general population and RA patients.

Disease specificity of autoantibodies to cytosolic 5′-nucleotidase 1A in sporadic inclusion body myositis versus known autoimmune diseases

ObjectivesThe diagnosis of inclusion body myositis (IBM) can be challenging as it can be difficult to clinically distinguish from other forms of myositis, particularly polymyositis (PM). Recent studies have shown...

A retrospective cohort study identifying the principal pathological features useful in the diagnosis of inclusion body myositis

ObjectiveThe current pathological diagnostic criteria for sporadic inclusion body myositis (IBM) lack sensitivity. Using immunohistochemical techniques abnormal protein aggregates have been identified in IBM, including some associated with neurodegenerative disorders....

Clinical assessment determines the diagnosis of inclusion body myositis independently of pathological features

Background and objectiveHistorically, the diagnosis of sporadic inclusion body myositis (IBM) has required the demonstration of the presence of a number of histopathological findings on muscle biopsy—namely, rimmed vacuoles, an...

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.

Electromyographs of the flexor digitorum profundus muscle are useful for the diagnosis of inclusion body myositis

The frequent observation of high-amplitude and long-duration motor unit potentials (MUPs) in inclusion body myositis (IBM) is problematic, because it may lead to a misdiagnosis of amyotrophic lateral sclerosis (ALS). To document the diagnostic utility of EMG from the flexor digitorum profundus (FDP) muscle for IBM. Quantitative analyses of MUP parameters were performed in the FDP and biceps brachii (BB) muscles from 7 biopsy-confirmed IBM patients. In the FDP muscle, all MUP parameters were significantly decreased in IBM patients, which indicated the predominance of low-amplitude and short-duration MUPs in this muscle. In the BB muscle, most parameters were increased, suggesting the frequent contamination of high-amplitude and long-duration MUPs. Low-amplitude MUPs in the FDP muscle indicate the presence of an advanced myopathy in this muscle that was extremely weak for all subjects. Examining the FDP muscle would reduce the chance of misdiagnosing IBM as ALS.

Is a Muscle Biopsy Necessary for the Diagnosis of Inclusion Body Myositis (IBM)? (P07.223)

Objective: To determine if a muscle biopsy is superior or adds to the clinical diagnosis of inclusion body myositis. Background Inclusion body myositis is a mixed degenerative and inflammatory disease. There is no effective treatment. The diagnosis is confirmed by muscle biopsy showing congophilic deposits and rimmed vacuoles or by electronmicroscope showing the filamentous inclusions. Design/Methods: Twenty-one patients with clinical diagnosis of inclusion body myositis underwent muscle biopsy for confirmation. All patients had proximal and distal muscle weakness with preferential involvement of finger flexors and quadriceps muscles. Muscle biopsies were performed from a moderate weak muscle and were examined for the presence of rimmed vacuoles or congophilic deposits or both. Results: There were fourteen females and seven males. Average age at presentation was 60 years (35-80). CK level was elevated in 18 patients. Mean CK elevation was 942 U/L and ranged from 72-4774. Mean disease duration before the biopsy was 6 years and ranged from 1-15 years. The muscle biopsy confirmed the diagnosis in 15 patients. Six patients (5 females and 1 male) had no rimmed vacuoles or congophilic deposits detected on their muscle biopsies, but all patients had autoaggressive endomysial inflammatory response with mononuclear cells invading none necrotic muscle fibers. Ten patients had received different types of immunotherapy, but continued to deteriorate. Conclusions: 1- None of the patients suspecting to have IBM was found to have a different diagnosis.2- The muscle biopsy did not show the characteristic features of IBM in six patients.3- These findings question whether or not the muscle biopsy is necessary or add to the clinical diagnosis of inclusion body myositis.4-The clinical diagnosis of IBM remains superior to the muscle biopsy. Disclosure: Dr. Lee has nothing to disclose. Dr. Chahin has nothing to disclose.

Development of inclusion bodies late in the course of necrotizing myositis due to systemic lupus erythematosus

Background: The diagnosis of myositis and its nosological differentiation into polymyositis, inclusion body myositis (IBM) and myositis associated to systemic autoimmune diseases strongly relies on muscle biopsy findings. We report a case of necrotizing polymyositis associated to systemic lupus erythematosus (SLE) which 11 years later developed inclusion bodies and other histopathological features typical for IBM. Case report: A 45-year-old man presented in 1997 with progressive proximal symmetric tetraparesis pronounced for the upper extremities (grade 4/5) and discoid skin lesions. Further investigations were diagnostic for systemic lupus erythematosus. Creatine kinase (CK) of 438 IU/l (normal <80), myopathic EMG findings and deltoid muscle biopsy confirmed a severe necrotizing polymyositis. Under prednisolone and azathioprine complete remission was achieved. After three years tetraparesis insidiously returned and progressed with transiently increased CK up to 300 IU/l. Replacement of azathioprine by mycophenolate mofetil and later by methotrexate had a brief stabilizing effect. In 2008 muscle rebiopsy showed a severe inflammatory myositis with an advanced fibrinous and lipomatous conversion. The lymphoid infiltrate was unchanged with an intense perivascular cuffing predominated by CD20+ B-cells and CD4+ T-cells whereas CD8+ T-cells were sparse. Mononuclear infiltration involved nonnecrotic muscle fibers and MHC-I was generally upregulated. Contrasting to the first biopsy, advanced chronic neurogen changes, rimmed vacuoles, ubiquitine-positive intracellular aggregates and electromicroscopic abnormal filamentous inclusions were evidenced. Conclusions: The composition of the inflammatory infiltrate in both biopsies is well compatible with a SLE-associated myositis and atypical for classical polymyositis or inclusion body myositis. The second biopsy fulfilled all formal criteria for the definite diagnosis of inclusion body myositis. Only two cases of IBM-like myopathy decades after SLE diagnosis have been reported, but both received hydroxycholorquine which is neuromyotoxic and can induce some IBM-like myopathological features. We suggest that rimmed vacuoles and inclusion bodies can develop late in chronic autoimmune myositis as secondary degenerative changes although the combination of these findings is usually considered specific for IBM. The nature of the underlying autoimmune process rather determines the composition of the inflammatory infiltrate.