Familial inclusion body myositis: a report on two Japanese sisters

Familial occurrence of inclusion body myositis is extremely rare, and only a few cases in Western countries have been reported. In these reports, a strong association of this disease with DR3 (DRB1*0301/0302) and the efficacy of immunosuppressants suggested that an immune pathomechanism is involved in the disease. We, for the first time, report two Japanese sisters who suffered myopathy clinicopathologically similar to inclusion body myositis. One sister received corticosteroid and azathioprine and the therapy relieved dysphagia. Both of our patients had DR15(2)/4 (DRB1*1502/0405), suggesting a distinct genetic association with the disease in the Japanese population.     

Treatment of inclusion body myositis.

Sporadic inclusion body myositis (s-IBM) is considered the most common muscle disease in patients older than 50 years, with a male predominance. Features of s-IBM include insidious onset, slowly and relentlessly progressive muscle weakness, a characteristic distribution and atrophy of both the proximal and distal muscle groups, and resistance to immunosuppressive drugs. The most characteristic pathologic feature is vacuolar degeneration of muscle fibers accompanied by intrafiber congophilia and clusters ("tangles") of paired-helical filaments, containing phosphorylated tau. The response of s-IBM to immunotherapy remains controversial. Some reports emphasized partial improvement in early stages of the disease. However, the lack of clear response to corticosteroids and immunosuppressive therapies, the deterioration of clinical strength despite suppression of inflammation but increasing number of fibers with vacuoles and amyloid deposits under therapy, and the accumulation of "Alzheimer-characteristic" proteins in vacuolated muscle fibers suggest that s-IBM may be a degenerative rather than an auto-immune inflammatory myopathy, and a secondary inflammation response.     

Diagnostic criteria for inclusion body myositis

Inclusion body myositis (IBM) was first identified as a specific disorder about 40 years ago and is now recognized to be the most frequently presenting primary myopathy in middle age and beyond. Initial characterization was based on the observation of specific pathological features distinguishing it from polymyositis. It was soon appreciated that there were also distinguishing clinical features. The earliest diagnostic criteria were heavily biased towards pathological features, but over time revised criteria have given increasing importance to certain clinical features. Until the specific cause of IBM is determined, and the basic pathogenetic mechanisms are better understood, there can be no diagnostic gold‐standard against which to compare the sensitivity and specificity of any proposed diagnostic criteria, but such criteria are essential to ensure that patients entering clinical, epidemiological, genetic, pathological or therapeutic studies represent a homogeneous population. It is likely that any currently accepted diagnostic criteria will, once a gold‐standard is eventually established, be shown to have ‘missed’ patients with atypical features, but that has to be accepted to make certain that current studies are not contaminated by patients who do not have IBM. In other words, in everyday clinical practice there will be the occasional patient who an experienced myologist strongly suspects has IBM, but does not meet current criteria – the criteria lack sensitivity. But if the criteria are so broad as to include all such atypical cases, they would be likely to include patients who do not in fact have IBM – they would lack specificity. The sensitivity and specificity of existing criteria have been reviewed recently, in so far as it is possible to do so, and found to have high specificity but variable sensitivity.     

Severe inclusion body myositis with interstitial pneumonia

We report a patient with a severe inclusion body myositis (IBM). His illness was unusual in terms of a rapid progression, high creatine kinase levels, and complication with interstitial pneumonia. He responded well to immunosuppressive agents such as corticosteroids, cyclosporin A, cyclophosphamide, and immunoglobulin. The present patient indicates the wide range of the disease, and that immunosuppressive agents may be useful for treatment of IBM.     

Steroid-responsive inclusion body myositis associated with endometrial cancer

Inclusion body myositis (IBM) is an uncommon chronic inflammatory myopathy. Although the association between other myopathies and cancer has been well established, the relationship between IBM and neoplasia is not completely understood. Unlike polymyositis (PM) or dermatomyositis (DM), IBM rarely responds to immunosuppressive treatment and the response is seldom long-lasting. We describe a case of IBM associated with endometrial carcinoma that also demonstrated a unique response to steroids alone which persisted despite cancer relapse. The factors that are associated with a response of IBM to steroids are discussed. An atypical, steroid-responsive form of the disease is delineated.     

A case of inclusion body myositis with systemic sclerosis

 We report a case of systemic sclerosis (SSc) associated with inclusion body myositis (IBM). A 58-year-old man was diagnosed as having SSc at the age of 35 years, and had been suffering from chronic progressive weakness and atrophy of the limb muscles. A diagnosis of IBM was established by muscle biopsy. Although most such patients show a poor response to corticosteroids and immunosupressants, glucocorticoid therapy was effective in the present case. Received: March 6, 2002 / Accepted: July 9, 2002 Correspondence to:M. Kusaoi     

Renal involvement by AA amyloidosis in inclusion body myositis

Inclusion body myositis is currently considered a variant of adult inflammatory myopathies. Clinical course is insidious and besides typical proximal muscles disorder, extension to distal ones is found in up to 95% of cases. Mean survival ranges from 3 to 5 years. Infections are the first death cause, secondary to existing disability a few years after diagnosis. Chronic rheumatic diseases related amyloidosis has became the most frequent kind of reactive amyloidosis or AA amyloidosis. Clinical manifestations of AA amyloidosis mainly affect the kidney. We present the case of a woman with Inclusion body myositis and renal involvement by AA amyloidosis. In our review of literature we haven t found any article relating AA amyloidosis with idiopathic inflammatory myopathies of the adult, what would turn this case into the first ever reported. We can probably find the reason in the bad prognosis of this entity. So we propose making a renal biopsy to all those patients with a long lasting rheumatologic disease and unexpected impaired renal function.     

Clinical heterogeneity and treatment response in inclusion body myositis

Inclusion body myositis has been described as an inflammatory myopathy with distinctive clinical and pathologic features that is refractory to treatment. Ten cases of inclusion body myositis, as defined by histopathologic findings, were reviewed to determine whether the clinical characteristics are different in patients whose disease has been defined by light and electron microscopic studies compared with those whose disease has been defined by light microscopic studies alone. The clinical characteristics of both groups of patients were similar, and 2 patients have had excellent responses to treatment. Although inclusion body myositis represents a histologic subset of polymyositis, from a clinical perspective, it must be considered a nonspecific designation. Despite a generally poor prognosis, therapeutic intervention is still warranted.     

包涵体肌炎的临床和病理分析

目的探讨包涵体肌炎的临床和病理特点。方法分析20例包涵体肌炎患者的临床、骨骼肌活检组织化学染色及电镜病理特点。结果骨骼肌活检组织化学染色病理特点：肌周膜、肌内膜、血管周围炎性细胞浸润,肌纤维大小不等,散在变性、坏死和再生肌纤维,结缔组织增生,肌纤维内可见边缘空泡,空泡周边淀粉样物质沉积,可伴破碎红纤维、肌纤维类型或分布异常。电镜：肌原纤维结构紊乱,Z线排列不整或消失,肌浆包涵体内可见大量髓磷脂小体和吞噬空泡聚集,周边可见脂滴、糖原颗粒。结论包涵体肌炎临床诊断、鉴别诊断困难,骨骼肌活检病理分析是确诊本病的可靠标准。     

Anti-PM-Scl antibodies in a patient with inclusion body myositis

SIR, The term inclusion body myositis (IBM) was coined in 1971by Yunis and Samaha [1] to describe a subset of patients withrefractory chronic myositis whose muscle biopsies showed, inaddition to inflammation, abnormal muscle fibers containingvacuoles and characteristic filamentous inclusions in the cytoplasmand nuclei. A sporadic and a hereditary form have been recognized[2]. The cause of sporadic IBM is not known and it is consideredan idiopathic inflammatory myopathy     

A case of inclusion body myositis responsive to prednisolone therapy

Inclusion body myositis, although rare, is the commonest cause of myopathy in patients aged over 50 years. The suggested pathogenesis remains uncertain and its prognosis remains poor. There have been select case reports of its association with an inflammatory etiology and it is postulated that this group of patients respond better to immunosuppressive therapy. We therefore report a rare case of inclusion body myositis that responded well to immunosuppressive therapy. We also report the possibility of its association with infliximab therapy     

Association of inclusion body myositis with subacute cutaneous lupus erythematosus

We present the case of a 71-year-old man with inclusion body myositis combined with subacute cutaneous lupus erythematosus and dysphagia. Although inclusion body myositis is usually resistant to immunosuppressive therapy, this patient improved under treatment with corticosteroids. The presented case is discussed in the context of earlier reports of inclusion body myositis and lupus erythematosus.     

Inflammatory myopathies. Dermatomyositis, polymyositis, and inclusion body myositis

Idiopathic inflammatory myopathies are a group of heterogeneous, acquired systemic diseases characterized by progressive symmetrical muscle weakness, elevated serum levels of muscle enzymes, electromyographic abnormalities, and inflammatory infiltrates on muscle biopsy. Characteristic histopathologic features allow classification of idiopathic inflammatory myopathies into polymyositis, dermatomyositis, and sporadic inclusion-body myositis. These are commonly regarded as autoimmune disorders, and various autoantibodies directed to specific nuclear and cytoplasmic antigens are found. Other organs besides the muscle can be involved being the skin and lung the most frequent. Occasionally dermatomyositis and polymyositis can be associated with cancer in a paraneoplastic manner. Corticosteroids and immunosuppressive agents are the mainstay therapy, although in refractory cases biologic therapy can be used. Physical therapy can not be forgotten.     

Magnetic resonance imaging criteria for distinguishing between inclusion body myositis and polymyositis

OBJECTIVE: To develop diagnostic imaging criteria for polymyositis (PM) and sporadic inclusion body myositis (sIBM). METHODS: We investigated 220 patients with suspected inflammatory myopathies by magnetic resonance imaging (MRI). Findings were compared with the results of clinical and biological examinations and muscle biopsy. PM and IBM were diagnosed in 25 patients each. Quantitative and qualitative MRI analysis of the 3 muscle groups of the 2 thighs included fatty infiltration, atrophy, inflammation, and the type and distribution of the lesions. RESULTS: MRI was abnormal in all patients. Fatty infiltration and atrophy were more frequent in patients with sIBM (p < 0.05). Inflammation as the sole abnormality was preferentially encountered in PM (p = 0.05). Widespread abnormalities were more frequent in sIBM (p < 0.01). Abnormalities in PM tended to be distributed along the fascia. Involvement of the anterior group, an asymmetrical distribution, and a distal predominance were all more frequent in sIBM (p < 0.001). CONCLUSION: Despite some overlap in MRI findings between the 2 diseases, MRI was useful for distinguishing PM from sIBM.