Toxoplasmic myositis as a presenting manifestation of idiopathic CD4 lymphocytopenia

Toxoplasma gondii encysts in skeletal muscle. Although only rarely found at muscle biopsy, this parasite has previously been regarded as a possible cause of polymyositis. We report a case of biopsy-proven toxoplasmic myositis in a non-HIV-infected patient that led to recognition of idiopathic CD4 lymphocytopenia (ICL), a rare condition typically associated with opportunistic infections. Interestingly, the CD25(+) subset that corresponds to the CD4(+) regulatory T cells controlling autoimmune processes was lacking. Steroid and antiprotozoal therapy led to recovery.     

Mycophenolate mofetil in the therapy of polymyositis associated with a polyautoimmune syndrome

Mycophenolate mofetil 1.5 g daily (30 mg/kg body weight) was given to a patient with ankylosing spondylitis, ulcerative colitis, and severe refractory polymyositis after conventional treatment regimes had failed. No severe side effects occurred. Considerable improvement of clinical symptoms and electromyographic findings were seen within 6 months after the initiation of mycophenolate mofetil, allowing for tapering and discontinuation of methylprednisolone. Mycophenolate mofetil may be considered as an useful alternative in the treatment of polymyositis when standard therapeutic regimens fail.     

FOLATE STATUS OF PATIENTS ON LOW-DOSE METHOTREXATE THERAPY

Methotrexate in small doses impairs the folate-dependent incorporation of formate into serine in lymphocytes.     

皮肌炎／多发性肌炎127例临床分析

目的 探讨DM/PM的临床表现，主要诊断要点和疗效。方法 分析了127例住院病例资料。结果 初发症状以皮损（52.8％）和皮损肌炎同发（31.5％）多见，而仅有肌炎占14.9％。皮损以眼睑及眶周浮肿性紫红色斑（85.2％），Gottron丘疹（58.3％），甲周红斑（43.5％）和皮肤异色病样改变（43.5％）多见，胆炎以四肢近端（82.3％）和吞咽肌群（44.9％）多见。此外可见血清肌浆酶和24h尿肌酸排出量增加，肌电图异常，少数合并恶性肿瘤及心肌受累。皮质激素治疗有效，与MTX合用能提高疗效。结论 眼睑及眶周浮肿紫红色斑，四肢近端肌无力，肌痛，肌力减退及24h尿肌酸排出量增加为主要诊断要点。皮质激素治疗有效，合用MTX能提高疗效。     

Measurement of platelet‐derived microparticle levels using an enzyme‐linked immunosorbent assay in polymyositis and dermatomyositis patients

Platelet‐derived microparticle (PDMP) levels were measured using an enzyme‐linked immunosorbent assay (ELISA) to elucidate the role of platelet activation in patients with polymyositis or dermatomyositis (PM/DM). PDMP levels in active PM/DM patients (median 13.3 U/ml, interquartile range 9.9–20.7 U/ml, n = 16) and those in patients undergoing treatment (12.1 U/ml, 7.4–16.7 U/ml, n = 12) were significantly higher than in controls (6.5 U/ml, 5.0–8.4 U/ml, n = 26, vs. active, P = 0.0001; vs. treatment, P = 0.004). In a paired sampling study, PDMP decreased significantly after glucocorticoid treatment (P = 0.04). PDMP in the active PM/DM patients correlated significantly with serum C‐reactive protein levels (r_s = 0.67, P = 0.01). These results suggest that platelets may play an important role in the inflammatory process, and that PDMP level could be a useful marker of inflammatory activity in PM/DM patients. Muscle Nerve 39: 586–590, 2009     

Diagnostic uncertainty in the inflammatory myopathies

A group of case histories with appropriate muscle biopsy findings is presented to demonstrate some atypical presentations of the inflammatory myopathies. Differential diagnostic possibilities are considered in presentations of idiopathic polymyositis, statin myotoxicity, the inflammatory component with the dysferlinopathies, treated dermatomyositis, a necrotizing myopathy with pipe-stem microvascular change, an inflammatory myopathy with abundant macrophages, inclusion-body myositis, and the differential diagnosis of problems with eosinophilic infiltration in the muscle biopsy. Attention is given to the role of membrane attack complex deposition in the microvasculature and the role of major histiocompatibility complex-1-expressing muscle fibers indicating activation of the endoplasmic reticulum stress response.     

Myeloid dendritic cells in inclusion-body myositis and polymyositis

Dendritic cells (DCs), immune system cells central to the development of immunity, have not previously been reported in muscle in inclusion-body myositis (IBM). We performed immunohistochemical studies on muscle biopsy specimens from 50 patients using monoclonal antibodies that distinguish two classes of DCs, myeloid DC and plasmacytoid DC. In 17 of 20 IBM and 9 of 10 polymyositis (PM) specimens, myeloid DCs were present in substantial numbers, frequently surrounded and sometimes invading otherwise intact myofibers, and were part of dense collections of cells that included T cells. Dermatomyositis muscle had more plasmacytoid DCs than myeloid DCs, whereas IBM and PM had greater numbers of myeloid DCs. The stellate morphology of myeloid DCs in dense collections of cells that included T cells suggests local intramuscular antigen presentation in IBM and PM.