Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0011633 (dermatomyositis)
 4,181 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

To clarify the mechanism of muscle fiber destruction in sarcoid myopathy, muscle biopsy specimens were examined from patients with sarcoid myopathy, polymyositis, or dermatomyositis. In sarcoid myopathy, noncaseating granulomatous lesions were located in the perimysium or endomysium or both. Little fiber atrophy, caused by mechanical compression of the granuloma, was seen, and there was no evidence of ischemia-induced changes (i.e., perifascicular atrophy) due to microangiopathy in muscles. Immunoreactivity for membrane-associated cytoskeletal proteins such as dystrophin and merosin was detected homogeneously along the surface of many small granulomas in intrafascicular lesions. These granulomas showed a characteristic phenotypic cellular distribution: CD68(+) and CD4(+) cells were present in the center, and some CD8(+) cells were found at the periphery, indicating typical sarcoid granuloma formation in each muscle fiber. Strong expression of proteases such as cathepsin B, calpain II and ubiquitin-proteasome was observed in macrophages and epithelioid cells but not in lymphocytes in granulomas within muscle fibers or those in the endomysium or perimysium. The expression intensity was stronger in premature-stage granulomas than in late-stage granulomas. Weak expression of these proteases was detected mainly in some muscle fibers invaded by epithelioid cells and macrophages and in a few atrophic or necrotic fibers adjacent to inflammatory foci but not in fibers of fascicles without granuloma formation or in fibers in perifascicular areas. Our results suggest that muscle fiber destruction in sarcoid myopathy is caused mainly by direct invasion of granulomatous inflammatory cells into muscle fibers during the process of granuloma formation rather than by mechanical compression or ischemia. Furthermore, the proteases derived from epithelioid cells and macrophages may play an important role in muscle fiber destruction.
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PMID:Cellular distribution of proteolytic enzymes in the skeletal muscle of sarcoid myopathy. 1207 Jun 62

Pulmonary sarcoidosis in association with dermatomyositis has rarely been reported. A 52-year-old woman was admitted for evaluation of a previously unrecognized bilateral hilar lymphadenopathy on a chest radiogram in August 1995. She had been receiving oral corticosteroids for dermatomyositis, which was confirmed by the typical skin rash and the myogenic changes on an electromyogram in 1977. She had no respiratory symptoms at the time of admission. Chest computed tomography showed hilar and mediastinal lymphadenopathy with reticular shadows in the peripheral lung parenchyma. A 67gallium-citrate scintigram apparently revealed accumulation in bilateral hilums. The tuberculin skin reaction was negative. Flowcytometry of bronchoalveolar lavage fluid indicated a CD4/CD8 ratio of 5.37. Thoracoscopic biopsy specimens sampled from the mediastinal lymph nodes and the lung demonstrated non-caseating granulomas. A definitive diagnosis of pulmonary sarcoidosis was made from these findings. The chest radiographic findings were spontaneously resolved after three years with no increase in the dosage of oral corticosteroids. It is well known that an abnormal immune response playa an important role in development of dermatomyositis and sarcoidosis. This case suggested close associations in both diseases.
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PMID:[Pulmonary sarcoidosis in a case of dermatomyositis under long-term steroid therapy]. 1209 1

To study the activation states and cytokine profiles of pulmonary T cells in corticosteroid-resistant and corticosteroid-sensitive interstitial pneumonitis (IP) in dermatomyositis (DM)/polymyositis (PM), we examined the activation markers and cytokine profiles of T cells in bronchoalveolar lavage fluids (BALF) from patients with IP in DM/PM before prednisolone therapy and then compared the activation states of T cells according to the therapeutic response of IP to prednisolone therapy. CD25+ CD4+ T cells in BALF were significantly increased in both corticosteroid-resistant and corticosteroid-sensitive IP in DM/PM as compared with those in controls without IP. Furthermore, CD25+ CD4+ T cells in BALF were significantly more increased in corticosteroid-resistant IP than those in cortico teroid- sensitive IP. Moreover, CD25+ CD8+ T cells in BALF were significantly increased only in corticosteroid-resistant IP, but not in corticosteroid-sensitive IP or controls without IP. IFN-gamma mRNA was detected in BALF T cells in corticosteroid-resistant and corticosteroid-sensitive IP but not in controls without IP, whereas IL-4 mRNA was virtually undetected in BALF T cells in both the IP groups. However, there were no significant differences in CD4/CD8 ratio of BALF T cells, HLA-DR+ BALF T cells or CD25+ and HLA-DR+ peripheral blood T cells between the two IP groups. These results indicate that activated Th1-type pulmonary T cells play an important role in the development of corticosteroid- resistant IP in DM/PM and that the increase in CD25+ CD8+ T cells in BALF is a useful indicator for corticosteroid-resistant IP in DM/PM and hence may be an indicator for early use of cyclosporin.
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PMID:Activation of pulmonary T cells in corticosteroid-resistant and -sensitive interstitial pneumonitis in dermatomyositis/polymyositis. 1219 97

Autoantibodies to histidyl-tRNA synthetase (HisRS) or to alanyl-, asparaginyl-, glycyl-, isoleucyl-, or threonyl-tRNA synthetase occur in approximately 25% of patients with polymyositis or dermatomyositis. We tested the ability of several aminoacyl-tRNA synthetases to induce leukocyte migration. HisRS induced CD4(+) and CD8(+) lymphocytes, interleukin (IL)-2-activated monocytes, and immature dendritic cells (iDCs) to migrate, but not neutrophils, mature DCs, or unstimulated monocytes. An NH(2)-terminal domain, 1-48 HisRS, was chemotactic for lymphocytes and activated monocytes, whereas a deletion mutant, HisRS-M, was inactive. HisRS selectively activated CC chemokine receptor (CCR)5-transfected HEK-293 cells, inducing migration by interacting with extracellular domain three. Furthermore, monoclonal anti-CCR5 blocked HisRS-induced chemotaxis and conversely, HisRS blocked anti-CCR5 binding. Asparaginyl-tRNA synthetase induced migration of lymphocytes, activated monocytes, iDCs, and CCR3-transfected HEK-293 cells. Seryl-tRNA synthetase induced migration of CCR3-transfected cells but not iDCs. Nonautoantigenic aspartyl-tRNA and lysyl-tRNA synthetases were not chemotactic. Thus, autoantigenic aminoacyl-tRNA synthetases, perhaps liberated from damaged muscle cells, may perpetuate the development of myositis by recruiting mononuclear cells that induce innate and adaptive immune responses. Therefore, the selection of a self-molecule as a target for an autoantibody response may be a consequence of the proinflammatory properties of the molecule itself.
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PMID:Histidyl-tRNA synthetase and asparaginyl-tRNA synthetase, autoantigens in myositis, activate chemokine receptors on T lymphocytes and immature dendritic cells. 1223 11

Inducible co-stimulator ligand (ICOSL), a member of the B7 family of co-stimulatory molecules related to B7.1/2, regulates CD4 as well as CD8 T-cell responses via interaction with its receptor ICOS on activated T cells. Here we examined the expression and the functional relevance of ICOSL in human muscle cells in vivo and in vitro. We investigated 25 muscle biopsy specimens from patients with polymyositis, dermatomyositis, inclusion body myositis, Duchenne muscular dystrophy and non-myopathic controls for ICOSL expression by immunohistochemistry. Normal muscle fibres constitutively express low levels of ICOSL. However, ICOSL expression is markedly increased in muscle fibres in inflammatory myopathies. Cell surface staining was most prominent in the contact areas between muscle fibres and inflammatory cells, which in turn show expression of ICOS as a marker of T-cell activation. Muscle endothelial cells show constitutive expression of ICOSL under normal and pathological conditions. We also detected mRNA and cell surface protein expression of ICOSL on myoblasts cultured from control subjects and patients as well as in TE671 muscle rhabdomyosarcoma cells. ICOSL expression was upregulated by tumour necrosis factor-alpha (TNF-alpha), whereas interferon-gamma (IFN-gamma) had no such effect. Co-culture experiments of major histocompatibility complex (MHC) class II-positive myoblasts with CD4 T cells together with superantigen demonstrated that the expression of muscle-related ICOSL has functional consequences: the production of Th1 (IFN-gamma) and Th2 cytokines [interleukin (IL)-4 and IL-10] by CD4 T cells was markedly reduced in the presence of a neutralizing anti-ICOSL monoclonal antibody (mAb HIL-131), thus showing the importance of ICOSL co-stimulation for T-cell activation. Taken together, our results demonstrate that human muscle cells express ICOSL, a functional co-stimulatory molecule distinct from B7.1 and B7.2. ICOSL-ICOS interactions may play an important role in inflammatory myopathies, providing further evidence for the antigen-presenting capacity of muscle cells.
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PMID:Muscle fibres and cultured muscle cells express the B7.1/2-related inducible co-stimulatory molecule, ICOSL: implications for the pathogenesis of inflammatory myopathies. 1269 43

B7-H1 is a novel B7 family protein attributed to costimulatory and immune regulatory functions. Here we report that human myoblasts cultured from control subjects and patients with inflammatory myopathies as well as TE671 muscle rhabdomyosarcoma cells express high levels of B7-H1 after stimulation with the inflammatory cytokine IFN-gamma. Coculture experiments of MHC class I/II-positive myoblasts with CD4 and CD8 T cells in the presence of antigen demonstrated the functional consequences of muscle-related B7-H1 expression: production of inflammatory cytokines, IFN-gamma and IL-2, by CD4 as well CD8 T cells was markedly enhanced in the presence of a neutralizing anti-B7-H1 antibody. This observation was paralleled by an augmented expression of the T cell activation markers CD25, ICOS, and CD69, thus showing B7-H1-mediated inhibition of T cell activation. Further, we investigated 23 muscle biopsy specimens from patients with polymyositis (PM), inclusion body myositis (IBM), dermatomyositis (DM), and nonmyopathic controls for B7-H1 expression by immunohistochemistry: B7-H1 was expressed in PM, IBM, and DM specimens but not in noninflammatory and nonmyopathic controls. Staining was predominantly localized to areas of strong inflammation and to muscle cells as well as mononuclear cells. These data highlight the immune regulatory properties of muscle cells and suggest that B7-H1 expression represents an inhibitory mechanism induced upon inflammatory stimuli and aimed at protecting muscle fibers from immune aggression.
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PMID:Human muscle cells express a B7-related molecule, B7-H1, with strong negative immune regulatory potential: a novel mechanism of counterbalancing the immune attack in idiopathic inflammatory myopathies. 1292 66

THREE GROUPS OF PRIMARY INFLAMMATORY MUSCLE DISEASES: The primary inflammatory muscle diseases comprise three main subsets: polymyositis (PM), dermatomyositis (DM) and inclusion body myositis (IBM). PM and DM are characterized by a proximal weakness that develops along weeks to months and by elevated creatine phosphokinase levels. Cutaneous involvement including both erythema and edema and infantile or adult onset are DM specific. PM and IBM only concern adults. Several PM/DM manifestations must be searched for because of their severity: swallowing disorders, various mechanisms of respiratory dysfunction (swallowing pneumopathies, interstitial lung disease, respiratory muscle deficiency) and cardiac involvement. DIAGNOSTIC ELEMENTS FOR PM AND DM: Two investigations, beside biopsy, are particularly useful: muscle MRI imaging showing inflammatory pattern and specific detection of antisynthetase autoantibodies (PM/DM with interstitial lung disease) and anti-Mi-1 and 2 in DM. PHYSIOPATHOLOGICAL DATA: PM and DM differ in their histological and physiopathological characteristics: perivascular B and CD4 lymphocyte infiltrates and complement deposits at the origin of humoral induced vascular disease in DM and perimysial CD8 lymphocytes inducing a cellular mediated cytotoxic injury in PM. Class I HLA antigen expression on the muscle fibers and production of cytokines play a crucial role in the pathogenesis of these two diseases. PM and DM may be associated with cancers, connective-tissue disease (overlap syndrome). Some PM are secondary to HIV, HTLV1 virus and toxoplasmosis infection. CHARACTERISTICS OF INCLUSION BODY MYOSITIS: IBM, the most frequent acquired myopathy after 50 years of age, is characterized by particular features: not only clinical (late onset, selective weakness, early distal involvement, slow course, unresponsiveness to corticosteroid and immunosuppressant agents); but also histological (rimmed vacuoles, filamentous inclusions) and pathogenic (cytotoxic and degenerative inflammatory process, similar to Alzheimer's disease, with beta-amyloid protein accumulation).
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PMID:[Polymyositis, dermatomyositis and inclusion body myositis, nosological aspects]. 1463 Dec 70

Here we clarified the morphology and phenotype of interleukin (IL)-17- and interferon (IFN)-gamma-producing cells in both in vitro and in vivo situations. Oligoclonal activation of normal peripheral blood mononuclear cells with the superantigen Staphylococcus aureus enterotoxin B and polyclonal activation with phorbol myristate acetate/phytohemagglutinin were used as in vitro models. This study was extended to various in vivo situations such as rheumatoid arthritis, dermatomyositis, and normal activated lymph nodes. The phenotype of IL-17- and IFN-gamma-producing cells was evaluated by immunohistochemistry using the CD3 and CD4 T-cell markers, the CD20, CD38, kappa and lambda light chain B-cell lineage markers. The expression of two chemokine receptors, CCR6 and CCR7, involved with their associated ligands CCL20 and CCL19/CCL21 in the migration of T lymphocytes, was evaluated in tissue sections. After both polyclonal and oligoclonal activation, IL-17+ and IFN-gamma+ cells acquired a plasma cell-like morphology associated with a high secretory activity, the reduced expression of CD3, and no change of CD4 expression. In rheumatoid arthritis, dermatomyositis, and activated lymph nodes, both IL-17- and IFN-gamma-producing cells had the same morphology. These Th1 cytokine-producing cells were CD4(+)-, CD3-, and B-cell lineage marker-negative. In both in vitro and in vivo situations, expression of CCR6 or CCR7 was not associated with a particular subset. In conclusion, activated T-helper CD4(+) T cells, by their release of cytokines, seem to have functional similarities with plasma cells secreting immunoglobulins.
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PMID:Plasma cell-like morphology of Th1-cytokine-producing cells associated with the loss of CD3 expression. 1474 47

To better elucidate the pathogenesis of lymphocyte recruitment of memory CD4(+) T cells in inflammatory myopathies, we studied the expression of CCR5 and CCR7 on CD4 memory T cells in muscle tissue from 11 patients with juvenile dermatomyositis, six adult patients with polymyositis, two patients with Duchenne muscular dystrophy, and two patients with spinal muscular atrophy. A prevalent infiltration of CCR5(+) effector CD4 T memory cells is observed in inflammatory myopathies. Moreover, we found a strong expression of CCR7 in perifascicular atrophic and in degenerating/regenerating muscle fibers in juvenile dermatomyositis (JDM) but not in fibers from adult polymyositis and Duchenne muscular dystrophy. The selective expression of CCR7 in JDM may open new perspectives in the understanding of the pathogenesis of inflammatory myopathies, offering a new tool for the differential diagnosis of these disorders.
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PMID:Chemokine receptor CCR7 is expressed in muscle fibers in juvenile dermatomyositis. 1595 Sep 36

Oxidative stress and nuclear factor-kappaB (NF-kappaB) activation are linked to the pathogenesis of many metabolic, degenerative, and chronic inflammatory diseases. Activation of the receptor for advanced glycation end products (RAGE) by its specific ligand N(epsilon)-carboxymethyllysine (CML) results in the activation of NF-kappaB and the production of proinflammatory cytokines. To determine whether engagement of RAGE contributes to the pathogenesis of inflammatory myopathies, we performed immunohistochemical studies on the presence of CML-modified proteins, RAGE and activated NF-kappaB in muscle biopsies of patients with polymyositis (PM, n=10), dermatomyositis (DM, n=10), limb girdle muscular dystrophy (LGMD, n=10) and in 10 controls with normal muscle biopsy results. In inflammatory myopathies CML, RAGE and NF-kappaB were detected in mononuclear cells and in regenerating muscle fibers. CML, NF-kappaB and, to a lesser extent, RAGE were also found in degenerating muscle fibers, but colocalization of CML, RAGE and NF-kappaB was only seen in infiltrating mononuclear cells and regenerating muscle fibers. Immunofluorescence double labeling demonstrated an expression of CML, RAGE and NF-kappaB in CD4-, CD8-, CD22- and CD68-positive mononuclear cells. Western blot analysis showed an increased immunoreactivity for CML-modified proteins in PM and DM. In LGMD, CML, RAGE and NF-kappaB were found in regenerating muscle fibers and less frequently in degenerating muscle fibers, and with lower staining intensities than in inflammatory myopathies. Our data suggests that the CML-RAGE-NF-kappaB pathway is an evident proinflammatory pathomechanism in mononuclear effector cells in PM and DM. RAGE-mediated NF-kappaB activation may be involved in muscle fiber regeneration in inflammatory myopathies and LGMD.
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PMID:The RAGE pathway in inflammatory myopathies and limb girdle muscular dystrophy. 1598 24


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