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Query: UMLS:C0027121 (myositis)
 4,538 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The mechanism of injury and death of muscle cells in the inflammatory myopathies (dermatomyositis, polymyositis, and inclusion body myositis) remains obscure. We and others have not detected apoptosis in the muscle biopsies from patients with myositis despite clear evidence of cell damage and loss. We provide evidence in this study that Fas ligand (FasL) as well as Fas is present on muscle cells and inflammatory cells in myositis biopsies: Fas is present on most muscle cells and lymphocytes, and FasL is present on degenerating muscle cells and many infiltrating mononuclear cells. The expression of both Fas and FasL in the inflamed tissue makes the absence of apoptosis more striking. To address the mechanisms of this resistance to classical apoptosis in muscle cells, we have investigated the expression of the antiapoptotic molecule FLICE (Fas-associated death domain-like IL-1-converting enzyme)-inhibitory protein (FLIP) in muscle biopsies of myositis patients and in cultured human skeletal muscle cells. Using laser capture microscopy, we have shown that FLIP is expressed in the muscle fibers and on infiltrating lymphocytes of myositis biopsies. Furthermore, we have shown that FLIP, but not Bcl-2, is expressed in cultured human skeletal muscle cells stimulated with proinflammatory cytokines, and inhibition of FLIP with antisense oligonucleotides promotes significant cleavage of poly(ADP-ribose) polymerase autoantigen, a sensitive indicator of apoptosis. These studies strongly suggest that the resistance of muscle to Fas-mediated apoptosis is due to the expression of FLIP in muscle cells in the inflammatory environment in myositis.
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PMID:The inhibition of apoptosis in myositis and in normal muscle cells. 1079 13

Recent studies have shown an up-regulation of the Fas/Fas ligand system in inflammatory myopathies. In myositis, however, the major Fas-mediated cytotoxicity which activates caspases bypasses apoptosis. We therefore evaluated the expression of proteins promoting cell survival, such as bcl-2, bcl-x(l) and cyclin-dependent kinase inhibitors, on muscle biopsies from 14 patients with polymyositis, dermatomyositis, inclusion body myositis and HIV-associated myositis. Our data demonstrate that inflammatory cells are immunoreactive for bcl-x(l), p16 and p57, three apoptosis-preventing proteins. Hence, we assume that these proteins might protect T cells from apoptotic nuclear changes. Our results could explain the non-self-limiting nature of inflammatory myopathies.
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PMID:T-cell anti-apoptotic mechanisms in inflammatory myopathies. 1106 32

Sporadic inclusion-body myositis (sIBM) is the most common disabling, adult-onset, inflammatory myopathy histologically characterized by intense inflammation and vacuolar degeneration. In spite of T cell-mediated cytotoxicity and persistent, clonally expanded and antigen-driven endomysial T cells, the disease is resistant to immunotherapies. Alemtuzumab is a humanized monoclonal antibody that causes an immediate depletion or severe reduction of peripheral blood lymphocytes, lasting at least 6 months. We designed a proof-of-principle study to examine if one series of Alemtuzumab infusions in sIBM patients depletes not only peripheral blood lymphocytes but also endomysial T cells and alters the natural course of the disease. Thirteen sIBM patients with established 12-month natural history data received 0.3 mg/kg/day Alemtuzumab for 4 days. The study was powered to capture > or =10% increase strength 6 months after treatment. The primary end-point was disease stabilization compared to natural history, assessed by bi-monthly Quantitative Muscle Strength Testing and Medical Research Council strength measurements. Lymphocytes and T cell subsets were monitored concurrently in the blood and the repeated muscle biopsies. Alterations in the mRNA expression of inflammatory, stressor and degeneration-associated molecules were examined in the repeated biopsies. During a 12-month observation period, the patients' total strength had declined by a mean of 14.9% based on Quantitative Muscle Strength Testing. Six months after therapy, the overall decline was only 1.9% (P < 0.002), corresponding to a 13% differential gain. Among those patients, four improved by a mean of 10% and six reported improved performance of daily activities. The benefit was more evident by the Medical Research Council scales, which demonstrated a decline in the total scores by 13.8% during the observation period but an improvement by 11.4% (P < 0.001) after 6 months, reaching the level of strength recorded 12 months earlier. Depletion of peripheral blood lymphocytes, including the naive and memory CD8+ cells, was noted 2 weeks after treatment and persisted up to 6 months. The effector CD45RA(+)CD62L(-) cells, however, started to increase 2 months after therapy and peaked by the 4th month. Repeated muscle biopsies showed reduction of CD3 lymphocytes by a mean of 50% (P < 0.008), most prominent in the improved patients, and reduced mRNA expression of stressor molecules Fas, Mip-1a and alphaB-crystallin; the mRNA of desmin, a regeneration-associated molecule, increased. This proof-of-principle study provides insights into the pathogenesis of inclusion-body myositis and concludes that in sIBM one series of Alemtuzumab infusions can slow down disease progression up to 6 months, improve the strength of some patients, and reduce endomysial inflammation and stressor molecules. These encouraging results, the first in sIBM, warrant a future study with repeated infusions
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PMID:Effect of Alemtuzumab (CAMPATH 1-H) in patients with inclusion-body myositis. 1989 69