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Neurology 2002;58:1779-1785 © 2002 American Academy of Neurology Differential expression of chemokines in inflammatory myopathiesFrom the Department of Neurology (Drs. De Bleecker and Vanwalleghem, and B. De Paepe), University Hospital, Gent, Belgium; and Institut für Neuropathologie (Dr. Schröder), Universitätsklinikum der Rheinisch-Westphälischen Hochschule Aachen, Aachen, Germany. Address correspondence and reprint requests to Dr. J.L. De Bleecker, University Hospital, Department of Neurology, De Pintelaan 185, B-9000 Gent, Belgium; e-mail: jan.debleecker{at}rug.ac.be Background: Chemokines represent a family of small-molecular-weight cytokines that recruit and activate inflammatory cells in response to inflammation. Invasion of cytotoxic memory T cells and macrophages in nonnecrotic muscle fibers characterizes polymyositis and sporadic inclusion body myositis. Dermatomyositis is a complement-mediated endotheliopathy. Elucidation of the mechanisms guiding lymphocyte diapedesis and trafficking could lead to selective therapeutic interventions. Methods: Immunoblots and multistep immunofluorescence studies with non–cross-reactive antibodies recognizing interleukin-8, monocyte chemoattractant protein-1 (MCP-1), MCP-3, TARC (thymus and activation regulated cytokine), and RANTES (regulated upon activation, normal T-cell expressed and secreted), using appropriate positive and negative controls. In situ hybridization was used to localize MCP-1 mRNA. Results: MCP-1 protein was strongly expressed on T cells and a subset of macrophages actively invading a proportion of the nonnecrotic muscle fibers in polymyositis and inclusion body myositis alike. Capillaries and arterioles in the vicinity of endomysial inflammatory foci were immunoreactive for MCP-1, with faint or no expression in unaffected parts of the tissue. By contrast, widespread and strong endothelial MCP-1 expression occurred on perifascicular and perimysial endothelia in dermatomyositis, also at sites remote from inflammatory infiltrates. In some control specimens, a subset of capillaries also expressed MCP-1, possibly reflecting a role of this chemokine in normal immune surveillance. MCP-1 mRNA was detected in scattered macrophages in each inflammatory myopathy. All other chemokines were absent. Conclusion: Chemokines are differentially expressed in the symptomatic stage of inflammatory myopathies. MCP-1 plays a major role in the myocytotoxicity in polymyositis and inclusion body myositis. MCP-1 may be induced by membranolytic attack complex binding to endothelial cells in dermatomyositis. This article has been cited by other articles:
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