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Expression of transglutaminase 2 does not differentiate focal myositis from generalized inflammatory myopathies
Author(s) -
Macaione V.,
Aguennouz M.,
Mazzeo A.,
De Pasquale M. G.,
Russo M.,
Toscano A.,
De Luca G.,
Di Giorgio R. M.,
Vita G.,
Rodolico C.
Publication year - 2008
Publication title -
acta neurologica scandinavica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.967
H-Index - 95
eISSN - 1600-0404
pISSN - 0001-6314
DOI - 10.1111/j.1600-0404.2007.00957.x
Subject(s) - inclusion body myositis , myositis , polymyositis , immunocytochemistry , pathology , dermatomyositis , tissue transglutaminase , skeletal muscle , medicine , biology , biochemistry , enzyme
Objectives – Idiopathic inflammatory myopathies (IIM), including dermatomyositis (DM), polymyositis (PM), sporadic inclusion‐body myositis (s‐IBM) and focal myositis (FM) are a heterogeneous group of autoimmune disorders of skeletal muscle. An increased transglutaminase 2 (TG2) expression has been found in DM, PM and s‐IBM. The aim of our study was to investigate TG2 expression in FM in comparison with other IIM. Materials and methods – We re‐examined tissue material we have gathered in the course of our previous studies on IIM, investigating muscle expression of TG2 in patients with FM in comparison with DM, PM and s‐IBM using immunocytochemistry and real‐time RT‐PCR. Results – Immunocytochemistry revealed an increased TG2 signal in endomysial vessels, in atrophic and degenerating/regenerating muscle fibres in PM, DM, s‐IBM and FM; in s‐IBM, some vacuoles were immunostained too. Real‐time RT‐PCR study confirmed a significantly increased expression of TG2 in all IIM muscles examined. Conclusions – Our study demonstrates the presence of TG2 in FM muscles. The study suggests that TG2 expression does not represent a distinctive marker to differentiate FM from generalized IIM. TG2 over‐expression in inflamed skeletal muscle does not seem have a pathogenetic role in such a disease, but it could represent a way to contain the inflammatory process.