Etude des cellules cytotoxiques par hybridation in situ et immunohistochimie dans les biopsies musculaires de polymyosites et dermatomyosites

Cytotoxic cells can kill target cells by secretion of several proteases, serine esterase B (SE-B), perforin (PF) and protein TIA-1. We analysed the presence of cytotoxic cells expressing the SE-B and PF genes by in situ hybridization and expression of TIA-1 by immunohistochimical study from muscular biopsies of 13 patients with inflammatory myopathies; compared to those from 11 subjects control. We found expression of PF in 9 patients, SE-B gene in 10 and liberation of TIA-1 in 12 out of the 13 muscular biopsies tested, supporting the role of cytotoxic cells in pathogeny of inflammatory myopathies.