RT Journal Article SR Electronic T1 In situ immunophenotype of the inflammatory infiltrate in eosinophilic fasciitis. JF The Journal of Rheumatology JO J Rheumatol FD The Journal of Rheumatology SP 1811 OP 1815 VO 30 IS 8 A1 Toquet, Claire A1 Hamidou, Mohamed Amine A1 Renaudin, Karine A1 Jarry, Anne A1 Foulc, Phryné A1 Barbarot, Sébastien A1 Laboisse, Christian A1 Mussini, Jean-Marie Gilbert YR 2003 UL http://www.jrheum.org/content/30/8/1811.abstract AB OBJECTIVE: Eosinophilic fasciitis (EF) is histologically characterized by a fibrous and inflammatory thickening of subcutaneous septal-fascial-perimysial collagenous scaffold. This study aims to define the immunophenotype of inflammatory cells of fascia and muscle underlying the in situ immune response in EF. METHODS: In 11 cases of EF, we determined the phenotype of inflammatory cells, expression of MHC class I and class II antigens, and C5b9 membranolytic attack complex (MAC) deposits by immunohistochemistry analysis of fascia tissue. Muscle biopsies from 9 patients with active dermatomyositis and 5 with active polymyositis were used as controls. Results. In all patients but one, the inflammatory infiltrate was mainly composed of macrophages associated with CD8+ T lymphocytes (CD4/CD8 ratio < 1) and few eosinophils. Cytotoxic properties were found in 14% of CD8+ T lymphocytes, as shown by granzyme B expression. MHC Class I antigens were overexpressed (5/7) by muscle fibers, with a paratrabecular reinforcement in 4 cases. MHC class II antigens were not expressed by muscle fibers except in one case. C5b9 MAC deposits were not detected. CONCLUSION: Our in situ characterization of inflammatory infiltrate demonstrates the predominancy of macrophages and CD8+ T lymphocytes. Some of these CD8+ lymphocytes contain granzyme B, thus suggesting a cytotoxic cellular immune response in EF, which could be triggered by infectious or environmental agents.