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Immunohistological Analysis of CD59 and Membrane Attack Complex of Complement in Muscle in
Juvenile Dermatomyositis
FLÁVIA G.P. GONÇALVES, LEILA CHIMELLI, ADRIANA M.E. SALLUM, SUELY K.N. MARIE, MARIA HELENA B. KISS, and VIRGÍNIA P.L. FERRIANI
ABSTRACT.
Methods. Muscle specimens obtained for diagnostic purposes from 10 patients with JDM, 6 with MD, and 7 children whose biopsies showed normal histology were analyzed. Immunohistological staining was performed using Mab against CD59 (YTH 53.1) and MAC (WU 7.2). Results. Immunohistochemical staining for CD59 was weak and irregularly distributed on muscle fibers of all patients with JDM. Two of the 9 biopsies that allowed analysis of vessels showed negative CD59 staining in all vessels; in the remaining 7 patients, there was weak staining in a proportion of the vessels. In contrast, uniform and strong or moderate immunoreactivity was detected on the sarcolemma and in intramuscular endothelium in all normal and MD samples. Immunostaining for MAC was strong in JDM muscle vessels, and weak in normal or MD muscle. An inverse relation was found between MAC deposition and presence of CD59 in vessels in 6/9 JDM biopsies and in all normal and MD samples. Conclusion. Decreased CD59 expression in JDM muscle fibers and vessels may be associated with muscle lesions mediated by deposition of MAC of complement in JDM. (J Rheumatol 2002;29:1301-7) Key Indexing Terms:
JUVENILE DERMATOMYOSITIS
From the Department of Pediatrics, Division of Immunology, Allergy and Rheumatology, and Department of Pathology, School of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, São Paulo; and Pediatric Rheumatology Unit and Department of Neurology, University of São Paulo School of Medicine, São Paulo, Brazil. F.G.P. Gonçalves, MD; V.P.L. Ferriani, MD, PhD, Assistant Professor, Head, Division of Immunology, Allergy and Rheumatology, Department of Pediatrics; L. Chimelli, MD, PhD, Associate Professor, Department of Pathology, School of Medicine of Ribeirão Preto, University of São Paulo; A.M.E. Sallum, MD; M.H.B. Kiss, MD, PhD, Associate Professor, Pediatric Rheumatology Unit; S.K.N. Marie, MD, PhD, Associate Professor, Department of Neurology, University of São Paulo School of Medicine. Address reprint requests to Dr. V.P.L. Ferriani, Department of Pediatrics, School of Medicine of Ribeirão Preto, University of São Paulo, Avenida Bandeirantes 3900, 14049-900 Ribeirão Preto, São Paulo, Brazil. E-mail: vplferri@fmrp.usp.br Submitted February 10, 2000; revision accepted December 19, 2001. |