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Novel Autoantibodies Against 7SL RNA in Patients with Polymyositis/Dermatomyositis
TAKASHI SATOH, TETSUROH OKANO, TOSHIMICHI MATSUI, HIROYUKI WATABE, TAKASHI OGASAWARA, KOUYA KUBO, MASATAKA KUWANA, NOREEN FERTIG, CHESTER V. ODDIS, HIROBUMI KONDO, and TOHRU AKAHOSHI
ABSTRACT. Methods. Sera from 10 Japanese and 22 North American PM/DM patients with anti-SRP antibodies were tested for the presence of anti-7SL RNA antibodies, using the sera to immunoprecipitate deproteinized RNA extracts derived from HeLa cells. Results. The immunoprecipitation analysis indicated that 5 Japanese (50%) and one North American (5%) patient with anti-SRP antibodies had novel autoantibodies against deproteinized 7SL RNA. The frequency of anti-7SL RNA antibodies was significantly higher in Japanese than North American patients (p = 0.006). The presence of anti-7SL RNA antibodies appeared to be associated with DM (2 patients) and finger swelling (2 PM patients). The seasonal onset of the disease was different (p = 0.008) for Japanese PM/DM patients with anti-7SL RNA antibodies, who developed the disease between October and January (mean month November; p = 0.01) from that of patients without these antibodies, who developed it between June and August (mean month July; p = 0.01). Conclusion. Novel autoantibodies against 7SL RNA were identified in patients with PM/DM, and the presence of these antibodies was correlated to ethnic background, clinical features, and season of disease onset. These findings indicated that autoantibodies against 7SL RNA are a novel serological marker for a subset of PM/DM cases. (J Rheumatol 2005;32:1727-33) Key Indexing Terms:
SIGNAL RECOGNITION PARTICLE
From the Department of Laboratory Medicine, Kitasato University School of Medicine, Kanagawa; Department of Clinical Immunology, Kitasato University School of Allied Health Sciences, Kanagawa; Department of Internal Medicine, Kitasato University School of Medicine, Kanagawa; Division of Rheumatic Diseases, Tokyo Metropolitan Ohtsuka Hospital, Tokyo; Institute for Advanced Medical Research, Keio University School of Medicine, Tokyo, Japan; and Divisions of Rheumatology and Clinical Immunology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA. Supported by the Kitasato University Medical Science Fund, a grant from the Japanese Ministry of Welfare, and a grant from the Ministry of Education, Science, Sports and Culture of Japan. T. Satoh, PhD; T. Akahoshi, MD, Department of Laboratory Medicine, Kitasato University School of Medicine; T. Okano, PhD; K. Kubo, BS, Department of Clinical Immunology, Kitasato University School of Allied Health Sciences; T. Matsui, MD; H. Watabe, MD; H. Kondo, MD, Department of Internal Medicine, Kitasato University School of Medicine; T. Ogasawara, MD, Division of Rheumatic Diseases, Tokyo Metropolitan Ohtsuka Hospital; M. Kuwana, MD, Institute for Advanced Medical Research, Keio University School of Medicine; N. Fertig, BS; C.V. Oddis, MD, Divisions of Rheumatology and Clinical Immunology, University of Pittsburgh School of Medicine. Address reprint requests to Dr. T. Akahoshi, Department of Laboratory Medicine, Kitasato University School of Medicine, 1-15-1 Kitasato, Sagamihara, Kanagawa 228-8555, Japan. E-mail: akahoshi@med.kitasato-u.ac.jp Accepted for publication April 8, 2005. |