Takada Tetsuya, Hirakata Michito, Suwa Akira, Kaneko Yuko, Kuwana Masataka, Ishihara Tadayuki, Ikeda Yasuo
Division of Rheumatology, Department of Internal Medicine, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan.
Mod Rheumatol. 2009;19(2):156-64. doi: 10.1007/s10165-008-0139-8. Epub 2008 Dec 17.
To elucidate the clinical and histopathological features associated with autoantibodies to the signal recognition particle (SRP), we have studied 23 Japanese patients with this specificity among 3,500 patients with polymyositis/dermatomyositis and other connective tissue diseases. Anti-SRP antibodies were determined based on analysis of RNA and protein components by immunoprecipitation assays. The pathological analysis was performed by using special stainings including alkaline phosphatase, myosin ATPase, and modified Gomori trichrome stainings. Twenty-one (92%) of these 23 patients had myositis, 8 of whom (38%) required cytotoxic agents or intravenous immunoglobulin therapy in addition to corticosteroid therapy. Four patients (16%) had rheumatoid arthritis, two of whom had no features of myositis. Muscle biopsy specimens of 11 patients were examined histologically in detail. All 11 had muscle fiber necrosis and/or regeneration, but only one had infiltration of inflammatory cells. Six of the 11 (55%) patients showed type I fiber predominance by ATPase staining, while eight control myositis patients without anti-SRP antibodies did not. There was no correlation of other neurogenic features in histology with the presence of anti-SRP antibodies. These studies suggest that anti-SRP autoantibodies are most likely to be related to myopathies that are resistant to corticosteroid therapy and without inflammation histopathologically.
为阐明与信号识别颗粒（SRP）自身抗体相关的临床和组织病理学特征，我们在3500例多发性肌炎/皮肌炎及其他结缔组织病患者中研究了23例具有这种特异性的日本患者。通过免疫沉淀分析RNA和蛋白质成分来测定抗SRP抗体。病理分析采用包括碱性磷酸酶、肌球蛋白ATP酶和改良的Gomori三色染色等特殊染色方法。这23例患者中有21例（92%）患有肌炎，其中8例（38%）除皮质类固醇治疗外还需要细胞毒性药物或静脉注射免疫球蛋白治疗。4例（16%）患有类风湿关节炎，其中2例无肌炎表现。对11例患者的肌肉活检标本进行了详细的组织学检查。所有11例均有肌纤维坏死和/或再生，但只有1例有炎性细胞浸润。11例患者中有6例（55%）经ATP酶染色显示I型纤维占优势，而8例无抗SRP抗体的对照肌炎患者则无此现象。组织学上的其他神经源性特征与抗SRP抗体的存在无关。这些研究表明，抗SRP自身抗体很可能与对皮质类固醇治疗耐药且组织病理学上无炎症的肌病有关。
