Yamashita Satoshi, Ando Yukio
Department of Neurology, Graduate School of Medical Sciences, Kumamoto University.
Brain Nerve. 2018 Apr;70(4):449-457. doi: 10.11477/mf.1416201017.
Sporadic inclusion body myositis (sIBM) is a chronically progressing inflammatory myopathy most common in the aged population. Asymmetric muscle weakness and waste of the quadriceps and finger and wrist flexor muscles are characteristic features of sIBM. Histological findings suggest the involvement of a crosstalk of inflammatory and myodegenerative mechanisms in the pathogenesis of sIBM. As an etiological clue to sIBM, identification of autoantibodies against cytosolic 5'-nucleotidase 1A (NT5C1A) in plasma and serum samples from patients with sIBM has been attracting attention. So far, various methods with clinical utility have been established to detect anti-NT5C1A autoantibodies. The measurement of the autoantibodies is useful for the diagnosis of sIBM due to its high specificity. Moreover, the autoantibodies may have pathogenic roles in the development of the disease by stimulating catabolic conditions and/or causing dysfunction in protein degradation of skeletal muscles; however, the molecular mechanisms by which the sarcoplasmic autoantigen is recognized and involved in the degeneration of myofibers remain unclear.
散发性包涵体肌炎（sIBM）是一种慢性进行性炎性肌病，在老年人群中最为常见。不对称性肌肉无力以及股四头肌、手指和腕部屈肌的萎缩是sIBM的特征性表现。组织学研究结果提示，炎症和肌纤维变性机制的相互作用参与了sIBM的发病过程。作为sIBM的病因线索，在sIBM患者的血浆和血清样本中鉴定出针对胞质5'-核苷酸酶1A（NT5C1A）的自身抗体一直备受关注。到目前为止，已经建立了多种具有临床应用价值的方法来检测抗NT5C1A自身抗体。由于其高特异性，自身抗体的检测对于sIBM的诊断很有用。此外，自身抗体可能通过刺激分解代谢状态和/或导致骨骼肌蛋白质降解功能障碍而在疾病发展中发挥致病作用；然而，肌浆自身抗原被识别并参与肌纤维变性的分子机制仍不清楚。
