Myasthenia gravis (MG) is an autoantibody-mediated disease of the neuromuscular junction. The neuromuscular junction damage associated with MG is caused by anti-acetylcholine receptor (AChR) antibody and complements. Recently, eculizumab (an anti-C5 monoclonal antibody) was approved for patients with anti-AChR antibody-positive generalized refractory MG. Here, we report a Japanese man with MG who well responded to eculizumab, but experienced acute severe worsening of myasthenic symptoms 2 months after its discontinuation. Plasmapheresis did not improve his symptoms; hence, eculizumab was re-administered, resulting in a dramatic response within a week. This is an informative case because eculizumab discontinuation in patients with MG has been very rarely reported. If eculizumab treatment is clinically well effective and AChR antibody titer does not decrease, clinicians should be aware that acute and critical deterioration of MG may occur after the eculizumab discontinuation.

中文翻译：

---

依库珠单抗停药后肌无力症状严重恶化

重症肌无力（MG）是一种自身抗体介导的神经肌肉接头疾病。与 MG 相关的神经肌肉接头损伤是由抗乙酰胆碱受体 (AChR) 抗体和补体引起的。最近，依库珠单抗（一种抗 C5 单克隆抗体）被批准用于抗 AChR 抗体阳性的全身难治性 MG 患者。在这里，我们报告了一名日本 MG 男性，他对依库珠单抗反应良好，但在停药 2 个月后出现肌无力症状急性严重恶化。血浆置换并没有改善他的症状；因此，依库珠单抗被重新给药，在一周内产生了显着的反应。这是一个信息量大的案例，因为很少有 MG 患者停用依库珠单抗的报道。