Mitsui T, Okada K, Kuhara T, Hashizume T, Okazaki S, Kawajiri M, Matsumoto T
First Department of Internal Medicine, School of Medicine, The University of Tokushima, Kuramoto-3, Tokushima, 770-8503, Japan.
J Clin Neurosci. 2001 Sep;8(5):454-6. doi: 10.1054/jocn.2000.0824.
A patient with myasthenia gravis developed nephrotic syndrome 3 years after thymectomy. The kidney biopsy specimen revealed mesangial proliferative glomerulonephritis with immune deposits. The glomerular mesangial cells and tubular epithelial cells were sensitive to alpha-bungarotoxin (alpha-BT), a ligand for nicotinic acetylcholine receptor (nAChR), and the binding was inhibited by native alpha-BT, as well as other nAChR ligands, nicotine and d-tubocurarine. In addition, FITC-alpha-BT-neuromuscular junction complexes could also bind to the mesangial cells, and preincubation with unlabeled nAChR inhibited the binding. These findings are consistent with the notion that both nAChR-like protein and anti-nAChR antibody are present in t he mesangial cells of the patient. Although the pathogenetic role of anti-nAChR antibody on the development of glomerulonephritis is unclear, the present observations provide an important insight into the autoimmune-mediated pathophysiological relationship between myasthenia gravis and mesangial proliferative glomerulonephritis.
一名重症肌无力患者在胸腺切除术后3年出现肾病综合征。肾脏活检标本显示为伴有免疫沉积物的系膜增生性肾小球肾炎。肾小球系膜细胞和肾小管上皮细胞对α-银环蛇毒素（α-BT）敏感，α-银环蛇毒素是烟碱型乙酰胆碱受体（nAChR）的一种配体，其结合可被天然α-银环蛇毒素以及其他nAChR配体（尼古丁和筒箭毒碱）抑制。此外，异硫氰酸荧光素-α-银环蛇毒素-神经肌肉接头复合物也能与系膜细胞结合，用未标记的nAChR进行预孵育可抑制这种结合。这些发现与该患者系膜细胞中同时存在nAChR样蛋白和抗nAChR抗体的观点一致。虽然抗nAChR抗体在肾小球肾炎发生中的致病作用尚不清楚，但目前的观察结果为重症肌无力与系膜增生性肾小球肾炎之间的自身免疫介导的病理生理关系提供了重要见解。
