肾轻链沉积病和轻链型淀粉样变的电镜及免疫电镜研究

目的：探讨电镜及免疫电镜方法在肾轻链沉积病(light chain deposition disease，LCDD)和轻链型淀粉样变(amyloid，AL)诊断中的作用。方法：对我院1994年1月至2002年2月间的肾活检病例进行电镜观察，对疑为LCDD及早期AL的病例进行轻链(κ、λ)的免疫电镜标记。结果：6例符合LCDD的诊断，36例符合AL的诊断。LCDD电镜下可见肾小管基底膜外侧、肾小球基底膜内侧、鲍曼囊外侧及小血管壁的点状、颗粒状电子致密物质沉积，其中2例早期病例表现颗粒状物质节段性分布；免疫电镜标记，颗粒状物质被单种轻链标记，其中K轻链4例，λ轻链2例。AL电镜下可见肾小球系膜区、毛细血管壁及小动脉壁的纤维物质分布，其中15例早期病例表现系膜区或／及毛细血管壁的纤维结构呈节段性分布；15例早期AL的免疫电镜标记结果，纤维结构被单种轻链标记，其中κ轻链4例，λ轻链11例。结论：肾脏LCDD及早期AL的诊断需依赖于电镜检查，免疫电镜检查对早期LCDD及早期AL的确诊具有不可替代的作用。

Ultrastructural and immunoelectron microscopic study on light chain deposition diseases and primary amyloidosis of the kidney

OBJECTIVE: To investigate the role of electron microscopy (EM) and immunoelectron microscopy (IEM) in the diagnosis of light chain deposition diseases (LCDD) and primary amyloidosis (AL) of the kidney. METHODS Renal biopsy specimens collected in our hospital from Jan. 1994 to Feb. 2002 were studied by EM, and ultrastructural immunogold labeling for light chains (kappa, Lambda) were made on the cases suggested of LCDD and early stage AL in the preliminary diagnosis. RESULTS: Six cases were diagnosed as LCDD, and punctate, granular, electron-dense material was identified in the outside of tubular basement membrane (TBM), inner layer of glomerular basement membrane (GBM) and vascular walls by EM. Two of which showed interrupted segmental localization of granular material in subendothelial areas of GBM. The granular material was labeled by monotypical light chains (4 cases of kappa chain, 2 cases of Lambda chain). Thirty-six cases were diagnosed as AL. EM revealed fibrillary material distributed in glomerular mesangium, GBM and vascular walls; 15 of them showed segmental distribution of fibrils in mesangium and/or GBM, and were further studied by IEM labeling for light chains. The fibrillary material was labeled by monotypical light chains (4 cases of kappa chain, 11 cases of Lambda chain). CONCLUSION The diagnosis of renal LCDD and early stage of AL depended on EM, IEM is a unique diagnostic tool in early stage of LCDD and AL.