肾脏早期淀粉样变临床病理特点

The clinicopathological features of early renal amyloidosis

目的 探讨光学显微镜尚未表现明显特点的早期肾淀粉样变 (amyloidosis,AL)的临床病理特点及诊断方法。方法 回顾性分析该院 1994～ 2 0 0 1年间诊断的肾AL病例 ,重点对其中 15例光镜未能及时诊断而通过透射电镜诊断的早期AL病例 ,进行临床病理特点的分析 ,并对其肾活检组织进行了轻链蛋白 (κ、λ)的免疫电镜定位检测。结果 15例均为早期肾AL ,发病年龄以中老年为主 ,突出表现为肾病综合征 ,偶见镜下血尿及高血压 ,肾功能正常。多数以肾脏病为初诊症状。肾活检组织光镜观察病变表现轻微 ,可有系膜轻度增生或基底膜空泡变性及轻度增厚 ;免疫荧光表现不一 ,部分病例全部阴性 ,部分表现免疫球蛋白及补体沿系膜区或毛细血管壁不同程度的沉积 ,均有单一品种的轻链蛋白沉积 ;光镜初步诊断为肾小球微小病变 4例 ,轻度系膜增生性肾小球肾炎 5例 ,Ⅰ期膜性肾病 5例和 1例管型肾病 ;电镜观察可见系膜区、基底膜及小动脉壁上的淀粉样纤维分布 ;补作刚果红染色时 ,呈阳性反应 ;免疫电镜可观察到轻链蛋白被标记于淀粉样纤维部位 ,证实 15例均为轻链型AL。结论 电镜检查是发现及早期诊断肾淀粉样变的重要手段 ,单一品种的轻链蛋白沉积有一定的诊断意义 。

Objective To investigate the clinicopathological manifestations of early renal amyloidosis (AL) and its diagnostic criteria. Methods Fifteen cases with early renal amyloidosis admitted from 1994 to 2001 were collected from the hospital, and their clinical and pathological features were reviewed. Of them, the initial diagnoses were not made by depending findings from the light microscopy (LM) and immunofluorescense (IF), but confirmed by electron microscopy (EM) afterwards. Immuno electron microscopy (IEM) were applied for amyloidosis typing. Results Most patients of early renal AL were in the middle to old age. Nephrotic syndrome was the most prominent symptoms and signs accompanying with rare microscopic hematuria and hypertension. Most of them had a normal renal function. Pathological examinations of renal biopsies using LM and IF showed mild mesangial proliferation and mild thickening of glomerular basement membrane (GBM). Immunoglobulins and complements were negative or only scanty in certain cases, but in all cases there was a light chain protein deposition homogeously. There were 4 cases of minimal change glomerlopathy, 5 cases of mild mesangial proliferative glomerulonephritis, 5 cases of stage I membranous nephropathy, and 1 case of cast nephropathy diagnosed with LM . The amyloid fibrils (diameter 8 10 nm) were randomly distributed in the mesangium, along GBM and at the arteriolar wall under EM. Additionaly, Congo red staining was positive. IEM demonstrated that amyloid fibrils labeled with colloid gold was combined with a kind of light chain protein which was confirmed as the light chain type of AL. Conclusions The diagnosis of early renal AL was occasionally neglected by depending only findings of LM and LF. However, special amyloid fibrils can be detected using EM. EM observation is an indispensable technique for the diagnosis of early renal AL and the typing of AL may further be determined by using IEM.