56例肾淀粉样变性的病理分型及临床分析

 目的 分析肾淀粉样变性的组织学特点及临床表现，提高对该病的诊断水平。方法 回顾性分析复旦大学基础医学院病理学系2007年1月至2016年7月肾活检病例中确诊的56例肾淀粉样变性，经免疫染色检测肾组织中免疫球蛋白轻链κ、λ及淀粉样蛋白A（amyloid A，AA）的表达，并分析病理形态学特点及临床表现。结果 56例肾淀粉样变性的发病年龄为（58.6±9.3）岁，高峰年龄段为50~69岁。42例（75.0%）临床表现为肾病综合征，10例（17.9%）伴2个或以上多器官淀粉样物质沉积。刚果红染色、偏振光显微镜及电镜检查显示淀粉样物广泛沉积于肾小球、肾小管基膜、间质及血管壁，肾小球重度沉积者24 h尿蛋白定量显著高于轻度沉积者。43例（76.8%）为AL型（36例AL λ型、7例AL κ型），3例（5.4%）为AA型，其余10例（17.9%）免疫染色均为阴性。46例确定分型的病例中，免疫染色显示多种免疫球蛋白及补体轻度沉积于各型尤其AL λ型，电镜下多未发现电子致密物沉积，提示为非特异性沉积。电镜检查显著提高早期病变的检出率。结论 AL λ型是本组肾淀粉样变性最常见的病理类型；电镜检查可显著提高其早期病变的确诊率；应常规应用免疫染色确定前体蛋白类型，必要时应进行质谱分析。

Pathological classification and clinical analysis of 56 cases of renal amyloidosis

Objective To analyze the clinical and pathological characteristics of renal amyloidosis and to improve the diagnosis accuracy and furthermore the therapeutic effect. Methods We retrospectively analyzed the clinical and pathological data of 56 patients diagnosed with renal amyloidosis during the period from Jan 2007 to Jul 2016.The cases were classified by immunostaining with antibodies against κ-light chain,λ-light chain,and amyloid A (AA) on renal biopsies. Results Renal amyloidosis commonly affected elderly patients (mean age 58.6±9.3 years at onset).The peak onset age was 50-69 years.Forty-two cases (75.0%) displayed typical nephrotic syndrome.Ten patients (17.9%) suffered 2 or more than 2 systems' amyloid deposition.Amyloidosis established by Congo red staining,polarized light microscopy and electron microscopy involved the glomeruli,the tubular basement membrane,the interstitium as well as the small vessels.The extent of glomerular amyloid deposition was positively correlated with 24 h proteinuria level.Forty-three cases (76.8%) patients among 56 cases were type AL (36 cases of AL λ,7 cases of AL κ).Three cases (5.4%) were type AA.The other 10 (17.9%) cases could not be classified due to the negative immunostaining on paraffin tissue.The unspecific depositions of immunoglobins and complements in glomeruli were commonly observed by immunostaining,especially in type AL λ. Electron microscopy significantly improved the detection ratio of early lesions. Conclusions Type AL λ is the most common type of renal amyloidosis in our lab. Electron microscopy is crucial for the diagnosis of early amyloidosis. Immunostaining should be performed routinely for the classification of amyloidosis. Mass spectrometry should be performed if necessary.