Ⅲ型胶原肾小球病的形态学观察

目的了解Ⅲ型胶原肾小球病的形态学改变,并对Ⅲ型胶原可能的细胞来源进行初步探讨。方法对3例肾活检组织进行光镜、免疫荧光、电镜和Ⅰ、Ⅲ、Ⅳ型胶原及d平滑肌肌动蛋白(α-SMA)的免疫组织化学染色(SP法)观察。结果2例患者临床表现为肾病综合征,其中1例伴高血压,第3例表现为肾功能不全和肾性高血压。3例均无肾病家族史。光镜检查可见肾小球基膜内和系膜区弥漫性过碘酸-希夫反应阳性物质沉积,系膜细胞无明显增生。电镜检查在基膜内疏松层和系膜区可见大量胶原纤维沉积,系膜细胞胞膜下平行排列的束状微丝明显增加。免疫组织化学显示这些胶原纤维为Ⅲ型胶原,Ⅰ型和Ⅳ型胶原阴性,同时系膜区多数系膜细胞α-SMA阳性。结论Ⅲ型胶原肾小球病光镜、电镜及免疫组织化学上都有其特殊的病理改变。肾小球内激活的系膜细胞可能是Ⅲ型胶原的来源。

Collagen type III glomerulopathy: a morphologic study

OBJECTIVE: To study the morphologic changes of collagen type III glomerulopathy and to investigate the possible cellular origin for collagen III production. METHODS: Light microscopy, immunofluorescent staining, immunohistochemistry (for collagen I, III and IV and alpha-SMA) and electron microscopy studies on 3 renal biopsy cases of collagen type III glomerulopathy were performed. RESULTS: Two cases presented with nephrotic syndrome, one of which was associated with systemic hypertension. The third case showed renal impairment and renal hypertension. None had any known family history of renal diseases. Light microscopy showed diffuse thickened glomerular basement membrane and expanded mesangium with deposition of weakly PAS-positive homogeneous material not associated with mesangial cell proliferation. Electron microscopy revealed massive collagen fiber deposits in the subendothelial spaces and mesangium. The mesangial cells also contained bundles of microfilaments in the subplasmalemmal regions. Immunohistochemically, the diffuse positivity for type III collagen corresponded to the homogeneous material seen under light microscopy. The staining for type I and IV collagens was negative. Alpha-SMA was expressed in many mesangial cells. CONCLUSIONS: The diagnosis of collagen type III glomerulopathy can be made on the basis of detailed morphologic examination and ancillary investigations. It is possible that activated mesangial cells may be the cellular origin of collagen III.