毛细血管袢腔内单克隆IgM沉积病

Intracapillary monoclonal IgM deposits disease

慢性肾脏病(CKD)老年男性患者,以少量蛋白尿,大量镜下血尿起病,CKD基础上出现急性肾损伤,肾外表现有脑梗塞,贫血,免疫固定电泳见IgMκ型单克隆免疫球蛋白条带,骨髓流式细胞检测提示克隆性浆细胞0.12%,血冷球蛋白阴性,冷凝集素试验阳性,低补体血症。肾活检病理示肾小球增生性病变,肾小球毛细血管袢腔内及肾间质小动脉管腔内较多PAS强阳性的栓塞,免疫荧光IgM-κ沉积,电镜下电子致密物无特殊超微结构。最终诊断为毛细血管袢腔内单克隆IgM沉积病。

A 71-year-old man presented with proteinuria and hematuria,acute kidney injury on chronic kidney disease,as well as extrarenal manifestations of cerebral infarction,anemia,monoclonal IgM-κ in serum immunofixation electrophoresis,positive in cold agglutinins test without cryoglobulinemia,decreased C3 and C4.Kidney biopsy showed mild proliferative glomerulonephritis with numerous PAS-positive protein thrombi intracapillary and in arterial lumen,Immunoflurerscence indicated IgM and kappa light chain staining in glomeruli and arterial lumen.Electron dense deposits were observed in the mesangial,subendothelial area and intracapillary without oranigzed ultrastructure,and severe subendothelial widening on electron-microscopic examination.The final diagnosis was intracapillary monoclonal IgM deposits disease.