Abstract：
Leukocyte chemotactic factor-2 amyloidosis (ALECT2) is a recently described subtype of amyloidosis. IgG4-related disease is a rare fibroinflammatory condition characterized by dense interstitial lymphoplasmacytic infiltrates and fibrosis. Membranous nephropathy and diabetic nephropathy are common causes of nephrotic syndrome. Here we report a 49-year-old Hispanic male patient with diabetes mellitus who presented with jaundice and pruritus. IgG4-related autoimmune pancreatitis was diagnosed through laboratory workup and ampulla biopsy. He subsequently presented with marked lower extremity edema and nephrotic syndrome. Kidney biopsy showed severe interstitial IgG4-positive plasma cell-rich inflammatory infiltrates and interstitial storiform fibrosis. Immunofluorescence microscopy revealed diffuse and finely granular glomerular capillary wall staining for IgG and the glomeruli were negative for anti-phospholipase A2 receptor. Congo red stain was positive for birefringent deposits in the interstitium, arteriolar walls, and glomeruli. Electron microscopy demonstrated subepithelial immune complex-type electron-dense deposits, thickening of glomerular basement membranes (GBM), and randomly oriented fibrils in the mesangium, GBM, and interstitium. Mass spectrometry identified a peptide profile consistent with ALECT2 amyloidosis. This is the first report of a case with concurrence of ALECT2 amyloidosis, IgG4-related disease involving the kidney, membranous nephropathy, and early diabetic kidney injury.
摘要：
白细胞趋化因子2淀粉样变性（ALECT2）是最近描述的淀粉样变性亚型。IgG4相关疾病是一种罕见的纤维炎症性疾病，其特征是致密的间质淋巴浆细胞浸润和纤维化。膜性肾病和糖尿病肾病是肾病综合征的常见原因。在这里，我们报告了一名49岁的西班牙裔男性糖尿病患者，患有黄疸和瘙痒。通过实验室检查和壶腹活检诊断IgG4相关的自身免疫性胰腺炎。他随后出现明显的下肢水肿和肾病综合征。肾活检显示严重的间质性IgG4阳性浆细胞丰富的炎性浸润和间质间质纤维化。免疫荧光显微镜检查显示IgG的弥散和细颗粒肾小球毛细血管壁染色，肾小球抗磷脂酶A2受体阴性。刚果红染色对间质中的双折射沉积物呈阳性，小动脉壁，和肾小球。电子显微镜显示上皮下免疫复合物型电子致密沉积物，肾小球基底膜（GBM）增厚，和在肾小球膜中随机定向的原纤维，GBM,和间质。质谱鉴定了与ALECT2淀粉样变性一致的肽谱。这是首例并发ALECT2淀粉样变性病例的报告，涉及肾脏的IgG4相关疾病，膜性肾病,和早期糖尿病肾损伤。
