Division of Nephrology and Kidney Center, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Chuo-ku, Kobe, Hyogo 650-0017, Japan.
Clin Exp Nephrol. 2011 Dec;15(6):810-9. doi: 10.1007/s10157-011-0526-x. Epub 2011 Aug 26.
Immunoglobulin (Ig) G4-related kidney disease characterizing tubulointerstitial nephritis (TIN) is an organ complication recognized in IgG4-related systemic diseases that has some unique aspects compared to other types of TIN. TIN lesions in the kidney can be tumor-like, focal or diffuse. Abnormal urinalysis is usually mild or absent even in the cases with deteriorated renal dysfunction. Some cases are accidentally diagnosed from radiological findings without renal dysfunction and/or abnormal urinalysis. The typical pathological findings of TIN are unique fibrosis and infiltration of massive lymphocytes and IgG4-positive plasma cells. Glomerular lesions are rare but the complication of mesangial proliferative glomerulonephritis and membranous nephropathy is occasionally reported. Pathogenic mechanisms are unclear until now; however, auto-immune and allergic mechanisms have been suspected from laboratory data. The initial response to steroid agents is generally favorable; however, recurrence is possible after the discontinuation of steroid treatment. Long-term follow-up is necessary with continuous systemic checks for organ disorders due to IgG4-related systemic diseases.
免疫球蛋白（Ig）G4 相关肾脏疾病的特征是肾小管间质性肾炎（TIN），是 IgG4 相关系统性疾病的一种器官并发症，与其他类型的 TIN 相比具有一些独特的方面。肾脏中的 TIN 病变可以是肿瘤样的、局灶性的或弥漫性的。即使在肾功能恶化的情况下，异常的尿液分析通常也很轻微或不存在。有些病例是在没有肾功能障碍和/或尿液分析异常的情况下偶然从影像学检查中诊断出来的。TIN 的典型病理表现是独特的纤维化和大量淋巴细胞及 IgG4 阳性浆细胞浸润。肾小球病变很少见，但偶尔会出现系膜增生性肾小球肾炎和膜性肾病的并发症。发病机制至今仍不清楚；然而，从实验室数据中怀疑存在自身免疫和过敏机制。对类固醇药物的初始反应通常是良好的；然而，在类固醇治疗停止后可能会复发。由于 IgG4 相关系统性疾病，需要进行长期的随访，并对器官疾病进行持续的系统性检查。
