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International Journal of Rheumatology
Volume 2012 (2012), Article ID 609795, 9 pages
http://dx.doi.org/10.1155/2012/609795
Clinical Study

Immunohistochemical Characteristics of IgG4-Related Tubulointerstitial Nephritis: Detailed Analysis of 20 Japanese Cases

1Division of Rheumatology, Department of Internal Medicine, Kanazawa University Hospital, Kanazawa, Ishikawa 920-8641, Japan
2Yamaguchi's Pathology Laboratory, Matsudo, Chiba 270-2231, Japan
3Division of Clinical Nephrology and Rheumatology, Niigata University Graduate School of Medical and Dental Sciences, Niigata 951-8510, Japan
4Division of Nephrology and Rheumatology, Department of Internal Medicine, Faculty of Medicine, Fukuoka University, Fukuoka 814-0180, Japan
5Division of Nephrology and Kidney Center, Kobe University Graduate School of Medicine, Kobe 650-0017, Japan
6Department of Pathology, Faculty of Medicine, Fukuoka University, Fukuoka 814-0180, Japan
7Tokyo Kidney Research Institute, Tokyo 113-0023, Japan
8First Department of Internal Medicine, Sapporo Medical University School of Medicine, Sapporo 060-8543, Japan
9Department of Hematology and Immunology, Kanazawa Medical University, Kanazawa 920-0293, Ishikawa, Japan
10Department of Internal Medicine, Nagaoka Red Cross Hospital, Nagaoka 940-2085, Japan

Received 30 November 2011; Accepted 11 June 2012

Academic Editor: Vikram Deshpande

Copyright © 2012 Mitsuhiro Kawano et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Although tubulointerstitial nephritis with IgG4+ plasma cell (PC) infiltration is a hallmark of IgG4-related kidney disease (IgG4-RKD), only a few studies are available about the minimum number of IgG4+ PC needed for diagnosis along with IgG4+/IgG+ PC ratio in the kidney. In addition, the significance of the deposition of IgG or complement as a reflection of humoral immunity involvement is still uncertain. In this study, we analyzed 20 Japanese patients with IgG4-RKD to evaluate the number of IgG4+ PCs along with IgG4+/IgG+ PC ratio and involvement of humoral immunity. The average number of IgG4+ PCs was 43.8/hpf and the average IgG4+/IgG+ or IgG4+/CD138+ ratio was 53%. IgG and C3 granular deposits on the tubular basement membrane (TBM) were detected by immunofluorescence microscopy in 13% and 47% of patients, respectively. Nine patients had a variety of glomerular lesions, and 7 of them had immunoglobulin or complement deposition in the glomerulus. In conclusion, we confirmed that infiltrating IgG4+ PCs > 10/hpf and/or IgG4/IgG (CD138)+ PCs > 40% was appropriate as an item of the diagnostic criteria for IgG4-RKD. A relatively high frequency of diverse glomerular lesions with immunoglobulin or complement deposits and deposits in TBM may be evidence of immune complex involvement in IgG4-related disease.