Takako Saeki1, Mitsuhiro Kawano2, Tasuku Nagasawa3, Yoshifumi Ubara4, Yoshinori Taniguchi5, Motoko Yanagita6, Shinichi Nishi7, Michio Nagata8, Satoshi Hisano9, Yutaka Yamaguchi10, Hideki Nomura11, Takao Saito12, Hitoshi Nakashima13. 1. Department of Internal Medicine, Nagaoka Red Cross Hospital, Senshu 2-297-1, Nagaoka, Niigata, 940-2085, Japan. saekit@nagaoka.jrc.or.jp. 2. Department of Rheumatology, Graduate School of Medical Science, Kanazawa University, 13-1 Takara-machi, Kanazawa, Ishikawa, 920-8641, Japan. 3. Division of Nephrology, Endocrinology, and Vascular Medicine, Tohoku Univesity Hospital, 1-1 Seiryo-machi, Aoba-ku, Sendai, Miyagi, 980-8574, Japan. 4. Rheumatology Department and Okinaka Memorial Institute for Medical Research, Toranomon Hospital, 2-2-2 Toranomon, Minato-ku, Tokyo, 105-8470, Japan. 5. Department of Endocrinology, Metabolism, Nephrology and Rheumatology, Kochi Medical School Hospital, Kochi University, 185-1 Kohasu, Oko-cho, Nankoku-shi, Kochi, 783-8505, Japan. 6. Department of Nephrology, Graduate School of Medicine, Kyoto University, 54 Shogoin Kawahara-cho, Sakyo-ku, Kyoto, Kyoto, 606-8507, Japan. 7. Division of Nephrology and Kidney Center, Kobe University Graduate School of Medicine, 7-5-2, Kusunoki-cho, Chuo-ku, Kobe, Hyogo, 650-0017, Japan. 8. Department of Pathology, Graduate School of Comprehensive Human Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki, 305-8575, Japan. 9. Department of Pathology, University of Occupational and Environmental Health, 1-1, Iseigaoka, Yahatanishi-ku, Kitakyushu-shi, Fukuoka, 807-8555, Japan. 10. Yamaguchi's Pathology Laboratory, Chiba, Japan. 11. Department of General Medicine, Kanazawa University Hospital, 13-1 Takara-machi, Kanazawa, Ishikawa, 920-8641, Japan. 12. Sanko Clinic, Fukuoka, 4-9-3 Roppon-Matsu, Chuo-ku, Fukuoka, 810-0044, Japan. 13. Division of Nephrology and Rheumatology, Department of Internal Medicine, Faculty of Medicine, Fukuoka University, 7-45-1 Nanakuma, Jonan-ku, Fukuoka, 814-0180, Japan.
Abstract
BACKGROUND: In 2011, the IgG4-related kidney disease (IgG4-RKD) working group of the Japanese Society of Nephrology proposed diagnostic criteria for IgG4-RKD. The aim of the present study was to validate those criteria and develop a revised version. METHODS: Between April 2012 and May 2019, we retrospectively collected Japanese patients with kidney disease, for whom data on serum IgG4 values and/or immunohistological staining for IgG4 in renal biopsy samples were available. These patients were classified as IgG4-RKD or non-IgG4-RKD based on the diagnostic criteria for IgG4-RKD 2011, and the results were evaluated by expert opinion. Accordingly, we developed some revised versions of the criteria, and the version showing the best performance in the present cohort was proposed as the IgG4-RKD criteria for 2020. RESULTS: Of 105 included patients, the expert panel diagnosed 55 as having true IgG4-RKD and 50 as mimickers. The diagnostic criteria for IgG4-RKD 2011 had a sensitivity of 72.7% and a specificity of 90.0% in this cohort. Of the 15 patients with true IgG4-RKD who were classified as non-IgG4-RKD, all lacked biopsy-proven extra-renal lesions, although many had clinical findings highly suggestive of IgG4-RD. The revised version to which "bilateral lacrimal, submandibular or parotid swelling, imaging findings compatible with type 1 autoimmune pancreatitis or retroperitoneal fibrosis" was added as an item pertaining to extra-renal organ(s) improved the sensitivity to 90.9% while the specificity remained at 90.0%. CONCLUSION: The revised version has considerably improved test performance after addition of the new extra-renal organ item (imaging and clinical findings).
BACKGROUND: In 2011, the IgG4-related kidney disease (IgG4-RKD) working group of the Japanese Society of Nephrology proposed diagnostic criteria for IgG4-RKD. The aim of the present study was to validate those criteria and develop a revised version. METHODS: Between April 2012 and May 2019, we retrospectively collected Japanese patients with kidney disease, for whom data on serum IgG4 values and/or immunohistological staining for IgG4 in renal biopsy samples were available. These patients were classified as IgG4-RKD or non-IgG4-RKD based on the diagnostic criteria for IgG4-RKD 2011, and the results were evaluated by expert opinion. Accordingly, we developed some revised versions of the criteria, and the version showing the best performance in the present cohort was proposed as the IgG4-RKD criteria for 2020. RESULTS: Of 105 included patients, the expert panel diagnosed 55 as having true IgG4-RKD and 50 as mimickers. The diagnostic criteria for IgG4-RKD 2011 had a sensitivity of 72.7% and a specificity of 90.0% in this cohort. Of the 15 patients with true IgG4-RKD who were classified as non-IgG4-RKD, all lacked biopsy-proven extra-renal lesions, although many had clinical findings highly suggestive of IgG4-RD. The revised version to which "bilateral lacrimal, submandibular or parotid swelling, imaging findings compatible with type 1 autoimmune pancreatitis or retroperitoneal fibrosis" was added as an item pertaining to extra-renal organ(s) improved the sensitivity to 90.9% while the specificity remained at 90.0%. CONCLUSION: The revised version has considerably improved test performance after addition of the new extra-renal organ item (imaging and clinical findings).