IgG4-related disease is characterized by a high level of serum IgG4 and dense infiltration of IgG4-positive plasma cells into multiple organs, with the kidney being one representative target. Although several sets of diagnostic criteria for autoimmune pancreatitis (AIP) are available and renal lesion is recognized as an extrapancreatic manifestation of AIP, it is difficult to differentiate IgG4-related tubulointerstitial nephritis (TIN) without
AIP from other types of TIN.
Diagnostic criteria for IgG4-related kidney disease (IgG4-RKD)
1. Presence of some kidney damage, as manifested by abnormal urinalysis or urine marker(s) or decreased kidney function with either elevated serum IgG level, hypocomplementemia, or elevated serum IgE level
2. Abnormal renal radiologic findings:
a. Multiple low-density lesions on enhanced computed tomography
b. Diffuse kidney enlargement
c. Hypovascular solitary mass in the kidney
d. Hypertrophic lesion of renal pelvic wall without irregularity of the renal pelvic surface
3. Elevated serum IgG4 level (IgG4 ≥ 135 mg/dl)
4. Histologic findings in the kidney
a. Dense lymphoplasmacytic infiltration with infiltrating IgG4-positive plasma cells >10/high power field (HPF) and/or IgG4/IgG-positive plasma cells >40%
b. Characteristic fibrosis surrounding nests of lymphocytes and/or plasma cells
5. Histologic findings in extra-renal organ(s):
Dense lymphoplasmacytic infiltration with infiltrating IgG4-positive plasma cells >10/HPF and/or IgG4/IgG-positive plasma cells >40% in extra-renal organ(s)
Definite: 1) + 3) + 4) a, b
2) + 3) + 4) a, b
2) + 3) + 5)
1) + 3) + 4) a + 5)
Probable: 1) + 4) a, b
2) + 4) a, b
2) + 5)
3) + 4) a, b
Possible: 1) + 3)
2) + 3)
1) + 4) a
2) + 4) a
Appendix:
1. Clinically and histologically, the following diseases should be excluded: Wegener’s granulomatosis, Churg–Strauss syndrome, extramedullary plasmacytoma
2. Radiologically, the following diseases should be excluded: malignant lymphoma, urinary tract carcinomas, renal infarction and pyelonephritis (rarely, Wegener’s granulomatosis, sarcoidosis and metastatic carcinoma)
3. Cases with suspected disease according to the diagnostic algorithm are classified into probable or possible IgG4-RKD according to these criteria
References:
- Saeki T, Kawano M, Nagasawa T, Ubara Y, Taniguchi Y, Yanagita M, Nishi S, Nagata M, Hisano S, Yamaguchi Y, Nomura H, Saito T, Nakashima H. Validation of the diagnostic criteria for IgG4-related kidney disease (IgG4-RKD) 2011, and proposal of a new 2020 version. Clin Exp Nephrol. 2021 Jan 4. [Medline]
- Wallace ZS, Naden RP, Chari S, Choi HK, Della-Torre E, Dicaire JF, et al. The 2019 American College of Rheumatology/European League against rheumatism classification criteria for IgG4-related disease. Ann Rheum Dis. 2020;79(1):77–87. [Medline]
- Kawano M, Saeki T, Nakashima H, Nishi S, Yamaguchi Y, Hisano S, Yamanaka N, Inoue D, Yamamoto M, Takahashi H, Nomura H, Taguchi T, Umehara H, Makino H, Saito T. Proposal for diagnostic criteria for IgG4-related kidney disease. Clin Exp Nephrol. 2011 Oct;15(5):615-626. [Medline]
Created Jan 21, 2021.