Immunoglobulin G4-related kidney diseases: An updated review

Table 6 Two proposed criteria for IgG4-TIN by the Mayo Clinic and the Japanese Society of Nephrology

Criterion	The Mayo Clinic criteria	JSN criteria
Histology	Plasma cell-rich TIN with > 10 IgG4+ plasma cells/HPF in the most concentrated field (mandatory criterion) TBM immune complex deposits by immunofluorescence, immunochemistry, and/or electron microscopy	Dense lymphoplasmacytic infiltrate with > 10 IgG4+ plasma cells/HPF and/or IgG4/IgG+ plasma cell ratio of > 40%; Characteristic storiform fibrosis
Imaging	Small peripheral low-attenuation cortical nodules, round or wedge-shaped lesions, or diffuse patchy involvement	Multiple low-density lesions or enhanced CT, diffuse kidney enlargement, hypovascular solitary nodule, hypertrophic lesion of the renal pelvic wall
Serology	Elevated serum IgG4 or total IgG level	Elevated serum IgG4 or total IgG level
Clinical features	None	Clinical or laboratory evidence of kidney damage
Other organ involvement	Characteristic findings of IgG4-RD in other organs	Characteristic findings of IgG4-RD in other organs
Definite IgG4-TIN	The histologic feature and at least one other feature from imaging, serology or other organ involvement	The histologic feature (a and b) and at least two of other features from imaging, serology or other organ involvement

IgG4-RD: Immunoglobulin G4-related disease; IgG4-TIN: Immunoglobulin G4-related tubulointerstitial nephritis; CT: Computed tomography.