Table 2 Mayo Clinic proposed diagnostic criteria of IgG4-TIN

TIN IgG4-RKD can be confirmed by the presence of tubulointerstitial nephritis with >10 IgG4+ plasma cells/hpf in the most concentrated field, plus at least one of the following:

• Histology:

  ο Tubular basement membrane immune complex deposits by immunofluorescence, immunohistochemistry, and/or electron microscopy

• Imaging:

  ο Small peripheral low-attenuation cortical nodules, round or wedge-shaped lesions, or diffuse patchy involvement

• Serology:

  ο Elevated serum IgG4 or total IgG level

• Other organ involvement such as the following:

  ο AIP, sclerosing cholangitis, inflammatory masses of any origin, sialadenitis, inflammatory aortic aneurysm, lung involvement, retroperitoneal fibrosis