Figure 1.

IgG4-related tubulointerstitial nephritis with membranous glomerulonephritis. (a) Periodic acid methenamine silver (PAM) staining reveals spike and bubbling formation (PAM ×400). (b) Immunofluorescence staining for IgG reveals granular deposits along the glomerular capillary walls (×400). (c) Many IgG4+ plasma cells are seen in the interstitium (IgG4 ×400). (d) Electron microscopy (EM) shows subepithelial deposits and variable reabsorption of these deposits with thickened glomerular basement membrane. (Ehrenreich-Churg stage II–IV).