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).