Fig. 2

a Tubular necrosis. The left image shows a typical sample, and the right image shows tubular necrosis (vacuolated cells and sloughed, necrotic cells in tubular lumina, with some tubules lined by a flattened epithelium and some showing frank necrosis). (Periodic acid Schiff staining, × 20). b Tubular atrophy. The left image shows a typical sample, and the right image shows tubular atrophy (tubular basement membranes thickening and wrinkling, with simplified tubular epithelial cells, small round tubules with markedly flattened, uniform intratubular casts, and contraction of the tubular lumen adjacent to intact tubules). (Periodic acid Schiff staining, × 20). c Interstitial lymphocyte infiltration. Upper figures: The left image shows a typical sample, and the right image shows interstitial lymphocyte infiltration. The renal cortex shows a diffuse interstitial, predominantly mononuclear, inflammatory infiltrate with no changes in the glomerulus. (Periodic acid Schiff staining, × 10). Lower figures: The left image shows a typical sample, and the right image shows interstitial lymphocyte infiltration. Tubules in the center of the field are separated by inflammation and edema. (Periodic acid Schiff staining, × 20s). d Interstitial fibrosis. The left image shows a typical sample, and the right image shows interstitial fibrosis (connective tissue expansion through tubulointerstitial parenchyma and tubular loss). (Masson’s trichrome, × 10). e Global glomerulosclerosis score. The left figures show a typical sample, and the right figures shows GGS (a solidified nonretracted glomerular tuft with often recognizable tuft adhesions, splitting of Bowman’s capsule, and prominent periglomerular fibrosis). (Upper figures, periodic acid Schiff staining, × 20 and lower figures, H&E staining)