Figure 4.

Pathologic findings of acute tubulointerstitial nephritis (patient 1). Light microscopy: (A) Massive interstitial inflammatory infiltrates with fibrosis (Masson’s trichrome, ×40) and (B) Mixed inflammatory cells infiltrated the tubular epithelium (tubulitis) and interstitium were observed. Large numbers of mononuclear cells, neutrophils, eosinophils, and plasma cells were present (hematoxylin and eosin, ×400). Electron microscopy: (C) The glomerulus showed a relatively normal appearance. No electron-dense deposits with a normal thickness of basement membrane and intact foot processes were present (×2500, 80 kv).