Figure 1.

Representative histology. (A) Immune checkpoint inhibitor–associated acute interstitial nephritis (ICI-AIN; periodic acid–Schiff [PAS] stain). (B) T cell–mediated rejection (TCMR; PAS stain). (C) Antibiotic drug–associated acute interstitial nephritis (Drug-AIN; hematoxylin and eosin stain). (D) Immune checkpoint inhibitor–associated crescentic GN (ICI-GN; Masson trichrome stain). ICI-AIN and TCMR exhibit overlapping histologic appearances characterized by lymphocyte-predominant tubulointerstitial inflammation (red asterisks). Mild intimal arteritis is also present in this case of TCMR (arrow). In contrast, Drug-AIN classically displays an eosinophil-rich interstitial infiltrate (blue asterisk and Inset). This case of ICI-GN shows cellular crescent formation (green asterisk) without significant tubulointerstitial inflammation.