Table 2.

Summary of clinical, endoscopic and pathological features of gastrointestinal irAEs

	Gastrointestinal irAEs
Clinical features	Acute onset
	Mild to life‐threatening diarrhea, bowel perforation in severe patients
	Severity of gastrointestinal differs in different ICIs
	Higher risk in patients with a medical history of inflammatory bowel disease
Endoscopic features	Diverse endoscopic manifestations; Rectum often spared; left colon often involved; diffuse lesion or segmental lesions
Pathological features	IBD‐like (increased basal plasma cells, crypts and apoptotic bodies are more common) Lymphocytic colitis‐like Celiac disease‐like (mostly seen in upper gastrointestinal tract) GVHD like
Immune changes	Clear immune pathogenesis
	CD4+ based T lymphocyte proliferation
	Th1/Th17 upregulation
	Interaction with intestinal microbiota

IBD, inflammatory bowel disease; ICIs, immune‐checkpoint inhibitors; GVHD, graft versus host disease.