Table S2. Histological score.

Category	Finding	0 (none)	1 (mild)	2 (moderate)	3 (severe)
Mucosal epithelium	Ulceration	None	Mild surface	Moderate	Extensive full thickness
Crypts	Mitotic activity	Lower third	Mild middle third	Moderate middle third	Upper third
	Mucus depletion	None	Mild	Moderate	Severe
Lamina propria	Mononuclear infiltrate	None	Mild	Moderate	Severe
	Granulocyte infiltrate	None	Mild	Moderate	Severe
	Vascularity	None	Mild	Moderate	Severe
	Fibrin deposition	None	Mucosal	Submucosal	Transmural
Submucosal	Mononuclear infiltrate	None	Mild	Moderate	Severe
	Granulocyte infiltrate	None	Mild	Moderate	Severe
	Edema	None	Mild	Moderate	Severe

Histological score = sum of all parameter scores. Total possible score is 30.