Table 1.

Definitions and classifications of histological changes

	Definitions
Acute and Chronic Inflammation Grades
I	No acute inflammation and no increased chronic inflammation
II	Chronic inflammation only
III	Acute inflammation including acute cryptitis - no abscesses
IV	Acute crypt abscesses in ≤ 10 % of crypts
V	Acute crypt abscesses in > 10 % of crypts
Eosinophilic Inflammation Grades
1	None or ≤ 32 eosinophils/hpf
2	Peak eosinophil count > 32/hpf but without epithelial invasion (< 2 eosinophils in surface epithelium/hpf, < 9 eosinophils in crypt epithelium/hpf)
3	Eosinophilic cryptitis (>9 intraepithelial eosinophils /hpf)
4	Few eosinophil crypt abscesses (≤ 10% of crypts)
5	Many eosinophil crypt abscesses (> 10% of crypts)
Chronic Architectural and Non-architectural Changes (present or absent)
Ulcer/Erosion	Absence of surface epithelium with granulation tissue (ulcer) or disrupted/absent surface epithelium with fibrin deposits (erosion)
Crypt distortion/atrophy	Crypt abnormalities including elongated crypts, branched crypts, atrophic crypts
Surface villiform changes	Villiform changes at the surface
Basal plasmacytosis	Aggregates of plasma cells below crypts and above the muscularis mucosa
Basal lymphoid aggregates	Aggregates of lymphocytes below crypts and above the muscularis mucosa
Paneth cell metaplasia	Paneth-like cells in crypt epithelium
Granuloma	Sarcoid-like granulomas in uninflamed areas (pericryptal granulomas in areas of damaged/inflamed crypts were permitted)