Characterization of gastrointestinal inflammatory cell type in equine glandular gastric disease

OBJECTIVE To compare small intestinal inflammation with gastric inflammation in horses with and without equine gastric glan- dular disease (EGGD), we evaluated endoscopic, macroscopic, and microscopic findings of the glandular stomach and microscopic findings of the small intestine.ANIMALS36 horses.METHODSHorses underwent endoscopy and were scored for EGGD. After euthanasia, stomachs were collected and mac-roscopically evaluated. Normal pyloric mucosa, glandular lesions, and small intestinal (duodenum, mid-jejunum, and ileum) samples were collected and processed for microscopic examination. Cellular infiltrate was scored. Immunohistochemistry (CD3, CD20, and Iba-1) was performed on the ventral pylorus and small intestine of horses with mild to moderate lymphoplasmacytic infiltrate. A Spearman's correlation coefficient was used to evaluate the relationship of EGGD grade with gastric glandular inflammation, and the relationships of cellular infiltrate type and severity among glandular stomach, duodenum, jejunum, and ileum.RESULTSGastrointestinal inflammation was common, with gastric inflammatory infiltrate identified in 92%, duodenal inflam- matory infiltrate in 83%, jejunal inflammatory infiltrate in 92%, and ileal inflammatory infiltrate in 92% of horses. Endoscopic evidence of gastric disease (hyperemia or EGGD grade >= 2/4) was not associated with the presence or severity of duodenal, jejunal, or ileal inflammation. Gastric lymphoplasmacytic inflammation grade >= 2 was associ-ated with duodenal lymphoplasmacytic inflammation grade >= 2. This was a convenience sample of horses presenting for euthanasia. Medical history (including deworming history) was unknown.CLINICAL RELEVANCEGastric lymphoplasmacytic inflammation is associated with duodenal lymphoplasmacytic inflammation but not more distal small intestinal inflammation. Intestinal inflammation is not associated with endoscopic findings (hyper- emia or EGGD grade >= 2/4).