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 glandular disease (EGGD), we evaluated endoscopic, macroscopic, and microscopic findings of the glandular stomach and microscopic findings of the small intestine.

ANIMALS: 36 horses.

METHODS

Horses underwent endoscopy and were scored for EGGD. After euthanasia, stomachs were collected and macroscopically 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.

RESULTS

Gastrointestinal inflammation was common, with gastric inflammatory infiltrate identified in 92%, duodenal inflammatory 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 associated with duodenal lymphoplasmacytic inflammation grade ≥ 2. This was a convenience sample of horses presenting for euthanasia. Medical history (including deworming history) was unknown.

CLINICAL RELEVANCE: Gastric lymphoplasmacytic inflammation is associated with duodenal lymphoplasmacytic inflammation but not more distal small intestinal inflammation. Intestinal inflammation is not associated with endoscopic findings (hyperemia or EGGD grade ≥ 2/4).