Emerging gastritides

Upper Gastrointestinal Manifestations of Inflammatory Bowel Disease

Although the features of lower gastrointestinal tract inflammation associated with ulcerative colitis and Crohn disease are generally familiar to pathologists, there is less awareness of and familiarity with the manifestations of inflammatory bowel disease in the esophagus, stomach, and duodenum. Nonetheless, their diagnosis has therapeutic and possibly prognostic implications, potentially foretelling severe complications. The recognition that ulcerative colitis can affect gastrointestinal organs proximal to the large intestine and terminal ileum represents a revision of concepts ingrained among generations of physicians. This article reviews the pathologic features and clinical significance of esophagitis, gastritis, and duodenitis associated with inflammatory bowel disease.

Concept of Crohn's disease being conditioned by four main components, and irritable bowel syndrome being an incomplete Crohn's disease

Several mechanisms have been proposed for the development of Crohn's disease. Evidence in favour of a unifying 4-component concept to explain the development of Crohn's disease is presented. The four components are a genetic predisposition to an increased intestinal permeability, the key and initial triggering factor being an oral-pharyngeal bacterium that increases the mucosal permeability of the small intestine with only a minimal inflammatory reaction, an adherent-invasive strain of Escherichia coli that penetrates the mucosa and causes an acute inflammatory reaction in the intestinal wall, and finally a secondary invasion of bacteria causing the chronic inflammatory characteristics. Irritable bowel syndrome (IBS) is a functional bowel disorder with intermittent symptoms of varying intensity. Clinically, there is evidence to suggest a link between IBS patients with diarrhoea and patients with Crohn's disease. The common denominator and initial trigger for IBS with diarrhoea and Crohn's disease seems to be an increased small intestinal permeability, probably caused by an oral-pharyngeal bacterial strain. The important missing factor in IBS patients seems to be the adherent-invasive strain of E. coli in the proximal colon, causing the acute inflammatory process in patients with Crohn's disease. IBS with diarrhoea can then be looked upon as an incomplete Crohn's disease.

Focal-enhanced gastritis in regressive autism with features distinct from Crohn's and Helicobacter pylori gastritis

BACKGROUND

Immunohistochemistry allowed recent recognition of a distinct focal gastritis in Crohn's disease. Following reports of lymphocytic colitis and small bowel enteropathy in children with regressive autism, we aimed to see whether similar changes were seen in the stomach. We thus studied gastric antral biopsies in 25 affected children, in comparison to 10 with Crohn's disease, 10 with Helicobacter pylori infection, and 10 histologically normal controls. All autistic, Crohn's, and normal patients were H. pylori negative.

METHODS

Snap-frozen antral biopsies were stained for CD3, CD4, CD8, gammadelta T cells, HLA-DR, IgG, heparan sulphate proteoglycan, IgM, IgA, and C1q. Cell proliferation was assessed with Ki67.

RESULTS

Distinct patterns of gastritis were seen in the disease states: diffuse, predominantly CD4+ infiltration in H. pylori, and focal-enhanced gastritis in Crohn's disease and autism, the latter distinguished by striking dominance of CD8+ cells, together with increased intraepithelial lymphocytes in surface, foveolar and glandular epithelium. Proliferation of foveolar epithelium was similarly increased in autism, Crohn's disease and H. pylori compared to controls. A striking finding, seen only in 20/25 autistic children, was colocalized deposition of IgG and C1q on the subepithelial basement membrane and the surface epithelium.

CONCLUSIONS

These findings demonstrate a focal CD8-dominated gastritis in autistic children, with novel features. The lesion is distinct from the recently recognized focal gastritis of Crohn's disease, which is not CD8-dominated. As in the small intestine, there is epithelial deposition of IgG.