Microscopic colitis (MC) is a chronic inflammatory disease of the colon that presents with chronic, nonbloody watery diarrhea and only few or no endoscopic abnormalities. Histologic examination discriminates lymphocytic (LyC; presence ?20 intraepithelial lymphocytes per 100 surface epithelial cells) collagenous (CC; colonic subepithelial collagen band >10 ?m in diameter).1,2 MC not otherwise sp...

Duodenal biopsy is an essential component in the diagnosis of celiac disease (CD). Although the classical findings of increased number of intraepithelial lymphocytes, crypt hyperplasia and villous atrophy are very characteristic, the diagnosis cannot be achieved on the basis of histopathology alone, as there are many entities that can mimic CD and a close collaboration of a pathologist and a cl...

The upper digestive tract is routinely scoped for several causes of malabsorption, and the number of duodenal biopsy specimens has increased notably in the last 10 years. Gluten-sensitive enteropathy (GSE) is an autoimmune disease, which shows an increasing prevalence worldwide and requires a joint clinico-pathological approach. The classical histopathology of GSE with partial or total villous ...

The proportional and absolute numbers of circulating thymus dependent lymphocytes (T cells) were reduced in untreated patients with coeliac disease but were normal after treatment with a gluten free diet. There was an inverse correlation between circulating T cell numbers and jejunal intraepithelial lymphocytes. This evidence suggests a possible role for T cells in the pathogenesis of coeliac d...

We have examined whether the thymus can produce immature T cell precursors for subsequent positive selection in the periphery. Using the intestine as a model system, we demonstrate that extrathymic MHC class I molecules positively select thymus-derived TCR-alpha beta CD8+ intestinal intraepithelial lymphocytes. Grafting of MHC class I+ thymus onto MHC class I- hosts resulted in the generation o...

A quantitative histological study was performed on small intestinal biopsies from eight ambulatory patients with HIV infection (AIDS/AIDS-related complex, ARC) and compared with those from 16 normal subjects. Enteropathy was assessed by measurement of villus area, crypt length and mitotic count, as well as duodenal counts of intraepithelial lymphocytes, mucosal mast cells and goblet cells. Ente...