No abstract

Coeliac disease is the manifestation of an immune hypersensitivity reaction towards gluten and related proteins, in genetically predisposed people. Although the precise pathogenesis of this condition remains to be fully elucidated, it is probably multifactorial in origin. The diagnosis of coeliac disease has traditionally depended on intestinal biopsies alone; nowadays, the diagnosis has been expanded to include an array of serological markers. This review is intended to offer pathologists an update of the relevant history and immunopathology pertaining to coeliac disease and also to offer recommendations on the ongoing responsibilities of the pathologist in the diagnosis and reporting of coeliac disease.

Background & Aims The Helicobacter pylori toxin vacuolating cytotoxin (VacA) promotes gastric colonization and its presence (VacA+) is associated with more-severe disease. The exact mechanisms by which VacA contributes to infection are unclear. We previously found that limited exposure to VacA induces autophagy of gastric cells, which eliminates the toxin; we investigated whether autophagy serves as a defense mechanism against H pylori infection. Methods We investigated the effect of VacA on autophagy in human gastric epithelial cells (AGS) and primary gastric cells from mice. Expression of p62, a marker of autophagy, was also assessed in gastric tissues from patients infected with toxigenic (VacA+) or nontoxigenic strains. We analyzed the effect of VacA on autophagy in peripheral blood monocytes obtained from subjects with different genotypes of ATG16L1, which regulates autophagy. We performed genotyping for ATG16L1 in two cohorts of infected and uninfected subjects. Results Prolonged exposure of AGS and mouse gastric cells to VacA disrupted induction of autophagy in response to the toxin, because the cells lacked cathepsin-D in autophagosomes. Loss of autophagy resulted in the accumulation of p62 and reactive oxygen species. Gastric biopsies samples from patients infected with VacA+, but not nontoxigenic strains of H pylori, had increased levels of p62. Peripheral blood monocytes isolated from individuals with polymorphisms in ATG16L1 that increase susceptibility to Crohn's disease had reduced induction of autophagy in response to VacA+ compared to cells from individuals that did not have these polymorphisms. The presence of the ATG16L1 Crohn’s disease risk variant increased susceptibility to H pylori infection in 2 separate cohorts. Conclusions Autophagy protects against infection with H pylori; the toxin VacA disrupts autophagy to promote infection, which could contribute to inflammation and eventual carcinogenesis.