Immunopathological Role of FAS-FASL Apoptotic Pathway in H.pylori CagA Positive Associated Chronic Atrophic Gastritis in Iraqi Patients

Abstract

Chronic atrophic gastritis (CAG) characterized by chronic inflammation of gastric mucosa with loss of gastric glandular cells and replacement by intestinal-type epithelium and fibrous tissue. CAG may be associated with Helicobacter pylori infection. The main Objective was to determine the role of FAS-FASL apoptotic pathway in H.pylori CagA positive associated chronic atrophic Gastritis .Forty five CAG patients and (20) control were chosen. Multiple gastric mucosal biopsies taken for rapid urease test and slides preparation from paraffin blocks. Biotinylated DNA probe for human FAS, FASL, genes used for detection of their expression in tissue lymphocytes and gastric epithelial cells using ISH technique. Biotinylated DNA probe for H.pylori Cag A gene used for detection of its expression in gastric epithelial cells. Insitu CagA was detected in (46.66%) of CAG cases. The toxin was not detected among control .Tissue FAS mRNA expression was higher than lymphocytes FAS mRNA among CagA positive and CagA negative CAG cases. Tissue infiltrating lymphocytes (TILs) FAS expression was higher among Cag Apositive than Cag A negative CAG cases. Significant difference in FASL mRNA   between Gastroduodenal tissue (GDT) and TILs among Cag A positive and Cag A negative CAG cases was detected. Lymphocyte grade has significant positive correlation with tissue FAS mRNA expression (p=0.005).Tissue FAS mRNA expression has significant positive correlation with CagA (p=0.000). Lymphocyte FAS mRNA expression has significant positive correlation with lymphocyte FASL mRNA expression (p=0.03) and CagA (p=0.000) .Tissue FasL has significant negative correlation with CagA (p=0. 001). Lymphocyte FASL mRNA expression has significant positive correlation with CagA (p=0.008).In Conclusions, FAS-FASL pathway play vital role in Immunopathology of H.pylori Cag A+ associated gastritis that leads finally to atrophic changes.

Keywords: atrophic gastritis, Fas, FasL, H.pylori