Autoimmune gastritis (AIG) is a condition with many unclarified issues. Circulating autoantibodies targeting the H+/K+-ATPase proton pump of parietal cells are considered markers of AIG, which are used to screen patients with other autoimmune disorders for AIG. However, their diagnostic accuracy in AIG remains unknown.
Active Helicobacter pylori (Hp) infection is detectable in about 25% of AIG patients whose treatment is indicated to reduce inflammation, disease progression and gastric cancer risk. In hypochlorhydric AIG patients bismuth-based eradication regimens without anti-secretory agents may represent an alternative treatment, but, studies on efficacy/ safety of these regimens are lacking.
AIG patients are at increased risk for gastric neoplasms, adenocarcinoma and type 1 carcinoids. In these patients also an increased risk for extra-gastric neoplasms throughout the body has been described, which are poorly investigated.
In AIG, the altered composition of the gastric microbiota due to reduced gastric acid secretion may have a role in gastric carcinogenesis, but data are lacking.
This project is composed of 4 parts to investigate some, not yet clarified issues concerning AIG:
1. To investigate the diagnostic performance of autoantibodies against parietal cells H+, K+-ATPase by an innovative serological assay in a prospective consecutive cohort of naive patients with clinical suspicion of AIG to find out whether these autoantibodies may be considered reliable serological markers of AIG.
2. To investigate the role of bismuth¿based eradication treatment regimens without anti-secretory agents in patients with AIG and active Hp infection by assessing their efficacy and safety.
3. To investigate the risk of extra-gastric neoplasms in patients with AIG and to understand whether surveillance may be needed in this specific clinical setting.
4. To investigate the relationship between the gastric microbiota in patients with AIG and the risk of gastric neoplasms.
