Immunohistochemical detection of Helicobacter pylori vacuolating cytotoxin in the hepatocytes of patients with isolated hypertransaminasaemia

Background and aim. Even if different Helicobacter species can colonise animal livers and induce hepatitis, there is no evidence that Helicobacter pylori can damage this organ and only a potential capacity of cytotoxic strains to increase transaminases in humans has been suggested. We have, therefore, carried out an immunohistochemical study on vacuolating cytotoxin in the hepatocytes of subjects with isolated hypertransaminasaemia. Patients, Methods and Results. Five male patients with isolated hypertransaminasaemia without signs of known causes of liver diseases were studied. Endoscopy demonstrated diffuse mucosal hyperamia in 3 patients and duodenal ulcer in one. Histology revealed active chronic pangastritis in all. Helicobacter pylori was assessed by histology and culture and its cytotoxicity demonstrated by positive immunoblotting for both anti-CagA and VacA. Percutaneous liver biopsy showed minimal changes. Hepatic and gastric sections were tested either with autologous serum and rabbit antibody to VacA toxin. Immune reaction was revealed by immunoperoxidase. Both autologous sera and anti-VacA toxin antibody showed a reaction with a similar pattern which involved 60% of hepatocytes. Anti-VacA toxin showed a reaction to gastric epithelial cells and autologous sera to parietal cells in 4/5 patients. All patients received triple therapy and eradication of Helicobacter pylori was assessed by urea breath test. Serum transaminase levels 3 months after eradication, are still abnormal. Conclusions. Our immunohistochemical findings suggest that vacuolating cytotoxin could reach the hepatocytes of patients suffering from both isolated hypertransaminasaemia and infection by cytotoxic strains of Helicobacter pylori. Nevertheless, a clear relationship between these two conditions remains uncertain.