Background: Most individuals with Helicobacter pylori infection in Western countries have no evidence of peptic ulcer disease (PUD). We therefore assessed the PiZ deficiency variant of the major plasma protease inhibitor alpha1-antitrypsin (alpha1AT) as a risk factor for PUD in H. pylori-infected individuals.
Methods: The cohort comprised 100 patients with endoscopically or surgically proven PUD (30 patients with duodenal ulcer (DU) and 70 patients with gastric ulcer (GU)) and 162 age- and sex-matched controls with PUD-negative endoscopic findings and no history of PUD. Plasma samples were screened for alpha1AT deficiency (PiZ) with an enzyme-linked immunosorbent assay (ELISA) and phenotyped by isoelectric focusing. H. pylori infection was evaluated with an IgG ELISA technique.
Results: Among the 262 patients 17 (6.5%) were positive for the PiZ alpha1AT deficiency, a frequency of the same magnitude as in the Swedish general population (4.7%). Of the PiZ carriers 76% (13 of 17) had H. pylori antibodies compared with 61% (151 of 245) of the non-PiZ carriers (NS). The prevalence of DU tended to be higher in H. pylori-positive PiZ carriers than in non-PiZ carriers (15.4%, 4 of 26 versus 0 of 4). Furthermore, among patients with DU a high PiZ allele frequency (13.3%, 4 of 30) was found compared with the general population (4.7%) (odds ratio (OR), 3.2; 95% confidence interval (CI), 1.09-8.94; P = 0.02). All DU patients carrying the PiZ allele were positive for H. pylori. In addition, four of five PiZ carriers with H. pylori infection and PUD had DU.
Conclusions: The PiZ allele may be a contributing factor in the development of DU in H. pylori-positive individuals.