Study Objective: To determine the diagnostic value of assays to measure serum antibodies to Campylobacter pylori, and to use these assays to determine the prevalence of C. pylori infection in a healthy population.
Design: A survey of patients having endoscopies for upper gastrointestinal symptoms, patients with other gastrointestinal illnesses, and healthy controls.
Setting: Outpatients attending endoscopy suites in two university-affiliated medical centers.
Patients: One hundred and twenty patients who had gastroduodenoscopies, 61 patients with lower intestinal illnesses, and 166 healthy controls.
Intervention: Assay to detect serum IgA, IgG, and IgM antibodies specific for C. pylori.
Measurements and Main Results: Absorption with other gram-negative pathogens showed that IgG and IgA assays, but not IgM assays, were specific for C. pylori. In patients in whom C. pylori had been isolated and who had gastritis diagnosed by histologic methods, significantly higher mean IgA and IgG levels were seen compared with patients without demonstrable C. pylori or gastritis. The sensitivity and specificity of a positive value in both IgA and IgG assays were more than 93%. Among healthy persons, IgG and IgA antibodies were rarely seen in patients less than 20 years old, but antibody prevalence progressed with age, reaching 50% in patients more than 60 years old. High IgA and IgG levels to C. pylori in five persons tested remained stable for more than 1 year, suggesting the organism persists for at least that period. In 61 patients with acute bacterial enteritis, acute pancreatitis, Crohn disease, or ulcerative colitis, prevalence of antibodies to C. pylori was consistent with age and unrelated to current disease.
Conclusions: Campylobacter pylori infection, which is highly associated with active gastritis, may be diagnosed by serologic assay. Acquisition of infection begins in adult life, and prevalence increases with age.