The value of anti-Helicobacter pylori IgG antibodies in establishing eradication of infection in children.

The aim of this study was to evaluate the performance of anti-Helicobacter pylori (H. pylori) IgG antibodies in monitoring eradication of infection in children. Forty-seven H. pylori-infected children (aged 12.5 +/- 3.0 years, range 6.5-18 years) were followed for a mean of 30.3 months (range 6.66 months). Patients were divided into those with eradicated infection and those with ongoing infection, as determined by antral biopsy-related tests (histology, urease and culture). Anti-H. pylori antibodies (EIA) were tested at diagnosis and follow-up and changes of antibody titers were compared between the two groups. Twenty-five of 26 non-eradicated patients showed persistently high levels of antibodies throughout the study. One patient had non-detectable antibodies despite an ongoing infection for 12 months. Patients with eradicated infection showed a progressive fall of antibody levels from 52.9 +/- 32.4 U/ml at diagnosis to 17.5 +/- 4.1 U/ml at 6 months (p < 0.007) and 4.4 +/- 0.7 U/ml at > or = 12 months (p < 0.002). In 17 of 21 eradicated patients, serum antibodies normalized during the follow-up period; in 4 of the 21 patients, a decrease of > or = 40% of the initial value was observed during the 8-month follow-up. The validity of serology in the evaluation of H. pylori infection had a sensitivity of 100%, specificity of 96% and positive predictive and negative predictive values of 95% and 100% respectively. Our conclusion is that serial determination of anti-H. pylori antibodies is a reliable method for the follow-up and monitoring of H. pylori eradication in children and adolescents.