Serodiagnosis of Helicobacter pylori infection is not accurate for children aged below 10

Background : In order to investigate the immune response to Helicobacter pylori in childhood, we compared anti-H. pylori IgG and IgA antibodies with H. pylori antigen in the stool and examined the clinical usefulness of the anti-H. pylori IgG and IgA antibodies. Methods : This study included 157 children who were seen at our hospital. Serum and stool samples were obtained for these children. Antibodies to H. pylori were examined using an H. pylori IgG enzyme-linked immunosorbent assays (ELISA) and an H. pylori IgA ELISA. Analysis of stool samples was carried out by the H. pylori stool antigen (HpSA) enzyme immunoassay. Results : Of the 157 children, 45 children were HpSA positive, 110 were negative and two were undetermined. Out of 45 HpSA positive patients, 25 children were both IgG and IgA positive and seven were negative for both IgG and IgA antibodies. Of the 110 patients who were HpSA negative, 97 were negative for both antibodies. All HpSA positive children older than 10 years were positive for IgG and IgA antibodies, but of the HpSA positive children under the age of 10, only 18 out of 35 (51.4%) were positive for IgG antibodies or IgA antibody. Conclusion : These facts suggested that an immature immune response or tolerance to H. pylori exists in childhood and serodiagnosis of H. pylori infection is less useful in children aged below 10.