Background: Helicobacter pylori infection results in a systemic immune response characterized by the initial rise of immunoglobulin (Ig) M followed by the elevation of IgG- and IgA-specific antibody levels in serum. Age and regional considerations may modify the accuracy of serological tests.
Objectives: To determine the accuracy of specific IgG, IgA, and IgM in H pylori infection determination in different age groups.
Patients and methods: We enrolled 179 patients referred for endoscopy. Patients were considered infected if they had positive histological or urease test results for H pylori. Titers of IgG, IgA, and IgM were determined in serum by enzyme-linked immunosorbent assay. Through receiver operator characteristic curves, cutoff, sensitivity, and specificity values were obtained. Agreement and correlation between immunoglobulin titers and inflammation markers were explored.
Results: Infection with H pylori was present in 58% of adults, 62% of adolescents, and 25% of children. Sensitivity and specificity were higher in children younger than 12 years old for IgG and IgA. All diagnostic performance values were lower for IgM. Agreement measures were approximately 0.5 in adults and reached values of approximately 0.7 for adolescents and children. IgM had negative agreement with other methods. There was a correlation between inflammation markers, H pylori load, and immunoglobulin titers for IgG and IgA. These associations decreased with age and were not observed for IgM.
Conclusions: IgG and IgA serological tests reached high performance values, particularly in children younger than 12 years old, indicating that they are reasonable screening methods once cutoff values are adjusted to local population and age. IgM does not present an additional contribution.