Serology to monitor the efficacy of anti-Helicobacter pylori treatment

Objective. To assess the usefulness of monitoring anti-Helicobacter pylori antibodies to judge the efficacy of anti-Helicobacter treatment. Patients and methods. Twelve patients in whom eradication of H. pylori by triple therapy failed were compared with 24 successfully treated patients, matched for age, sex, diagnosis and time lag between the start of treatment and the second serum sample. Anti-H. pylori IgG antibodies were measured using a commercial enzyme-linked immunosorbent assay before and 3–4 months after treatment Results. Antibody titres decreased by 25–78% in 22 out of 23 successfully treated patients with a pretreatment antibody titre above the cut-off point. The antibody titre decreased in only two out of the nine evaluable patients in whom eradication failed. Kolmogorov-Smirnov test results were consistent with a normal distribution of the decrease in the natural logarithm of antibody titres. Based on these data, a 40% decrease in the antibody titre 3–4 months after treatment confirms eradication with almost 100% specificity and 75% sensitivity. Conclusion. When the pretreatment antibody titre is above the cut-off level, a decrease in this titre 3–4 months after treatment can be used to monitor the efficacy of anti-H. pylori treatment