antibody responses in association with eradication outcome and recurrence: a population-based intervention trial with 7.3-year follow-up in China.

Objective: To identify serum biomarkers that may predict the short or long term outcomes of anti- () treatment, a follow-up study was performed based on an intervention trial in Linqu County, China.

Methods: A total of 529 subjects were selected randomly from 1,803 participants to evaluate total anti- immunoglobulin G (IgG) and 10 specific antibody levels before and after treatment at 1-, 2- and 7.3-year. The outcomes of anti- treatment were also parallelly assessed byC-urea breath test at 45-d after treatment and 7.3-year at the end of follow-up.

Results: We found the medians of anti- IgG titers were consistently below cut-off value through 7.3 years in eradicated group, however, the medians declined in recurrence group to 1.2 at 1-year after treatment and slightly increased to 2.0 at 7.3-year. While the medians were significantly higher (>3.0 at 2- and 7.3-year) among subjects who failed the eradication or received placebo. For specific antibody responses, baseline seropositivities of FliD and HpaA were reversely associated with eradication failure [for FliD, odds ratio (OR)=0.44, 95% confidence interval (95% CI): 0.27-0.73; for HpaA, OR=0.32, 95% CI: 0.17-0.60]. The subjects with multiple positive specific antibodies at baseline were more likely to be successfully eradicated in a linear fashion (P=0.006).

Conclusions: Our study suggested that total anti- IgG level may serve as a potential monitor of long-term impact on anti- treatment, and priority for treatment may be endowed to the subjects with multiple seropositive antibodies at baseline, especially for FliD and HapA.