2025 Volume 63 Issue 3 Pages 383-388
Aim: The aim of this study was to assess serum antibody titers of a latex agglutination immunoassay, H. pylori-Latex “Seiken” (Denka LA), after eradication based on the titer before eradication. The time for titers to decrease to below the cut-off and the usefulness in the estimation of eradication were examined.
Subjects and Methods: This multicenter study included 38 subjects (71.9 ± 8.6 years old, 20 males, 18 females). Serum antibody titers before and after Helicobacter pylori eradication (up to 6 years) were measured using a latex agglutination immunoassay, H. pylori-Latex “Seiken” (Denka LA), at enrollment and follow-up. Subjects were classified into high and low antibody titer groups based on the median antibody titer. The times for titers to decrease to below the cut-off were compared between the groups. We also examined the usefulness of changes in antibody titers in evaluating the results of eradication therapy.
Results: Among the 19 subjects in the high-titer group, titers below the cut-off were observed in only nine subjects at 6 years after eradication, and the mean time to achieve seronegative status was 37.6 ± 20.8 months. In contrast, 16 out of 19 subjects in the low-titer group showed titers below the cut-off, and the mean time to achieve seronegative status was 21.3 ± 16.2 months (p<0.05 vs high-titer group). Antibody titers were measured 1 year after eradication in 33 of 38 subjects. Antibody titers decreased to less than half the pre-eradication value in 16 out of 17 subjects in the high-titer group and 15 out of 16 subjects in the low-titer group.
Conclusions: With the Denka LA, if antibody titers are high before eradication, seropositivity is expected to persist for a longer period, and one should watch for false positives. Comparison of antibody titers before and after eradication may be useful in evaluating eradication regardless of the antibody titer before eradication.
