Long‐term Follow‐up and Serological Study after Triple Therapy of Helicobacter pylori‐associated Duodenal Ulcer

Objective: The purpose of this study was to monitor the change of IgG antibodies to Helicobacter pylori during the course of a long‐term follow‐up after the eradication of H. pylori, as well as to evaluate the efficacy of triple therapy in preventing the recurrence of duodenal ulcer (DU). Methods: Twenty‐three DU patients with positive II. pylori were studied; among those patients, 20 ulcers healed after initial treatment of triple therapy. Each patient received a follow‐up endoscopy and biopsy examination every 3 months for 1 yr, or whenever the ulcer symptoms recurred. Serological tests for IgG antibodies were performed with a commercial ELISA. Results: Of the 20 patients with healed ulcers, one dropped out of this study; the recurrence rate of DU at 1 yr was 5% (1/19). There was no recurrence of ulcer in 17 H. pylori‐negative patients and only one recurrence out of two H. pylori ‐ positive patients. After the eradication of H. pylori, the seroconversion rates of IgG were 5%, 21 %, 42%, 76%, and 94% at 0, 3, 6, 9, and 12 months, respectively. After 6 months, 95% (18/19) of the patients in which H. pylori was eradicated had at least a one‐grade fall in IgG titers (P < 0.001). One patient had a relapse of H. pylori which was accompanied with re‐elevating IgG titers. Conclusions: We conclude that seroconversion, which usually occurs after 1 yr, indicates complete eradication of H. pylori. Furthermore, we suggest that the success of the eradication of H. pylori can be judged without endoscopic examination, 8 months after treatment by triple therapy, according to the fall of IgG titers or seroconversion. Re‐elevating IgG titers may be a warning of the possibility of relapse or reinfection of H. pylori.