False Sero-Negative Results for Helicobacter Pylori Infection Indicate Increased Risk of Severe Atrophic Gastritis in Japanese Patients

Abstract

Background/objective: H. pylori infection is commonly diagnosed using an anti-H. pylori IgG antibody test. However, a proportion of results are falsely sero-negative. We investigated characteristics of patients falsely seronegative for H. pylori in relation to gastric atrophy. Methods: H. pylori infection (Hp+ or Hp-) was determined based on culture test, rapid urease test (RUT), and polymerase chain reaction (PCR) test in 280 outpatients. Anti-H. pylori antibody titers ≥ 10 U/ml were diagnosed as sero-positive for H. pylori (IgG+), while those <10 U/ml were sero-negative (IgG-). Serum pepsinogen (PG) I/PG II ratios were calculated as a serological marker of gastric atrophy. Endoscopic gastric mucosal atrophy was also assessed according to the Kimura-Takemoto classification system. Results: The mean PG I/PG II ratio in each group was as follows: Hp-/IgG- (4.99 ± 1.04, n=10), Hp+/IgG+ (2.59 ± 1.51, n=240), Hp-/IgG+ (5.65 ± 2.72, n=4) and Hp+/IgG- (3.02 ± 2.61, n=26). The mean serum PG I/PG II ratio in the Hp+/IgG- group was lower than those of Hp-/IgG- and Hp-/IgG+ groups (P=0.028 and 0.072). Incidence of severe gastric mucosal atrophy in the Hp+/IgG- group was highest of the four groups. Conclusions: Individuals falsely sero-negative for H. pylori infection is at increased risk of severe atrophic gastritis, which is well known as precancerous lesion.