Figure 1: Mean serum PG I (A), PG II (B), PG I/PG II ratios (C) and anti- H. pylori IgG antibody titer (D) in Hp-/IgG-, HP+/IgG+, Hp-/IgG+ and Hp+/IgG- groups. Bars indicate standard errors. Abbreviations are: Hp-/IgG-, uninfected with H. pylori and negative for anti-H. pylori IgG antibody; Hp+/IgG+, infected with H. pylori and positive for anti-H. pylori IgG antibody; Hp-/IgG+, uninfected with H. pylori but positive for anti-H. pylori IgG antibody; Hp+/IgG-, infected with H. pylori but negative for anti-H. pylori IgG antibody.