HP and gastritis: The study was conducted in 84 children: 24 patients with newly diagnosed H. pylori-related gastritis (Hp+ children, median age 11.5 years, range 4–17 years); 25 patients after H. pylori eradication therapy, including 17 after successful treatment (children after SE median age 16 years, range 12–17 years); 8 patients after unsuccessful eradication (children after NE, median age 11.5 years, range 6–17 years); 24 H. pylori-negative patients without gastritis (Hp- children, median age 12.5 years, range 3–17 years); and 11 controls (median age 15 years, range 5–17 years).