Munari et al. [28] investigated Th17 response in H. pylori-associated gastritis in humans, and found that there was a high level of IL-17 cytokines in the gastric mucosa of H. pylori-positive patients with chronic gastritis, whereas IL-17 was only weakly expressed in H. pylori-negative patients with chronic gastritis; in addition, IL-17 levels were found to decrease after eradication of the bacteria. The gene discussed is IL17A; the disease is chronic gastritis.