Helicobacter pylori antigen-specific T-cell responses at gastric level in chronic gastritis, peptic ulcer, gastric cancer and low-grade mucosa-associated lymphoid tissue (MALT) lymphoma.

Host T-cell response to Helicobacter pylori is important for the clinical outcome of the infection. A Th1-polarized response, preferentially against CagA, is associated with peptic ulcer, whereas mixed Th1 and Th0 responses are present in non-ulcer gastritis. A deregulated H. pylori-driven Th0 cell-dependent B-cell activation is found in low-grade B-cell lymphoma of mucosa-associated lymphoid tissue.