Mucosal FOXP3-expressing CD4+ CD25high regulatory T cells in Helicobacter pylori-infected patients

• Helicobacter pylori chronically colonizes the stomach and duodenum and causes peptic ulcers or gastric adenocarcinoma in 10 to 20% of infected individuals. We hypothesize that the inability of patients to clear H. pylori infections is a consequence of active suppression of the immune response. Here we show that H. pylori-infected individuals have increased frequencies of CD4(+) CD25(high) T cells in both the stomach and duodenal mucosa compared to uninfected controls. These cells have the phenotype of regulatory T cells, as they express FOXP3, a key gene for the development and function of regulatory T cells, as well as high levels of the cytotoxic T lymphocyte-associated antigen 4 (CTLA-4) protein. In contrast, mucosal CD4(+) CD25(low) and CD4(+) CD25(-) cells express little FOXP3 mRNA and low levels of the CTLA-4 protein. Mucosal CD4(+) CD25(high) T cells are present in individuals with asymptomatic H. pylori infections as well as in duodenal ulcer patients. The frequencies of CD4(+) CD25(high) cells are also increased in the stomachs of H. pylori-infected patients with gastric adenocarcinoma, particularly in cancer-affected tissues. These findings suggest that regulatory T cells may suppress mucosal immune responses and thereby contribute to the persistence of H. pylori infections.

Nyckelord

Adenocarcinoma/immunology

Adult

Antigens

CD

Antigens

CD4/*analysis

Antigens

Differentiation/analysis

CD4-Positive T-Lymphocytes/physiology

DNA-Binding Proteins/*genetics

Duodenal Ulcer/immunology

Female

Forkhead Transcription Factors

Gastric Mucosa/*immunology

Helicobacter Infections/*immunology

*Helicobacter pylori

Humans

Immunologic Memory

Male

Middle Aged

Receptors

Interleukin-2/*analysis

Stomach Neoplasms/immunology

T-Lymphocytes

Regulatory/*physiology

Publikations- och innehållstyp

ref (ämneskategori)

art (ämneskategori)