Abstract: Objective   To evaluate the influence of cytotoxin associated gene A to the differentiation of helper T lymphocytes in chronic gastritis. Methods   Eighty patients with chronic gastritis were in roll, the serum antibody against CagA was detected through ELISA. We divided the patients into CagA-positive and CagA-negative groups. Pathologic changes in gastric mucus were respectively analyzed. In addition, the expressions of nuclear transcriptive factors in gastric mucus reflecting the differentiation of Th subsets including TBX21、GATA-3、FoxP3 and Rorγt were further detected. Results   The gastric inflammation in CagA-positive group was more serious than that in CagA- negative one. However, the statistical difference of Hp density between them was not observed. The expressions of GATA-3 and FoxP3 were much higher while those of TBX21 and Rorγt much lower in CagA-positive group than that in CagA-negative one. Conclusions   Although the inflammation in gastric mucus of CagA-positive patients was relatively more serious, Hp can not be effectively eliminated，which may relate to the differentiation of Th0 into Th2/Treg cell.

Key words: Helicobacter pylori, gastritis, T-lymphocytes, helper-inducer, GATA3 transcription factor, CagA, TBX21, TBX21