Objectives: Regulatory T cells play an active role in the maintenance of the immune system's tolerance of both foreign and self antigens. Particularly, CD(4) (+) CD(25) (+) regulatory T cells participate in tumor immunity. The study provided further evidence on the involvement of CD(4) (+ )CD(25) (+) regulatory T cells in immune system impairment in patients with gastrointestinal malignancies.
Methods: Using flow cytometry, CD(4) (+ )CD(25) (+) regulatory T cells were analyzed in peripheral blood from 114 patients with gastrointestinal malignancies and 15 healthy controls.
Results: The prevalence of the CD(25) (+) subset in CD(4) (+) T cells was increased in patients with colorectal carcinoma compared with healthy controls. The phenotic characteristics of the CD(4) (+ )CD(25) (+) T cells in patient with malignancies were low expression of CD(45) RA and no expression of CD(69). Our results indicated that when compared with healthy control, the proportions of CD(4) (+) CD(25) (+) T cells in the peripheral blood of patients with colorectal, gastric, and esophageal carcinoma were significantly higher (P < 0.05) in colorectal carcinoma (22.11 +/- 9.65%), gastric carcinoma (17.74 +/- 4.24%), and esophageal carcinoma (24.37 +/- 4.82)%, respectively. Further analysis on the proportion of CD(4) (+ )CD(25) (+) T cells revealed that those patients with gastrointestinal malignancies in stages IV were higher than those of in stage I-III, though no significant difference was observed (P > 0.05). However, the proportion of CD(4) (+ )CD(25) (+) T cells in the patients with relapse gastric carcinoma (23.32 +/- 4.98%) was significantly higher than that of patients with primary gastric carcinoma (P < 0.01).
Conclusions: The increased CD(4) (+ )CD(25) (+) T cells in patients with gastrointestinal malignancies may be related to immunosuppression and tumor progression. This suggests that elimination or reduction of CD(4) (+ )CD(25) (+) regulatory T cells can improve effective tumor immunity for immunotherapy.