BackgroundRegulatory T cells (Tregs) play an important role in regulation of immune response and immunologic tolerance in cancer. Gastrointestinal cancer is still a leading cause of cancer-related death in the world. This study aimed to detect Tregs in patients with gastrointestinal cancer.MethodsIn this study, 45 gastric cancer patients, 50 colorectal cancer patients and 50 healthy controls were enrolled. Flow cytometry was used to detect CD4+CD25hiCD127lowTregs, CD4+CD25hi, and CD4+cells in peripheral blood. Cytokine interleukin-10 (IL-10) and transforming growth factor-β1 (TGF-β1) in peripheral blood and in the supernatant of Tregs cultures were measured by enzyme linked immunosorbent assay.ResultsCompared with healthy controls, the levels of CD4+CD25hiCD127lowTregs and CD4+CD25hicells increased significantly in patients with gastrointestinal cancer. Patients with gastrointestinal cancer also showed a significantly increased levels of IL-10 and TGF-β1 in both peripheral blood and CD4+CD25hiCD127lowTregs culture medium.ConclusionThe present study firstly demonstrated that gastrointestinal patients have a compromised immune status where the CD4+CD25hiCD127lowTregs, as well as levels of IL-10 and TGF-β1 are elevated. The data offered new information for understanding the immunological features of gastrointestinal patients, as well as provided new insights into approaches to develop new immunotherapies for patients with gastrointestinal cancer.