Perioperative cimetidine administration improves systematic immune response and tumor infiltrating lymphocytes in patients with colorectal cancer.

Cimetidine has been shown to play an important role in the treatment of cancer and the regulation of the immune system. Therefore, we aimed to observe the effects of cimetidine on the systematic immune response in the perioperative period. Sixty patients with colorectal cancer were enrolled from Jan 2005 to Dec 2005 from Taizhou Hospital. The patients were administrated with cimetidine (0.8 g.d-1 or 1.2 g.d-1) or saline from the day of admission to the 10th POD. Venous blood sample was collected and the T-, B- and NK-lymphocyte subsets were determined by flow cytometry. The specimens were subjected to tumor-infiltrating lymphocytes (TILs) response examination. The levels of CD3 and CD4 T-lymphocytes were increased significantly in both low and high dose cimetidine groups 10 days after operation. The number of CD19 B cells was also elevated by cimetidine. However, no significant changes were observed in the CD8, CD4/CD8 value. TIL responses in the cimetidine groups were also enhanced significantly. Cimetidine can alleviate systematic immunosuppression and improve the local immune function of the colorectal cancer patients in the perioperative period.