Ketamine, as adjuvant analgesics for patients with refractory cancer pain, does affect IL-2/IFN-g expression of T cells in vitro? A prospective, randomized, double-blind study

Abstract

Background: Ketamine has been used as an analgesic adjuvant with morphine in the treatment of refractory cancer pain recently. But both morphine and ketamine have been reported to produce a number of immunomodulatory effects. The current study was performed to assess whether the concentration of ketamine, as adjuvant analgesics for patient with refractory cancer pain, was related to its effect on T cells interleukin-2 (IL-2)/interferon-g (IFN-g) expression in vitro. Methods: Peripheral blood mononuclear cells (PBMCs) were isolated from venous blood of patients with refractory cancer pain over a Ficoll-Hypaque density gradient. T cells were isolated from by positive selection using anti-CD3 beads. T cells were then treated with vehicle (C group), morphine (200ng/mL, M group), morphine (200 ng/mL), and different dose of ketamine (100, 200, 1000ng/mL; MK1, MK5, MK10 group) for 24hours before stimulation with anti-CD3 and anti-CD28. Then supernatant IL-2 and IFNg protein analysis, quantitative reverse transcription polymerase chain reaction (RT-PCR) for IL-2 and IFN-g were done. Results: There were no significant difference of supernatant IL-2 and IFN-g among C group, M group, and MK1 group, but the mRNA of M group and MK1 group were decreased compared with C group (P