In-vivo effect of nicotine on cytokine production by human non-adherent mononuclear cells.

Objective : Ulcerative colitis (UC) is predominantly a disease of non-smokers and treatment with transdermal nicotine improves symptoms in UC patients, whereas smoking seems to have a deleterious effect in patients with Crohn's disease (CD). In CD the cytokine profile is of a dominant T H 1 (T helper 1) pattern whereas in UC the T H 2 pattern predominates. To find an explanation for the beneficial effect of nicotine in UC and the deteriorative effect in CD we studied the in-vivo effect of nicotine on the interleukin 2 (IL-2), IL-10 and tumour necrosis factor alpha (TNFα) production by human cells. Design : Eleven healthy male non-smokers were included in this study. The volunteers applied nicotine patches with a regulated release of 5 mg (day 1 and 2), 10 mg (day 3 and 4) and 15 mg (day 5, 6 and 7) nicotine per day. Methods : Heart rate and blood pressure were recorded, nicotine and cotinine concentrations in plasma measured before and after 2, 4 and 7 days of treatment. Non-adherent mononuclear cells (NAC) were isolated from peripheral blood obtained from the subjects before and after 7 days of treatment. The NAC were cultured in the absence or presence of phytohemagglutinin for 48 h. Total amount of IL-2, IL-10 and TNFα formed were measured in the supernatants using specific ELISAs. Results : Treatment with nicotine caused a significant inhibition of IL-10 production by NAC. In contrast, nicotine patch treatment had no effect on the production of IL-2 and TNFα. Conclusions : Nicotine in vivo has an inhibitory effect on T H 2 cell function as measured by inhibition of IL-10 production, but does not appear to have any effect on T H 1 cell function.