Aim: To study the effect of oral budesonide and prednisolone on peripheral blood natural killer (NK) cell activity in patients with active ileocaecal Crohn's disease (Crohn's disease activity index, CDAI > or = 200).
Methods: One group of patients was treated for 10 weeks with oral budesonide (n = 9; 9 mg/day), and another group of patients for the same period with prednisolone (n = 9; 40 mg/day). Budesonide was tapered to 6 mg/day after 8 weeks and prednisolone after 2 weeks to 5 mg/day in the last week. Before treatment, and at 2, 4 and 10 weeks of treatment, natural killer cell activity was determined with a 51Cr release assay, and the number of CD16+ NK cells by Fluorescence activated cell sorter (FACS) analysis.
Results: Budesonide, as well as prednisolone treatment, significantly decreased natural killer cell activity at weeks 2 and 4. This decrease was found to be accompanied by a similar decrease in the number of CD16+ NK cells. At 10 weeks, natural killer cell activity had almost returned to pre-treatment levels in the budesonide group and was significantly higher than pre-treatment levels in the prednisolone group. Disease activity was significantly decreased in all patients at week 2 until the end of the trial period.
Conclusion: Both budesonide and prednisolone treatment suppress peripheral blood natural killer cell activity of patients with active ileocaecal Crohn's disease by decreasing the numbers of CD16+ NK cells in the circulation.