Acute interferon-beta (IFN-beta) administration transiently activates the hypothalamic-pituitary-adrenal (HPA) axis, increases granulocytes, and reduces lymphocytes in peripheral blood. To test whether these effects are still present after long-term treatment, 13 patients with relapsing-remitting multiple sclerosis were analyzed at baseline, and 1, 2, 4, and 8 h after IFN-beta 1a injection at two occasions: at the initial administration and after 1 year of continuous treatment. Long-term treatment reduced the responsiveness of the HPA axis to the injection, and abolished the distributional changes in leukocyte numbers. One-year treatment with IFN-beta 1a did not induce mood alterations as assessed by the Profile of Mood States. These results suggest that long-term IFN-beta therapy has a profound impact on leukocyte distribution and the neuroendocrine response to the drug.
Copyright 2005 S. Karger AG, Basel.