Interferon γ and interleukin 4 producing T cells in peripheral blood of multiple sclerosis patients undergoing immunomodulatory treatment

Intracellular cytokine flow cytometry was used to analyse the percentages of interferon (IFN) γ and interleukin (IL)-4 producing T cells in the peripheral blood of multiple sclerosis patients, before and after immunomodulotory treatment, and of heolthy controls. After six months of treatment, different doses of IFN β1 o (Avonex or Rebif) decreased CD4⁺ (Th1, Th2) ond CD8⁺ (Tc1) cells to a similar extent, without affecting the Th1/Th2 ratio. These T cell subsets were unmodified after nine months: of glatiramer acetate (Capaxone) treatment, and after six day courses of high dose 6-methylprednisolone. The data suggest that IFN β1 a produces sustained downmodulation of IFN γ and IL-4 producing T cells in vivo, which may contribute to its therapeutic efficacy; that glatiramer acetate possibly acts without altering non-specific cellular immunity; and that glucocorticoid induced lymphocytopenia does not affect the percentages of Th1, Th2 and Tc1 cells; at least in the periphery, none of the treatments caused a Th1 to Th2 shift that could account for their respective therapeutic effects.