Beneficial effects of fumarate therapy in psoriasis vulgaris patients coincide with downregulation of type 1 cytokines

Background: Fumarates have been shown to be effective in psoriasis vulgaris. Objectives: To find out whether successful therapy is associated with modulation of cytokines. Methods: We determined interferon (IFN)-γ, interleukin (IL)-4 and IL-10 secretion capacities of peripheral blood mononuclear ceils (PBMC) after phytohaemagglutinin stimulation, and IL-12p70 and IL-10 secretion capacities of PBMC after endotoxin stimulation in psoriasis vulgaris patients during treatment with fumarates. In a cohort study, 12 patients (five men, median age 50 years; seven women, median age 46 years) with psoriasis vulgaris were followed during 24 months of fumarate treatment. In addition, we followed 14 healthy controls (six men, median age 31 years; eight women, median age 29 years) without skin diseases during 12 months to investigate possible changes in the cytokine secretion capacity of PBMC as a result of seasonal changes. Disease activity in patients was determined by Psoriasis Area and Severity Index (PASI) score. Blood was collected for measurement by enzyme-linked immunosorbent assay of cytokine levels after stimulation of PBMC. Results: Within 6 months of fumarate treatment, the mean ± SD PASI score had decreased to 22 ± 9% of its initial value. These beneficial effects coincided with lymphocytopenia and a significant (P < 0.05) downregulation of IFN-γ expression by circulating blood cells, followed by a significant downregulation of IL-4 expression. Notably, production of the cytokine synthesis inhibitor IL-10 by PBMC was unchanged. Conclusions: The beneficial effects of fumarates may be attributed to their downregulatory action on type 1 cytokines.

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