Psoriasis vulgaris, a type-1 cytokine-mediated chronic skin disease, can be treated successfully with fumaric acid esters (FAE). Beneficial effects of this medication coincided with decreased production of IFN-γ. Since dendritic cells (DC) regulate the differentiation of T helper (Th) cells, this study focussed on effects of monomethylfumarate (MMF, bioactive metabolite of FAE) on polarization of monocyte-derived DC. MMF-incubated, lipopolysaccharide-stimulated DC (MMF-DC) produced dramatically (p<0.05) reduced levels of IL-12p70 and IL-10 (8±4% and 20±4%, respectively) compared to control DC. MMF-DC were mature. MMF affected polarization of DC irrespective of polarization factor(s) and ligands for the various Toll-like receptors used. Coculture of MMF-DC with naive and primed allogenous Th cells resulted in lymphocytes producing less IFN-γ, i.e. 59% and 54% of that by the respective Th cells cocultured with control DC. IL-4 production by primed, but not naive Th cells cocultured with MMF-DC was decreased as compared to cocultures with control DC. IL-10 production by naive and primed Th cells cocultured with MMF-DC and control DC did not differ. In addition, MMF inhibited LPS-induced NF-κB activation in DC. Together, beneficial effects of FAE in psoriasis involve modulation of DC polarization by MMF such that these cells down-regulate IFN-γ production by Th cells.

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European Journal of Immunology
Department of Dermatology

Litjens, N.H.R, Rademaker, M, Ravensbergen, N.J.C, Rea, D, van der Plas, M.J.A, Thio, B.H, … Nibbering, P.H. (2004). Monomethylfumarate affects polarization of monocyte-derived dendritic cells resulting in down-regulated Th1 lymphocyte responses. European Journal of Immunology, 34(2), 565–575. doi:10.1002/eji.200324174