Fumaric acid esters (FAEs) suppress CD 15- and ODP 4-positive cells in psoriasis.

A histological-immunohistological study was conducted to investigate the effect of systemically administered fumaric acid esters (FAEs) on epidermal thickness and composition of the inflammatory infiltrate in psoriatic plaques. The very first effect of systemic therapy with FAEs is the disappearance of CD 15-positive cells in the beneath the epidermis, accompanied by a significant reduction in T-helper cells beneath the epidermis, pointing to an immunosuppressive effect. This is followed after some delay by a reduction in acanthosis and hyperkeratosis. The reduction in infiltrating T-lymphocytes corresponds to that seen after systemic or intralesional therapy with cyclosporin. However, the normalization of the psoriatic plaques takes longer under the influence of FAEs than under cyclosporin.