Differential effects of phototherapy, adalimumab and betamethasone–calcipotriol on effector and regulatory T cells in psoriasis

I.S. Kotb, B.J. Lewis, R.N. Barker, A.D. Ormerod

Psoriasis is a chronic T cell-mediated skin disease with marked social and economic burdens. Current treatments are unsatisfactory, with unpredictable remission times and incompletely understood modes of action. Recent advances in our understanding of the pathogenesis of psoriasis identify the imbalance between CD4+ T effector cells, particularly the T helper (Th) 17 subset, and regulatory T cells (Treg) as key to the development of psoriatic lesions, and therefore a novel therapeutic target. To quantify in patients the effects of three commonly used psoriasis treatment modalities on the Th1, Th2, Th17 and Treg subsets, and test whether any change correlates with clinical response. Using flow cytometry to enumerate Th1, Th2, Th17 and Treg subsets in blood and skin of psoriatic patients before and after receiving any of the following treatments; narrow band UVB (NB-UVB), adalimumab and topical betamethasone/calcipotriol combination (Dovobet® ). All patients responded clinically to treatments. NB-UVB significantly increased the numbers of circulating and skin Treg, while, by contrast, adalimumab reduced Th17 cells in these compartments, and Dovobet had dual effects by both increasing Treg and reducing Th17 cells. The differential effects reported here for the above-mentioned treatment modalities could be exploited to optimize or design therapeutic strategies to better overcome the inflammatory drivers and restore the Th17/Treg balance in psoriasis. This article is protected by copyright. All rights reserved.