Characterization of skin Th17 transcriptional profiles in psoriatic patients under adalimumab biotherapy

Background: In psoriasis, a specific cytokine network has been described to play a central role in the pathophysiology of the disease. Anti-cytokine therapeutic approaches have been largely developed and TNF alpha constitutes the main target. Adalimumab is a human anti-TNF alpha monoclonal antibody that has been reported to demonstrate clinical efficacy and safety, resulting in reversal of epidermal hyperplasia and cutaneous inflammation. Objectives: We aimed to analyse changes in the skin inflammatory transcriptomic profile in psoriatic patients during adalimumab therapy. In addition, the circulating cytokine profile was analysed to define systemic inflammation. Materials&methods: Eighteen patients with chronic plaque psoriasis were treated with adalimumab. After four and 16 weeks, clinical efficacy was assessed using PASI and DLQI, and skin mRNA profiles were determined and circulating cytokines quantified. Results: We identified a rapid effect of adalimumab therapy on a large array of Th17 cytokines of the skin, which may account for the modification of keratinocyte expression profile and clinical response. In contrast, analysis of serum cytokine concentrations was uninformative, confirming the need for characterization of local cytokines in skin lesions. Finally, in non-responders, local cytokine expression was shown to be unchanged. Conclusion: We show that TNF alpha inhibition in psoriasis patients treated with adalimumab has a broad effect on the expression profile of cytokines and keratinocyte markers of skin inflammation, which may account for its clinical efficacy.