Th1, Th2, Th17 and regulatory T cell pattern in psoriatic patients: modulation of cytokines and gene targets induced by etanercept treatment and correlation with clinical response

Background: Psoriasis is sustained by pro-inflammatory CD4+ T helper cells mainly belonging to the Th1, Th17 and Th22 lineage.

Objective: To identify whether treatment with the anti-tumour-necrosis-factor antagonist etanercept is able to induce significant modulations in transcription factor and cytokine mRNA gene expressions related to the different T cell immune response polarization (Th1, Th2, Th17 and regulatory T cells, Treg and to correlate them with clinical response.

Methods: The study population included 19 psoriasis patients treated with etanercept and 19 healthy subjects. Blood samples were collected at baseline and every 4 weeks during treatment. Taqman quantitative real-time polymerase chain reaction was applied to analyse the expression of: Stat-4, T-bet, IL-12p35 and IFN-γ (Th1-related); GATA-3, IL-4 (Th2-related); Stat-3, RORγt, IL-23p19 (Th17-related); Foxp3, IL-2 (Treg-related). Flow cytometry was applied to analyse CD4+CD25+(bright)Foxp3+ cells in peripheral blood.

Results: Upregulation of Th1 and Th17 and downregulation of Treg subsets was found at baseline. The response to etanercept could be associated with a significant reversal of the Th1/Th17 activation, and a concomitant upregulation of Th2 and Treg subsets.

Conclusion: Our data may contribute to a better understanding of the mechanisms underlying the achievement of clinical response in psoriasis and could be helpful for the identification of early predictive markers of response.