Down-regulation of the Th1, Th17, and Th22 pathways due to anti-TNF-α treatment in psoriasis

Abstract

Background: Psoriasis is a T-cell-mediated chronic inflammatory dermatosis. Th1, Th17 and Th22 cells are suggested to contribute to the pathogenesis of psoriasis.

Objective: To determine whether treatment with the anti-tumor-necrosis-factor antagonist, adalimumab, induces significant modulation of the Th1, Th17 and Th22 pathways, and correlates cellular activity with clinical response.

Methods: This study included 21 patients with moderate-to-severe psoriasis who were treated with adalimumab, and 10 healthy control subjects. Blood samples were collected at baseline and at week 12. Flow cytometry was used to analyze the frequency of circulating Th1, Th17 and Th22 cells. Real-time polymerase chain reaction was used to analyze the expression of T-bet (Th1-related), retinoid-acid receptor-related orphan receptor gamma t (RORγt, Th17-related) and aryl hydrocarbon receptor (AHR, Th22-related). An enzyme-linked immunosorbent assay was used to analyze the serum levels of IFN-γ, IL-17, IL-22, IL-6 and tumor necrosis factor-α (TNF-α).

Results: At baseline, the frequencies of Th1, Th17 and Th22 cells were higher in psoriasis patients compared to the healthy controls. The expression of transcription factors T-bet, RORγt and AHR, and the serum levels of IFN-γ, IL-17, IL-22, IL-6 and TNF-α were higher in psoriasis patients compared to the healthy controls. After adalimumab therapy, there was a significant decline in the frequencies of Th1, Th17 and Th22 cells, and a concomitant decrease in the levels of their associated transcription factors and cytokines.

Conclusion: The results suggest that the anti-tumor-necrosis-factor antagonist, adalimumab, disrupts the Th1, Th17 and Th22 pathways, resulting in clinical improvement of psoriasis.

Keywords: Adalimumab; Anti-tnfα; Psoriasis; Th1 cell; Th17 cell; Th22 cell.