T-helper 17 cells: The driving force of psoriasis and psoriatic arthritis

Aim There is growing evidence that two recently recognized, unique subsets of CD4+ T-cells, T-helper 17 cells (Th17) and CD4+ CD25+ regulatory T-cells (Treg), may play important roles in the pathogenesis of psoriasis. This study sought to investigate the relationship between Th17 cells and psoriasis or psoriatic arthritis (PsA). Methods Peripheral blood CD4+ T-cells were isolated from 47 patients with psoriasis and 47 controls, and were cultured under various stimulatory conditions. The Th17 cells and regulatory Treg cells were detected by flow cytometry. Plasma interleukin (IL)-17 was measured by enzyme-linked immunosorbent assay. Results The proportion of Th17 and Treg cells from peripheral blood mononuclear cells showed no difference between patients with psoriasis and controls. However, psoriasis and PsA patients demonstrated a higher proportion of induced Th17 cells, which was correlated with psoriasis area severity index score. The level of plasma IL-17A in psoriasis was higher than that in controls. Conclusion Th17 cells may play important roles in the pathogenesis of psoriasis and psoriatic arthritis.