RESUMEN
Behçet's disease (BD) was considered a T-helper 1 (Th1)-mediated autoimmune disease, but with the introduction of Th17 cells, their role in the pathogenesis of BD was also addressed. Despite studies on IL-17 in BD, the prognostic value of this cytokine in BD is unclear. The aim of this study is to determine the IL-17 mRNA expression rate and serum levels in patients with BD and its correlation with clinical manifestations and activity of BD. Forty-six BD patients in the active phase of the disease and 70 healthy controls were recruited in this study. BD activity was measured by Behçet's disease current activity form (BDCAF), Iranian Behçet's disease dynamic activity measure (IBDDAM) and total inflammatory activity index (TIAI). The IL-17 mRNA expression and serum levels were significantly higher in the BD patients compared with the healthy controls. These parameters in the BD patients aged <25 at disease onset, positive pathergy test, and positive HLA-B5 and HA-B51 were significantly higher than the healthy controls (P < 0.05). The IL-17 serum level in the patients with active uveitis was lower than the patients with in-active uveitis. There was no association between other clinical manifestations of BD and these parameters. No significant correlation was found between BDCAF and IBDDAM with IL-17 mRNA expression and serum levels. However, TIAI had a significant and negative correlation with the serum levels of IL-17.