P072 Arginine metabolism and IL-17 pathway in Behçet disease: A study in Algerian patients

Introduction Behcet disease (BD) is an inflammatory, chronic, systemic affection with uncertain etiology. In previous works, we showed that BD is characterized by a Th1/Th2 cytokines profile. However, recent works showed the presence of Th17/Treg responses. In this study, we measured the IL-6, IL-17 and TGF- β levels in vivo during BD and their effect on in vitro production of two inflammatory metabolic products: NO and urea. Methods PBMC were separated from peripheral blood samples of 43 patients with BD and 23 controls. Then, cells were cultured in RPMI 1640 complemented with 5% FBS, 20% patient’s plasma, 2 mM of glutamine and antibiotics during 24 h in presence or absence of either anti-IL-6, anti-TGF- β (1/20) or IL-17 (20 pg/ml). IL-6, TGF- β and IL-17 were measure by ELISA sandwich; NO was measured by a modified Griess method and urea was measured by a modified Berthelot method. Statistical analysis was performed using ANOVA method. Results We observed a significant increase in IL-6 and TGF- β concentrations in patients’ plasma when compared to controls ( p p In vitro IL-6 and/or TGF- β neutralization also showed different results depending on the clinical manifestations. Furthermore, IL-17 addition induced two major responses. It reduced significantly NO and urea production in ocular and vascular impairments while it increase their production during nervous and rheumatoid manifestations ( p Conclusion In conclusion, our results showed heterogeneous presence of IL-17/Th17 responses during BD. Th1 responses seems to be the main physiopathological mechanism implicated in the disease’s acute phases.