Therapeutic potency of Poly I:C in HSV-induced inflammation through up-regulation of IL-15 receptor alpha.

Interleukin-15 receptor alpha (IL-15Rα) forms stable complex with IL-15 on the cell surface of activated monocytes and mediates the proliferation of memory CD8+ T cells. Recent studies informed that polyinosinic:polycytidylic acid (Poly I:C) is an immunostimulant which boosts the generation of memory T cells through induction of IL-15Rα. The aim of this study is to evaluate the relevance of IL-15Rα in Herpes simplex virus (HSV)-induced Behçet's disease (BD) mouse model and BD patients. The frequencies of IL-15Rα expression in PBMCs of BD patients and BD-like symptomatic mice were analyzed by flow cytometry. In addition, Poly I:C supplementation could reduce inflammation through the up-regulation of memory T cells and IL-15Rα+ cells accompany with down-regulation of pro-inflammatory cytokine, IL-17A in BD mice. In BD patients, the frequencies of IL-15Rα expression in PBMCs were also significantly different between the inactive and active disease states. These results suggest that IL-15Rα is a relevant factor in BD.