Pro-inflammatory cytokine and caspase-1 responses to pattern recognition receptor activation of neutrophils and dendritic cells in Behcet's disease

Objectives: Activated innate immunity is implicated in the pathogenesis of Behcet’s Disease (BD). To clarify the mechanisms of innate immune responses, we investigated inflammasome activation in dendritic cells (DC) and neutrophils, following stimulation with two different pattern recognition receptors (PRR) “RIG-1 like” (RLR) and “NOD-like” (NLR) in patients with BD. Methods: Sixteen active BD patients with mucocutaneous lesions and 17 healthy controls (HC) were included in this study. Dendritic cells were generated from monocytes. DCs and isolated neutrophils were activated by RLR and NLR ligands. Caspase-1 activation and expressions of p38 and RIP2 were determined by flow cytometry. Levels of IL-1ß, IL-6, TNF-?, IFN-? and IL-18 in culture supernatants were measured by ELISA. Results: Activation of caspase-1 following intracellular PRR stimulation was found to be in similar levels in DCs and neutrophils of BD patients compared to HC. However, activation of DCs from BD patients to NOD2 stimulus measured with the expressions of RIP2, p38 as well as IL-18 levels was found to be slightly defective (p