Fig. 5

Intracellular cytokine expression in monocyte subsets of rheumatoid arthritis (RA) patients after stimulation with toll-like receptor (TLR2) agonists. Mononuclear cells from RA patients and healthy donors were enriched and stimulated with lipoteichoic acid (LTA) (a) and Epstein–Barr virus (EBV) particles (TLR2 ligands) (b) in vitro. After a 5-hour stimulation, the stimulated cells were harvested and cytokine expression levels were assessed by intracellular flow cytometry. Briefly, cells were stained with CD45, CD91, CD14 and CD16, permeabilized and intracellular staining was performed on proinflammatory cytokines: IL-6, IL-1β, TNFα and monocyte chemoattractant protein-1 (MCP-1). Intracellular cytokine expression is shown for classical CD14⁺⁺ CD16⁻, intermediate CD14⁺ CD16⁺ and nonclassical CD14^low CD16⁺⁺ monocyte subsets. Gray non-stimulated samples, Blue healthy donors, red RA patients. Representative cytometry histograms are representative of ten donors