TNFSF11 and rheumatoid arthritis: After 2 days of incubation of healthy blood neutrophils in medium containing 80% SF from patients with RA and 20% CM, membrane RANK-L significantly increased and was detected on 13.4% ± 4.7% of cells (n = 5) (versus 2.5% ± 0.8% neutrophils in CM alone, a percentage similar to that of freshly isolated neutrophils).