TNFRSF11A and rheumatoid arthritis: Having established that inflammatory cytokines can stimulate healthy blood neutrophils to express OPG and RANK (Figure 3) and that SF neutrophils from patients with RA spontaneously expressed RANK-L, OPG, and RANK proteins (Figure 2), we next investigated the effect of SF on the expression of these genes by incubating healthy human blood neutrophils in the presence of SF from patients with RA (Figure 4).