IL1B and rheumatoid arthritis: In monocyte-derived macrophages of RA patients, 1,25(OH)2D was able to reduce the production of pro-inflammatory cytokines (i.e., TNF-α, IL-1α, IL-1β, and IL-6) and receptor activator of nuclear factor κβ ligand (RANKL), a molecule that induces the differentiation and activation of osteoclasts, thus favoring bone resorption [106].