TNFRSF11B and osteoarthritis: As a consequence of monocyte activation during incubation of blood, anti-inflammatory cytokines such as IL-13, which was shown to inhibit the production of IL-1β and enhance production of IL-1ra [24], and osteoprotegerin (OPG) [25], which protected cartilage in a murine model of surgically induced osteoarthritis from further degeneration [26], may be upregulated.