Effects of whole blood conditioning on serum cytokine levels of 22 OA patients. Cytokine levels in serum of 22 OA patients, before incubation (control) and after six hours of incubation in the presence of glass beads (ACS). Note the increase in anti-inflammatory cytokines (IL-1ra, TGF-β1, IL-10) and pro-inflammatory cytokines (IL-1β, IL-6, IFN-γ, OSM, TNF-α) after incubation. OPG levels were decreased. All values are displayed as mean ± SD in pg/ml. * P < 0.01; ** P < 0.001.