YKL-40 as a Novel Factor Associated with Inflammation and Catabolic Mechanisms in Osteoarthritic Joints
Relation of YKL-40 to proinflammatory cytokines IL-6 and IL-7. In synovial fluid, YKL-40 correlated positively with (a) IL-6 and (b) IL-17 (, and , , resp.). In the case of IL-17, the levels were measured from SF samples from 47 patients but the levels remained below the detection limit in about half of the patients () and they were excluded from the correlation analysis. (c) In a 24 h incubation IL-6 together with its soluble receptor (sIL-6R) and IL-17 stimulated YKL-40 production by over 30% in primary chondrocytes from OA cartilage. Results are presented as mean ± SEM. compared to the control sample.