YKL-40 as a Novel Factor Associated with Inflammation and Catabolic Mechanisms in Osteoarthritic Joints

Figure 4

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 (𝑟=0.57, 𝑃<0.001 and 𝑟=0.52, 𝑃=0.010, 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 (𝑛=23) 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. ^∗∗𝑃<0.01 compared to the control sample.

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