Association of CCL13 Levels in Serum and Synovial Fluid With the Radiographic Severity of Knee Osteoarthritis

Objective: CCL13, a recently identified CC chemokine, plays an important role in the process of joint destruction, which is considered a common cause for osteoarthritis (OA). This study aims to examine the relation of CCL13 levels in serum and synovial fluid (SF) with the radiographic severity of OA. Methods: CCL13 levels in serum and SF were evaluated using enzyme-linked immunosorbent assay method in 240 patients with knee OA and 134 control subjects. The progression of OA was classified using the Kellgren-Lawrence (KL) system by evaluating x-ray changes observed in anteroposterior knee radiography. Results: Knee OA patients had higher levels of serum CCL13 compared with control subjects. Knee OA patients with KL grade 4 showed significantly elevated CCL13 levels in serum and SF compared with those with KL grades 2 and 3. Knee OA patients with KL grade 3 had significantly higher SF levels of CCL13 compared with those with KL grade 2. CCL13 levels in serum and SF of knee OA patients were significantly correlated with disease severity evaluated by KL grading criteria. Conclusions: CCL13 levels in serum and SF were correlated with the radiographic severity of OA. CCL13 levels in serum and SF may serve as a biomarker for the progression of OA.