Role of interleukin-10 in the synovial fluid of the anterior cruciate ligament injured knee

OBJECTIVE: This review assesses the roles of IL-10 in post ACL reconstruction OA, and highlights the potential therapeutic effects of this cytokine. MATERIALS AND METHODS: We conducted a systematic review of the literature in order to consolidate evidence of IL-10 profiles in synovial fluid (SF) of patients with ACL tears. The review was conducted in accordance with the PRISMA statement. In total, 10 studies were found to be pertinent and were considered in depth. Seven studies reported on trends in IL-10 concentrations after an ACL tear; in addition, three studies described IL-10 concentrations after ACL reconstruction. In all studies, IL-10 levels were assessed using enzyme-linked immunosorbent assay. RESULTS: IL-10 levels in SF were higher after ACL injury and ACL reconstruction compared to control knees. IL-10 levels were most elevated shortly after injury, but, decreased to more normal levels in chronic lesions. In contrast, the inflammatory cytokine TNF-α remained higher than controls immediately subsequent to, and, even 5 years post-injury. CONCLUSIONS: IL-10 is a modulatory cytokine with an active role in antagonizing TNF-α in the knee joint environment. Consideration of the role of IL-10 in the knee has now shifted from simply a key biomarker to having active therapeutic potential in the prevention of OA after ACL injury.