Cytokines profoundly affect the balance between anabolic and catabolic processes in synovial joints. The purpose of this study was to evaluate the cytokine profile of human knee synovial fluid and correlate this with the degree of articular cartilage degradation, radiographic score, and synovial histology.
With IRB approval, synovial fluid was withdrawn before knee meniscetomy in 15 subjects with varying degrees of OA. Synovial fluid was analyzed for 22 different cytokines. Articular cartilage surfaces were scored via ICRS classification and radiographs graded by Kellgren-Lawrence classification. Synovial biopsies were taken for histological analysis.
Synovial tissue histology did not correlate with grade of arthritis. Overall, there was an increase in all cytokine levels with increasing grades of O.A. Correlation with ICRS grading showed consistent elevations of IL-1and TNF with increasing ICRS scores (IV > III > II > I). The ICRS was much more accurate than Kellgren-Lawrence for correlating levels of cytokine activity.
This is the first study to extensively evaluate cytokine concentrations and correlate this with grade of human O.A. knee. Immunoassay profile proved to be sensitive and capable of yielding highly reproducible patterns of cytokine panels. This data demonstrated the molecular basis of disease progression and can assist in understanding the inflammatory response with OA progression. Cytokine biomarkers will help monitor disease progression and assist in future pharmacologic or surgical intervention.
© 2007 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.