Human knee synovial fluid cytokines correlated with grade of knee osteoarthritis--a pilot study.
The purpose of this pilot study was to evaluate the cytokine profile of human knee synovial fluid and correlate this with the subject's degree of articular cartilage degradation, radiographic score, and synovial histology.


METHODS
Synovial fluid was withdrawn before knee meniscectomy in 12 subjects with varying degrees of osteoarthritis and assayed for 21 cytokines, using a multiplex cytokine assay and flow cytometry instrumentation. Articular cartilage surfaces were scored by a single orthopaedic surgeon on the basis of the International Cartilage Repair Society (ICRS) classification during the arthroscopy, and posterior-anterior knee radiographs were graded using the Kellgren-Lawrence (KL) classification. Synovial biopsies were taken in four zones at the time of surgery for histological analysis.


RESULTS
Significant concentration differences in IL-2, IL-5, MCP-1, and MIP-1 were found between subjects with advanced arthritis and subjects with little or no arthritis on the ICRS scale (p < .05). No such differences could be appreciated using KL scores. There was no correlation between histology samples and visualized surface osteoarthritis.


CONCLUSIONS
This data suggests a molecular basis of disease progression, with higher levels of cytokines indicative of greater degrees of osteoarthritis. These results add pilot data that can assist investigators in conducting a comparative observational study of the levels of inflammatory cytokines with radiologic and arthroscopic assessments of osteoarthritis.
Department of Orthopaedic Surgery, Keck School of Medicine,University of Southern California, 1520 San Pablo Street, LosAngeles, CA 90033, USA. vangsness@usc.edu
C Thomas
CT
Vangsness
Wendy S
WS
Burke
Steven J
SJ
Narvy
Robert D
RD
MacPhee
Alexander N
AN
Fedenko
D000293:Adolescent; D000328:Adult; D000368:Aged; D001182:Arthroscopy; D015415:Biomarkers / Q000032:analysis; D001706:Biopsy; D002358:Cartilage, Articular / Q000473:pathology; D018932:Chemokine CCL2 / Q000032:analysis; D054405:Chemokine CCL3 / Q000032:analysis; D016207:Cytokines / Q000032:analysis*; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D007118:Immunoassay; D007376:Interleukin-2 / Q000032:analysis; D015848:Interleukin-5 / Q000032:analysis; D015141:Los Angeles; D008297:Male; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000000981:diagnostic imaging / Q000276:immunology* / Q000473:pathology / Q000601:surgery; D010865:Pilot Projects; D011859:Radiography; D012720:Severity of Illness Index; D013582:Synovial Fluid / Q000276:immunology*; D013583:Synovial Membrane / Q000473:pathology; D015854:Up-Regulation
D015415:Biomarkers; C111835:CCL2 protein, human; C515429:CCL3 protein, human; D018932:Chemokine CCL2; D054405:Chemokine CCL3; D016207:Cytokines; C508594:IL2 protein, human; C508599:IL5 protein, human; D007376:Interleukin-2; D015848:Interleukin-5