T Helper 17-Like Regulatory T Cells in Equine Synovial Fluid Are Associated With Disease Severity of Naturally Occurring Posttraumatic Osteoarthritis.

backgroundInfiltration of cluster of differentiation (CD) 3 HYPOTHESIS: An imbalance of the ratio of regulatory T cells and T helper 17 cells would be associated with disease progression in posttraumatic osteoarthritis, suggesting opportunities for immunomodulatory therapy. STUDY

designDescriptive laboratory study.

methodsSynovial fluid was aspirated from the joints of equine clinical patients undergoing arthroscopic surgery for posttraumatic osteoarthritis resulting from intra-articular fragmentation. Joints were classified as having mild or moderate posttraumatic osteoarthritis. Synovial fluid was also obtained from nonoperated horses with normal cartilage. Peripheral blood was obtained from horses with normal cartilage and those with mild and moderate posttraumatic osteoarthritis. Synovial fluid and peripheral blood cells were analyzed by flow cytometry, and native synovial fluid was analyzed by enzyme-linked immunosorbent assay.

resultsCD3

conclusionsAn imbalance of the ratio of regulatory T cells and T helper 17 cells and an increase in T helper 17 cell-like regulatory T cells in synovial fluid from joints with more severe disease provide novel insights into immunological mechanisms that are associated with posttraumatic osteoarthritis progression and pathogenesis. CLINICAL RELEVANCE: Early and targeted use of immunotherapeutics in the mitigation of posttraumatic osteoarthritis may improve patient clinical outcomes.