To examine mononuclear cell (MNC) subtypes in osteoarthritis (OA) synovial fluid (SF) and compare these results with MNC subtypes in SF from patients with rheumatoid arthritis (RA).
MNC were obtained from SF by gradient centrifugation with Ficoll-Hypaque. MNC subtypes were identified using color immunofluorescence with monoclonal antibody pairs and flow cytometry.
Significantly lower percentages of CD3+ (p < 0.01) and CD4+ cells (p < 0.01) were found in patients with OA. No differences were noted between CD8+ cells and the CD4/CD8 ratio. Significantly higher percentages of CD14+ (p < 0.001) and CD16+/CD56+ (p < 0.001) were found in patients with OA.
Significant differences in MNC subtypes in OA and RA were noted that may reflect differences in pathophysiologic mechanisms operational in each disease.