The Characteristics of T-cell Receptor Repertoires in Synovial Fluid and Peripheral Blood of Osteoarthritis Patients

T lymphocytes are required for adaptive immune responses and play a pivotal role in immune surveillance. However, the characteristics of T-cell receptors (TCR) remain largely unexplored in human synovial fluid. Consequently, evidence for local immune response in OA is also lacking. Here we investigated the TCR repertoire using high-throughput sequencing in synovial fluid samples collected from 9 OA patients. As compared to peripheral blood, TCR repertoire in synovial fluid is dominated a small number of clonotypes, which contributes to significantly lower TCR diversity (P<0.001). Additionally, a series of CDR3 clonotypes were highlighted for exclusively detected in synovial fluid while absent in peripheral blood. This study demonstrated the unique property of TCR repertoire in synovial fluid, which could provide possibility for future improvements in immune-related diagnosis and therapy for osteoarthritis.