Effects of hyaluronic acid (HA) viscosupplementation on peripheral Th cells in knee and hip osteoarthritis

Summary Objective Determine Th lymphocytes concentration in patients with knee or hip osteoarthritis (OA). Evaluate their change after HA viscosupplementation. Methods Patients with early primary knee or hip OA (ACR Criteria) were recruited in two groups: group A was only observed longitudinally, group B was treated with a course of three weekly intra-articular injections of HA. A healthy control group gender and age matched was enrolled too. All subjects were followed for 3 months. Flow cytometry was performed from blood samples to assess T cells subpopulations (CD3, CD4, CD8, CCR6, CD38, CxCR3, HLA DR) at baseline and at 3-months visit. Results 86 patients were recruited with OA: 49 in Group A (35 knee OA, 14 hip OA), 37 in Group B (24 knee OA, 13 hip OA). 23 in Control Group. Activated CD4 T cells (CD4 + CD38 + DR + , CD4 + CD38 − DR + ), Th2 (CD4 + CXCR3 − CCR6 − ),Th1 (CD4 + CXCR3 + CCR6 − ) were higher at baseline in group A and B than in control group. After the HA course activated T cells were lower in group B than in group A ( P  = 0.01). Th17 (CD4 + CXCR3 − CCR6 + ) at baseline were higher in groups A and B than in control group and decreased levels in Group B after the HA course were observed ( P  = 0.03). Conclusion The presence of activated T cells in patients with OA confirm that OA is a disease with an immunological/inflammatory involvement. Our preliminary results seems to show that HA injections could lower the levels of activated T cells, and so regulate the articular milieu.