Circulating IL-10 is compromised in patients predisposed to developing and in patients with severe knee osteoarthritis

The purpose of this investigation was to identify if serum interleukin (IL)-10 and tumor necrosis factor (TNF)-alpha concentrations and their ratio (IL-10/TNF-alpha) are altered in subjects predisposed to developing knee osteoarthritis following ligamentous injury and in those with severe knee osteoarthritis. Serum IL-10 and TNF-alpha concentrations were measured in four groups of subjects (n=218): (1) reportedly-healthy and non-injured control subjects (CON; n=92), (2) subjects scheduled to undergo anterior cruciate ligament surgery (ACL; n=42), (3) non-surgical subjects with knee osteoarthritis (OA; n=60), and (4) subjects with knee osteoarthritis scheduled to undergo total knee arthroplasty (TKA; n=24). X-ray images were used to grade the severity of knee osteoarthritis. Serum IL-10 and the serum IL-10/TNF-alpha ratio were significantly lower while serum TNF-alpha was not significantly perturbed with severe compared to moderate knee osteoarthritis (i.e., Kellgren-Lawrence grade 4 vs. 3, respectively). Serum IL-10 was significantly lower in the absence of serum TNF-alpha alterations in the ACL group. We conclude that serum IL-10 concentrations are compromised in subjects predisposed to developing knee osteoarthritis following ligamentous trauma and in subjects with radiographic evidence of severe knee osteoarthritis.