Osteoarthritis (OA) is a very debilitating disease, and there are currently no common treatment options that act to retard or prevent its progression. It is well-known that inflammatory cytokines such as interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α) play a pivotal role in the developmental stages of OA. An in vitro assay has been developed to test the theory that an autologous protein solution (APS) containing high levels of anti-inflammatory cytokines can be prepared and used to reduce the effects of corresponding inflammatory cytokines. Preparation of the APS consisted of processing human blood in a gravitational platelet separator (GPSIII ^®, Biomet Biologics, Inc.) to produce platelet-rich plasma (PRP) and subsequently processing the PRP in a modified Plasmax^® device to produce a highly concentrated anti-inflammatory solution. A functional assay was designed using IL-1β to upregulate interleukin-8 (IL-8) production by human monocytes. IL-8 is a known mediator of the local inflammatory response. The IL-8 production was then reduced by the addition of interleukin-1 receptor antagonist (IL-1ra). Subsequent studies were then performed in which APS was used as a substitution for IL-1ra to determine if a reduced inflammatory response could be identified in vitro. Analyses were performed using the enzyme-linked immunosorbent assay (ELISA) method, and all statistical analyses were performed using the student’s t-test. The results revealed that APS can be used to reduce the effects of inflammatory cytokines in vitro, thereby validating its potential use as an autologous treatment for OA.