Abstract: Platelet-rich-plasma (PRP) are processed blood products containing primarily platelet-enriched portion of the plasma. The enrichment of platelets provides a source for growth factors and molecules with regenerative properties. In many clinical conditions that use PRP as a treatment, such as osteoarthritis, inflammation and immune-mediated events are also present. Therefore, we tested for the immunomodulatory effects that PRP may provide with effector immune cells, including the timing and optimal dosage of PRP treatment using an in vitro assay. We isolated peripheral blood mononuclear cells (PBMCs) of healthy individuals and treated them with PRP derived from allogeneic donors. Our results show that PRP treatment resulted in reduced T cell production of pro-inflammatory cytokines (TNF-alpha, IL-1beta and IL-6) in a dose-dependent manner, yet with a narrow window of concentration to achieve overall immunosuppressive effects. In addition, the timing of PRP exposure to T cells also impacted their level of immunosuppressive capacity. Altogether, our data implies that an optimal condition of dosage and timing of PRP exposure to immune cells plays a role in how effective PRP can mitigate inflammation and potentially impact wound healing in host tissues.
