Interaction with Autologous Platelets Multiplies Interleukin-l and Tumor Necrosis Factor Production in Mononuclear Cells

The effect of activated platelets on cytokine production by human peripheral blood mononuclear cells (PBMC) was investigated. When PBMC were coincubated with activated autologous platelets amid lipopolysaccharide (LPS, 50-100 pg/mL) for 8 h, the production of interleukin (IL)-1alpha increased 11- to 18-fold and tumor necrosis factor (TNF)-alpha 3- to 5-fold compared with PBMC without platelets. Activated platelets in a dual-chamber well that prevented platelet-PBMC contact but permitted passage of soluble factors enhanced IL-1alpha production (P < .01). Platelet-PBMC contact in the chamber resulted in a further enhancement of IL-1alpha production. These data suggest that platelet-PBMC interaction, both directly and with platelet-derived factors, enhances production of shock-producing IL-1alpha and TNF-alpha, albeit differently. The interaction of platelets with monocytes may play an important role in the pathophysiology of sepsis and disseminated intravascular coagulation.