Interaction with autologous platelets multiplies interleukin-1 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 pglmL) for 8 h, the production ofinterleukin (IL)-la increased 11- to 18-fold and tumor necrosis factor (TNF)-a 3- to 5-fold compared with PBMC without platelets. Activated platelets in a dual-chamber well that prevented platelet-PBMC contact but permitted pas-sage of soluble factors enhanced IL-la production (P <.01). Platelet-PBMC contact in the chamber resulted in a further enhancement of IL-la production. These data suggest that platelet-PBMC interaction, both directly and with platelet-derived factors, enhances production of shock-producing IL-la and TNF-a, albeit differently. The interaction of platelets with monocytes may play an im-portant role in the pathophysiology of sepsis and disseminated intravascular coagulation. Gram-positive and-negative septicemias remain serious clin-ical problems that are often complicated by disseminated intra-vascular coagulation (DIC) [1-3]. Interleukin (IL)-l and tumor necrosis factor (TNF)-a are key mediators in the pathogenesis and lethality of both types of sepsis [4, 5]. In experimenta