['To describe the concentrations of sTREM-1 in patients with sepsis and to explore the effects of their serum on the expression of TREM-1 on U937 monocytes.', 'Blood was sampled at regular time intervals in 56 patients with sepsis. Concentrations of tumour necrosis factor-alpha (TNFalpha), interleukin-1beta (IL-1alpha), IL-6, IL-8, IL-10 and IL-12p70 and sTREM-1 were measured. U937 monocytes were incubated in the presence of serum at sepsis onset.', 'Median sTREM-1 concentration on day 1 for patients with septic shock was 915 pg/ml and 228.5 pg/ml for those without shock (p = 0.002). TNFalpha, IL-1alpha, IL-6, IL-8 and IL-10 did not differ between them. A positive correlation was found between changes of sTREM-1 and SOFA scores from day 1 to 7. Sera of patients with septic shock evoked a significant increase of the expression of TREM-1. The concentrations of TNFalpha and IL-8 in supernatants increased only after stimulating with sera of patients without shock, but not after stimulating with sera of patients with shock.'] Does serum of patients with septic shock stimulate the expression of Trem-1 on U937 monocytes?