Soluble triggering receptor expressed on myeloid cells 1 as an anti-inflammatory mediator in sepsis

To define the significance of soluble triggering receptor expressed on myeloid cells 1 (sTREM-1) in the septic cascade by comparing its kinetics to those of other proinflammatory mediators and of interleukin (IL) 10.

Prospective study in a tertiary unit.

Blood was sampled from 90 patients with septic syndrome due to ventilator-associated pneumonia for 7 days after the appearance of symptoms. Concentrations of tumor necrosis factor (TNF) alpha, IL-6, IL-8, IL-10, and sTREM-1 were determined by enzyme-linked immunosorbent assay.

Serum levels of TNFalpha, IL-6, IL-10, and sTREM-1 were higher in nonsurvivors than in survivors; similar differences were not found for IL-8. Positive correlations were found between the ratios IL-10/TNFalpha and sTREM-1/TNFalpha, between IL-10/IL-6 and sTREM-1/IL-6, and between IL-10/IL-8 and sTREM-1/IL-8. Median values of IL-10/TNFalpha upon presentation of sepsis, severe sepsis, and septic shock were 3.21, 2.16, and 2.86, respectively (NS). Respective values for sTREM-1/TNFalpha were 21.28, 7.33, and 27.78 (p=0.047 between sepsis and severe sepsis, p=0.003 between severe sepsis and septic shock).

sTREM-1 follows the kinetics of IL-10 and should therefore be considered an anti-inflammatory mediator in sepsis. Decreased ratios of sTREM-1/TNFalpha might determine transition from sepsis to severe sepsis and from severe sepsis to septic shock.