Early serum levels of soluble triggering receptor expressed on myeloid cells–1 in septic patients: Correlation with monocyte gene expression

Abstract Purpose To define early kinetics of soluble triggering receptor expressed on myeloid cells-1 (sTREM-1) and of TREM-1 monocyte gene expression in critically ill patients with sepsis. Methods Blood was sampled at regular time intervals from 105 patients with sepsis. Concentrations of tumour necrosis factor α (TNF α ), interleukin (IL)–6, IL-8 and IL-10 and IL-12p70 and sTREM-1 were measured by an enzyme immunoassay. Blood mononuclear cells were isolated on day 0 from 20 patients and 10 healthy volunteers; RNA was extracted and gene expression of TREM-1 and TNF α were assessed by reverse transcriptase polymerase chain reaction. Results Early serum concentrations of sTREM-1 were greater among patients with severe sepsis/shock than among patients with sepsis; those of TNF α , IL-6, IL-8 and IL-10 were pronounced among patients with septic shock. Gene transcripts of TNF α were lower among patients with severe sepsis/shock than among patients with sepsis; that was not the case for TREM-1. Early serum levels of sTREM-1 greater than 180 pg/mL were predictors of shorter duration of mechanical ventilation. Conclusions Although serum levels of sTREM-1 are increased early upon advent of severe sepsis/shock, gene expression of TREM-1 on monocytes in severe sepsis/shock is not increased. These findings add considerably to our knowledge on the pathophysiology of sepsis.