Does soluble triggering receptor expressed on myeloid cells-1 play any role in the pathogenesis of septic shock?

In order to define the significance of soluble triggering receptor expressed on myeloid cells-1 (sTREM-1) upon progression from sepsis or severe sepsis to septic shock a prospective study was designed with 90 enrolled patients with septic syndrome due to ventilator-associated pneumonia. Blood was sampled on seven consecutive days upon initiation of symptoms and concentrations of tumour necrosis factor-alpha (TNF alpha), interleukin-6 (IL-6), IL-8 and sTREM-1 were estimated in serum by an enzymeimmunoassay. No differences in concentrations of TNF alpha, IL-6 and IL-8 were found between patients with sepsis, severe sepsis and septic shock on the first day of presentation of symptoms. Patients presenting with septic shock had concentrations of sTREM-1 significantly higher than both patients with sepsis and severe sepsis on the first day; no difference was found between patients with sepsis and severe sepsis. A positive correlation was detected between sTREM-1 and the white blood cell count. Serum levels of sTREM-1 were significantly lower in patients where VAP resolved compared to those where VAP did not resolve; similar findings were noted between patients who eventually survived and those who died. IL-6 followed the kinetics of sTREM-1 in correlation to patients's prognosis; levels of TNF alpha and IL-8 were unrelated to prognosis. It is concluded that sTREM-1 is particularly increased upon evolution from sepsis or severe sepsis to septic shock. Its sustained increase is an indication of poor outcome. The underlined pathophysiological role of sTREM-1 for the transition from sepsis or severe sepsis to septic shock might constitute a novel target for immunomodulatory therapy.