Circulating soluble triggering receptor expressed on myeloid cells-1 (sTREM-1) as diagnostic and prognostic marker in neonatal sepsis.

Objective: Triggering receptor expressed on myeloid cells-1 (TREM-1) is an important receptor involved in the innate inflammatory response and sepsis. We assessed soluble TREM-1 (sTREM-1) in 112 septic neonates (63 culture-positive and 49 culture-negative) and 40 healthy controls as a potential early diagnostic and prognostic marker for neonatal sepsis (NS).

Methods: Studied neonates were evaluated for early- or late-onset sepsis using clinical and laboratory indicators upon admission. sTREM-1 was measured on initial sepsis evaluation and at 48h after antibiotic therapy. For ethical reasons, cord blood samples were collected from control neonates and only samples from neonates that proved to be healthy by clinical examination and laboratory analysis were further analyzed for sTREM-1.

Results: Baseline sTREM-1 levels were significantly elevated in culture-proven (1461.1±523pg/mL) and culture-negative sepsis (1194±485pg/mL) compared to controls (162.2±61pg/mL) with no significant difference between both septic groups. Culture-positive or negative septic preterm neonates had significantly higher sTREM-1 compared to full term neonates. sTREM-1 was significantly higher in neonates with early sepsis than late sepsis and was associated with high mortality. sTREM-1 was significantly decreased 48h after antibiotic therapy compared to baseline or levels in neonates with persistently positive cultures. sTREM-1 was positively correlated to white blood cells (WBCs), absolute neutrophil count, immature/total neutrophil (I/T) ratio, C-reactive protein (hs-CRP) and sepsis score while negatively correlated to gestational age and weight. hs-CRP and sepsis score were independently related to sTREM-1 in multiregression analysis. sTREM-1 cutoff value of 310pg/mL could be diagnostic for NS with 100% sensitivity and specificity (AUC, 1.0 and 95% confidence interval [CI], 0.696-1.015) while the cutoff value 1100pg/mL was predictive of survival with 100% sensitivity and 97% specificity (AUC, 0.978 and 95% CI, 0.853-1.13). However, hs-CRP cutoff 13.5mg/L could be diagnostic for NS with a sensitivity of 76% and specificity of 72% (AUC, 0.762 and 95% CI, 0.612-0.925) and levels were not related to survival as no significant difference was found between dead and alive septic neonates.

Conclusions: Elevated sTREM-1 could be considered an early marker for NS that reflects sepsis severity and poor prognosis.