[Prognostic value of the sTREM-1 plasma values in patients with sepsis: a cohort study]. / Valor pronóstico de los niveles plasmáticos de sTREM-1 en pacientes con sepsis: un estudio de cohortes.

OBJECTIVE: To evaluate the association between plasma levels of soluble Triggering Receptor Expressed on Myeloid Cells-1 (sTREM-1) and mortality of patients with sepsis. DESIGN: Prospective cohort study. SETTING: Two general Intensive Care Units. PATIENTS: Patients with sepsis in whom sTREM-1 plasma levels were determined daily in the first 3 days of their presentation. VARIABLES OF INTEREST: Mortality at 28 days. RESULTS: We analyzed 121 patients (23% severe sepsis, 44% septic shock, 33% non-severe sepsis). Mortality at 28 days was 24.8%. The initial sTREM-1 levels were slightly higher in nonsurvivors than in survivors (median 366.9 versus 266.5 pg/ml, p=0.2668). An increase in sTREM-1 levels higher than 90 pg/ml within the first 3 days (delta-TREM) was associated with an excess of mortality (hazard ratio [HR] 2.68, p=0.0047), with a sensitivity of 47% and a specificity of 78%. This excess of mortality disappeared after adjusting for severity by Cox analysis (adjusted HR 1.07, p=0.8665). CONCLUSIONS: The increase in the levels of sTREM-1 during the first 3 days of evolution is associated with an excess of mortality in critically ill patients with sepsis. This is explained by the greater initial severity of these patients. The discriminative capacity of this finding is insufficient to be clinically useful.

Leucocyte activation markers in clinical practice.

The response against tissue injury and infection begins with the early activation of molecular and cellular elements of the inflammatory and immune response. Severe tissue injury, necrosis, and infection induce imbalanced inflammation associated with leukocyte over-stimulation and excessive or dysregulated release of cellular mediators. Clinical and experimental studies have shown that these mediators are directly related to progressive post-injury complications. Persistent increased levels of pro-inflammatory mediators produce tissue injury. Excessive production and activity of anti-inflammatory mediators cause anergy and/or immune dysfunction with increased susceptibility to infection. Leukocyte activation is assessed by cell surface phenotype expression, cellular mediators determination, or by measuring functional responses using isolated cells. Potential routine clinical uses are: evaluation of severity and prognosis in critically ill patients, immunomonitoring of sepsis, and detection of tissue injury, necrosis, and infection. In practice, the determination of cellular activation markers is restricted by a limited number of automated methods and by the cost of reagents. The availability of flow cytometry and immunoassay automated systems can contribute to a wider use in practice. Here we review the immunopathophysiology of polymorphonuclear neutrophil, monocyte, macrophage, and lymphocyte activation in response to tissue injury and infection. In addition, laboratory methods for their determination, and clinical applications in practice, are discussed.