Defining the early systemic neutrophil signature after severe trauma: decreased CD10/CD16 levels on admission precedes metabolic dysregulation

PURPOSE: Dysregulation of the post-traumatic immune response forms the basis for life threatening complications such as acute respiratory distress syndrome and (multiple) organ failure. Automated flowcytometry analysis of peripheral blood samples enables rapid immunomonitoring in the shock room. It was hypothesized that a specific systemic neutrophil receptor expression pattern in peripheral blood is associated with early metabolic deterioration, as indicated by high lactate levels after eight hours in severely injured trauma patients.

METHODS: Severely injured trauma patients with an Injury Severity Score > 25 and healthy volunteers, were prospectively included in a Level I trauma center in Central Europe. The systemic neutrophil receptor signature in peripheral blood was determined by measuring the neutrophil markers CD16, and CD10 with an AQUIOS CL ® "load & go" flow cytometer.

RESULTS: A total of 24 patients with a mean age of 51.5 years and a median ISS of 36.5 were included, as well as a control group of 9 healthy volunteers. Mean admission leukocyte levels of 15.2 G/L were seen. Circulatory leukocyte counts were significantly higher and cell surface expression levels of CD10 und CD16 were significant lower in trauma patients compared to healthy controls. Spearman's rank correlation coefficients for CD10 (ρ = -0.649) and CD16 (ρ = -0.493) showed significant negative correlations with elevated lactate levels after 8 h.

CONCLUSION: This study shows that admission CD10 and CD16 expression levels on neutrophils correlate with elevated lactate levels 8 h post-injury in severe polytrauma. A specific CD10/CD16 neutrophil signature, linked to leukocytosis, precedes metabolic dysregulation, determined by higher lactate levels. A better understanding of the early neutrophil receptor profile may form the basis for future immunomonitoring and guide treatment decisions.