Early immunologic responses to trauma in the emergency department patients with major injuries

BackgroundA traumatic insult initiates an inflammatory cascade, which is a contributor to cell damage and could be a marker of injury severity.ObjectiveTo compare the initial and 4-h post-injury lymphocyte subsets and cytokine levels between patients with minor and major injury.MethodsProspective, cross-sectional study of trauma patients in an urban level I trauma center. Inclusion criteria: Adult patients with significant mechanism of injury requiring admission. Variables: cell counts (B-cells, Natural Killer cells, monocytes; and CD4 and CD8 T lymphocytes) and cytokines (IL-1, IL-5, IL-6, IL-10, and TNFα). We divided subjects into two groups (major and minor injury). We defined major injury as an injury severity score ≥15, or drop in hematocrit ≥10 points or blood transfusion requirement. Statistical Analysis: Univariate analysis was performed using each inflammatory marker, and multivariate logistic regression analysis was performed to identify the inflammatory markers associated with major injury.Results79 patients were studied (mean age: 35 ± 17, age range: 13-88, 84% male, 38% penetrating trauma, 96% African-American). 25% of patients (n = 20) experienced major injury. Larger base deficit (−3.6 ± 6.2 vs. −0.9 ± 4.2) levels were observed in major trauma patients. We found that major injury is associated with a drop in absolute CD4 cell count (but not in the CD8 cells), a rise in absolute B-cell count (but not in the NK-cells or monocytes), and a rise in IL-6 (but not in the IL-1, IL-5, IL-10, TNF-a).ConclusionWe found evidence of a measurable early inflammatory response to trauma, using cytokine levels and lymphocyte subset counts.