Abstract
Objective
To investigate the effects of trauma and fracture surgery on leukocyte maturation and function.
Background
Unbalanced inflammation triggered by trauma has been linked to multiorgan dysfunction (MOD) and death. In animal and cellular models, changes in neutrophil function and failure of monocyte infiltration and resolution have been implicated as possible causes. The investigators combine assays on neutrophil function with surface antigen expression on circulating neutrophils and monocytes. These are correlated with severity of traumatic injury, type of surgery and clinical outcome to help explain the aetiology of distant organ injury, and pose a case for damage control surgery.
Results
A total of 20 patients requiring internal fixation of femoral shaft fractures, acetabular fractures and pelvic fractures were recruited. Those undergoing surgery following an interval period were used as control, with blood and plasma samples pre-operatively, and 2 and 5 days post-operatively, whilst patients with acute trauma also had an admission sample. Using flow cytometry, the neutrophils were gated on CD15+ CD14- with high side scatter whilst the monocytes were gated on CD14+ CD15- with low side scatter. Two days following surgery the neutrophils showed reduced CXCR2 expression and increased CXCR1, CD11b and IL-6R expression whilst the monocytes showed reduced CCR2 and HLA-DR receptor expression. The change in receptor expression was enhanced in the trauma patients in comparison to the control patients, and correlated with cellular function, using respiratory burst, elastase release and transmigration assays.
Conclusions
This first human trial evaluating the immunologic/anti-inflammatory effects of trauma and trauma surgery on the specific antigen expression helps explain one mechanism for organ damage in the post-trauma patient.
