Introduction: Elevated plasma elastase levels have been reported following major trauma and isolated femoral fracture. Reamed femoral nailing has been shown to further increase plasma elastase levels. The aim of this study was to investigate neutrophil (PMN) priming for degranulation following major trauma and isolated long-bone pelvis fracture by assessing the ability of PMN to release elastase in-vitro in response to phorbol myristate acetate (PMA) an analogue of dia-cylglycerol (DAG) a component of the “second messenger” system.

Methods: 11 major trauma (ISS≥18) patients and 18 patients with isolated long-bone/pelvis fracture, were consented to enter the study. Patients in the isolated fracture group were further stratified depending upon the type of fracture stabilization they underwent [reamed nail (n=12), Ex-Fix (n=6)]. Blood samples were obtained on admission, at 24 hours post injury, at day 3 and day 5. 11 healthy volunteers were used as controls. PMN were isolated by dextran sedimentation and ficoll-hypaque density gradient centrifugation. The ability of PMN to degranulate was assessed by an elastase substrate assay.

Results: A significant increase in the capacity of PMN to release elastase in response to a PMA stimulus was seen in major trauma patients on admission as compared with healthy volunteers. However in patients with isolated long-bone/pelvis fracture, there was no difference in levels of elastase release. Further no difference in the ability of PMN to release elastase was seen between the reamed nail and Ex-Fix groups.

Conclusions: In conclusion we show that PMN are primed for increased degranulation (elastase release) following major trauma but not following isolated long-bone/pelvis fracture. These primed PMN are capable of increased tissue damage following major trauma thus increasing the risk of development of multiple organ failure.

Aims: Neutrophil (PMN) dysfunction is implicated in both acute respiratory distress syndrome (ARDS) and sepsis. We aimed to determine the PMN response following isolated long-bone/pelvic fracture by investigating temporal changes in PMN migration and surface receptor expression (CXCR1, PECAM- 1, & CD18/ CD11b) following injury. Methods: Of the 20 patients consented to enter the study, 14 underwent reamed nailing/ORIF within 24 hours, and 6 were treated with an Ex-Fix or conservatively. 11 normal volunteers (NLV) were used as controls. Blood samples were obtained within 2 hours of admission, at 24 hours, at day 3 and day 5. PMN were isolated and the number of PMN migrating across porous collagen IV coated tissue culture inserts, in response to IL-8 were quantitated by myeloperoxidase activity. PMN surface receptor expression was assessed by whole blood FACScan analysis. Results: Signiþcantly greater numbers of fracture patient PMN migrated on admission as compared with NLV. In the Ex-Fix group the numbers migrating declined steadily and showed a hypo-response on day 5. In the reamed nailing group there was a further elevation in the PMN numbers migrating post-operatively. CXCR1 & CD18 expression was signiþcantly increased on admission. PECAM-1 was signiþcantly down-regulated on admission.

Conclusions: Following isolated long-bone/pelvic fracture PMN are primed for increased migration in response to IL-8. This is associated with up-regulation of CXCR1 and CD18, and down-regulation of PECAM-1. Treatment by reamed nailing and ORIF confers a Ç second hit È manifest as a further increase in IL-8 mediated PMN migration.

Total knee arthroplasty (TKA) is a common, effective operation but postoperative infection has devastating consequences. Several papers have associated perioperative autologous transfusion with reduced infection rates. Salvaged blood may augment the inflammatory response and central within it is polymorphonuclear leukocyte (PMN). Our hypothesis was that autologous transfusion enhances PMN activity by: increased PMN transmigration to potential infection site, enhanced phagocytosis, augmented respiratory burst activity.

Our randomised controlled prospective study showed a significant increase in superoxide production by PMN of patients who received unwashed autologous transfusion supporting the clinical studies where infection rates following autologous transfusion were reduced.

Objective: It has been observed in previous studies of autologous blood transfusion in total knee arthroplasty, that this technique is associated with a lower infection rate, though studies have not been sufficiently large to demonstrate a significant difference. We hypothesised that autologous salvage blood contained high levels of pro-inflammatory mediators which may prime or augment the patients’ inflammatory response, and, in particular, the function of the polymorphonuclear leukocyte (PMN).

Methods: Patients were randomised after consent to those receiving autologous transfusion and those having conventional treatment which was homologous transfusion only if clinically indicated. PMN were then isolated from the patients pre-admission immediately after the operation and 24 hours post-total knee arthroplasty. Three different aspects of PMN activity were measured: 1) The respiratory burst activity; 2) the ability to phagocytose microbes using radiolabelled staphylococcus epidermis; 3) and the ability to migrate across a collagen coated porous inserts.

Results: 80 patients were studied, of whom 43 were in the autologous transfusion group and 37 in the first group. Of these 37, 6 had homologous transfusion. The study showed no significant difference between the phagocytic ability of the PMN from both groups. The main stimulus to transmigration is surgery itself. There was a significant increase in the production of reactive oxygen species by the PMN of those patients who received an autologous transfusion post-operatively.

Conclusions: Using molecular biology techniques to study the PMN directly, our study indicates that autologous transfusion alters the activity of PMN and this indicates a possible mechanism whereby the immune response to infection could be enhanced. This, in turn, would explain the observed differences in infection rate in previous studies.