Influence of colloid fluids on polymorphonuclear granulocyte function in vivo

Background: Granulocytes have a role in the immediate immune response. In a previous investigation we could demonstrate in vitro a moderate increase of the complement receptors CR1 (CD35) and CR3 (CD11b/CD18) on the surface of polymer phonuclear neutrophils (PMN) after incubation of whole blood with colloids. To elucidate the clinical significance, we investigated if these changes were also present in vivo. Methods: The study was performed prior to anaesthesia for orthopaedic surgery. A total of 60 ASA-I patients was evaluated. Patients received in a randomised manner 7 mL/kg of the following solutions: human albumin 5% (HA), gelatine 4% (GEL), hydroxyethylstarch solution 6% with MW 200 000 Da, degree of substitution 0.5 (HES), or Ringer's solution. Prior to the infusion, at the end (30 min) and again 30 min later, blood samples were taken. Blood was incubated with fluorescein-conjugated monoclonal antibodies (CD11b, CD16, CD35, CD62L) and analysed with flow cytometry. Results: HA, GEL, HES, and Ringer's solution failed to induce significant differences in the expression of complement receptors CR1 (CD35) and CR3 (CD11b/CD18), Fc gamma receptor IIIb (CD16), and of L-selectin (CD62L) receptor on the surface of PMN. Conclusions: Application of colloids like HA, GEL, or HES in moderate amounts shows no short-term effect on adhesion or activation molecules on granulocytes. However, in high doses, infused in situations such as multiple trauma and sepsis, the consequences on the function of PMN may be speculative and require further investigations.