Autologous blood transfusion. Focus on erythropoietin and inflammatory mediators

Abstract

Background: Allogeneic blood transfusions cause immunosuppression measured by release of inflammatory mediators. Preoperative autologous blood donation (PAD) causes increased serum erythropoietin (sEPO) levels. Recombinant human erythropoietin (rhEPO) in combination with PAD is an established regime to avoid allogeneic blood transfusions. Inflammatory mediators are released in association with blood salvage. The present investigation was performed to discover differences in release of inflammatory mediators and sEPO levels and impact of rhEPO after autologous and allogeneic blood transfusion. In addition, we studied whether different salvage devices remove inflammatory mediators and whether these mediators participate in the modulation of the erythropoiesis.Methods: Patients undergoing hip or knee replacement surgery were studied regarding the activation of complement with formation of C3a, C5a and TCC; release of the cytokines IL-6 and IL-8, and the relationship between hemoglobin (Hb), sEPO and reticulocytes in association with allogeneic versus autologous blood transfusion. The effect of PAD with or without rhEPO treatment was evaluated analyzing Hb, hematocrit (hct), sEPO and reticulocytes. Release of C3a, C4b, Factor Bb, TCC, Hb and free Hb was evaluated using three different systems for blood salvage. Hemoglobin recovery was followed analyzing Hb, hct and reticulocytes.Results: IL-6, IL-8 and reticulocytes were significantly higher in recipients of autologous compared with allogeneic blood. sEPO was higher in the allogeneic group. No differences were found regarding Hb, hct and sEPO after PAD with or without rhEPO treatment. The reticulocytes increased more in the EPO group. High levels of C3a, TCC and free Hb were found in shed blood, but were effectively removed by a continuous autotransfusion system. Significantly higher concentrations of IL-6 were found in patients receiving filtered whole blood compared to washed red blood cells. The recovery of Hb levels did not differ in the groups.Conclusions: Allogeneic blood transfusion causes immunosuppression, which is shown by decreased IL-6 and IL-8 levels, compared to autologous transfusion. The postoperative sEPO concentration is greater after receiving allogeneic red blood cells than after autologous whole blood. Patients with a preoperative Hb within the normal range, participating in PAD, combined with rhEPO treatment, receive no benefit, as regards Hb levels and the avoidance of allogeneic blood transfusions. No difference in sEPO was seen. Salvaged blood contains high amounts of complement factors and interleukins, which are effectively removed by both conventional and continuous autotransfusion techniques, but not by using the unwashed, filtering technique. Reinfusion of unwashed, filtered blood leads to increased systemic concentrations of IL-6, but does not affect the postoperative hemoglobin recovery