Augmentation of interleukin-2 production after cardiac operations in patients treated with erythropoietin

[Blood transfusion in surgery: can it still be reduced by human recombinant erythropoietin?]

New agents such as recombinant human erythropoietin (rHu EPO) modify conventional transfusionnal strategies. For accurate indications, such as, anaemia associated with chronic renal failure, cancer or cardiac disease, the preoperative prescription of rHu EPO may reduce transfusion requirements. rHu EPO may also be associated with pre-deposit transfusion in patients with anaemia before blood donation, when the transfusion needs are high, or the period for blood pre-deposit donation shortened. Postoperatively rHu EPO is only efficient if it is administered for a prolonged period; this condition limits its indications and value because of its high cost.

Responses of interleukin-6 and tumor necrosis factor during and after cardiac surgery undergoing cardiopulmonary bypass and pancreatoduodenectomy

To evaluate the effect of cardiopulmonary bypass on immunological function, we measured interleukin-6 (IL-6) and tumor necrosis factor (TNF) in 12 patients undergoing cardiac surgery during and after cardiopulmonary bypass, and in 10 patients with pancreatoduodenectomy. Plasma IL-6 levels were determined using the Human Interleukin 6 ELISA Kit, and TNF levels were determined using a highly sensitive sandwich enzyme immunoassay. In patients with cardiac surgery, plasma levels of IL-6 and TNF increased during cardiopulmonary bypass, and in patients with pancreatoduodenectomy, IL-6 and TNF levels significantly increased at the end of intraabdominal manipulation. These results suggest that endotoxin may have activated the immune system and stimulated cytokine production after pancreatoduodenectomy and during bypass.

Anemia of uremia is associated with reduced in vitro cytokine secretion: immunopotentiating activity of red blood cells

Many in vitro studies demonstrate various stimulatory effects of red blood cells (RBC) on T cell reactivity. Only a few suggest a role for RBC in vivo, such as decreased B and T cell function in iron deficiency anemia. Immune deficiency of uremia is only partially corrected by dialysis treatment. We postulated therefore that this anemia may contribute in part to the immune deficiency of uremia. The aim of our study was to evaluate this postulate and to investigate the role RBC may have in the immune system in vivo. The in vitro secretion of interleukin-2 (IL-2), gamma-interferon (gamma-IFN), tumor necrosis factor (TNF) and colony stimulating factor (CSF) by human peripheral blood mononuclear cells isolated from patients and controls was used as a measure of immune function. The following protocols were carried out: IL-2 secretion was measured in patients with end-stage renal disease (ESRD) and in controls. RBCs were transfused to patients with ESRD and secretion of cytokines was measured before, and 4 hours, 4, 7 and 14 days afterwards; patients with ESRD received recombinant human erythropoietin (rHuEpo) and secretion of cytokines was measured before treatment and two and four months later. Finally, the effect of phlebotomy and transfusion of the autologous blood on cytokine secretion in healthy subjects was measured. Secretion of IL-2 by patients with ESRD was substantially lower than that of healthy subjects. In each group, IL-2 secretion correlated positively with hemoglobin level, r = 0.73, P < 0.01 and r = 0.71, P < 0.01.(ABSTRACT TRUNCATED AT 250 WORDS)

Erythropoietin in cardiac surgery

Erythropoietin is the primary growth factor for red blood cells. A glycoprotein hormone synthesized by the kidneys, erythropoietin serves to increase red blood cell production in response to tissue hypoxia. It exerts its effect by increasing the numbers of erythroid progenitor cells in the bone marrow, and by increasing the rate at which their development is accomplished. With the introduction of recombinant erythropoietin in 1987, an important pharmacological agent became available for the manipulation of erythropoiesis. While used primarily for the treatment of the anemia of renal failure, recombinant erythropoietin has also shown usefulness in treating other types of anemias in which the endogenous erythropoietin response is insufficient. Perioperative use of the drug grew as a natural extension of this, and erythropoietin has been applied to correct preoperative anemia, augment autologous blood donation, and improve postoperative red cell recovery. Analysis of these perioperative clinical studies reveals success in these areas, but it also reveals that closer attention to the physiology of the natural response, and to the pharmacology of the recombinant product, might significantly improve results. Such an improvement in efficacy is both desirable and necessary when use of the drug is viewed in the setting of today's changing health care environment. By optimizing dosing schedules and targeting the drug to those most at risk for red cell transfusion, recombinant erythropoietin will likely become an important tool in efforts to achieve the elusive goal of bloodless cardiac surgery.