MODULATION OF IMMUNE-RESPONSE BY BLOOD-TRANSFUSION - EVIDENCE FOR A DIFFERENTIAL EFFECT OF ALLOGENEIC AND AUTOLOGOUS BLOOD IN COLORECTAL-CANCER SURGERY

Even though blood transfusion-associated immunomodulatory effects have been reported, the basic immune mechanism is still not understood. Da ta from studies an the clinical effects of allogeneic blood-induced im munosuppression are contradictory, However, there are indications that autologous blood transfusion is not immunologically neutral but has i ntrinsic immunomodulatory potential. Therefore we investigated in vivo different immunological mediators in 56 randomized patients of a stud y comparing autologous and allogeneic blood transfusion in colorectal cancer surgery. Soluble IL-2 receptor, which is an indicator of genera l immune activation and the following immunologic refractory phase, in dicated immunosuppression was more elevated at the seventh postoperati ve day in patients with allogeneic transfusions (p=.013) and autologou s transfusions (p=.0003), The immunologic determination of TNF-alpha s howed a significant postoperative increase in patients with autologous transfusions only (p=.0031). However, postoperative increase of solub le TNF-receptors p55 and p75 was also significant in patients transfus ed with allogenic blood (p=.022; p=.0014). The response to tetanus tor oid vaccination, an indicator of humoral immunity, was higher in patie nts transfused with allogeneic rather than autologous blood (p= .082), whereas responses of patients with autologous transfusions were even lower than in nontransfused patients; The reciprocal was already found for cell-mediated immunity determined by epicutaneously tested delaye d-type hypersensitivity-reactions. IL-10 levels, an indicator of cellu lar immunosuppression, were determined in 27 additional patients befor e operation, immediately postoperative, and at the seventh postoperati ve day. IL-10 was found elevated immediately postoperative in allogene ic (p=.011) and nontransfused patients only (p=.042). The data from th is study substantiate recent findings of a different immunomodulatory potential of allogeneic and autologous blood transfusion. They further more support the hypothesis that autologous blood transfusion does not contain immunologically neutral effects of allogeneic blood, but itse lf exerts an immunomodulatory effect.