The purpose to include non-transfused otherwise fully comparable patients is to distinguish between trauma (operation) and transfusion and their influence on immune modulation. Within the studies about blood transfusion and immune modulation only some few made this differentiation. In patients with colorectal cancer surgery randomized groups with autologous predonation and patients with allogeneic transfusion only have been compared. However, within the latter (allogeneic) group of 27 patients only 13 had to be transfused, thus creating a non-transfusion group of 14 patients. These 14 non-transfused patients remained within the study being compared with autologous and allogeneic transfused patients. Operative trauma and allogeneic transfusion both increased the secretion of several cytokines including tumor necrosis factor (TNF) alpha and Interleukin-10; this effect was less pronounced in patients with autologous- and without any transfusion. Another group studied forty three orthopedic patients with total knee- or hip-arthroplasty, initially to compare autologous to allogeneic red cell transfusion. They had to change their protocol due to the small number of allogeneic transfusions (8 of 43). Including perioperatively transfused patients only (n = 37) they found an increase in immune regulatory cytokine Interleukin (IL)-10 after red cell transfusion, which was most pronounced 7 days after surgery, whereas there was only a mild increase in non- or autologous transfused patients. Unfortunately they did not differentiate between autologous-and non-transfused patients. Thus their data could not reveal the effect of surgery itself on the analyzed parameters.