Effect of aprotinin on the red cell immunity in cardiopulmonary bypass

To investigate the effects of aprotinin on red cell (RC) immune function in the patients undergoing cardiopulmonary bypass (CPB), 20 patients who received valve replacement procedure were prospectively studied. The patients were randomly assigned to aprotinin group and control group. Red blood cell C3b receptor ratio (RC3bRR), red blood cell immune-component ratio (RICR), plasma C3, C4, CH50 and IgG level were determined before operation, at the end of CPB and 1st, 3rd, 7th postoperative days. Our results showed that: (1) The blood requirement was reduced in aprotinin group. (2) After bypass, plasma C3, C4, CH50 was maintained in aprotinin group, while they declined in control group. (3) Plasma level IgG fell in both groups, but at 7th postoperative day it recovered in aprotinin group while the level stayed at low level in control group. (4) The RC3bRR and RICR was mildly inhibited in aprotinin group. It is concluded that the impairment of RC immune function caused by CPB can be mitigated by aprotinin, which may be related to the effects of aprotinin in blood sparing, restriction of complement activation, and reduction of blood requirement which could mitigate the non-specific inflammatory reaction.