Effects of methylprednisolone on complement activation and leukocyte counts during cardiopulmonary bypass

Generation of the complement activation products C3dg and terminal complement complex (TCC) and numerical changes in peripheral granulocytes (PMN) and lymphocytes were assessed in patients undergoing aortocoronary bypass surgery with extracorporeal circulation (ECC). Fluid from bronchial lavage performed preoperatively and 4 hours postoperatively was analyzed for granulocyte elastase activity and PMN content. Ten of the 20 patients received methylprednisolone (30 mg/kg b.w.) immediately before ECC. No difference was found between them and the control group regarding C3dg and TCC, and both groups showed similar postoperative decrease of peripheral blood lymphocytes. The postoperative PMN count in peripheral blood was significantly higher in the methylprednisolone group than in the controls from 12 hours onwards. In bronchial lavage fluid the postoperative PMN count was unaltered in the methylprednisolone group, but significantly increased in the controls. No granulocyte elastase activity was found before or after surgery in either group. The results indicated that methylprednisolone does not affect complement activation during cardiopulmonary bypass, but increases the granulocytes in peripheral blood postoperatively.