ANTI-CD18 ANTIBODIES IMPROVE CARDIAC-FUNCTION FOLLOWING CARDIOPULMONARY BYPASS IN DOGS

Purpose: Cardiopulmonary bypass is associated with activation of neutr ophils, which may adhere to vascular endothelium causing lung, heart, and brain injury. We tested whether blocking neutrophil adherence woul d improve organ function following cardiopulmonary bypass in dogs. Mat erials and Methods: All dogs received a standard anesthetic, and then one group (n = 6) received 2 hours of cardiopulmonary bypass followed by 4 hours of observation. A second group (n = 6) received a monoclona l antibody (6 mg/kg) to CD18, a neutrophil adherence factor, immediate ly before cardiopulmonary bypass. A third group (n = 6) did not receiv e cardiopulmonary bypass or antibody.Results: Using flow cytometry we found that the antibody bound essentially all neutrophil CD18 sites. A ll th ree groups had similar gas exchange and hemodynamics. Lung and h eart histology results were similar between groups. By echocardiograph y, five animals receiving cardiopulmonary bypass alone showed regional wall abnormalities, whereas only one receiving antibody showed wall m otion abnormality (P < .05). Following cardiopulmonary bypass, intrace llular myocardial pH was higher (P < .05) in the antibody-treated grou p compared with the group that had cardiopulmonary bypass alone (7.23 +/- 0.05 v 7.07 +/- 0.07 respectively). Conclusion: Monoclonal antibod ies to CD18 can prevent the deterioration in cardiac function routinel y observed following cardiopulmonary bypass. Copyright (C) 1996 by W.B . Saunders Company