Time course of beta 2-integrin CD11b/CD18 (Mac-1, alpha M beta 2) upregulation on neutrophils and monocytes after coronary artery bypass grafting. CD11b upregulation after CABG surgery.

Although upregulation of CD11b/CD18 receptor, i.e. activation of neutrophils and monocytes, during cardiopulmonary bypass is well documented, the duration of the active state after uncomplicated operation is less understood. We therefore investigated CD11b expression of phagocytes in blood samples collected 2-4, 24, 48 and 72 h after coronary artery bypass grafting. CD11b expression on neutrophils was significantly elevated at 2-4 and 24 hours after operation as compared with baseline. On monocytes, expression peaked at 24 h and returned to baseline by 72 h. Because CD11b is a sensitive marker, effects of different sampling techniques on its expression were also studied. CD11b expression was similar in samples collected with a syringe from arterial or central venous catheter or with open technique from cubital vein. On neutrophils from healthy subjects, sampling with syringe caused small (10%) but statistically significant increase of expression. We conclude that activated neutrophils disappear from circulation within hours after CABG surgery while activated monocytes may continue circulating for 2-3 days, and that CD11b sampling can be done with a syringe.