Induction of interleukin-8 expression during cardiopulmonary bypass

Patients undergoing cardiopulmonary bypass (CPB) are known to suffer from a postsurgical systemic inflammatory response, the nature of which remains to be fully elucidated. Interleukin-8 (IL-8) is a newly described, powerful leukocyte chemotactic factor known to be generated after stimulation of interleukin-1 (IL-1). As we have previously documented the generation of IL-1 beta after CPB, it followed that IL-8 generation should be measured in a comparable group of patients.

Twenty-two adult patients aged 41 to 81 years undergoing coronary revascularization were studied for measurements of C3a, C5a, IL-1, IL-8, and OH(.). Blood was collected before surgery, after CPB, and at 24, 48, and 72 hours. A significant increase in IL-1 beta and IL-8 was detected in circulating leukocytes with peak levels at 24 hours after bypass. No IL-1 beta or IL-8 antigen was detected at any time in patient plasma. Comparable to interleukin generation, human complement-derived C5a also peaked after 24 hours, whereas C3a was increased dramatically immediately after CPB, followed by a decline at 24 hours and a progressive increase over the next 48 hours.

The results demonstrated for the first time the presence of cell-associated IL-8 in CPB patients. This suggests that this powerful polymorphonuclear and T-lymphocyte chemotactic factor may be an important element in leukocyte activation and recruitment after CPB.