Induction of interleukin-10 during extracorporeal circulation

Twenty patients undergoing open heart operations without evidence of a concomitant malignant or immunologic disease; HIV and HBV seronegative were studied. EDTA-blood samples were drawn on six occasions. WBC was performed and FACS analysis enrolled. IL-10 was measured after cryopreservation of plasma by quantitative 'sandwich' enzyme immunoassay technique (sensitivity 1 pg/ml).The total leukocyte count decreases at the institution of ECC (3521 ± 871) and remains nearly unchanged through the aortic clamping time (3503 ± 1370). After removal of aortic clamp a significant leucocytosis occurs (8085 ± 3571), through 3.POD (10708 ± 3606). The phasic changes of leukocytes is mainly caused by identical course of neutrophils. IL-10 shows a monophasic course with a peak concomitant to removal of aortic clamp (45.5 ± 49.6 pg/ml) and falls to preoperative levels at 3.POD (3.2 ± 4.5 pg/ml).The increased level of IL-10 during the ECC indicates an activation of Th2 cells. IL-10 inhibits the production of IFN-γ, induces the differentiation of Th2 cells from uncommitted T cells. The inhibitory effect of IL-10 on Th1 cell differentiation causes a further depression of cell-mediated immunity during the early postoperative phase.