INTERINDIVIDUAL VARIATIONS IN CYTOKINE LEVELS FOLLOWING CARDIOPULMONARY BYPASS

Cardiopulmonary bypass (CPB) is associated with an inflammatory respon se, mainly caused by the trauma of surgery, contact of blood with the artificial surface of the circuit, and reperfusion injury, resulting i n increased capillary permeability, respiratory distress, low cardiac output, and multiorgan failure. The inflammatory reaction includes an activation of the humoral and cellular immune system with enhanced rel ease of cytokines. The present study focused on the effect of CPB on t he time course of pro- and antiinflammatory cytokines. In 20 patients undergoing coronary artery bypass grafting, the plasma concentration o f interferon (IFN)-gamma, tumor necrosis factor (TNF)-alpha, interleuk in (IL)-1 beta, IL-2, IL-4, IL-6, IL-8, and IL-10 was investigated pre -, intra- and postoperatively by enzyme-linked immunosorbent assay tec hnique. With the exception of IFN-gamma, all the other cytokines could be detected in the patients plasma. However, neither TNF-alpha nor IL -1 beta and IL-2 revealed significant changes in concentration during the investigated time period. In contrast, IL-6 and IL-8 levels peaked early postoperatively, reaching median concentrations of 430 pg/ml (2 21 pg per ml/558 pg per ml; lower/upper quartiles, respectively) and a pproximately 12 pg/ml (0/17 pg/ml; lower/upper quartiles, respectively ). IL-4 and IL-10, respectively, revealed maximal concentrations of ap proximately 2 pg/ml (0/39 pg/ml; lower/upper quartiles, respectively) and 208 pg/ml (76 pg per ml/380 pg per ml, lower/upper quartiles, resp ectively) immediately after protamine administration, preceding the ma ximal concentration of IL-6. The degree of the observed modulation of cytokine patterns during and after CPB seemed to be patient-dependent, since large interindividual variations in cytokine levels were observ ed, not only preoperatively, but especially during and following CPB. However, IL-6 and IL-10 showed the least interindividual variations, s uggesting that these cytokines may give reliable information regarding modulation of the immune response following CPB and its consequences for the patient's outcome.