Secretion of Soluble ST2-Possible Explanation for Systemic Immunosuppression after Heart Surgery

Background: Cardiopulmonary bypass is known to affect cytokine release leading to a generalized endogenous immune reaction similar to that described in sepsis, without having been explored in great detail. Therefore we evaluated the anti-and pro-inflammatory cytokine responses after heart surgery. Methods: 16 patients who underwent coronary artery bypass graft (CABG) Surgery with extracorporeal circulation were included. ST2, IL-4 and IL-10 served as markers for TH2 cytokine response; IL-6, IL-8 and IFN-gamma as TH1 markers. Furthermore, total immunoglobulin subtype analysis (IgM, IgG, IgE) was performed. Results; Serum levels of soluble ST2 started to R climb at 60 minutes (from 38 +/- 14 preoperatively to 1480 +/- 890 pg/ml) and peaked 24 hours after Surgery (13360 +/- 2840 pg/ml, p<0.001). IL-10 reached a maximum at 60 minutes and returned to baseline levels 24 hours later, IL-6 and IL-8 levels peaked 60 minutes after surgery. IL-4 and IFN-gamma did not change. Only IgM showed a significant peak on day eight (p<0.001). Conclusion: Our results demonstrate that CABC surgery induces a massive long-lasting secretion of ST2, a protein related to immune suppression.