Induced interleukin-19 contributes to cell-mediated immunosuppression in patients undergoing coronary artery bypass grafting with cardiopulmonary bypass.

Abstract

Coronary artery bypass graft (CABG) surgery with cardiopulmonary bypass (CPB) promotes immunosuppression, which predisposes patients to infectious complications. We investigated the role of interleukin (IL)-19 in the functions of CD4+ T cells in patients undergoing CABG with CPB. Blood samples were withdrawn from 42 patients undergoing elective CABG with CPB. Serum levels of IL-19 were analyzed by enzyme-linked immunosorbent assay (ELISA). The CD4+/CD25+ T-cell population was determined with flow cytometry. Isolated CD4+ T cells were cultured and assayed for proliferation and cytokine production under phorbol myristate acetate/ionomycin stimulation. Cytokine production and Foxp3 mRNA expression in CD4+ T cells from healthy volunteers with or without IL-19 treatment were determined with ELISA and real-time polymerase chain reaction, respectively. Proliferation percentages were 162%, 48%, 34%, and 39%, and interferon (IFN)-γ production was 1.22 ng/mL, 0.56 ng/mL, 0.33 ng/mL, and 0.35 ng/mL in the CD4+ T cells of patients before CPB and at 24 hours, 48 hours, and 96 hours, respectively, after CPB. Serum levels of IL-19 were higher but negatively correlated with CD4+ T-cell proliferation and IFN-γ production. The populations of CD4+/CD25+ T cells and expression of Foxp3 mRNA in T cells were higher and were positively correlated with IL-19 levels after CPB. Treatment with IL-19 reduced T-cell proliferation and IFN-γ production, increased Foxp3 mRNA expression, and induced the regulatory activity of CD4+ T cells. Interleukin-19 reduces T-cell responses and promotes the regulatory activity of CD4+ T cells. Induced IL-19 in patients undergoing CABG with CPB contributes to cell-mediated immunosuppression.