Bile CXC motif chemokine 10 levels correlate with anti-donor cytotoxic T cell responses after liver transplantation.

BACKGROUND: CXC motif chemokine 10 (CXCL10), known as interferon-γ-induced protein 10, is an inflammatory cytokine secreted by various cells in response to interferon-γ. CXCR3, the receptor of CXCL10, is predominantly expressed on activated T, B, natural killer, and dendritic cells, as well as macrophages. CXCR3 promotes chemotaxis upon binding CXCL10. Serum CXCL10 levels have recently attracted attention as a post-transplantation biomarker for graft rejection. However, the correlation between the degree of T cell response to allostimulation and CXCL10 levels remains unclear. In this study, we investigated the serum and bile CXCL10 levels of patients who underwent living donor liver transplantation (LDLT) and compared them with the T cell responses to allostimulation. PATIENTS AND METHODS: Between February 2009 and August 2012, 41 patients underwent LDLT at Hiroshima University Hospital. Serum and bile CXCL10 levels were measured weekly for 4 weeks after surgery, while the T cell responses to allostimulation were evaluated using a mixed lymphocyte reaction with an intracellular carboxyfluorescein diacetate succinimidyl ester-labeling technique that we regularly use to monitor the immune response to anti-donor and anti-third-party stimulation after liver transplantation. The stimulation index (SI) and CD25 expression of the CD4+ and CD8+ T cell subsets in response to allostimulation were then analyzed using flow cytometry. RESULTS: Serum CXCL10 levels were significantly correlated with the SI values for CD8+ T cells in response to both types of allostimulation. Bile CXCL10 levels were significantly correlated with CD25 expression of CD8+ T cell subsets, especially in response to anti-donor stimulation. Patients with higher bile CXCL10 levels suffered from severe acute cellular rejection that was refractory to steroid pulse. CONCLUSION: Measurements of bile CXCL10 levels could predict anti-donor cytotoxic T cell responses in liver transplant recipients.