Plasma Level of Interleukin-35 as an Independent Prognostic Indicator in Hepatocellular Carcinoma

Background Hepatocellular carcinoma is a major type of liver cancer with poor prognosis. Aim The aim of the study was to determine the prognostic significance of plasma interleukin-35 level in hepatocellular carcinoma. Methods A total of 153 hepatocellular carcinoma patients and 153 healthy controls were enrolled. Blood samples were obtained at admission. Plasma interleukin-35 level was analyzed by enzyme-linked immunosorbent assay. Distribution of T cell subset and expression of Fas/FasL protein were detected by flow cytometry. The patients were followed up for 2 years. Poor prognosis was defined as death of hepatocellular carcinoma. Results The plasma levels of interleukin-35 were significantly higher in the patients than the controls (25.1 ± 13.1, 9.3 ± 6.3 pg/mL, P < 0.001). After adjusted for multiple confounding factors, the multivariate logistic regression analyses reported that high level of interleukin-35 (≥25.0 pg/mL) was associated with the poor prognosis in the patients (OR 6.63, 95 % CI 3.27–13.47). Compared with the patients with low level of interleukin-35 (<25.0 pg/mL), the patients with high level of interleukin-35 showed higher frequencies of CD4+CD25+FoxP3+ and CD3+Foxp3+ regulatory T cells ( P < 0.001 and P < 0.001) and also showed higher apoptosis levels of CD8+ T cells ( P < 0.001). Conclusion Circulating interleukin-35 concentration might be an independent prognostic indicator in hepatocellular carcinoma. Such prognostic significance could be partly involved in the activation of regulatory T cell and the apoptosis of CD8+ T cell.