Myeloid-derived suppressor cells correlate with patient outcomes in hepatic arterial infusion chemotherapy for hepatocellular carcinoma

Hepatic arterial infusion chemotherapy (HAIC) has been employed as an alternative therapy to sorafenib for the patients with advanced hepatocellular carcinoma (HCC). In this study, we performed a comparative analysis of various immune cell responses including tumor-associated antigen (TAA)-specific T cells, regulatory T cells (Tregs) and myeloid-derived suppressor cells (MDSCs) in advanced HCC patients treated with HAIC. Thirty-six HCC patients were examined in the study. Interferon gamma enzyme-linked immunospot assays were performed to examine the frequency of TAA-specific T cells. The frequencies of Tregs and MDSCs were examined by multicolor fluorescence-activated cell sorting analysis. The treatment with HAIC using interferon (IFN)/5-fluorouracil (FU) or IFN/FU + cisplatin modulated the frequencies of various immune cells. In 22.2 % of patients, the frequency of TAA-specific T cells increased after HAIC. Although the frequency of Tregs decreased after HAIC, it was not associated with the prognosis of patients. An analysis of prognostic factors for overall survival identified diameter of the tumor (<3.0 cm), absence of major portal vein invasion, absence of distant metastasis, Union Internationale Contre Le Cancer tumor lymph node metastasis stage (I or II), neutrophil lymphocytic ratio (<2.1) and the frequency of MDSCs (<30.5 %) as factors that prolonged overall survival time after HAIC. Even in the group adjusted with progressive levels of tumors, patients with a low frequency of MDSCs had a significantly longer overall survival time. In conclusion, the frequency of MDSCs before the treatment is a prognostic factor in HAIC against HCC.