OBJECTIVE To investigate the practical possibility of inducing dendritic cells (DCs) from mononuclear cells in the lost blood during operation of hepatocellular carcinoma (HCC) patients, and attempted to find a new source of precursor cells for the personalized immunotherapy based on DCs. METHODS Collected lost blood during hepatectomy from 9 HCC patients and human cord blood from 8 cases of healthy donors undergoing caesarean section. Their mononuclear cells were divided into monocytes and nonadherent lymphocytes. RhGM-CSF and rhIL-4 were administered to induce the monocytes differentiation into DCs, and then loaded with different antigens (lysate antigen of autologous liver cancer cells and cell line SMMC-7721 cells). The lymphocytes were induced into cytokine-induced killer cells (CIK) with IL-2, CD3-Ab, gamma-IFN and PHA. MTT assay was performed to detect the proliferation rate of T lymphocytes mediated by DC and the cytotoxicity of CIK to liver cancer cells. RESULTS DCs induced from monocytes of the intra-operative lost blood possessed typical morphology and phenotypes. Compared with the DCs from cord blood, the DCs from intra-operative lost blood expressed lower level of surface markers, but both could effectively induce proliferation of CIK and enhance the cytotoxicity of activated CIK against liver cancer cells at similar levels. When the DCs from lost blood and their counterpart from cord blood were both loaded with autologous tumor cell antigen, the proliferation rates of CIK were (388.9 +/- 137.3)% and (315.1 +/- 44.5)%, respectively, and the killing rates against tumor cells were (87.1 +/- 8.0)% and (90.0 +/- 5.1)%, respectively. When the two similar DC groups were loaded with lysate antigen of SMMC-7721 cells, the proliferation rates of CIK were (239.9 +/- 48.7)% and (226.3 +/- 32.3)%, respectively, and the killing rates against tumor cells were (76.4 +/- 7.9)% and (81.1 +/- 4.3)%, respectively. There were no significant differences between those two DC groups. The data also showed that the proliferation and cytotoxicity of CIK induced by DCs loaded with autologous antigen were higher than that of DCs loaded with SMMC-7721 antigen. CONCLUSION Mononuclear cells separated from intra-operative lost blood of HCC patients can be induced into mature DCs, which can effectively activate CIK and significantly increase its killing effect on the liver cancer cells, and may become a new source of DCs to study and develop vaccines for clinical application.