Vaccination of Leukemia Patients with Autologous In Vitro Cultured Leukemia Dendritic Cells.

OBJECTIVE:To investigate the safety and immunomodulation effect of dendritic cells(DCs)vaccine to leukemia patients cultured in vitro from autologous leukemia cells.

METHOD:Leukemic-dendritic cells were cultured from autologous bone marrow leukemia cells in vitro using combined cytokines. Patients received four administrations of autologous in vitro cultured leukemia-DCs by intravenous injection during chemotherapy intervals when obtain complete remission (CR), once a week for four times. Peripheral blood were collected to analyze the serum Th1/Th2 cytokines as IL-2, IL-4, IL-6, IL-10, IFN-γ, TNF-α by cytokine bead array(CBA) analysis and T cell subpopulations by flow cytometric method (FCM).

RESULTS:A total of 31 patients who are hematologically confirmed as leukemia received the DC vaccination therapy from December 2002 to October 2005. 20 patients can be evaluated. Firstly, autologous leukemic-dendritic cells were cultured in vitro successfully. Secondly vaccinations were well tolerated. No major toxicity occurred in any of the patients. Thirdly, serum cytokines were all elevated 24hs after the first administration of DC vaccination compared to those before that. And IL-2, IFN-γ, IL-4 and IL-6 have statistically significant increases with Z values −2.576, −2.033, −2.777, −2.053 and p values 0.010,0.042,0.005,0.040, respectively. Relative increase of the cytokine levels induced by DC vaccination show a trend of TH1 cytokines advantage, suggesting an enhancing of cellular immune response. T cell subsets significantly increase in CD4/CD8 ratio and CD56 proportion with Z values −2.040, −1.988 and P values 0.041, 0.043, respectively.

CONCLUSIONS:Autologous leukemic-DCs could be generated in vitro from leukemia cells. And the intravenous injection of autologous L-DC vaccine is safe and feasible, and it could enhance the immune response in vivo to a certain degree.