Immunization With Autologous Dendritic Cells and Tumor Lysates in Melanoma Patients

Vaccination of Melanoma Patients Using DCs Loaded with Allogeneic Melanoma Extracts. In Chile, this study constitutes the first phase I clinical trial for treating advanced malignant melanoma using dendritic cell vaccines loaded with allogeneic tumor extracts complemented or not with low doses of rIL-2. Since chemotherapy and radiotherapy only offer palliative effects in advanced melanoma, resulting in an inferior prognosis for these patients, the trial intends to develop a protocol that would adapt to the reality of Chile, allowing for a combination of high technology and low costs. After obtaining approval from the human research ethics committee from Universidad de Chile, 86 patients will be recruited who will be duly informed about the scope of these protocols and the realistic prospects of success. The participants then will undergo a comprehensive health check to assess their overall health. The participants will undergo a leukapheresis at the blood bank of the Clinical Hospital of the University de Chile. Peripheral blood mononuclear cells (PBMCs) will be separated using a Ficoll-Hypaque gradient in the laboratory of Antitumor Immunology at the Institute of Biomedical Sciences, Faculty of Medicine of the University de Chile. Some of the cells will be cryopreserved in liquid nitrogen for future use. Approximately 1.8x108 PBMCs will be placed in 6-well culture plates and incubated at 37°C and 7% CO2 for two hours. The suspended cells, peripheral blood lymphocytes (PBLs), will be removed and frozen for later use. The monocytes adhering to the plastic will be incubated for seven days in a serum-free culture medium (AIM-V therapeutic, GIBCO, BRL) in the presence of 500 U/ml of IL-4 and 800 U/ml of GM-CSF. On the sixth day, the DCs will be pulsed with tumor extracts from allogeneic melanoma cell lines, previously checked for sterility, and incubated for 6 hours at 37°C and 7% CO2, followed by maturation stimulus with TNF-alpha for 12 to 18 hours. Mature DCs will be characterized by flow cytometry. Approximately 10 to 20 x 106 pulsed DCs will be subcutaneously injected. This routine will be repeated weekly for at least four times and a maximum of 6 times. After the fourth dose, the participant's general condition, possible clinical regressions, adverse side effects, and the effects of the treatment on the immune system will be evaluated. This evaluation will be done through in vivo delayed-type hypersensitivity (DTH) assays using melanoma extracts and their respective controls. Planned in vitro assays for immune response measuring will include the detection of anti-melanoma CTL precursors by ELISPOT, cytokine production, proliferation assays, and quantifying the CD4/CD8 ratio by flow cytometry.