Immunotherapy of malignant melanoma with tumor lysate-pulsed autologous monocyte-derived dendritic cells

Purpose: Dendritic cell (DC) vaccination for melanoma was introduced because melanoma carries distinct tumor-associated antigens. The purpose of this study was to investigate the efficacy and safety of DC vaccination for melanoma in Korea. Materials and Methods: Five patients with stage IV and one with stage II were enrolled. Autologous monocyte-derived DCs (MoDCs) were cultured and pulsed with tumor-lysate, keyhole limpet hemocyanin, and cytokine cocktail for mature antigen-loaded DC. DC vaccination was repeated four times at 2-week intervals and 2-4×10 ⁷ DC were injected each time. Results: Reduced tumor volume was observed by PET-CT in three patients after DC vaccination. Delayed type hypersensitivity responses against tumor antigen were induced in five patients. Tumor antigen-specific IFN-γ-producing peripheral blood mononuclear cells were detected with enzyme-linked immunosorbent spot in two patients. However, the overall clinical outcome showed disease progression in all patients. Conclusion: In this study, DC vaccination using tumor antigen-loaded, mature MoDCs led to tumor regression in individual melanoma patients. Further standardization of DC vaccination protocol is required to determine which parameters lead to better anti-tumor responses and clinical outcomes.