Abstract: Objective To investigate the efficacy of autologous tumor vaccine modified to carry the dinitrophenyl hapten to treat advanced malignant melanoma. Methods Clinical data were retrospectively analyzed for 84 patients who underwent resection for stage Ⅲb，Ⅲc or IV malignant melanomas. Patients were divided into two groups depending on whether or not their biochemotherapy was supplemented with dinitrophenyl-modified autologous tumor vaccine. The two groups were compared in terms of the following parameters：relative numbers of CD4⁺CD25⁺ regulatory T cells and lymphocyte subsets in peripheral blood， which were determined using flow cytometry；observed strength of delayed type hypersensitivity（DTH）；and clinical outcomes such as overall survival（OS） and disease-free survival （DFS）. Results The subpopulations of CD4⁺-IFN-γ^PE and CD8⁺-IFN-γ^PE lymphocytes were significantly larger in the vaccinated patients than in the biochemotherapy-only patients（P<0.05），while the relative proportions of CD4⁺CD25⁺ regulatory T cells were significantly smaller（P<0.05）. DTH-positive response（defined as spot size ≥5 mm） occurred in 94.6% of vaccinated patients but in only 45% of biochemotherapy-only patients（P<0.05）. The 1-，2- and 3-year survival rate were 95.0%，73.0 and 65.5% in the vaccinated group,respectively，90.1%，59.0%and 43.5% in the biochemotherapy-only group,respectively. OS and DFS in the vaccinated group were 79.3% and 81.1%，compared to 64.2% and 81.1% in the biochemotherapy-only group. The difference in OS between the two groups was significant （P<0.05）. Conclusion Administering autologous tumor vaccine modified with the dinitrophenyl hapten may increase the overall survival of patients with specific cell-mediated melanoma，and it appears to do so by en-hancing their immune response and inhibiting immune tolerance.

Key words: Melanoma, Dinitrophenyl, Hapten, Tumor vaccine, Immunotherapy