Dendritic cells (DCs) are unique specialized antigen-presenting cells capable of priming naive T cells and inducing antigen-specific cytotoxic T lymphocytes. This study presents an update of clinical results from a DC-based phase I-II clinical vaccine trial in stage IV melanoma. From 2003 to 2010, 27 patients with metastatic melanoma were treated with mature DCs pulsed with autologous tumor lysate and keyhole limpet hemocyanin and with subcutaneous low-dose interleukin-2. Delayed-type hypersensitivity (DTH) tests for in-vivo immunomonitoring were performed at baseline and every four vaccinations thereafter. Two complete, two mixed and six partial responses, and five stable diseases were observed (overall response, 37.0%; clinical benefit, 55.5%). All 15 responders showed DTH positivity. A median overall survival of 22.9 months [95% confidence interval (CI): 13.4-61.3] for DTH-positive patients (19) and 4.8 months (95% CI: 3.9-11.9) for DTH-negative patients (8; log rank=7.26; P=0.007) was observed. The overall median overall survival was 16 months (95% CI: 9-33). Our results would seem to highlight a relationship between positive-DTH test and an improved survival.