Abstract

To investigate vaccination with apoptosis colorectal cancer (CRC) cell pulsed autologous dendritic cells (DCs) in advanced CRC, 14 patients with advanced colorectal cancer (CRC) were enrolled and treated with DCs vaccine to assess toxicity, tolerability, immune and clinical responses to the vaccine. No severe toxicity was observed and the vaccine was well tolerated. The levels of interleukin-2 (IL-2), interleukin-12 (IL-12) and interferon-γ (IFN-γ) significantly increased after DCs vaccination (P < 0.05). Mean of carcinoembryonic antigen (CEA) lever decreased from 99.5 to 71.4 ng/ml. Five patients showed a positive skin response to the apoptotic cells loaded DC vaccines in the delayed type hypersensitivity (DTH). In the five DTH positive patients, we found a patient with a lymphoglandulae coeliacae metastasis; temporary seroperitoneum regression was demonstrated by CT scan after full immunizations during 12 weeks. However, a rescan after 6 weeks showed new lesions on the abdomen as well as re-growth of the primary lesion. During the two years of clinical observation, all patients survived the first year, while the survival rate decreased from 80 to 20% during the second year owing to the advancement of CRC. In conclusion, the strategy for vaccination of apoptosis colorectal cancer cell pulsed-DCs may raise the clinical response of CRC patients by activating Th1 responses. Furthermore, indications of both immunologic and clinical effect were found in heavily pretreated patients with advanced colorectal cancer.

Key words: Dendritic cells, immunotherapy, colorectal cancer.