Abstract
We report a phase I trial in melanoma patients using tumor-lysates pulsed dentritic cells (DCs). DCs were generated from peripheral blood in the presence of granulocyte/macrophage-colony stimulating factor and inrterleukin 4 and were pulsed with autologous tumor lysates. Three patients with advanced melanoma received 5～8 intra-lymph-node infusions of DCs. Although regression of individual skin metastasis was evident in one patient, increased size of metastases and/or development of new lesions were observed in all three patients during the therapy. Clinical side effects were mild. Two patients developed vitiligo after DC vaccinations. DTH reactivity toward tumor lysates was induced in two patients. Resolution of skin metastases and positive DTH response site were accompanied CD8+/CD45RO+ lymphocytic infiltration. Immunohistochemical study revealed down-regulation of HLA class I antigen and β2 microglobulin in both primary and metastatic lesions of these three patients. These results suggested that HLA-class 1 down-regulation plays a role in immune escape from cytotoxic T cells.
