Dendritic cell-based immunotherapy for cancer and relevant challenges for transfusion medicine

The encouraging results from dendritic cell-related cancer immunotherapy have created tremendous interest for its broad clinical application. Dendritic cells are the most potent antigen-presenting cells. In cancer patients, dendritic cell production and function along with other antitumor immune defenses are compromised. Autologous dendritic cells enriched and sensitized in vitro with tumor-associated antigens can effectively elicit host cellular immunity against cancer and result in clinical antitumor responses through either direct injection or ex vivo generation of antitumor T lymphocytes. In small group studies, clinical response rates have reached 50% in patients with advanced stage of cancer. These cellular products caused minimal side effects and were well tolerated. The isolation and preparation of clinical grade dendritic cells have been driven by transfusion medicine specialists who are well versed in similar processes for hematopoietic stem-cell preparation. The purpose of this article is to review the mechanisms of tumor immune surveillance and the biology of dendritic cells relevant to tumor antigen presentation, sensitization, and T-lymphocyte stimulation. Information on tumor-associated antigens and clinical trial results with dendritic cell-based cancer immunotherapy are summarized. The potential challenges for blood banking/transfusion medicine involving both technical and regulatory issues are discussed.