[Novel immunotherapeutic approach]

Malignant astrocytoma is the most common primary brain tumor in adults. The median survival time of patients with high-grade malignant astrocytoma is about 1 year, despite aggressive treatment with surgical resection, radiotherapy, and cytotoxic chemotherapy. Novel therapeutic approaches are therefore needed to prolong survival. Immunotherapy is one such novel approach that has been investigated for application with different types of tumors, including brain tumors. The author reviews immunotherapeutic approaches for malignant gliomas and the relevance of recent clinical trials and their outcomes. A number of potentially targetable antigens have been identified in gliomas. Both tenascin and epidermal growth factor receptor (EGFR) have been studied extensively as targets for direct immune attack via specific antibodies. As a novel target, interleukin 13 receptor alpha 2-chain (IL-13 R alpha 2) has been identified. IL-13 R alpha 2 is abundantly and specifically overexpressed in glioblastoma multiforme, and recently a MHC class I-restricted CTL epitope has been identified. Dendritic cells (DCs) are professional antigen presenting cells (APCs) that have a unique potency for activating T cells. DCs have been investigated in several clinical trials in patients with malignant tumors including malignant gliomas. So far, seven papers concerning immunotherapy with DCs against malignant gliomas have been published. These reports demonstrate that immunotherapy with DCs induces immune responses and clinically antitumor effects in some patients with malignant glioma. In addition, none of these studies reported evidence of autoimmune neurotoxicity.