Membrane TNFα (mTNFα) is expressed on many immune cell types and performs various biological functions. Dendritic cells (DC) of high-grade glioma patients exhibit impaired cytotoxic activity against TNFα-sensitive HEp-2 tumor cells. The mechanisms leading to the impairment of the TNFα- dependent tumoricidal activity of DC and the possibility of regulating the cytotoxic activity of DC mediated by the TNFα/TNF-R1 signaling pathway have been studied. The study was conducted on healthy donors and patients with newly diagnosed high-grade glioma. DC were generated by culturing the plastic-adherent peripheral blood mononuclear cell fraction in the presence of GM-CSF and interferon-α (IFN-DC). It was shown that the impairment of the cytotoxic activity of patient IFN-DC was associated with a low number of DC expressing mTNFα and a low level of TNFα mRNA expression in DC. IFN-DC of patients exhibited a tendency of high activity of the TNFα-converting enzyme (TACE), which accomplishes shedding of mTNFα from the cell membrane. An increased number of IFN-DC with mTNFα caused by TACE blocking enhanced cytotoxic activity of the patient’s IFN-DC against HEp-2 cells. It was established that exogenous interleukin-2 and extracellular DNA are up-regulators of the mTNFα expression on IFN-DC of the patients, but their effects are mediated by different mechanisms.