[Regulatory T cells and NK cells in cancer patients].

NK cells represent the cells of the immune system most effective for eradication of infected or neoplastic cells. Regulatory T cells and the two main subgroups thereof-the naturally occurring nTregs and the tumor-associated induced Tregs (iTregs)-play an important role in the antitumor immune response in cancer patients. The current study explores the intercellular interactions of these groups of cells in tumor patients, particularly in head and neck cancer. Critical interactions between these cells and the cancer cells could be observed in extensive experimental analyses. Firstly, we generated tumor-associated iTregs in a specific human culture. Subsequently, various phenotypic and functional relationships between these cells, nTregs, NK cells and tumor cells were analyzed in an autologous system. Although the activity of naive NK cells was enhanced by iTregs in the presence of tumor cells, the cytotoxic function of NK cells activated by interleukin-2 was markedly inhibited by iTregs and nTregs. Our group was able to document new insights into the complex regulation of human NK cells and regulatory T cells in the tumor microenvironment. These new insights may be of relevance for an improved understanding of the antitumor immune response and the development of immunotherapeutic strategies.