Natural killer cells and interleukin-12 in patients with advanced cervical cancer under neoadjuvant chemotherapy

Abstract

Patients with advanced cervical cancer have deficient natural killer (NK) cell activity, usually as a consequence of tumor invasion, which results in tumor NK cell sequestration. The reason for the occurrence of such alterations in patients under chemotherapy is unknown. We evaluated the activity and number of NK cells and T cell subpopulations in ten patients before and three weeks after neoadjuvant chemotherapy (CT). The schedule used was cis-platinum (100 mg/m2 per cycle) and bleomycin (15 mg/cycle), repeated every 28 days. Although there were similar levels of NK cells before and after CT in both groups, we observed greater cytotoxicity of peripheral blood lymphocytes and increased levels of CD4+ and CD8+ T cells (P < 0.01) in five patients who presented a good clinical response when compared to the group with a poor response. IL-12, known to increase NK cell activity when added to peripheral blood lymphocyte cultures, markedly increased lytic activity before and after CT only in the group with a good clinical response. These results suggest that NK cells from the poorly responding patient group express less lytic activity per NK cell and are insensitive to IL-12 stimulation, probably as a result of reduced IL-12 receptor expression or a defective intracellular transduction mechanism. The present findings may be useful as a prognostic factor in clinical practice and also provide support for human clinical trials of IL-12 and neoadjuvant CT for the treatment of malignant cervical tumors.