Natural Killer Cell Activity: A Test For Immune Reactivity With Clinical Perspectives.

87Background: Natural Killer (NK) cells are essential in the biological fight against cancer and the activity of these cells has been suggested as a biomarker for immunological reaction in cancer patients. An assay has been introduced to measure NK cell activity (NKA) in a simple and standardized manner. Following stimulation of NK cells in whole blood with a recombinant protein, it utilizes the concentration of interferon-gamma (IFNγ) in plasma as a surrogate marker for NKA. This study aimed to verify that the test was indeed measuring NKA and whether it could predict the response to cytostatic treatment in metastatic colorectal cancer (mCRC). Methods: Blood was collected in dedicated tubes (NK Vue Promoca) and placed at 37°C. After 24 hours the plasma was analyzed for IFNγ by ELISA (NK Vue ELISA). Blood from patients with mCRC (n = 22) were sampled at baseline and prior to each treatment cycle, and IFNγ levels were compared to response data from first evaluation. The protocol is ongoing hence the result...