Natural Killer Cells
Role Of Natural Killer Cells
Immune surveillance mechanism
The youthful person normally has an ongoing search and destroy mechanism working constantly against cancer. This process is known as “immune surveillance”. The natural killer lymphocyte (NK cell) is the killing effector (hit man) of the immune surveillance mechanism. IL-2 is a direct stimulant of NK cells. NK cells may decline in old age or cancer.
Natural killer lymphocyte percentage in the peripheral blood (NK%) of carcinoma patients is easily measured and is normally 3-15%. Survival is increased in patients with elevated serum interleukin-2 (IL-2), the most recognized cytokine stimulant of NK proliferation.
Some cancer patients during immunotherapy develop extreme NK% elevations. Expected progression of clinical cancer may at times become radically and unexpectedly extended, such anomalous cases being often described as anecdotal survival.
Many carcinomas secrete one or more serologic biomarkers (SB) of tumor activity. The trend over time of these markers is indicative of tumor progression or regression. There may be an inverse relationship between NK% and SB, and may be a causal relationship between greatly elevated NK% and extraordinary or anecdotal survival.