Natural Killer Cell Activity in Patients With Septic Shock

ATURAL KILLER CELLS (NKC), a small subpopulation (approximately 8%) of lymphoid cells,’ which in vitro present a spontaneous ability to lyse transformed, virally infected, and some normal cells in a nonrestricted fashion, have been shown to play an important role in the immune surveillance against primary tumors and metastases.1-4 The high incidence of malignancy and the special susceptibility to viral infections shown by individuals with a selective and marked deficit in NKC function further stresses the importance of these cells as an in vivo defense system against disease.4,5 A number of endogenous mediators have been suggested to play a role in the etiology of septic shock.‘-* This heterogeneous condition, arising as a complication of septicemia, is accompanied by numerous pathophysiologic changes.’ Reports of a bactericidal response of NKC to direct contact with certain bacteria, either through a direct action or via the Iymphokineactivation of other immune cells,‘o91’ led us to examine NKC activity (NKCA) in a population of septic shock patients in critical conditions and compare it with values obtained from a group of normal volunteers.