NK and K cell activity of human blood: differences according to sex, age, and disease. Ann Rheum Dis

SUMMARY We report a study on the activity of NK cells ('natural ' killer cells) and K cells (anti-body-dependent killer cells) in human peripheral blood in health and disease. The 'targets ' used were cells of the Chang cell-line, sensitised with rabbit anti-Chang cell antibody for K cell activity, and killing was assessed by release of radiochromium at effector: target ratios of 50:1 and 100:1. The positive findings were that NK cell activity, but not K cell activity, was greater in males and in youth, that NK cell activity was reduced in systemic lupus erythematosus, that neither NK nor K cell activity was altered in rheumatoid arthritis, and that K cell activity was reduced in chronic active hepatitis. Immunopathic diseases may be associated with alterations in numbers and function of various of the subpopulation of mononuclear cells of the blood. The major subpopulation, that of T cells, has been particularly studied and, T-lympopenia and deficient T cell function characterise systemic lupus erythema-tosus (SLE) and related diseases (Toh et al., 1973)