Natural killer and killer cell activities in patients with primary immunodeficiencies or defects in immune interferon production.

Natural cell-mediated cytotoxicity (NCMC) against K-562 target cells was explored in patients with various primary immunodeficiencies. (a) NCMC was present in 2 patients lacking detectable B cells. Conversely, NCMC was depressed in 2 patients with severe combined immunodeficiency presenting a normal number of circulating B cells. These data exclude a major role for B cells in NCMC. (b) NCMC was depressed mainly in patients with severe combined immunodeficiency or with defects affecting cellular immunity, which suggests a major role in NCMC for cells of T lineage. (c) Four patients with various clinical features associated with a lack of immune interferon production exhibited a strikingly depressed NCMC. Interferon thus appears as a major in vivo activator of natural killer (NK) cell activity. (d) Eight patients exhibiting a depressed NK cell activity had a normal killer (K) cell activity against L1210 cells in the presence of rabbit anti-L1210 antiserum. These data are consistent with the assumption that NK and K cell activity are mediated through two distinct cellular mechanisms.