Natural killer cell activity in asthma.

Peripheral blood natural killer (NK) activity was analysed from 32 asthma patients and 13 control donors. Male patients and female patients with atopic asthma had significantly stronger NK activity against the leukaemic cell line K-562. Fractionation of patient mononuclear cells by discontinuous density gradient centrifugation suggested that large granular lymphocytes (LGL) were the main mediators of the NK activity in asthmatics. Based on the lytic unit calculations, the strong NK activity in asthmatics is mainly due to increased frequency of LGL in peripheral blood rather than activity of individual NK cells.