An assessment of natural cell-mediated cytotoxicity in patients with malignant lymphoma

Fifty per cent of untreated malignant lymphoma patients were shown to have profoundly reduced levels of peripheral blood lymphocyte-natural cell mediated cytotoxicity (PBL-NCMC) when tested against the leukaemic cell-line K562; assessment of NCMC in unfractionated blood from a large number of these patients showed a comparable reduction in activity. High levels of NCMC were observed in some patients with stage III/IV non-Hodgkin's lymphoma (NHL), while Hodgkin's disease (HD) patients over 40 yr of age had normal levels. In both NHL and HD patients there was no correlation between NCMC and absolute lymphocyte count or lymphoma histology. Human interferon was seen to boost NCMC in the majority of NHL patients, but most HD patients were nonresponders. Almost all patients tested had normal number of target binding lymphocytes, and most had numbers of HNK-1+ cells within the control range. However, on exposure to IFN, the number of target binding lymphocytes increased in over half of the patients tested, with some patients showing an increase in HNK-1+ cells, in the majority of cases without enhancement of NCMC.