Surface markers and cytotoxic activity of blood natural killer cells studied at the single cell level in Hodgkin's disease.

Purified peripheral blood lymphocytes (PBL) from nine untreated patients with Hodgkin's disease (HD), two HD patients in complete remission and 17 healthy donors were studied for natural killer (NK) cell activity against the K-562 cell line using a single cell cytotoxic assay, which allowed enumeration of effector cells and characterization of their surface membrane phenotypes after staining with monoclonal antibodies. The frequency of NK cells was significantly lower in HD patients than in controls (mean % +/- s.d., 1.9 +/- 0.9 and 2.8 +/- 1.2, respectively), while the fraction of target binding cells was similar in the two groups. The fraction of cytotoxic lymphocytes increased after pre-treatment of PBL with 500 iu leucocyte interferon in all tested control donors (n = 12) and the two patients in remission but only in four of seven untreated patients. No relation between the impaired NK cell frequency and age, tumour histology and clinical stage could be revealed. Subtyping of the target cell binding NK cells by monoclonal antibodies disclosed a marked heterogeneity of effector cells. NK effector cells reactive with M1 and anti-Ia antibodies were enriched while T3+ and T4+ NK lymphocytes tended to be reduced as compared to PBL. There was no difference between patients and healthy donors with regard to the surface antigen patterns of NK cells. Interferon treatment did not alter significantly the phenotypic characteristics of cytotoxic lymphocytes in patients and controls. It is concluded that the impairment of NK cell activity in HD is partly attributed to a lower frequency of cytotoxic effector cells among a normal number of target binding cells. The defect could not be attributed to a selective defect of effector cell subsets.