[Natural killer lymphocytes in kidney transplantation]

We conducted a dual study of phenotype and function of natural killer cells (NK) using flow cytometry, this study being applied to renal transplantation. The CD 16 and CD 56 clusters correlated well with NK cytotoxicity, especially for CD 3 lymphocytes, whereas CD 57 should no longer be considered a NK marker. NK activity was determined on K 562 or Daudi cells, either spontaneously or after in vitro activation with r-interleukin 2 (LAK). Cytotoxicity was analyzed after labeling of target cells by carboxyfluoro-diacetate and measured by flow cytometry. We found that in renal transplant recipients NK cells were deficient in numbers and functions and showed that LAK activity was also diminished. Azathioprine appeared to be the main immunosuppressant impairing NK cells. Viral infections increased the numbers and functions of NK cells, whereas during malignancies they remain as low as in uncomplicated recipients. NK cells deficiency might be involved in the high incidence of de novo malignancies in renal transplant recipients.