DISSOCIATION OF NATURAL KILLER CELL ACTIVITY AND ANTIBODY-DEPENDENT CELL-MEDIATED CYTOTOXICITY IN KIDNEY ALLOGRAFT RECIPIENTS RECEIVING HIGH-DOSE IMMUNOSUPPRESSIVE THERAPY

Abstract

Peripheral blood lymphocytes (PBL) of normal subjects and of kidney allograft recipients treated with immunosuppressive drugs (azathioprine and prednisone) were tested for natural killer (NK) cell activity against [leukemia] K-562 cells, and for killer (K) cell activity against [mouse] L-1210 cells in the presence of rabbit anti-L-1210 antiserum. The natural cell-mediated cytotoxicity (NCMC) was abolished in the immunosuppressed patients, while the antibody-dependent cell-mediated cytotoxicity (ADCC) remained normal. No correlation was observed between both activities in the treated group, whereas a strong positive correlation did exist in the control population. Uremic routinely hemodialyzed patients tested for NK cell activity exhibited no significant difference with the control group. NCMC and ADCC are different functions, apparently correlated in normal population but discriminated by immunosuppressive medical treatment. The abrogation of NCMC in patients in whom risk of malignancy is highly increased strengthens the concept of a crucial role of NK cells in in vivo surveillance toward malignancies.