NATURAL-KILLER-CELL AND ANTIBODY-DEPENDENT CELLULAR CYTOTOXICITY IN GASTRIC-CARCINOMA PATIENTS - MODULATORY EFFECTS OF IL-2 AND 5-FLUOROURACIL

Non-adherent peripheral blood mononuclear cells (PBMC) from 15 patient s with carcinoma of the stomach and 6 normal healthy controls were ass essed for natural killer cell mediated cytotoxicity (NKCMC) and antibo dy dependent cellular cytotoxicity (ADCC) in a 4 hour (51)Chromium rel ease assay against target cells, K-562 and sensitized chicken red bloo d cells (CRBC), respectively. NKCMC and ADCC were significantly reduce d in patients with respect to normal controls. However, significant en hancement in NKCMC and ADCC was observed when PBMC from patients were cultured in RPMI-1640 containing 200 IU/ml of Interleukin-2 (IL-2) for 4 days in 5% CO2 atmosphere at 37 degrees C. Augmentation of NKCMC an d ADCC was also detected when a follow-up study of the patients was co nducted after one month following initial trial of chemotherapy with 5 -fluorouracil (5-Fu). Patients, who had undergone clinical trial with 5-Fu were better responders of IL-2 activation as reflected on NK cell and ADCC potential of these patients. Our investigations highlight th e synergistic effect of 5-Fu and IL-2 on effecters of natural immunity in patients with carcinoma of the stomach, Judicious modulation of ef fecters may be beneficial in killing residual cancer cells in vivo.