Natural killer and lymphokine-activated killer activities in stomach cancer patients with special emphasis on the effect of 5-fluorouracil, adriamycin and mitomycin-C chemotherapy.

The cytotoxicities of peripheral blood lymphocytes (PBL) and lymphokine-activated killer (LAK) cells were studied to evaluate the effect of chemotherapy on cellular immunity, in 18 patients with unresectable stomach cancer before and after chemotherapy with 5-fluorouracil, adriamycin and mitomycin-C (FAM), and in 21 healthy volunteers. LAK cells were generated in vitro by culturing PBL with 100 U recombinant human interleukin-2 (rH-IL-2)/ml for 72 h. K562 (human myelogenous leukemia), MKN-45 (human stomach adenocarcinoma) and PC-14 (human pulmonary adenocarcinoma) were used as target cells. The cytotoxicity of PBL to K562 and MKN-45 was suppressed in patients with stomach cancer before chemotherapy, compared with that in healthy volunteers (P less than 0.05). The cytotoxicity of LAK cells was significantly higher to all three cell lines tested than that of PBL in both the healthy volunteers and stomach cancer patients (P less than 0.01); however, a lower level of LAK activity was generated in patients with cancer compared to that in the healthy volunteers. FAM therapy did not suppress the cytotoxicities of PBL and LAK cells. The surface markers of PBL and LAK cells were measured, demonstrating that there was no significant change in the percentage of lymphocytes with CD3+, CD4+, CD8+, CD16+ or CD19+ after chemotherapy. The ratios of CD4+ to CD8+ cells in PBL and LAK cells were also not significantly changed after chemotherapy. In the present study, we have demonstrated that the PBL of stomach cancer were defective in generating LAK activity compared to those of controls, but the LAK activity generated from PBL receiving chemotherapy was similar to that from PBL without chemotherapy in stomach cancer patients.