Augmentation of the generation of OK-432 activated killer cells after a single dose of mitomycin C in cancer patients.

Effect of mitomycin C (MMC) administration on the generation of cytotoxic cells induced by in vitro activation of peripheral blood mononuclear cells (PBM) with OK-432, a bacterial immunopotentiator, was studied in patients with various carcinomas. Following i.v. injection of a single dose of 12 mg/m2 MMC, the ability of PBM to generate OK-432 activated killer cells was markedly increased. Thus, the cytotoxic activity observed 7 days after MMC administration was significantly augmented as compared to that before treatment. Therefore, the ability to generate lymphokine activated killer (LAK) cells was examined, and significantly increased capacity was observed 5 and 7 days after MMC injection. Then, the OK-432 activated killer cell activity significantly correlated with the LAK activity. After treatment, the distribution of lymphocyte subsets exhibited a significant decrease in the percentage of OKT8+ cells. Leu-11+ cells were also reduced. The results appear to indicate that the imbalance in T-cell subsets and the increase in the ability to induce LAK cells may be related to the augmenting effect of MMC administration on the generation of OK-432 activated killer cells in cancer patients.