Cellular and humoral immune responses to human urinary bladder carcinomas

Leukocytes from 17 of 19 patients with urinary bladder carcinomas were cytotoxic for autochthonous as well as allogeneic bladder carcinoma cells in vitro. The cells from all 11 individual bladder carcinomas studied were susceptible to this cytotoxic action of patients' leukocytes. In contrast, no cytotoxicity was observed when cells from unrelated tumours or various normal tissues were used as target cells. Purified blood lymphocytes from patients whose leukocytes were active, were also cytotoxic. Sera of 8 out of 13 patients with bladder carcinomas contained complement‐dependent antibodies which were cytotoxic for autochthonous and allogeneic bladder tumour cells. When serum was taken from the same patient on different occasions over a period of 8 months cytotoxicity was found in some samples but not in others. Sera from 4 out of 9 patients exhibited a blocking activity, which completely abolished the cytotoxic effects of patients' leukocytes. The serum of one out of 9 patients contained antibodies which were not cytotoxic without leukocytes but which conferred a cytotoxic activity onto leukocytes from control subjects. This opsonizing antibody was complement‐dependent and probably of IgM nature. The effect of hydrostatic pressure therapy on the immune state of the patients was followed by examination of the leukocytes from 16 patients with bladder carcinoma. Leukocytes from 10 patients were cytotoxic before as well as after the pressure treatment. Leukocytes from six patients did not react before the treatment while those from four became active after treatment. A more detailed study of three individual cases indicated that cytotoxicity of the leukocytes appeared after pressure treatment and was of relatively short duration (approximately 1 month). In one case, the development of cytotoxic antibodies was similar. The patient who had opsonizing antibodies had no cytotoxic antibodies. The opsonizing antibodies appeared when the cytotoxicity of the leukocytes decreased.