Cytotoxic lymphocytes in melanoma patients

Abstract

Abstract Peripheral blood lymphocytes from 61 melanoma patients were tested by a microcytotoxicity test for cell‐mediated immunity against melanoma cells. Lymphocytes from 13/25 patients were cytotoxic for autologous tumour cells, while lymphocytes from 31/56 patients were cytotoxic in the allogeneic situation. In the cases tested no cytotoxic reaction was found against autologous or allogeneic normal skin fibroblasts. Normal control lymphocytes were cytotoxic in 2/50 individuals tested. Lymphocytes from patients with other neoplastic diseases showed a positive cytotoxic effect in 1/18 patients tested. In seven cases lymphocytes from melanoma patients, which were cytotoxic for melanoma cells, did not show any cytotoxic effect on plated choriocarcinoma cells. There was no correlation between the presence of specifically immune lymphocytes and the clinical staging of the disease. In the serum of patients with distant metastases, preliminary results indicated the presence of factors which could block the cytotoxic effect of specifically immune lymphocytes. The data suggest that most malignant melanomas contain a common antigen which is immunogenic in patients with this neoplasm. However, individual‐ or subgroupspecific melanoma antigens may exist. Evidence is found that lymphocytes can lose their capacity to kill melanoma cells in the course of the disease. Change of antigenic expression or sensitivity to the killing effect of lymphocytes during culturing of the melanoma cells may explain the irregularity of some results.