Tumour-associated lymphocyte cytotoxicity superimposed on "spontaneous" cytotoxicity in melanoma patients

Lymphocytes from 16 stage I, 6 stage II and 31 stage III melanoma patients (MP) and 51 healthy donors (HD) were tested as far as possible in parallel on a melanoma cell line (NKI-4), a bladder carcinoma cell line (T 24) and 18 different short-term melanoma cultures. Lymphocytes from MP and HD showed cytotoxic effects towards all three types of target cells. Lymphocytes from HD showed the strongest "spontaneous" cytotoxic effects on NKI-4 cells whereas, in general, weak cytotoxic effects were seen on short-term cultured melanoma cells. Within the different lymphocyte donor groups an enormous variation in cytotoxic effects was observed. However, the overall cytotoxic effects of stage I and II MP were significantly higher than those of the HD-group. Stage I MP showed significantly stronger cytotoxic effects on NKI-4 cells than on T 24 cells, indicating that tumour-associated lymphocyte cytotoxicity was superimposed on spontaneous cytotoxicity.