Lymphocyte toxicity test in clinical melanoma

Between July 1970 and April 1972, peripheral lymphocytes of 35 patients with malignant melanoma were tested for in vitro cytotoxicity to autologous or homologous melanoma cells. Twenty-one cases (60%) had lymphocytes with a specific cytotoxic activity. No correlation was found with sex, age or clinical stage of the disease. To evaluate the prognostic significance of the in vitro cytotoxic activity of peripheral lymphocytes, 18 patients at stage I and II, who had been subjected to radical surgery prior to the cytotoxic test, were divided into two groups according to the result of the test (12 positives and 6 negatives) and were followed up for a maximum period of 32 months. Twelve cases had recurrence of the disease: 7 of the 12 cases with positive lymphocytes, and five of the 6 patients with negative lymphocytes. The difference between the two groups was not significant. The tumour-free interval has been 8·4 months in the seven cases with cytotoxic lymphocytes and 8 months in the 5 cases with no reactive ones.