A study of cell-mediated immunity has been undertaken in vitro by the leukocyte migration test (LMT) on 57 patients with operable carcinoma. Tumor extracts induced an inhibition of autologous leukocyte migration in 58% of the cases: 10 out of 17 lymphomas, 10 out of 15 malignant mesenchymal tumors, 8 out of 13 mammary carcinomas, 2 out of 4 melanomas, and 3 out of 8 various other tumors. Migration of mononuclear cells was especially inhibited but not that of neutrophils. Thus a previous sensitization of the lymphocytes by tumor antigen (s) has been shown. On the contrary, 9 extracts of benign and 17 extracts of normal tissue did not significantly inhibit the migration of autologous cells. Almost all tumor extracts were tested against allogeneic leukocytes from patients bearing the same or a histologically different type of tumor, or from healthy subjects (101 cases). Cross-reactions were observed in five melanomas, in one case of Hodgkin's disease, and in one breast carcinoma. In all but two cases, inhibition of leukocyte migration did not occur in patients with a different type of tumor or in non-cancerous patients. It is too early to judge the possible prognostic value of a positive LMT showing a state of cellular hypersensitivity against tumor antigens. Only a survival time analysis and a wider follow-up study of the “immunological balance” during the course of the disease can provide an answer.
