Suppression of the tuberculin response in malignant disease.

Recently there has been an increasing interest in immunological aspects of cancer. Evidence for the presence of some degree of host control over certain tumours has been accumulating (Black and Speer, 1959), and results of treatment of experimental animal and human tumours by immunological methods raise hopes of useful advances to come (Woodruff and Nolan, 1963). However, less work has been done on the competence of the lymphoreticular system in established cases of human cancer than on seeking cancer-specific antigens and associated antibodies. It has recently been shown that the circulating antibody response to challenge with tetanus toxoid is reduced in cancer patients to an extent not found in patients who are debilitated by advanced non-malignant disease (Lytton et al., 1964). At the same time there is evidence of a delayed hyper-sensitivity reaction to a cell-free microsomal fraction of auto-logous cancer tissue in 25 % of cancer patients, indicating attempted cellular rejection of the turnour (Hughes and Lytton, 1964). For this reason, in cancer patients cellular immune reactions may warrant more attention than circulating antibody response. We have made an attempt to investigate the competence of the cellular immune mechanism in cancer patients before the onset of general debility by studying the incidence and degree of tuberculin sensitivity in matched cancer and control patients. Methods Cancer Patients.-We studied 122 patients with malignant disease admitted to King's College Hospital Group. Lympho-reticular neoplasms were excluded and the primary sites were Patients with evidence of general debility, such as marked loss of weight, fever, anaemia, and weakness, were excluded, but otherwise there was no selection of cases. Some cases later proved to have widespread disease, but in all instances the general state of the patient was regarded as good. The spread of the tumour was classified into grade A, localized neoplasm; grade B, spread to local lymph nodes, but curative surgery still possible; grade C, spread beyond local lymph nodes. It is realized that such a classification is arbitrary, and of limited usefulness, especially as histology on the lymph nodes was not available in all cases. Twenty patients who had been tested pre-operatively were followed up and retested, when possible, 18 months after surgical removal of their tumour. Control Patients.-Patients with various non-malignant conditions admitted to the surgical wards of the same hospitals were used as controls. For each cancer patient a control was chosen in the same five-year age group, but no …