Cell-mediated cytotoxicity to human pulmonary neoplasms.

Peripheral blood leukocytes from patients with confirmed pulmonary neoplasia were tested for cytotoxicity against cultured cells derived from lung tumours of various histological types, foetal and normal adult lung tissue and tumours arising in organs other than the lung. Leukocytes from 73 percent of patients were cytotoxic for lung-tumour derived cells compared with age- and sex-matched normal donors, while the frequencies of reactivity against normal adult lung-derived cells and cells from unrelated tumours (e.g. bladder, colon, breast) were 42 percent and 18 percent respectively. Leukocytes from lung cancer patients were also cytotoxic for cells derived from foetal lung but susceptibility to cytolysis was variable, cells from 13- and 14-week embryos revealing greatest reactivity (88 percent). Leukocytes from patients with a variety of tumours of non-pulmonary origin or with non-malignant conditions (including respiratory disorders) were also reactive with lung-tumour-derived target cells but with a lower overall frequency (35 percent) than those from lung-cancer patients. The significance of these cytotoxicity data for the existence of tumour-specific host immunoreactivity in lung neoplasia is discussed.