[Study of pulmonary T cell subsets and killer activity in lung cancer]

Studies were performed to determine natural killer (NK) activity (ability to lyse 51Cr labeled K562 target cells) and T cell subsets (with OKT3, OKT4, or OKT8 antigen detected by indirect immunofluorescence technique) both in bronchoalveolar lavage fluid (BALF) and peripheral blood of 40 lung cancer patients with different pathological type and 39 healthy controls. Our results showed that the percentage of total T cell (T3) and T suppressor cells in BALF were elevated both in the tumour involved and healthy lungs of the patients when compared with those of the normal controls. NK activity levels in BALF of the uninvolved lung and the controls were low. However, NK activity at tumour sites and the adjacent airways were significantly higher. There was no difference of NK activity in peripheral blood between lung cancer patients and the controls. The results demonstrated immune assays for BALF are very important parameters to investigate the changes of immune surveillance of the lung cancer patients. The higher NK activity and the reduced T4/T8 ratio in the lung with cancer may play important roles in local immunity.