Spontaneous cell-mediated cytotoxicity in patients with transitional cell carcinoma of the urinary bladder

Summary Lymphocytes isolated from the blood of TCC patients, like those of control patients, were capable of mediating spontaneous cell-mediated cytotoxicity against K-562 cells. When this natural cytotoxicity was analyzed with regard to the effector cell type it was found that in TCC patients the SLMC was mostly displayed by E-rosetting T lymphocytes, whereas compared with controls, a significant decline in the SLMC of the non-T lymphocytes was observed. The SLMC of the T lymphocytes derived from TCC patients was further demonstrated on a T leukemia target cell (Peer). When the SLMC on K-562 and on Peer target cells was compared, a specificity difference was observed between TCC and the control patients' effector cells. The SLMC activity of the TCC patients' T cells was not abolished after depletion of Fc receptor-positive cells or following treatment with monoclonal antibodies OKT 8 or OKT 4 and complement (C'). These NK-like cells are therefore distinguished from cytotoxic T lymphocytes and NK cells.