Assessment of cell-mediated immunity to malignant mesothelioma by microcytotoxicity tests

Cell cultures were established from pleural effusions of patients with pleural mesothelioma, and peripheral mononuclear effector cells were tested for cytotoxicity against these cells by means of microcytotoxicity assay. Effector cells were obtained from normal healthy donors and from persons exposed occupationally to asbestos, including apparently healthy persons, patients with benign pleural conditions and patients with malignant mesothelioma. The overall incidence of cytotoxicity was low, and there was no evidence of increased cytotoxicity in mesothelioma patients or other asbestos-exposed donors. It is concluded that little or no tumour-directed cell-mediated immunity is detectable against malignant mesothelioma by microcytotoxicity methods.