[Immunocytochemical characterization of malignant pleural effusions of small cell bronchial cancer].

In pleural effusions, histologically proven to be malignant in 13 patients with small cell lung cancer, the immunocytological profile of tumour cells, together with the distribution of the lymphocyte subpopulations, were established. In all cases, tumor cells were demonstrable with the monoclonal antibodies EMA, HEA-125, Sam 2, 6, 8 and 10. In contrast, conventional cytology was positive in only 6 of the 13 cases. As in other malignant or inflammatory effusions, phenotyping of the lymphocytes revealed an elevated T4/T8 ratio in comparison with the normal value for peripheral blood.