THE CHARACTERIZATION OF PERITONEAL AND PLEURAL EXUDATE CELLS FROM MALIGNANT EFFUSIONS

The immune function of peripheral blood cells and cells from the pleur al and abdominal effusions of patients with advanced cancer was compar ed to that of peripheral blood cells from controls. The parameters exa mined included lymphocyte subsets, natural killer (NK) cell activity, and anti-Daudi and lymphokine-activated killer (LAK) cell activity. Th e percentage of CD4+ pleural and peritoneal exudate cells (PEC) was si gnificantly higher than the percentage of peripheral blood mononuclear cells (PBMC) in the patients. The percentage of CD8+CD11+ PEC and PBM C, being the suppressor T-cells, of the patients was increased compare d with controls, while the percentage of CD8+CD11- PEC, being the cyto toxic T-cells, was identical to the PBMC of both patients and controls . The NK activity of PEC was significantly lower than that of PBMC in both patients and controls, and there was no correlation between the N K activity of PBMC and PEC. Although the anti-Daudi activity of PEC wa s markedly low, LAK cells with high activity could be induced by cultu re with interleukin-2 for 4 days. These results suggest that the immun e function of cells in malignant effusions may be depressed due to a l ow population of cytotoxic T cells, low NK activity and increased supp ressor T cells, while the local administration of interleukin-2 may in duce LAK cells. Therefore, effective local immunotherapy for malignant effusions should not only augment effector cells, but also inhibit su ppressor cells.