Structure and function of human effusion macrophages from patients with malignant and benign disease. 1. Isolation, morphology, proliferation and phagocytosis.

The inflammatory cell composition of pleural or ascitic effusion fluids from 13 patients with malignant disease and 8 patients with benign disease was analyzed. The macrophage content in the effusions was 4.1 x 10(5) +/- 1.3 cells/ml (mean +/- SEM), with large variation (range 0.1 - 27.9 x 10(5) cells/ml) among patients. Major blood cell contamination was excluded by the finding of low red blood cell/nucleated cell ratios in the effusions. Effusion macrophages were isolated by Ficoll/Isopaque centrifugation and plastic adherence. Monolayers of > 90% alpha-napthyl-esterase-positive and/or phagocytic cells were produced in most experiments. Adherent effusion cells incorporated low amounts of methyl-3H-thymidine (methyl-3H-TdR). Most cells in DNA-synthesis were removed by trypsin, indicating that they were not macrophages. Lymphokine supernatants induced increased methyl-3H-TdR incorporation in adherent cells in 3 of 8 experiments, and microscopic proliferation of phagocytic cells was evident in one experiment. Endotoxin and Corynebacterium parvum reduced adherent cell DNA-synthesis slightly. Effusion macrophages ingested more 125I-labelled Candida albicans than peripheral blood monocytes. The ability to degrade ingested Candida and the cell adherence after phagocytosis were found to be greater in the macrophages than in monocytes. Effusion macrophages with monocyte-like, undifferentiated appearance differentiated like monocytes in vitro. Further in vitro differentiation of macrophages with more differentiated appearance often seemed to be blocked, the cells dying gradually after 4-8 days in vitro.