Macrophages and mesothelial cells in pleural and peritoneal effusions

The characteristics of macrophages and mesothelial cells in serous effusions were studied morphologically, cytochemically and functionally.The macrophages and mesothelial cells had distinct characteristics, respectively.These findings appear important to the cytologic diagnosis of effusions.The two kinds of cells seem essentially different in properties, and do not seem to transform themeselves into each other.The mesothelial cells in effusions morphologically differed from the peritoneal mesothelium cells of patients without ascites, but resembled those of patients with longstanding ascites. It was suggested that the mesothelial cells in effusions had originated from the cells of pathological mesothelium.