Mononuclear phagocytes of peritoneal fluid

Abstract

Cells in the peritoneal fluid from 179 horses were examined in Giemsa-stained preparations by light microscopy. Mononuclear phagocytes were a common cell type observed in normal fluids. In the absence of stimulation they were morphologically similar to the peripheral blood monocyte and the unstimulated mesothelial cell. In acute inflammatory effusions their proportion decreased significantly but, as the condition resolved, monocytes began to migrate into the cavity, gradually becoming more numerous, transforming into larger macrophages and assuming an increasing phagocytic role. They were often strikingly enlarged and actively phagocytic of degenerate neutrophils and aged red cells.