A macrophage activating factor is present and active in the ascitic fluid of patients with ovarian cancer.

Morphological and functional changes in human monocytes and peritoneal macrophages from six patients with ovarian cancer were studied. The surface architecture of exudate macrophages from ascitic fluid have already been shown to exhibit extensive spreading and ruffled membranes. Consequently, peripheral monocytes from the patients were cultured with ascitic fluid from the same individuals. They gradually displayed active membrane pseudopodia, thorn-like processes and petal-like ruffles after 2 h to 4 h of cultivation. Adherent peritoneal macrophages from the patients demonstrated increased consumption of glucose. These results suggest a macrophage activating factor (MAF) exists in ascitic fluid in patients with ovarian cancer which plays an initial role in the change of monocytes into macrophages.