Ascitic starch phagocytosis in experimental guinea-pig peritonitis

Phagocytosis of starch granules in ascitic fluid was sought in guinea-pigs 1 to 10 days after i.p. injection of a suspension of starch powder. Starch phagocytosis occurred in 75.9% of control animals with free peritoneal fluid. It probably represents a nonspecific reaction to the particulate nature of starch granules. Guinea-pigs sensitized to starch by nuchal inoculation of an emulsion of Freund's adjuvant and starch showed no increase in frequency or intensity of ascitic starch phagocytosis beyond that seen in control animals. Since only sensitized animals develop granulomatous peritonitis, ascitic starch phagocytosis is thus not indicative of granulomatous hypersensitivity peritonitis. This experimental model suggests that examination of ascitic fluid is not a reliable clinical investigation to establish a diagnosis of human granulomatous starch peritonitis.