Increased activity of lysosomal enzymes in the peritoneal fluid of bacterial peritonitis

The activity of lysosomal enzymes is increased in the cerebrospinal fluid of bacterial meningitis, suggesting that inflammation may cause leakage of lysosomal enzymes into the extracellular fluid. Our objective was to study the activity of 3 lysosomal enzymes in cell-free peritoneal fluid of patients with peritoneal inflammation.

The beta-galactosidase, beta-glucuronidase, and alpha-mannosidase activity (nmol 4-methylumbelliferone/mL/h); the total, polymorphonuclear, and mononuclear cell number; and chemical parameters were determined in the peritoneal fluid of 26 patients with culture-positive acute bacterial peritonitis, 13 patients (under antibiotic treatment) with culture-negative bacterial peritonitis, 6 patients with acute mesenteric lymphadenitis, and 26 control subjects who were operated on for surgical conditions without peritoneal inflammation.

The median beta-galactosidase activity in the culture-positive bacterial peritonitis, mesenteric lymphadenitis, and controls was 175 (range: 63--2210), 50 (range: 37--56), and 16 (range: 8--32), respectively. The beta-glucuronidase was 488 (range: 79--998), 53 (range: 27--98), and 15 (range: 3--22), respectively. The alpha-mannosidase was 801 (range: 100-3172), 78 (range: 33--157), and 41 (range: 16--63), respectively. The differences of the enzyme activities among the groups of the subjects studied were significant, with the exception of the alpha-mannosidase activity between mesenteric lymphadenitis and controls. There was no significant correlation between the enzyme activities and the cytologic or chemical parameters studied.

The elevation of the lysosomal enzymes' activity in the peritoneal fluid of patients with bacterial peritonitis seems to be a reliable index of peritoneal infection. Of the enzymes studied, the beta-glucuronidase and beta-galactosidase activities provide the best means for diagnosing bacterial inflammation of the peritoneal cavity.