Pancreatic phospholipase A2 activity in acute pancreatitis: a prognostic marker for early identification of patients at risk.

Remarkably elevated levels of phospholipase A2 (PLA2) are measurable in human blood samples in cases of acute pancreatitis. The source of the enzyme was first thought to be exclusively the pancreas, but now it is generally accepted that two isoenzymes--the pancreatic PLA2, group I, and the extrapancreatic PLA2, group II--contribute to the raised activity. In contrast to the group II-PLA2, the pancreatic PLA2 is heat-resistant for 1 hour at 60 degrees C. The catalytically inactive proenzyme of the pancreatic PLA2 can be activated by trypsin. The aim of our study was to evaluate the diagnostic value of PLA2 isoenzyme activity measurements to identify patients with severe complications in acute pancreatitis. Blood samples from patients suffering from acute pancreatitis were analyzed for catalytically active pancreatic PLA2 on day 1 and 2 of hospitalization with a modified radiometric Escherichia coli-based PLA2 assay. In 10 of 41 patients clearly elevated values of catalytically active, heat-resistant pancreatic PLA2 (7.2 to 81.2 U/l) were observed. This group of patients was characterized by severe complications (necrotizing pancreatitis, shock, sepsis, respiratory problems) of which two patients subsequently died. Patients with low or undetectable activity (<7 U/l) of pancreatic PLA2 recovered rapidly. According to these results the presence of catalytically active pancreatic PLA2 in serum is associated with severe complications of acute pancreatitis. In contrast to total serum-PLA2, the catalytic concentration of pancreatic PLA2 can serve as a prognostic marker in acute pancreatitis.