DEVELOPMENT AND USE OF ELISA TO QUANTIFY TYPE-II PHOSPHOLIPASE A(2) IN NORMAL AND UREMIC SERUM

Previously we reported that uremic plasma contained eight times more p hospholipase A(2) (PLA(2)) activity than control plasma (Costello et a l., Clin Chem 1990;36:198-200). That study, however, did not distingui sh between various PLA(2)s that could contribute to the observed incre ase. Therefore, we developed a sandwich ELISA to specifically quantify serum type II PLA(2). By ELISA, uremic sera contained significantly m ore type II PLA(2) than control sera (median = 1025 mu g/L, range = 52 -3320 mu g/L vs median = 9.2 mu g/L, range = 4.6-17.5 mu g/L; P = 0.00 2). When serum samples were incubated with 1-[C-14]oleate-labeled auto claved Escherichia coli, activity was increased 14.6-fold in uremic vs normal serum, with a median of 6.5 mu mol/min per liter (range 1.1-16 .3) vs a control median of 0.49 mu mol/min per liter (range 0.32-0.60; P = 0.002). Thus, ELISA detects about eightfold more immunoreactive t ype II PLA(2) in uremic serum than does enzymatic analysis. Evidently, the increase in PLA(2) activity previously observed in uremic plasma is primarily due to increased concentrations of type II PLA(2).