Phospholipase A2 values increase in serum in various inflammatory states, infections, and postoperatively in surgical patients. Several organs, including the liver and spleen have been suggested as sources of circulating phospholipase A2. The purpose of the present work was to examine the possible role of the spleen as a source of elevated serum concentrations of phospholipase A2 after surgery. Pre- and postoperative serum samples of patients undergoing splenectomy were studied for group I phospholipase A2, group II phospholipase A2, and C-reactive protein mass concentrations and catalytic activity concentration of phospholipase A2. The catalytic activity concentration of phospholipase A2 and the mass concentrations of group II phospholipase A2 and C-reactive protein increased postoperatively (8.08 +/- 1.40 U/l vs. 3.96 +/- 0.89 U/l (mean +/- SEM) for phospholipase A2 catalytic concentration (p < 0.03), and 154.8 +/- 32.1 micrograms/l vs. 47.5 +/- 14.7 micrograms/l (mean +/- SEM) for group II phospholipase A2 mass concentration (p < 0.02, n = 7). The mass concentration of group I phospholipase A2 remained unchanged. The catalytic concentration of phospholipase A2 correlated well with the mass concentration of group II phospholipase A2 (p < 0.001, r = 0.846, n = 43). The concentration of C-reactive protein correlated well with the mass concentration of group II phospholipase A2 (p < 0.001, r = 0.566, n = 43) in serum. The results indicate that group II phospholipase A2 is released into the circulation after splenectomy, and the spleen seems not to be the source of circulating group II phospholipase A2.