Effects of high-dose intraperitoneal aprotinin treatment on complement activation and acute phase response in acute severe pancreatitis

Forty-eight patients with severe acute pancreatitis were treated with intraperitoneal lavage in a double-blind randomized multi-center trial. One group (aprotinin group, n = 22) was also treated intraperitoneally with high doses of the protease inhibitor aprotinin. In the group not treated with aprotinin (control group), 6 patients were operated on because of pancreatic necrosis, compared with none in the treated group. Complement activation and the acute phase response were studied with measurements of anaphylatoxin C3a, C1 inhibitor (C1 Inh), interleukin 6 (IL-6), and C-reactive protein (CRP). The control group had higher plasma levels of C3a and lower levels of C1 Inh compared with the aprotinin group. The differences were statistically significant for C3a but not for C1 Inh. Both groups had high plasma levels of IL-6 and CRP. There were no differences between the groups in CRP levels, but the control group had higher IL-6 levels (not statistically significant) than the aprotinin group. This was caused by very high levels in the 6 patients operated on because of pancreatic necrosis, indicating that IL-6 could be a good plasma marker of pancreatic necrosis. The results also show that massive antiprotease treatment reduces complement activation, as illustrated by the lower C3a levels in the aprotinin group. The lower C1 Inh levels in the control group could have been caused by an increased consumption of the inhibitor.