Serum complement factors in human acute pancreatitis

C3, C4 and total haemolytic activity of serum complement were measured in 35 patients with acute pancreatitis, and were found to be normal or raised in 24 patients (23 survivors). In 3 further patients complement values were low initially, but returned to normal with clinical recovery. In the remaining 8 patients serum complement factors were generally lowered or declined during the course of the disease; all of them died from haemorrhagic pancreatitis. Thus lowered complement factors may be an unfavourable prognostic sign for the course of the disease. Reasons for the decline may be protein loss, blood coagulation disturbances or intrapancreatic activation of complement. The latter possibility is supported by the immunohistological detection of C3 deposits surrounding parenchymal necroses in two patients.