Complement Profiles In Disseminated Intravascular Coagulation

Complement levels were examined in cases of disseminated intravascular coagulation (DIC), as well as in experimental animal models of DIC, and it was found that complement played a part either in the development or in the early diagnosis of DIC.

Thirteen patients with DIC; 4 associated with bacterial infection, 1 chronic myelogenous leukemia and 8 liver diseases, were serially investigated for their serum complement levels. By the onset of DIC, marked decrease of CH50, C4 and C3 levels were observed in all cases. Those who responded well to anticoagulant therapy revealed a gradual recovery of complement levels, while who failed kept their low serum levels, suggesting that the estimation of complement levels in patients with DIC might be a valuable parameter for their prognosis.

Experimental model of DIC was produced in rats by the continuous intravenous infusion of bacterial endotoxin for 4 hours. Histological examination and several coagulation parameters such as fibrinogen, platelet counts, prothrombin time, PTT and FDP confirmed the presence of DIC. The complement levels, CH50 and C3, were markedly decreased at the onset of DIC and then gradually increased after stopping the infusion of endotoxin. By the pretreatment of rats with heparin, this decrease of serum complement levels by endotoxin was completely prevented.

It is concluded that, although many factors have been known to be involved in the production of DIC, complement might also be an important factor, one by contributing to the coagulation process and the other by being affected by secondary fibrinolysis.