Complement changes and disseminated intravascular coagulation in Plasmodium falciparum malaria.

Complement activation as shown by increased clearance of radioactive C1q and reduction in serum-C3 level was found in fifteen (83%) of eighteen patients studied during Plasmodium falciparum infection. Six patients had haemostatic defects suggesting disseminated intravascular coagulation (D.I.C.), and five others had other clinical complications. A correlation was found between reduction of C3 and clinical complications as well as with the degree of anaemia and with thrombocytopenia. Moreover, the most severe thrombocytopenia and the most severe reduction of C3 levels were found in those patients with D.I.C. An immune reaction associated with complement activation in P. falciparum infection is believed to contribute to injury of red blood-cells and platelets and to promote the development of D.I.C. and other serious clinical complications.