Severe Plasmodium falciparum Malaria Is Associated with Circulating Ultra-Large von Willebrand Multimers and ADAMTS13 Inhibition
Figure 1
Severe Plasmodium falciparum malaria influences plasma VWF antigen level and collagen binding activity.
(A) Plasma VWF∶Ag levels (white bars – left Y axis) were measured by ELISA, and VWF activity by collagen binding activity (VWF∶CB) (grey bars – right Y axis). Each plasma sample was tested in duplicate at three dilutions, and median values for each group are shown. VWF∶Ag and VWF∶CB levels were markedly elevated in patients with cerebral malaria and in children with severe malaria at presentation compared to levels in healthy control children. (B) In a cohort of children with cerebral malaria (CM), the time-course of VWF∶Ag and VWF∶CB levels following admission and commencement of anti-malarial therapy was assessed using follow-up plasma samples collected after 24 and 72 hours respectively. (C) Although both VWF∶Ag and VWF∶CB were increased in all cases of P. falciparum malaria, the relative increase observed in plasma VWF∶CB levels was significantly higher (p<0.05), such that the ratio of CB to Ag was consistently >1 in children with CM (n = 13; ●) or SM (n = 20; ▲) at presentation compared to healthy control subjects (n = 25; □). (Hashed line indicates 1∶1 ratio).