Characterisation of the host response to Plasmodium falciparum infection. I. Cerebral malaria.

Cerebral malaria is a major form of complicated malaria consequent upon cerebral damage associated with endothelial cell necrosis. We have used assays of Plasmodium falciparum growth inhibition in vitro to study serum inhibitory factors in patients with cerebral malaria. Serum from children with cerebral malaria inhibited parasite growth in a non-synchronised 72-hour assay to a greater extent than did sera from immune adults or asymptomatic children (p less than 0.001). The high level of non-specific inhibition of parasite growth was particularly evident when sera were tested against three P. falciparum isolates, and contrasted with the inhibitory effect of sera from non-malaria febrile controls. In this study, serum from patients with cerebral malaria was more inhibitory than serum from the other groups (p less than 0.001) and its between-isolate variation, when tested against a panel of P. falciparum isolates in growth assays, was significantly less than that of the other groups tested (p less than 0.005). These results are consistent with the hypothesis of toxin-induced endothelial cell damage, with the sequence of pathogenic events involving host-derived serum factors capable of damaging P. falciparum.