Blood Test Could Identify Biomarker Signature of Cerebral Malaria

The most severe form, cerebral malaria, develops rapidly when infected red blood cells obstruct blood flow in the brain, leading to coma, swelling, and often death. Survivors may suffer lasting cognitive and motor impairments, yet practical tools to diagnose cerebral malaria early and monitor disease progression are limited. Now, new research shows that brain injury resulting from cerebral malaria may be reduced and detected earlier using an existing drug and a blood-based biomarker approach.

In a study led by the Yong Loo Lin School of Medicine, National University of Singapore (Singapore), together with international collaborators, researchers investigated whether methylene blue, an inexpensive and widely available compound, could counteract brain damage during severe malaria. In parallel, they explored whether specific gene expression patterns in blood could reliably distinguish cerebral malaria from milder infections and healthy states.

Using laboratory models infected with Plasmodium coatneyi, a close analogue of Plasmodium falciparum, methylene blue was administered intravenously after severe symptoms emerged. The team analyzed gene activity changes in the brain and blood, focusing on molecular pathways linked to inflammation and tissue damage. These analyses aimed to identify both therapeutic effects and measurable blood signals associated with cerebral malaria.

The study, published in Nature Communications, showed that methylene blue reversed many infection-induced genetic changes in the brainstem, the region most affected in cerebral malaria. Treated models displayed reduced pigment deposition, bleeding, and swelling, alongside normalization of gene expression. Researchers also identified a consistent nine-gene blood signature that clearly separated cerebral malaria cases from mild malaria and healthy controls.

The nine-gene signature appeared stable across adult and pediatric datasets, suggesting potential for a standardized blood test to diagnose cerebral malaria, assess severity, and monitor recovery. Several of the genes were linked to neutrophils, highlighting a previously underappreciated role for these immune cells in brain injury and blood–brain barrier disruption. The researchers plan to validate the biomarkers in larger patient cohorts and evaluate methylene blue dosing, timing, and safety in clinical trials.

“The biomarker signature we identified was remarkably consistent. This suggests that a simple blood test could be developed to differentiate cerebral malaria from other severe conditions, enabling earlier intervention and clearer treatment decisions,” said Assistant Professor Benoit Malleret, lead investigator of the study.

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