Could a new defence against malaria be found in human blood?
Research suggests that human platelets — a component of the blood — form a first-line defence against the malaria parasite. Such a discovery could lead to an entirely new approach to treating the disease and could aid India in curbing the number of malaria cases, especially around the monsoon season when malaria is more prevalent.
“These are important findings and are the first direct evidence of protection by platelets in any human infectious disease,” said the lead author, doctoral student Steven Kho from the Menzies School of Health Research, an Australia-based non-profit organisation.
“Research suggests that human platelets – a component of the blood – form a first-line defence against the malaria parasite. Such a discovery could lead to an entirely new approach to treating the disease”
The study was published in the journal Blood. Though conducted on a relatively small sample size of only 376 people, the investigation was successful in identifying compounds which could eventually be used as a medicinal treatment.
The research tested the response of human platelets against the four main types of parasite responsible for malaria within humans: Plasmodium falciparum, P. vivax, P. malariae and P. knowlesi.
Platelets are used by the body to prevent excessive bleeding. This is accomplished by platelets being able to bind to other platelets in order to plug gaps where blood vessels are broken. Up until now it was not known that they had an active role in preventing disease, although a low platelet count can be considered a risk factor for infection.
The research found that platelets may kill around twenty percent of circulating Plasmodium parasites in clinical malaria. In P. vivax this effect was more pronounced, with reductions in circulating parasites as high as sixty percent.
It was found that a specific peptide released by the platelets, known as PF4, was responsible for killing off the malaria parasite. The platelets bound to the red blood cells containing the malaria parasite and released PF4 into the cell. The PF4 then displayed a toxic effect on the malaria parasite.
This result warrants further study, specifically on the PF4 peptide itself. If the peptide alone is found to demonstrate the same toxicity to the parasites responsible for causing malaria, it may be a potential new route to take when attempting to create new medicines to fight malaria. As the process by which the peptide attacks malaria is a novel pathway, it may also be a key compound in addressing the issue of drug-resistant malaria.
India faces a considerable burden from malaria, reporting 63 cases per thousand people in 2016. As mentioned above, the risk of developing malaria multiplies during the monsoon season. Novel treatments could be a boon for the country, especially in this vulnerable period of the year.