Researchers find possible cause of severe malaria

April 24, 2009 11:57 pm 

WASHINGTON, April 24 — Scientists have identified a specific type of immune cells that they said may cause malaria patients to develop more serious disease, according to a report to be published Friday in the journal PLoS Pathogen.

These immune cells, known as regulatory T (Treg) cells, switch off the immune system and can allow the parasite to grow uncontrollably.

Magdalena Plebanski from Monash University and colleagues studied 33 malaria-infected adults in the southern lowlands of Papua, Indonesia, and identified elevated levels of Treg cells in the 16 patients with severe malaria.

"The regulatory (Treg) cell subset associated with severe disease in humans expresses a unique combination of surface markers, including TNFRII … (suppressing) the activation and expansion of effector immune cells, which partake in parasite elimination," Plebanski said.

"Our results indicate that severe malaria is accompanied by the induction of highly suppressive Treg cells that can promote parasite growth, she said, reminding of caution against the induction of these Treg cells when developing effective malaria vaccines.

It is estimated that 500 million people live in areas where there is a risk of getting malaria. The severe disease causes around 1 to 3 million deaths each year.

"Targeting this cell type may lead to new drugs and immunotherapeutics against malaria," Plebanski said, adding that further studies are needed to determine if this new cell may also promote severe forms of other inflammatory diseases. (PNA/Xinhua)



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