HONG KONG - A TYPE of immune cells appear to cause more serious disease in malaria patients because they shut down the immune system, allowing the parasite to multiply uncontrollably, researchers have found.

In an article published in PLoS Pathogens, the international team of scientists found that patients who had the most severe malaria symptoms had higher amounts of these immune cells, which are called regulatory T (Treg) cells.

US: End malaria deaths by 2015 WASHINGTON - PRESIDENT Barack Obama is committed to making the United States a global leader in ending the nearly 1 million deaths annually from malaria by 2015, the US ambassador to the United Nations says. The goal is shared by UN Secretary-General Ban Ki-moon and the African Union, according to excerpts from Susan Rice's prepared speech to a malaria summit on Friday made available to The Associated Press. ... more

'The immune system will normally get rid of the parasite and if you are turning off the immune system, you are allowing the parasite to grow uncontrollably. We find that the more of these cells we have, the more parasites we have,' Magdelena Plebanski, immunology professor at Monash University in Australia said in a telephone interview.

The researchers studied 33 patients who contracted Plasmodium Falciparum malaria in the lowlands of Papua in Indonesia.

This parasite causes over a million deaths worldwide and there is as yet no completely effective vaccine. Of these patients, 16 suffered severely and researchers found that they had markedly higher levels of Treg cells.

'The subset of regulatory cells that had the most powerful capacity to turn off the immune response was only increased in those with severe disease,' Plebanski said.

Looking ahead, the team wants to investigate why some people have the tendency of developing more Treg cells than others.

'It is unknown why some people have high (amounts of) parasites and some people don't and by finding that these cells are present in people with severe, lethal disease, we are getting insight into what will lead you to development of severe disease,' she said.

'It gives us the possibility of potentially getting rid of these cells or targeting therapy to get rid of these cells to then enable the immune system to get the upper hand again in controlling the disease.' It is estimated that 500 million people live in areas where there is a risk of getting malaria. The severe form of the disease causes death in 1 to 3 million people each year.

It is still not known what bodily factors enable some patients to fight and survive the disease, while other patients contract the severe form of the disease and sometimes die.

The article is available online on: http: dx.plos.org/10.1371/journal.ppat.1000402 -- REUTERS