'Survival gene' may be key to controlling HIV and hepatitis

The gene, called Arih2, is fundamental to the function of the immune system - making critical decisions about whether to switch on the immune response to an infection.

Its discovery has implications for the treatment of chronic overwhelming infections, such as Human immunodeficiency virus (HIV), that 'exhaust' and switch off the immune system, as well as for chronic inflammatory (also known as autoimmune) conditions such as rheumatoid arthritis

and sepsis, said researchers from Walter and Eliza Hall institute in Australia and the University of Toronto, Canada.

Researcher Dr Marc Pellegrini said that Arih2 is found in dendritic cells, the sentinels of the immune system that play an essential role in raising the alarm about the presence of foreign invaders in the body.

"Arih2 is responsible for the most fundamental and important decision that the immune system has to make - whether the immune response should be initiated and progressed or whether it should be switched off to avoid the development of chronic inflammation or autoimmunity," he said.

"If the wrong decision is made, the organism will either succumb to the infection, or succumb to autoimmunity," Pellegrini said in a statement.

He explained that although our immune system works well against many infections, some organisms have developed mechanisms to evade or counteract the immune system, allowing them to persist in the body.

"During evolution, some organisms have evolved

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