Sunday 26 August 2012

Another Asian Contagion?

A new form of acquired immune deficiency is creeping up on Asians.

It's interesting how there are diseases specific to Asians, so it will be fascinating to see whatever it is in the 'Asian' environment and lifestyles ... coupled with the 'Asian' genotype that makes Asians susceptible to such disease outcomes.


Mystery Aids-like disease hits Asians
Researchers in US, Thailand and Taiwan are at a loss to explain the cause of an autoimmune disorder that is striking middle-aged patients
Associated Press
Aug 24, 2012    

Researchers have identified a mysterious and sometimes fatal new disease that has left scores of ethnic Asians with Aids-like symptoms, even though they are not infected with HIV.

The patients, both in Asia and the US, had immune systems that became damaged, leaving them unable to fend off germs.

The new form of acquired immune deficiency in adults is neither contagious nor inherited, said Dr Sarah Browne, a scientist at the US National Institute of Allergy and Infectious Diseases. It does not spread the way Aids does through a virus, she said.

Browne helped lead the study with researchers in Thailand and Taiwan where most of the cases have been found since 2004. Their report was published in yesterday's New England Journal of Medicine.

"This is absolutely fascinating. I've seen probably at least three patients in the last 10 years," who might have had this, said Dr Dennis Maki, an infectious disease specialist at the University of Wisconsin in Madison.

It's still possible that an infection of some sort could trigger the disease, even though the disease itself does not seem to spread person-to-person, he said.

The disease develops at around age 50 on average but does not run in families, which makes it unlikely that a single gene is responsible, Browne said. Some patients have died of overwhelming infections, including some Asians now living in the US, although Browne could not estimate how many.

Kim Nguyen, 62, a seamstress from Vietnam who has lived in Tennessee since 1975, was gravely ill when she sought help for a persistent fever, infections and other bizarre symptoms in 2009. She had been sick off and on for several years and had visited Vietnam in 1995 and 2009.

"She was wasting away from this systemic infection" that at first seemed like tuberculosis but wasn't, said Dr Carlton Hays, a doctor in Jackson, Tennessee.

Nguyen was referred to specialists at the National Institutes of Health who had been tracking similar cases. She spent nearly a year at an NIH hospital in Bethesda, Maryland, and is there now for further treatment.

"I feel great now," she said on Wednesday. But when she was sick, "I felt dizzy, headaches, almost fell down," she said. "I could not eat anything."

Aids, or acquired immune deficiency syndrome, is a specific disease in which the immune system becomes impaired during someone's lifetime, rather than from inherited gene defects like the "bubble babies" who are born unable to fight off germs.

HIV, the virus that causes Aids, destroys T-cells, key soldiers of the immune system that fight germs. The new disease doesn't affect those cells but causes a different kind of damage. Browne's study of more than 200 people in Taiwan and Thailand found that most of those with the disease make substances called auto-antibodies that block interferon-gamma, a chemical signal that helps the body clear infections.

Blocking that signal leaves people like those with Aids vulnerable to viruses, fungal infections and parasites, but especially micobacteria, a group of germs similar to tuberculosis that can cause severe lung damage. Researchers are calling this new disease an "adult-onset" immunodeficiency syndrome because it develops later in life and they don't know why or how.

The fact that nearly all the patients so far have been Asian or Asian-born people living elsewhere suggests that genetic factors and an environmental factor such as an infection may trigger the disease, researchers said.

"We know there are many others out there," including many cases mistaken as tuberculosis, Browne said.

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