AIDS-like disease found in Asians, trigger unknown
The illness leaves patients unable to fight off germs. Some patients have died of overwhelming infections, including some Asians now living in the US, said Dr. Sarah Browne, a scientist at the National Institute of Allergy and Infectious Diseases, who led the study of the disease.
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 study was conducted in Thailand and Taiwan, where most of the cases have been found starting from 2004. Their report was published in the New England Journal of Medicine on August 23.
This kind of acquired immune deficiency is not inherited and occurs in adults only around the age of 50. However, it doesn't spread the way AIDS does through a virus, said Browne. The study found that the disease does not run in families, this it is unlikely that a single gene is responsible.
When someone is suffering from AIDS, their immune system becomes impaired during the lifetime. The virus destroys T-cells, key soldiers of the immune system that fight germs. The new disease, however, does not affect those cells, but causes a different kind of damage.
Browne studied of more than 200 people in Taiwan and Thailand and found that most of those with the disease produce substances called autoantibodies that block interferon-gamma, a chemical signal that helps the body clear infections.
Once that signal is blocked, it leaves people vulnerable to viruses, fungal infections and parasites, but especially microbacteria, a group of germs similar to tuberculosis that can cause severe lung damage.
Researchers believe the faulty immune system is likely a chronic condition even though the disease settles in some patients once the infections are tamed. Antibiotics are not always effective and doctors have tried a multitude of other approaches, including a cancer drug that helps suppress production of antibodies.
Nearly all the patients so far have been Asian or Asian-born people living elsewhere, this suggests that genetic factors and something in the environment such as an infection may trigger the disease, the research concluded.