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| Patient Kim Nguyen, right, and her husband Quang Nguyen are seen at National Institute of Health in Bethesda |
Researchers have identified a mysterious new disease that has
left scores of people in Asia and some in the United States with
AIDS-like symptoms even though they are not infected with HIV.The
patients’ immune systems become damaged, leaving them unable to fend
off germs as healthy people do. What triggers this isn’t known, but the
disease does not seem to be contagious.
This is another kind of
acquired immune deficiency that is not inherited and occurs in adults,
but doesn’t spread the way AIDS does through a virus, said Dr. Sarah
Browne, a scientist at the National Institute of Allergy and Infectious
Diseases.
She helped lead the study with researchers in Thailand
and Taiwan, where most of the cases have been found since 2004. Their
report is in Thursday’s New England Journal of Medicine.
“This is
absolutely fascinating. I’ve seen probably at least three patients in
the last 10 years or so” 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 doesn’t seem to
spread person-to-person, he said.The disease develops 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
U.S., 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
throughout her bones and other bizarre symptoms in 2009. She had been
sick off and on for several years, and had visited Vietnam in 1995 and
again in early 2009.
“She was wasting away from this systemic
infection” that at first seemed like tuberculosis, but wasn’t, said Dr.
Carlton Hays Jr., a family physician at the Jackson Clinic in Jackson,
Tenn. “She’s a small woman to begin with, but when I first saw her, her
weight was 91 pounds, and she lost down to 69 pounds.”
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, Md., and is there now for monitoring and further treatment.
“I
feel great now,” she said Wednesday. But when she was sick, “I felt
dizzy, headaches, almost fell down,” she said. “I could not eat
anything.”
AIDS is a specific disease, and it stands for acquired
immune deficiency syndrome. That means 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.
The
virus that causes AIDS — HIV — 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 autoantibodies 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.
“Fundamentally, we do not know what’s causing them to make these antibodies,” Browne said.
Antibiotics
aren’t always effective, so doctors have tried a variety of other
approaches, including a cancer drug that helps suppress production of
antibodies. The disease quiets in some patients once the infections are
tamed, but the faulty immune system is likely a chronic condition,
researchers believe.
The fact that nearly all the patients so far
have been Asian or Asian-born people living elsewhere suggests that
genetic factors and something in the environment such as an infection
may trigger the disease, researchers conclude.
The first cases turned up in 2004, and Browne’s study enrolled almost 100 people in six months.
“We know there are many others out there,” including many cases mistaken as tuberculosis in some countries, she said.
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