Date: Thu 22 Aug 2012
Source: Associated Pres [edited]
http://hosted.ap.org/dynamic/stories/U/US_MED_MYSTERY_DISEASE?SITE=AP&SECTION=HOME&TEMPLATE=DEFAULT&CTIME=2012-08-22-18-04-18
New AIDS-like disease in Asians, not contagious
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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 [22 Aug 2012] New England Journal of Medicine [see below]. "This is absolutely fascinating. I've seen probably at least 3 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.
A 62-year-old seamstress from Viet Nam 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 Viet Nam in 1995 and again in early 2009. "She was wasting away from this systemic infection" that at 1st 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 1st saw her, her weight was 91 pounds, and she lost down to 69 pounds."
This patient 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 [21 Aug 2012]. 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 [human immunodeficiency virus) -- 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 mycobacteria, a group of germs 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 quietens 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 1st cases turned up in 2004 and Browne's study enrolled about 100 people in 6 months. "We know there are many others out there," including many cases mistaken as tuberculosis in some countries, she said.
[Byline: Marilynn Marchione]
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Communicated by:
ProMED-mail
[It is assumed the preceding press statement is based on the paper titled: Adult-Onset Immunodeficiency in Thailand and Taiwan. By Sarah K. Browne and other, published in the current issue of the New England Journal of Medicine (N Engl J Med 2012; 367:725-734 August 23, 2012; http://www.nejm.org/doi/full/10.1056/NEJMoa1111160). The authors' summary follows.
Background
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Autoantibodies against interferon-gamma are associated with severe disseminated opportunistic infection, but their importance and prevalence are unknown.
Methods
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We enrolled 203 persons from sites in Thailand and Taiwan in 5 groups: 52 patients with disseminated, rapidly or slowly growing, nontuberculous mycobacterial infection (group 1); 45 patients with another opportunistic infection, with or without nontuberculous mycobacterial infection (group 2); 9 patients with disseminated tuberculosis (group 3); 49 patients with pulmonary tuberculosis (group 4); and 48 healthy controls (group 5). Clinical histories were recorded, and blood specimens were obtained.
Results
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Patients in groups 1 and 2 had CD4+ T-lymphocyte counts that were similar to those in patients in groups 4 and 5, and they were not infected with the human immunodeficiency virus (HIV). Washed cells obtained from patients in groups 1 and 2 had intact cytokine production and a response to cytokine stimulation. In contrast, plasma obtained from these patients inhibited the activity of interferon-gamma in normal cells. High-titer anti-interferon-gamma autoantibodies were detected in 81 percent of patients in group 1, 96 percent of patients in group 2, 11 percent of patients in group 3, 2 percent of patients in group 4, and 2 percent of controls (group 5). 40 other anticytokine autoantibodies were assayed. One patient with cryptococcal meningitis had autoantibodies only against granulocyte-macrophage colony-stimulating factor. No other anticytokine autoantibodies or genetic defects correlated with infections. There was no familial clustering.
Conclusions
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Neutralizing anti-interferon-gamma autoantibodies were detected in 88 percent of Asian adults with multiple opportunistic infections and were associated with an adult-onset immunodeficiency akin to that of advanced HIV infection.
The adult-onset immunodeficiency syndrome, mediated by the production of anti gamma-interferon antibodies, does not appear to be contagious and the condition develops around age 50 on average but does not run in families, which makes it unlikely that a single gene is responsible, The prevalence of this condition in Asian people, though not necessarily resident in Asia, implies a genetic origin rather than a cryptic infectious agent. But anything is possible
