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, 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 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 about 100 people in six months.

“We know there are many others out there,” including many cases mistaken as tuberculosis in some countries, she said. (AP)

<관련 한글 기사>

정체불명의 ‘유사 에이즈’ 발병!


에이즈와 증세는 유사하지만 전염성은 없는 것으로 보이는 정체불명의 새로운 선천성 면역결핍질환이 아시아와 미국에서 나타나고 있다.

이 면역결핍 질환은 2004년 이후 주로 태국과 대만에서 나타나고 있으며 환자는 면역체계 손상으로 각종 감염에 장기간 시달리다 일부는 사망한다고 이 병을 추적중 인 미국 국립알레르기-전염병연구소(NIAID)의 새러 브라운(Sarah Browne) 박사가 밝혔다.

브라운 박사는 의학전문지 '뉴 잉글랜드 저널 오브 메디신'(New England Journal of Medicine) 최신호에 실린 연구보고서를 통해 에이즈 바이러스(HIV)는 감염에 대항하는 핵심 면역세포인 T세포를 파괴하지만 이 면역결핍질환은 면역체계에 다른 형태의 손상을 일으킨다고 말했다.

태국과 대만에서 발생한 환자 200여 명의 경우 대부분 감염 차단에 필요한 화학 신호인 인터페론-감마를 가로막는 자가항체를 만드는 것으로 밝혀졌다는 것이다.

발병 연령은 평균 50세로 가족력과 관계가 없는 것으로 미루어 단일 유전자 변이가 원인일 가능성은 낮은 것으로 보인다.

지금까지 환자를 3명 보았다는 위스콘신 대학 전염병전문의 데니스 마키 박사는 어떤 형태의 감염이 원인일 가능성이 있지만 사람과 사람 사이에 감염이 이루어지는 것 같지는 않다고 말했다.