Infection With 2 HIV Strains Slows Disease Progression

HealthDay – Thu, Jul 19, 2012 WEDNESDAY, July 18 (HealthDay News) -- While many people don't know it, there's more than one kind of AIDS virus. Besides the HIV-1 strain that's common throughout the world, a type known as HIV-2 is found in some parts of Africa. Now, a new study finds that people infected with HIV-2 and later with HIV-1 appear to be better equipped to fight off the virus.

Double-infected people can still go on to develop AIDS, and there's no indication that anyone infected with HIV-1 should go out in search of HIV-2.

However, "this study should prompt researchers to take a fresh look at HIV-2 infection" and why it seems weaker, and the potential implications for a vaccine, said Sarah Rowland-Jones, an AIDS specialist and professor of immunology at John Radcliffe Hospital in Oxford, England.

The big questions, she said, are these: Is there something about the HIV-2 virus that makes it less dangerous to the human body's immune system defenses? Or is it perhaps the other way around, and the body's defenses are the key?

"If we understood this, it would have a lot of relevance for HIV vaccine design," said Rowland-Jones, who's familiar with the new study's findings.

The HIV-2 strain is largely found in West Africa and hasn't spread much beyond there, although there have been cases reported in Europe, India, Japan and the United States, Rowland-Jones said. Many people who are infected with the HIV-2 virus develop AIDS and die, but some live normal lives, she said.

The new study looked at West Africans in the country of Guinea-Bissau and focused on 223 people who first became infected with HIV-2 and then with HIV-1 or those who only got the HIV-1 strain.

The researchers tracked the patients for about 20 years. They found that it took an average of 104 months (nine years) for those with dual infections to develop AIDS, but just 68 months (nearly six years) for those infected solely with the HIV-1 virus.

"Those infected with HIV-2 first seem to be better prepared to handle the more aggressive HIV-1 infection and thereby have a longer progression time to AIDS," said study lead author Joakim Esbjörnsson, a postdoctoral researcher at Lund University, in Sweden.

"It is clear that the effect is huge," Esbjörnsson said, and it probably affects death rates, too.

Esbjörnsson emphasized that the research only looked at people who became infected with HIV-2 first: "People already single-infected with HIV-1 should under no circumstances try to get infected with HIV-2," he said.

Phyllis Kanki, an AIDS specialist and professor of immunology and infectious diseases at the Harvard School of Public Health, suggested that people who get infected with HIV-2, which affects the body more slowly, may develop better defenses against the virus. That, in turn, could help them more effectively fight the HIV-1 strain, she said.

The study appears in the July 19 issue of The New England Journal of Medicine.

More information

To learn more about HIV, visit the U.S. National Library of Medicine.

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Drug Widely Used to Treat MS May Not Slow Progression

HealthDay – 3 mins 47 secs ago TUESDAY, July 17 (HealthDay News) -- Interferon beta, a widely used treatment for multiple sclerosis, does not stave off the time to disability, new research finds.

However, prior studies have found that interferon beta does reduce MS flare ups, so patients should continue taking it, researchers said.

The new study is published in the July 18 issue of the Journal of the American Medical Association.

In multiple sclerosis, the body's immune system attacks myelin, or the substance that insulates nerve fibers of the central nervous system. The damage disrupts nerve signals traveling to and from the brain, which can lead to numbness, movement difficulties, blurred vision, fatigue and eventually, problems with thinking and memory.

About 85 percent of those with multiple sclerosis start with a relapsing-remitting course, in which attacks are followed by partial or total recovery, according to the National Multiple Sclerosis Society. More than half go on to develop a more progressive form of the disease, in which symptoms worsen over time and there are fewer, shorter periods without symptoms. Over time, the disease can lead to loss of vision and paralysis.

The study included data on nearly 2,700 multiple sclerosis patients from British Columbia, Canada, with relapsing-remitting MS who were followed for four to 11 years. About one-third of the patients were treated with interferon beta after it became available in the early 1990s and one-third were not treated with interferon beta. The researchers also examined data on a third group of MS patients who were diagnosed and followed before interferon beta was a treatment option.

The investigators found no statistically significant difference in how long it took for patients prescribed interferon beta to become disabled, defined as needing a cane to walk 330 feet.

"We were not able to find a significant association between interferon beta exposure and progression to disability," said Helen Tremlett, an associate professor of neurology at the University of British Columbia.

Most patients with multiple sclerosis, though not all, develop severe disability 10 to 20 years after diagnosis, according to background information in an accompanying editorial. Several studies have suggested that interferon beta, by reducing relapses, could also prolong progression to disability, Tremlett said. Still other research has found that brain scans of people taking interferon beta show less damage.

Though the exact mechanism of how interferon beta benefits multiple sclerosis patients isn't fully understood, the drug acts on the immune system and reduces inflammation.

"What the field pretty strongly believed is if you reduced relapse rate, surely that should translate into beneficial impact on disease progression," Tremlett said. "Subsequent studies seem to indicate there is disassociation between relapses and long-term irreversible disease progression."

Interferon beta is typically given by injection when people are first diagnosed.

That shouldn't change as a result of these findings, said Timothy Coetzee, chief research officer for the National MS Society. The new study doesn't negate prior studies that have found that the drugs reduce the frequency of relapses.

"If patients are taking the existing disease-modifying therapies

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