published by We The People Living with AIDS/HIV of the Delaware Valley, Inc.
Stronger MAC treatment found by researchers
Scientists say gene protects against HIV
Rightwingers introduce "prevention" act
FDA approves urine test for HIV
Stronger MAC treatment found by researchers
Three teams of researchers from the United States, Canada and Europe say they may have found a better way to treat and prevent, at least temporarily, a bacterial infection that is one of the hallmarks of AIDS.
The ailment, Mycobacterium avium Complex (MAC), is the third most common infection in people with AIDS. One in five people with AIDS will typically develop it.
The findings, from studies that looked at various drug regimens, "are welcome news," said Dr. Robert Horsburgh Jr. of Emory University in Atlanta. All the studies are being published in the New England Journal of Medicine.
In the first study, a group led by Dr. Stephen Shafran of the University of Alberta in Edmonton, Canada, found that a combination of three drugs cleared up the infection in 78 percent of the patients, compared with a cure rate of only 40 percent in patients who got a four-drug combination.
The three drugs were rifabutin sold by Pharmacia & UpJohn under the brand name Mycobutin; ethambutol, also known as Myambutol and sold by Lederle, a unit of American Home Products; and clarithromycin, sold by Abbott Laboratories Inc under various names, including Biaxin and Klaricid.
The four-drug regimen that was far less effective consisted of clofizimine, sold by Ciba-Geigy as Lamprene; ciprofloxacin, sold under the brand name Cipro by Miles Pharmaceutical; rifampin, sold by Marion Merrell Dow under the brand name Rifadin, and ethambutol.
The research is the first time a combination treatment has been found to increase survival in AIDS patients, Horsburgh said in an editorial in the Journal.
In the second study, Dr. Mark Pierce of Vanderbilt University in Nashville and his colleagues in the United States and Europe found that regular use of clarithromycin tablets twice a day lowered the risk of infection from 16 percent, which was the rate among placebo recipients, to 6 percent for volunteers who got the drug.
All of the 667 volunteers in the study, conducted by a team that included four Abbott researchers, were in the advanced stages of AIDS.
The third study, led by Dr. Diane Havlir of the University of California at San Diego, looked at a different drug, azithromycin, and found that only 7.6 percent of the patients who took it once a week developed mycobacterium avium compared with 15.3 percent who took rifabutin.
Combining the drugs worked even better, producing an infection rate of only 2.8 percent. But the abdominal pain, diarrhea and nausea produced by the combination made the two-drug treatment significantly more unpleasant than the azithromycin therapy alone, the researchers said.
With the new findings, Horsburgh said, drug treatment designed to prevent Mycobacterium avium "should be considered the standard of care."
Scientists say gene protects against HIV
In the first discovery that explains why some people are resistant to HIV, researchers have announced that they have found a genetic mutation that prevents HIV infection.
The mutation in the immune system prevents HIV from infecting cells, said scientists at the Aaron Diamond AIDS Research Center in New York.
But, researcher Richard Koup cautioned, "very few people will actually have resistance to sexually transmitted HIV through this mechanism." In fact, he said, preliminary estimates indicate fewer than 1 per cent of Caucasians have the mutation. Estimates for other groups haven't been made.
The existence of people who have been exposed repeatedly to the virus but remain uninfected has puzzled researchers for years. A study of prostitutes in Gambia concluded their immune systems somehow fought off the virus, but the mechanism wasn't clear.
The study by Koup, Nathaniel Landau and others, in the journal Cell, is the first to point to a genetic reason for some people's immunity to the disease. But Koup pointed out the genetic explanation isn't true for all cases of resistance. In fact, of the 25 people studied -- all exposed but uninfected -- only three had the mutation and the Cell paper only reports on two.
"This is the first observation that nails it (resistance) down on the molecular level," said Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases. But Fauci cautioned that the mutation isn't a "free ticket" for those who have it; the virus may have other ways of infecting a cell than the one blocked by the mutation.
And he, like Koup, noted the mutation isn't a complete explanation of why some people fight off the virus.
The three with the mutation were exposed early in the HIV epidemic, Koup said. "These are individuals who watched 40 or 50 of their friends become infected and die, who watched their lovers become infected and die, and never themselves became infected," he said.
The mutation affects a molecule called CKR-5 that has only this year been linked -- by Landau and others at the Aaron Diamond center -- to the ability of the sexually transmitted form of the virus to enter host cells.
The invading HIV particles first attach themselves to cells of the immune system, using a molecule called CD4. Then they enter the cell using the CKR-5 molecule, which serves as an entryway through the cell wall.
The three individuals Koup and Landau studied had a mutation that meant their CKR-5 molecules were too short to go through the wall of the cell, so the invading HIV particles had no entrance.
The CKR-5 molecule usually plays a role in transmitting the signals that govern the immune system. But despite their lack of these molecules, Koup said, the three individuals appeared perfectly healthy -- something that may be good news for others at risk from the disease.
"People don't seem to need these molecules," Koup said. "What that probably means is that we can try to block that molecule -- and thus block the ability of HIV to use the molecule as an entry -- and we shouldn't see any adverse effects."
Koup said blocking the virus out of cells could help people even after they've been infected: Infected cells eventually die naturally and if no new cells were being infected, the level of the virus in the system would fall.
"If you block any new infection," Koup said, "you're going to have an anti-viral effect."
CKR-5 is one of a large class of molecules known as chemokine receptors. Koup said other chemokine receptors may take up the slack when CKR-5 isn't present, accounting for the lack of adverse effects.
At the same time, he said, there have been rare cases where HIV used two other chemokine receptors -- CKR-2B and CKR-3 -- as entries to cells, so that a CKR-5 blocker would not be a sure-fire preventive.
A more-virulent form of HIV, which usually appears later, just before the symptoms of AIDS occur, uses another molecule, called the fusin receptor, to enter cells.
But although the three people in the study had normal fusin receptors, they did not become infected with the late-stage virus either, Koup said, even though in lab tests their cells were easily infected.
Koup said there may be some other protective mechanism at work. Or, he said, it could simply be a result of the fact that the late-stage virus is hard to transmit sexually.
Rightwingers introduce "prevention" act
The HIV Prevention Act of 1996 has been introduced in the U.S. Congress by Rep. Tom Coburn (R-OK), who is also a physician.
The HIV Prevention Act calls for establishing a confidential national HIV reporting system, which would require government agencies to keep a list of all HIV+ people in the nation. The bill also strengthens existing requirements that states to inform individuals that they have been exposed to HIV by a current or past partner.
The Act also mandates HIV testingfor individuals accused of sex offenses. In most states, such testing can only be forced on individuals who have been convicted of an offense.
The bill also claims to protect healthcare professionals and patients from inadvertent exposure to HIV by identifying patients known to be HIV-positive to medical staff. The bill does not explain how medical staff would be protected from individuals whose HIV status is not known -- the overwhelming majority of HIV+ people in the U.S.
Coburn's legislation would also criminalize a variety of sexual activities by people with HIV, or what he calls "irresponsible behaviors by HIV-positive individuals."
Representatives from several conservative social policy groups, including Americans for a Sound AIDS/HIV Policy, the Independent Women's Forum, Women Against Violence, along with New York Assemblywoman Nettie Mayersohn (D), were among those who attended a Washington press conference to announce the bill.
"This legislation will give women the power to avoid becoming infected with this deadly disease," said Barbara Ledeen, executive director of the Independent Women's Forum. "It will also ensure that women who do become infected will be able to take advantage of recent scientific breakthroughs...Unfortunately, most women do not become aware that they are infected with HIV until they begin to show signs of AIDS-related illnesses."
She added that the HIV Prevention Act is a major step forward in fighting the epidemic because it also focuses on collection of surveillance data.
FDA approves urine test for HIV
The Food and Drug Administration has approved the first urine test HIV, which should boost detection of the virus in developing nations and where blood testing is inconvenient.
HIV is usually diagnosed from blood samples.
Calypte Biomedical Corp.'s urine test "makes testing safer, easier and more accessible compared to traditional methods," Darrel Cummings of the Los Angeles Gay and Lesbian Community Services Center, an HIV testing center, said in a statement issued by Calypte.
It "holds particularly important promise for developing countries ... where access to specially trained health professionals and clean needles for drawing blood is not always available," added Dr. Luc Montagnier, a member of Calypte's scientific advisory board.
The new test detects antibodies to HIV-1, the form of the virus which causes the vast majority of U.S. cases of acquired immune deficiency.
Calypte plans to make the test available immediately.
Calypte, a Berkeley, Calif.-based developer of urine-based tests for a variety of sexually transmitted diseases and other illnesses, said the new HIV test will be especially beneficial in settings where blood testing is inconvenient, including prisons and the military.
For that reason, it said it was unsure whether its new test would take business away from the many companies that make blood-based tests.
"The (blood) tests are primarily used to to screen blood that is being donated or being transfused," said Calypte President Jack Davis. "We think our test will be used in different settings."
The company said, however, that the test will also be made available to doctors in public health clinics, hospitals and private practices.
Patients being tested will simply provide a urine sample in a plastic cup.
Davis said he suspected many patients would prefer that means of testing over giving a blood sample. But he acknowledged that the the urine test, while more than 99 percent accurate, was not as reliable as blood tests.
"Blood tests will result in one false positive or one false negative result per thousand people tested," said Davis. "The urine test will yield five to 10 false results per thousand."
He added that the sensitivity of the urine test varied depending on the population being tested but was at least 99 percent accurate in all cases.
The test underwent clinical trials involving 298 people diagnosed with HIV who underwent both Calypte's test and a blood test for HIV, the FDA said.
The FDA said in a statement that if a urine sample tested positive it would be retested and that even a second positive result would have to be confirmed with a blood test.
The agency also said Calypte's test was not approved for screening blood donors for HIV-1.
Like a saliva-based test recently introduced by Oregon-based Epitope Inc., Calypte's urine test works by detecting HIV-fighting antibodies, rather than the virus itself.