AIDS/HIV
Protein identified that turns off HIV-fighting T cells
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In HIV-infected patients the body’s immune system is unable to fight off the virus. A new study to be published online on November 10th in the Journal of Experimental Medicine shows that T cells in HIV-infected individuals express a protein called TIM-3, which inactivates their virus killing capacity. Blocking this protein, the study suggests, might one day help patients to eliminate HIV as well as other chronic infections.
Large numbers of virus-fighting T cells can be found in the blood of most chronically infected HIV patients. However these cells eventually become exhausted and cannot function. To identify the cause of this exhaustion, a team of researchers at the University of Toronto, lead by Mario Ostrowski, compared blood from healthy individuals and HIV patients. In the patients, TIM-3 was found on a large number of HIV-specific T cells, and the number of TIM-3-positive cells increased with the severity of infection.
Under normal circumstances, exposing T cells to bits of virus causes the cells to replicate and produce virus-killing chemicals. Cells expressing TIM-3, however, were unreactive and TIM-3 was to blame; disrupting its signals restored the cells’ virus-fighting functions.
Study examines repeated exposure to HIV in treatment-suppressed HIV patients
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A new study looking at unprotected intercourse within gay couples when each partner has established HIV-infection found a correlation between anti-HIV immune response and sexual activity.
Study results showed that individuals who had regular unprotected receptive anal intercourse with partners with significant levels of HIV in their blood showed a stronger anti-HIV immune response. In addition, the magnitude of anti-HIV specific immune response correlated with their exposure to HIV through sex.
Published in the October 24th, 2008 issue of PLoS Pathogens, the study paper is authored by a research team from UCSF and the Gladstone Institute for Virology and Immunology.
Markers of inflammation and blood-clotting tied to hazards of intermittent HIV treatment
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Episodic treatment of HIV/AIDS with antiretroviral drugs increases the overall risk of death when compared with continuous antiretroviral treatment (ART), but the reasons why have been unknown. Now, researchers have found that higher levels of certain markers of inflammation and blood-clotting are strongly associated with intermittent ART and with a higher risk of death from non-AIDS diseases.
The new report, published in the open access journal PLoS Medicine, is a further analysis of the “Strategies for Management of Antiretroviral Therapy” (SMART) study supported by the National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health.
SMART, which ended in 2006, compared the standard practice of continuous ART to suppress HIV in infected individuals with episodic ART based on CD4+ T-cell counts. The goal was to determine whether reducing exposure to antiretroviral drugs, which may have toxic side effects and can engender drug resistance, would be equally or more beneficial than suppressing HIV continuously. Unexpectedly, those who received episodic ART were more than twice as likely to develop disease or die, and the study ended early as a result.
What HIV Needs: Identification of Human Factors May Yield Novel Therapeutic Targets for HIV
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The Salk Institute for Biological Studies and Burnham Institute for Medical Research today announced 295 host cell factors that are involved in human immunodeficiency virus (HIV) infection. The study, published in the Oct. 3 issue of Cell, could lead to the development of a new class of HIV therapeutics aimed at disrupting the human-HIV interactions that lead to viral infection.
The research, a collaborative effort between the laboratories of Sumit K. Chanda, Ph.D, previously at the Genomics Institute of the Novartis Research Foundation (GNF) and now at Burnham and John Young, Ph.D. at Salk, combined several layers of genome-wide analysis to identify cellular proteins that aid the virus in establishing an infection.
“HIV has just nine genes, coding for 15 proteins, compared to bacteria, which harbor several thousand genes, or humans, with over 20,000 genes,” said Chanda, associate professor in the Infectious & Inflammatory Disease Center at Burnham and an adjunct faculty member at Salk. “We have known for a long time that HIV hijacks our cellular proteins to complete its life cycle. This study now lays out its flight plan.”
HIV Status Unknown for Most “Negative” Men Online
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Seventeen percent of HIV-positive men who have sex with men (MSM) and nearly three quarters of MSM who’ve never been tested for HIV say they are HIV negative in their online profiles, according to a study published in the September issue of the Journal of Urban Health.
The popularity of sex and dating websites for MSM ballooned quickly during the past decade and a half. Relatively little research, however, has been published on how MSM use the Internet to find sex partners and how it influences communication and choices about safer sex. To investigate the online communication and behavior of MSM, Keith Horvath, PhD, and his colleagues from the University of Minnesota recruited men through banner advertisements on a popular gay sex and dating website, which was not named in the journal article.
The advertisements attracted 15,425 people, of whom 7,547 were screened for eligibility and 2,716 completed a thorough survey. Sixty-one percent of the respondents were younger than 30 and only 12 percent were 40 or older. Twenty-five percent described themselves as Latino, 15 percent as black, 19 percent as Asian and 27 percent as white. Twenty percent lived in small towns or rural areas, 49 percent in medium-sized cities or suburbs, and 31 percent in urban areas. A quarter of the men said they had only one online profile, 20 percent said they had four or more profiles, and 16 percent said they had no online profiles.
A Young Woman’s Battle With HIV
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When Tennessee native Marvelyn Brown was diagnosed with HIV at age 19, she didn’t realize that HIV could be transmitted through heterosexual contact. She was hospitalized with pneumonia, and doctors discovered she had HIV during a battery of tests, a mere three weeks after she had been infected. By writing her new autobiography, The Naked Truth: Young, Beautiful, and (HIV) Positive, the now 24-year-old says she tries to raise awareness among young people of HIV/AIDS and how it’s transmitted.
Since her diagnosis, Brown has toured the country providing HIV education and has appeared on the Oprah Winfrey Show and America’s Next Top Model. On her blog, she says that she persists in promoting HIV awareness despite all the flak she takes from people who believe she is “glamorizing” HIV/AIDS. “I contracted a 100% PREVENTABLE disease, people, which…is my message, not how glamorous I look doing it,” she wrote in a recent blog posting. “Bottom line, HIV sucks, I swear.”
A former high school track and basketball player, Brown worked and partied hard after high school, she says, but didn’t consider herself to be in a high-risk group for HIV.
WHO publishes how-to guide on fighting AIDS
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What is the best way to set up an AIDS testing clinic? Which are the best drugs to give to people infected with HIV? The World Health Organization released a one-stop guidebook on Tuesday to help low- and middle-income countries seeking to battle the pandemic.
It includes advice on distributing condoms, guidance on counseling and lists of the available tests for diagnosing HIV.
“This document responds to a long-standing country need,” WHO’s HIV/AIDS Department Director, Dr. Kevin De Cock, said in a statement.
African ex-leaders to press politicians over AIDS
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Former leaders of African countries ravaged by AIDS are launching a regional campaign to put pressure on politicians who they say have not done enough to combat the virus.
Former presidents of Botswana, Mozambique, Tanzania and Zambia and other well-known figures, including South Africa’s Archbishop Desmond Tutu, are demanding more government action and public education campaigns to prevent new infections in countries where up to one in four people have AIDS.
“The fact that we are prominent individuals from all parts of Africa, if we strongly disagree with someone I think we can mobilize shame against that person,” former Botswanan President Festus Mogae told Reuters in an interview.
Mexicans in U.S. illegally at more risk of AIDS
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Mexican men living and working illegally in the United States are more likely to sell their bodies for sex, take drugs or frequent prostitutes than they would have in their homeland, increasing their risk of HIV infection, U.S. researchers reported on Wednesday.
And if they are deported, they can take the virus back home with them, the researchers told an international conference on AIDS in Mexico City.
“They are in a new environment, they are discriminated against, they are living in harsh conditions, sometimes just in boxes covered in plastic near the farms where they work,” said George Lemp of the California HIV/AIDS Research Program at the University of California, who studied 458 Mexicans before and after they left their homeland.
Government to release revised U.S. HIV estimates
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The U.S. Centers for Disease Control and Prevention said on Tuesday it will soon release long-awaited revised estimates of how many Americans become infected with the AIDS virus every year.
Activists have been saying the numbers are sharply higher and have been urging the CDC to release the numbers.
In June, Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, said he believed the numbers had risen from 40,000 to 50,000 a year, although the CDC denied he had seen the new estimates.
U.S. drops trial of one AIDS vaccine
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U.S. AIDS researchers are dropping plans to test one experimental vaccine in people, saying the high-profile failure of a Merck and Co. vaccine last year shows the need to do quicker, more focused studies.
The National Institute of Allergy and Infectious Diseases, part of the government’s National Institutes of Health, said on Thursday it was canceling the HIV vaccine study known as PAVE 100.
“However, NIAID believes the vaccine developed by its Vaccine Research Center (VRC) is scientifically intriguing and sufficiently different from previously tested HIV vaccines to consider testing it in a smaller, more focused clinical study,” the institute said in a statement.
Genetic Variation Raises HIV Risk in People of African Descent
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A genetic variation that may have protected people of African descent against a pandemic of malaria long ago now appears to increase their susceptibility to HIV infection, a report published this week shows.
The variation, described in the journal Cell Host & Microbe, is one of the first genetic risk factors for HIV to be identified only in those of African descent, and puts a spotlight on the differences in our genetic makeup that play a critical role in susceptibility to HIV-AIDS.
In a population of 1,266 HIV-positive U.S. military personnel and 2,000 non-infected healthy personnel, researchers studied the gene that expresses Duffy antigen receptor. This molecule on the surface of red blood cells serves as the docking site for the malaria species Plasmodium vivax.
Gene variant common in Africa increase HIV risk
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A gene variant that emerged thousands of years ago to protect Africans from malaria may raise their vulnerability to HIV infection but help them live longer once infected, researchers said on Wednesday.
The findings could help explain why AIDS has hit Africa harder than all other parts of the world.
People with the version of the gene have a 40 percent higher risk of becoming infected with the human immunodeficiency virus, or HIV, researchers in the United States and Britain wrote in the journal Cell Host & Microbe.
HIV screening not just for the young
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Screening for HIV infection in people older than 55 years of age is likely to be worthwhile in terms of the cost of screening balanced against the potential savings in heath care costs and the gain in years of life, according to a report in the Annals of Internal Medicine.
Recent guidelines by the U.S Centers for Disease Control and Prevention recommend screening for HIV infection in everyone between 13 and 64 years of age. Whether screening is cost-effective for people in the 55-to-75 age range, however, was unclear.
The cost and benefits of screening depend on the total expense of testing and counseling, the amount of disease in the community and how likely any given person is to be infected, and the potential benefits when the disease is caught early.
HIV drives children’s pneumonia in sub-Saharan Africa
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Pneumonia in HIV-positive children is proving to be a challenge across sub-Saharan Africa. Claire Keeton reports from Cape Town.
Nokhwezi Hoboyi knows about the devastation of pneumonia after losing her first two babies to the disease.
The 27-year-old mother from Cape Town saw her first child die of pneumonia at four months of age. Her second child started coughing at two months and was diagnosed with pneumonia. She was hospitalized, became ill at three months and did not respond to antibiotics.
