Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Small increases or ’blips’ in HIV levels do not signal mutations leading to drug-resistant HIV

16.02.2005


Researchers at Johns Hopkins have concluded that sudden, temporary spikes in the amount of HIV in the body, commonly called "blips," generally do not mean the virus is developing resistance to AIDS drugs and gaining strength in numbers.



"These results should provide relief to hundreds of thousands of HIV-positive patients in the United States currently taking drug therapy, called highly active anti-retroviral therapy, or HAART, and reassure them that their medications have not failed," says senior study author and infectious disease specialist Robert Siliciano, M.D., Ph.D., a professor at The Johns Hopkins University School of Medicine and a Howard Hughes Medical Institute investigator. "Physicians and patients now have a much better idea of when to worry about these blips and when not to worry."

Because HIV mutates very rapidly, physicians and patients have worried that even small, temporary increases in the amount of virus could indicate the virus had mutated to evade anti-viral drugs being taken.


Instead, the Hopkins team has shown that these so-called blips are mathematical artifacts, or variations, that stem from the test used to gauge the amount of virus in the body, a measurement known as viral load.

According to the Hopkins findings, to be published in the Journal of the American Medical Association online Feb. 16, unless the blip is higher than 200 copies per milliliter of blood, or persists upon repeated testing, it does not signal that the virus has mutated, or changed form.

True drug resistance requires changes in therapy which can be very difficult for the patient, says Siliciano. Different combinations of medications can have toxic side effects, such as lipid abnormalities and diabetes, and can be considerably harder to tolerate than the originally prescribed drug cocktail. Today’s anti-HIV drug treatments quickly suppress the virus to nearly undetectable levels, but blips are a frequent problem. Earlier studies suggested that blips occur in 11 percent to 46 percent of patients, while the Hopkins study, which used intensive sampling, found blips in nine-tenths of patients.

To see whether or when blips mean possible mutation, the Hopkins team conducted a detailed genetic analysis of multiple blood samples from 10 HIV-positive patients, taking samples every two to three days for a period of three months between June 2003 and February 2004. All patients had their infection under long-term control, on HAART, and with viral loads of less than 50 copies per milliliter for at least six months. In total, 36 blood samples were taken from each patient.

Statistical analysis of the results showed that blips occurred in nine of the 10 patients with a median viral load of 79 copies per milliliter. The duration of the blips was typically less than three days, and blips were not related to any demographic factors, such as gender or age, nor to any clinical factors, such as illness, vaccination, or differences in antiretroviral drug regimens.

For every blip, the researchers conducted genetic tests on the samples before, during and shortly after the blip, to uncover any mutations in the virus. Measures of viral load were confirmed by using two independent laboratories to test each sample.

No new mutations were found in an analysis of nearly 1,000 viral clones for mutations in HIV’s two key enzymes which are blocked by drug therapy, protease and reverse transcriptase. The authors also found that blips were not, again, detected when blood samples were assayed twice in independent laboratories.

"The lack of any consistency among the tests performed on blood samples confirms that there is no danger from these blips in viral load," says study lead author and infectious disease specialist Richard Nettles, M.D., an assistant professor at Hopkins. "These blips can be attributed to random statistical artifact inherent in measurements of very low amounts of virus."

Siliciano warns that drug resistance is a growing problem in AIDS therapy, as the virus can mutate faster than medical research can develop new drugs. When HIV becomes resistant to one drug, it may also become resistant to other drugs in the same class. With only four classes of HAART drugs - for a total of 20 drugs - the number of available combinations is limited for people who have developed drug resistance.

David March | EurekAlert!
Further information:
http://www.jhmi.edu

More articles from Health and Medicine:

nachricht Researchers release the brakes on the immune system
18.10.2017 | Rheinische Friedrich-Wilhelms-Universität Bonn

nachricht Norovirus evades immune system by hiding out in rare gut cells
12.10.2017 | University of Pennsylvania School of Medicine

All articles from Health and Medicine >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Neutron star merger directly observed for the first time

University of Maryland researchers contribute to historic detection of gravitational waves and light created by event

On August 17, 2017, at 12:41:04 UTC, scientists made the first direct observation of a merger between two neutron stars--the dense, collapsed cores that remain...

Im Focus: Breaking: the first light from two neutron stars merging

Seven new papers describe the first-ever detection of light from a gravitational wave source. The event, caused by two neutron stars colliding and merging together, was dubbed GW170817 because it sent ripples through space-time that reached Earth on 2017 August 17. Around the world, hundreds of excited astronomers mobilized quickly and were able to observe the event using numerous telescopes, providing a wealth of new data.

Previous detections of gravitational waves have all involved the merger of two black holes, a feat that won the 2017 Nobel Prize in Physics earlier this month....

Im Focus: Smart sensors for efficient processes

Material defects in end products can quickly result in failures in many areas of industry, and have a massive impact on the safe use of their products. This is why, in the field of quality assurance, intelligent, nondestructive sensor systems play a key role. They allow testing components and parts in a rapid and cost-efficient manner without destroying the actual product or changing its surface. Experts from the Fraunhofer IZFP in Saarbrücken will be presenting two exhibits at the Blechexpo in Stuttgart from 7–10 November 2017 that allow fast, reliable, and automated characterization of materials and detection of defects (Hall 5, Booth 5306).

When quality testing uses time-consuming destructive test methods, it can result in enormous costs due to damaging or destroying the products. And given that...

Im Focus: Cold molecules on collision course

Using a new cooling technique MPQ scientists succeed at observing collisions in a dense beam of cold and slow dipolar molecules.

How do chemical reactions proceed at extremely low temperatures? The answer requires the investigation of molecular samples that are cold, dense, and slow at...

Im Focus: Shrinking the proton again!

Scientists from the Max Planck Institute of Quantum Optics, using high precision laser spectroscopy of atomic hydrogen, confirm the surprisingly small value of the proton radius determined from muonic hydrogen.

It was one of the breakthroughs of the year 2010: Laser spectroscopy of muonic hydrogen resulted in a value for the proton charge radius that was significantly...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ASEAN Member States discuss the future role of renewable energy

17.10.2017 | Event News

World Health Summit 2017: International experts set the course for the future of Global Health

10.10.2017 | Event News

Climate Engineering Conference 2017 Opens in Berlin

10.10.2017 | Event News

 
Latest News

Terahertz spectroscopy goes nano

20.10.2017 | Information Technology

Strange but true: Turning a material upside down can sometimes make it softer

20.10.2017 | Materials Sciences

NRL clarifies valley polarization for electronic and optoelectronic technologies

20.10.2017 | Interdisciplinary Research

VideoLinks
B2B-VideoLinks
More VideoLinks >>>