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 One gene closer to regenerative therapy for muscular disorders
01.06.2017 | Cincinnati Children's Hospital Medical Center

nachricht The gut microbiota plays a key role in treatment with classic diabetes medication
01.06.2017 | University of Gothenburg

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: Can we see monkeys from space? Emerging technologies to map biodiversity

An international team of scientists has proposed a new multi-disciplinary approach in which an array of new technologies will allow us to map biodiversity and the risks that wildlife is facing at the scale of whole landscapes. The findings are published in Nature Ecology and Evolution. This international research is led by the Kunming Institute of Zoology from China, University of East Anglia, University of Leicester and the Leibniz Institute for Zoo and Wildlife Research.

Using a combination of satellite and ground data, the team proposes that it is now possible to map biodiversity with an accuracy that has not been previously...

Im Focus: Climate satellite: Tracking methane with robust laser technology

Heatwaves in the Arctic, longer periods of vegetation in Europe, severe floods in West Africa – starting in 2021, scientists want to explore the emissions of the greenhouse gas methane with the German-French satellite MERLIN. This is made possible by a new robust laser system of the Fraunhofer Institute for Laser Technology ILT in Aachen, which achieves unprecedented measurement accuracy.

Methane is primarily the result of the decomposition of organic matter. The gas has a 25 times greater warming potential than carbon dioxide, but is not as...

Im Focus: How protons move through a fuel cell

Hydrogen is regarded as the energy source of the future: It is produced with solar power and can be used to generate heat and electricity in fuel cells. Empa researchers have now succeeded in decoding the movement of hydrogen ions in crystals – a key step towards more efficient energy conversion in the hydrogen industry of tomorrow.

As charge carriers, electrons and ions play the leading role in electrochemical energy storage devices and converters such as batteries and fuel cells. Proton...

Im Focus: A unique data centre for cosmological simulations

Scientists from the Excellence Cluster Universe at the Ludwig-Maximilians-Universität Munich have establised "Cosmowebportal", a unique data centre for cosmological simulations located at the Leibniz Supercomputing Centre (LRZ) of the Bavarian Academy of Sciences. The complete results of a series of large hydrodynamical cosmological simulations are available, with data volumes typically exceeding several hundred terabytes. Scientists worldwide can interactively explore these complex simulations via a web interface and directly access the results.

With current telescopes, scientists can observe our Universe’s galaxies and galaxy clusters and their distribution along an invisible cosmic web. From the...

Im Focus: Scientists develop molecular thermometer for contactless measurement using infrared light

Temperature measurements possible even on the smallest scale / Molecular ruby for use in material sciences, biology, and medicine

Chemists at Johannes Gutenberg University Mainz (JGU) in cooperation with researchers of the German Federal Institute for Materials Research and Testing (BAM)...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Plants are networkers

19.06.2017 | Event News

Digital Survival Training for Executives

13.06.2017 | Event News

Global Learning Council Summit 2017

13.06.2017 | Event News

 
Latest News

Quantum thermometer or optical refrigerator?

23.06.2017 | Physics and Astronomy

A 100-year-old physics problem has been solved at EPFL

23.06.2017 | Physics and Astronomy

Equipping form with function

23.06.2017 | Information Technology

VideoLinks
B2B-VideoLinks
More VideoLinks >>>