Featured Research

from universities, journals, and other organizations

New Study Sheds Light On Reasons For Persistence Of HIV

Date:
October 14, 1998
Source:
Johns Hopkins School Of Public Health
Summary:
In the largest study of its kind, a group of investigators from the Johns Hopkins School of Public Health in Baltimore and Washington University in St. Louis have found distinct patterns of human immunodeficiency virus (HIV) evolution in individuals with different rates of disease progression.

In the largest study of its kind, a group of investigators from the Johns Hopkins School of Public Health in Baltimore and Washington University in St. Louis have found distinct patterns of human immunodeficiency virus (HIV) evolution in individuals with different rates of disease progression. The findings, which appeared in the October 1998 Proceedings of the National Academy of Science, USA, suggested that the course of disease is determined by factors within the infected individual that affect how the virus evolves, and that the level of HIV genetic diversity in a group of infected individuals was predictive of that group's deterioration over the next year. The study also suggested that, when developing ways to combat the virus, scientists must develop means to stimulate the immune system to fight multiple genetic variants of the virus simultaneously.

Related Articles


Lead author Richard B. Markham, associate professor, Molecular Microbiology and Immunology, the Johns Hopkins School of Public Health, said, "In HIV infection, the problem with directly studying the effect of host factors on the course of the disease is that the virus is evolving so rapidly. When you attempt to measure the individual's immune response to the virus, for example, you don't know to which of the many different HIV viruses in the individual he or she might be responding. But instead of viewing that viral variation as a complicating factor, we used the pattern of variation to analyze how the host might be influencing the virus' evolution."

The researchers studied the genetic sequence patterns in over 800 viruses obtained from the study subjects, examining how HIV was evolving in 15 HIV-infected injection drug users at six-month intervals, from the time of seroconversion over a period of up to four years later. Rapid progressors were defined as those subjects whose CD4 T cell levels--a measure of how robust the immune system is--had fallen to fewer than 200 within two years of seroconversion; moderate progressors, as those whose CD4 T cell levels declined to 200-650 by four years; and nonprogressors, as those whose CD4 T cell levels remained above 650 throughout the four-year observation period.

The study found that the HIV virus followed a different pattern of genetic evolution in HIV-infected individuals whose disease was progressing moderately or rapidly compared to those defined as nonprogressors. In the study group as a whole, those individuals in whom the virus showed the greatest genetic diversity were likely to experience significantly greater declines in immune system health over the next year, and thus faster progression of the disease. Although the most prevalent strain of the viruses at a given point in the disease would usually be eliminated over time, those individuals with more rapidly progressive disease were able to eliminate only a small proportion of the diverse range of viruses present in the host. Hence, the viral population continued to become more heterogeneous.

Continuing viral evolution was also observed in individuals with slow or non-progressive disease, but the immune systems of these individuals apparently inhibited the appearance of more diverse strains, a finding that led the investigators to speculate that these slowly progressing individuals were launching a broader immune attack against the virus.

Dr. Markham said, "With current drug therapy, we are able to slow virus growth but not eradicate HIV infection. These studies provide direction to future therapeutic efforts by suggesting that the failure to eliminate the virus results from host defenses that are directed against only a limited portion of the viruses that infect an individual. As we think about how to intervene, one of our goals should be to broaden the range of viruses that are targeted by the host immune response."

This work was supported by the National Institute on Drug Abuse (National Institutes of Health).


Story Source:

The above story is based on materials provided by Johns Hopkins School Of Public Health. Note: Materials may be edited for content and length.


Cite This Page:

Johns Hopkins School Of Public Health. "New Study Sheds Light On Reasons For Persistence Of HIV." ScienceDaily. ScienceDaily, 14 October 1998. <www.sciencedaily.com/releases/1998/10/981014071228.htm>.
Johns Hopkins School Of Public Health. (1998, October 14). New Study Sheds Light On Reasons For Persistence Of HIV. ScienceDaily. Retrieved November 27, 2014 from www.sciencedaily.com/releases/1998/10/981014071228.htm
Johns Hopkins School Of Public Health. "New Study Sheds Light On Reasons For Persistence Of HIV." ScienceDaily. www.sciencedaily.com/releases/1998/10/981014071228.htm (accessed November 27, 2014).

Share This


More From ScienceDaily



More Health & Medicine News

Thursday, November 27, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Ebola Leaves Orphans Alone in Sierra Leone

Ebola Leaves Orphans Alone in Sierra Leone

AFP (Nov. 27, 2014) — The Ebola epidemic sweeping Sierra Leone is having a profound effect on the country's children, many of whom have been left without any family members to support them. Duration: 01:02 Video provided by AFP
Powered by NewsLook.com
Experimental Ebola Vaccine Shows Promise In Human Trial

Experimental Ebola Vaccine Shows Promise In Human Trial

Newsy (Nov. 27, 2014) — A recent test of a prototype Ebola vaccine generated an immune response to the disease in subjects. Video provided by Newsy
Powered by NewsLook.com
Pet Dogs to Be Used in Anti-Ageing Trial

Pet Dogs to Be Used in Anti-Ageing Trial

Reuters - Innovations Video Online (Nov. 26, 2014) — Researchers in the United States are preparing to discover whether a drug commonly used in human organ transplants can extend the lifespan and health quality of pet dogs. Video provided by Reuters
Powered by NewsLook.com
Today's Prostheses Are More Capable Than Ever

Today's Prostheses Are More Capable Than Ever

Newsy (Nov. 26, 2014) — Advances in prosthetics are making replacement body parts stronger and more lifelike than they’ve ever been. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:

Strange & Offbeat Stories

 

Health & Medicine

Mind & Brain

Living & Well

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins