NEW YORK (Reuters Health) - There are new data suggesting that superinfection with a new strain of HIV in a chronically infected individual can lead to genetic recombination, investigators report.
Until this report, it was unclear whether viral recombination could arise only during primary infection or if it can result from superinfection in an untreated, chronically infected individual. But in the study, intersubtype recombination took place between an original strain and a superinfecting strain.
This finding may help to explain the increasing global prevalence of recombinant HIV, senior author Dr. Harold Burger and his associates write in the January 23rd issue of AIDS. It also identifies challenges in eliciting the broad immune responses necessary for an effective vaccine, they add.
Dr. Burger’s group sequenced plasma HIV RNA from seven subjects in a Nairobi female sex worker cohort who had survived infection for more than 10 years. None had received antiretroviral treatment.
One subject had evidence of recombination and superinfection. Initially diagnosed in 1985 and followed approximately twice each year, she developed a first acute febrile illness in 1992. Her CD4 count had dropped from 796 million cells/liter a year earlier to 136 million cells/liter. It soon fell below 100 million cell/liter, remaining low until her death in 1998.
The authors explain that their RNA analyses used “complete viral genomic sequencing, computational and phylogenetic analyses including SimPlots, and heteroduplex tracking assays, a highly sensitive technique to detect minor species.”
Gene sequencing in 1986 showed she was entirely infected with subtype A. In 1995 and 1997, similar testing showed subtype A/C recombinants. The subtype A fragment in 1995 and 1997 was derived from the original 1986 A sequence, the authors report.
The researchers point out that they were unable to detect the nonrecombinant subtype C virus. So, “although our data are highly suggestive of superinfection, ultimate proof of superinfection, as opposed to dual infection, has not been obtained in this or any of the previous reports.”
Source: AIDS 2004;18:153-159. [ Google search on this article ]
MeSH Headings:Genetic Techniques: Investigative Techniques: Sequence Analysis: Sequence Analysis, RNA: Analytical, Diagnostic and Therapeutic Techniques and EquipmentCopyright © 2002 Reuters Limited. All rights reserved. Republication or redistribution of Reuters content, including by framing or similar means, is expressly prohibited without the prior written consent of Reuters. Reuters shall not be liable for any errors or delays in the content, or for any actions taken in reliance thereon. Reuters and the Reuters sphere logo are registered trademarks and trademarks of the Reuters group of companies around the world.
