NEW YORK (Reuters Health) - Although highly active antiretroviral therapy (HAART) may fail, some patients retain increases in CD4 cell counts and viral loads remain low because drug resistant viral strains may have less replicative capacity than the wild-type virus, Italian researchers report in the April issue of the Journal of Medical Virology.
Dr. M. Andreoni of the University of Rome “Tor Vergata” and colleagues studied the replicative capacity of HIV strains isolated from 18 HIV patients undergoing genotypic guided change of therapy after failing HAART.
At baseline, both groups had similar plasma levels of HIV and CD4 cells.
Twelve patients were classified as responders if they achieved a CD4 count of more than 100 cells per microliter compared with baseline levels. The remaining 6 patients were classified as treatment failures after experiencing no immune recovery.
One year after changing therapy, all subjects showed decreases in the replication capacity of HIV strains. The replicative capacity of HIV strains in the responder group fell from 46.8% to 3.6%. In the nonresponders, the corresponding drop was from 60% to 26.4%.
An increase in the number of drug resistant mutations in the protease gene was seen in both groups. Moreover, the replicative capacity of three of four HIV strains with the M184V mutation, isolated from responders, was less than 1% of that of the wild type.
Among implications of these findings, is that “patients experiencing treatment failure may opt to continue the failing therapy if the virus has low-replication capacity and there are few treatment options available,” the researchers conclude.
Source: J Med Virol 2004;72:511-516. [ Google search on this article ]
MeSH Headings:Biochemical Phenomena: Biochemical Phenomena, Metabolism, and Nutrition: Biological Phenomena: Biological Phenomena, Cell Phenomena, and Immunity: Drug Therapy: Drug Therapy, Combination: Microbiologic Phenomena: Therapeutics: Virus Replication: Viral Physiology: CD4 Lymphocyte Count: Anti-HIV Agents: Analytical, Diagnostic and Therapeutic Techniques and Equipment: Biological SciencesCopyright © 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.
