Is 3-DCR HIV NYC A Recombinant?
Recombinomics Commentary
February 14, 2005
>> The test results indicate that the virus uses a receptor that has been linked to accelerated immune destruction and rapid progression to clinical AIDS. Viruses with significant resistance often replicate less well than wild-type viruses. In this case however, the ViroLogic Replication Capacity (RC) assay indicated that virus replication was comparable to most wild-type strains. Replication Capacity is the focus of intensive study at ViroLogic and preliminary data indicate that viruses with high RC values are associated with more rapid immunosuppression……….
"This episode serves as a sobering reminder of the potential danger of transmitted resistant viruses," said David D. Ho, M.D., Scientific Director and Chief Executive Officer of ADARC in New York and a Professor at The Rockefeller University. "This is an interesting case because it has features that we often see, although not typically in the same virus. While we see triple-class resistance fairly commonly in patients with a long history of antiretroviral drug experience, this case is noteworthy in that a single virus harbors triple-class resistance, a high RC, and CXCR4 receptor tropism in the setting of recent infection. <<
The above detail clearly point toward a novel HIV rather than an immuno-compromised host in the DCR NYC case cluster. The 3-DCR profile along with a wild type replication capacity is further reason for obtaining a full sequence. Analysis will reveal if the virus in question is a recombinant, combining two well characterized biological properties to generate a novel virus with increased virulence and transmissibility, combined with drug resistance.
The presence of this unique set of properties in a single virus should speed up analysis of the significance of the NYC cluster. The key assays are commercially available, so screening of suspect virus should allow rapid determination of the worldwide distribution of this novel strain. Tracing will help define how successful containment might be, and also identify treatment options, although treating with one drug is unlikely to provide a long term solution.
The identification of a second case in San Diego is not a good indicator, unless there is some linkage between the patient in California and one or both patients in NYC. However, since initial comments indicated the viruses were similar, as opposed to almost identical, the chance that this virus is spreading well beyond the three cases being investigated is high.
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