Prospects for the Eradication or Long-Term Control of HIV Infection

  • Prospects for the Eradication or Long-Term Control of HIV Infection (MoOr103)
    Authored by Robert Siliciano
    Non-abstract driven session

Dr. Siliciano put another nail in the coffin of HIV eradication. He clearly stated that with the currently available agents it will not be possible to eradicate HIV from the reservoirs where it hides, even if no new reservoirs are found.

He did not present new data, and his presentation was similar to his previous ones at different conferences stating the same issue. However this time he did it in front of a massive audience at the Palau Sant Jordi, where the plenary sessions of this very large meeting took place. It was a somber way to start the meeting, basically highlighting for us the difficulties involved in dealing with HIV.

His studies, as well as several others over the past few years, have demonstrated that HIV can be cultured from lymphocytes obtained from patients whose viral load has been maximally suppressed for several years. HIV integrates in CD4+ memory T cells, in what appears to be true "latency." If the selective pressure of the drugs is removed, the virus again replicates rather quickly. Siliciano has calculated that the half life of this compartment is quite long (in fact, that is the mission of this type of CD4+ cells) and the estimated time to eradication could be several decades, assuming that antiretroviral therapy is successful in totally suppressing viral replication, and that no other, even longer-lived "reservoirs" exist. Also, we know now that this reservoir tends to replenish from the division of memory cells and not from viral replication, which makes eradication even less likely.

He also explained that the reservoir of CD4+ memory cells serves as an archive of all the antiretroviral resistance among the different quasi-species that the patient harbors, and that even if current resistance testing is not able to detect those viruses, they tend to arise very quickly after therapy is restarted.

Dr. Siliciano's last words were optimistic and he said that eradication might not be necessary to control this disease, and that it might be possible to control viral replication in the absence of antiretroviral therapy by boosting the immune system.

In summary, a nice presentation, as usual, without a lot of new information.