immune based therapies (IMMUNE BASED THERAPIES, 2011)
Happy New Year Dr. Bob,
Quick question: what are immune based therapies?
Many thanks for your wit and wisdom,
Crixus? Interesting name. It's also the name of a hunky lead gladiator in the "Spartacus: Blood and Sand" television series. But I digress . . . .
Briefly put, immune-based therapies are treatments that utilize the immune system in some creative way to flight HIV. Over recent years we learned that HIV cannot be cured by just driving the HIV plasma viral load to undetectable levels and keeping it there with effective combination antiretroviral therapy (ART). HIV is a clever virus that actually inserts its DNA into certain types of human cells where the viral DNA can rest quietly essentially forever and where it is out of reach of antiretroviral therapy. If antiretroviral therapy is stopped or interrupted for any reason, these HIV-infected resting cells wake up and begin frantically producing new virus particles. Our current antiretroviral medications only work on replicating virus. They have no effect on viral DNA that's hiding out in resting CD4 cells. One immune-based therapy involves activating all the resting CD4 cells to wake up the snoozing virus, so it begins reproducing (replicating), which then would allow ART to attack and knock out the infected cells! This has been tried with interleukin-2 and with valproic acid. Unfortunately there are several problems with this seemingly nifty plan. First, you would need to activate every single resting CD4 cell in the entire body. If you missed even a few, you'd still have a reservoir, which could and would replicate like mad as soon as ART was stopped and you'd be right back where you started. The second problem is that CD4 cells aren't the only reservoirs for resting HIV and the current immune-based therapies only wake up CD4 cells.
Another type of immune-based therapy is therapeutic vaccines. This approach tries to stimulate the immune system to more effectively battle HIV. This might delay the need for ART or perhaps even produce a "functional" cure whereby a vaccinated HIV-positive individual could effectively control his HIV infection without ever needing additional treatment such as ART. Immune-based therapies are certainly not ready for prime time yet, but research into these and other immune-based approaches is heating up. So stay tuned!