Is a cure for HIV possible?

To date, only a single patient has been cured.  This unusual case involved a patient with HIV infection who was doing well on antiretroviral therapy.  He developed leukemia and was given a bone marrow transplant from a carefully selected donor who has a mutation that made his cells genetically resistant to HIV infection.  The transplant process resulted in elimination of the leukemic cells and replacement of the recipient's immune system (including HIV infected cells) with uninfected, HIV resistant immune cells from the donor.  Thus, the patient was cured of both leukemia and HIV infection.  Unfortunately, this does not represent a general approach to curing HIV infection.  Bone marrow transplantation has a high mortality rate and can only be done if the patient needs it as treatment for an otherwise fatal disease like leukemia.  Although we do not yet have a general cure for HIV infection, the treatment is very good.  Antiretroviral therapy can completely stop the virus from replicating and damaging the immune system.  Modern antiretroviral therapy consists of one pill, taken once a day, with minimal side effects.  Patients starting modern antiretroviral therapy have near normal life expectancy.  Although antiretroviral therapy can stop the virus from replicating, it is not curative.  As soon as patients stop taking antiretroviral therapy, viral replication resumes.  This reflects the fact that HIV can establish latent infection in a small number of long lived memory T cells.  In these cells, the viral genetic information is stably integrated in the host cell DNA, but it is not being actively expressed.  Thus, latently infected cells are not seen by the immune system and are not affected by antiretroviral drugs.  Every day, a few of these latently infected cells become activated and begin to produce virus.  If the patient has stopped antiretroviral therapy, the virus can begin to grow.  Thus, this latent reservoir is the major barrier to curing HIV infection.  It  is currently the target of an intense international research effort.  In summary, the infection cannot currently be cured.  Antiviral drugs are remarkably effective at stopping the virus from replicating and damaging the immune system, but they do not eliminate the latent form.  Interestingly, Hepatitis C infection can now be cured by antiviral drugs that are similar to those used to treat HIV infection.  The big difference is that hepatitis C has no latent form.  If scientists can find a way to eliminate latent HIV, HIV infection will be cured.