HIV infection can be treated but not cured. So far there have been two exceptions to this rule: the so-called “Berlin patient” and the “London patient”. In both cases, healing from HIV was a side effect of successful cancer treatment. The patients had received a stem cell transplant with cells that are insensitive to the HI virus. A third case of a cure from HIV has now been presented at a conference in Denver. The “New York patient” also suffered from an aggressive blood cancer.
The special thing about this patient: the doctors gave her cells that are insensitive to HIV. The virus cannot get into the cells because a structure important for the virus, the so-called ccr5 co-receptor, has changed on the surface of the cells. Figuratively speaking, the doorknob on the door through which the virus normally enters the cell has been removed.
What is new is that this time the patient received stem cells from umbilical cord blood. Normally, stem cells have to be selected very carefully: the tissue characteristics of the stem cell donor and recipient must be very similar. There is more leeway with stem cells from donor umbilical cord blood. The cells don’t have to match up so strictly. The disadvantage: Stem cells from umbilical cord blood still have to mature into blood stem cells in the body. It takes longer for them to build up the new immune system. Patients are longer susceptible to other pathogens. To bridge this time, the New York patient also received a blood stem cell transplant from a close relative.
And stem cell therapy is no guarantee of an HIV cure. Nevertheless, some patients had to take AIDS medication again after a certain time because the body could not eliminate the virus on its own. Experts say: For HIV-positive people without cancer, this treatment is far too risky. There are proven and safe alternatives – the effective HIV drugs. They guarantee a good life and a life expectancy that corresponds to that of people without HIV.
One aspect of the therapy can be used to develop less risky healing methods to weatherproof the immune system. That means instead of transplanting foreign stem cells, gradually making the own immune cells of HIV patients insensitive to HIV. By modifying immune cells or stem cells from the bone marrow – i.e. using the CRISPR-Cas method, for example, to dismantle the molecular door handle that the HI virus needs. Then you return the cells. And because they are protected against HIV, they will prevail in the long term. At least that’s the concept. Whether it is realistic and safe is currently being researched.