In the world there is a very small group of people who is immune to the HIV virus that causes AIDS . For years, scientists have attempted to replicate this natural resistance.

Now researchers at the University of Pennsylvania, in the United States, managed to genetically engineer the immune cells of 12 patients with HIV to make them resistant to the virus.

Using a relatively new techniques, scientists edited the genome of the cells in the immune system and removed a protein that makes most people susceptible to the virus.

To do this, patients who participated in the research published in the New England Journal of Medicine white blood cells extracted, became resistant to HIV and injected them again.

The technique called for zinc finger nucleases (ZFN) which were used to “edit ” the structure of lymphocytes in white blood cells. The main goal was to see how these cells behaved in the presence of the HIV virus.

The result was that they survived longer than those who were not modified, preventing the virus from replicating.

12 patients , 12 weeks

For the study, the researchers used two groups of patients, who were treated with a single infusion of modified cells. Six of them were withdrawn from medication at four weeks of being injected with the infusion and left them without ARVs for the next 12 weeks.

The other 12 individuals continued drug therapy .

In the patients who withdrew antiretrovirals, the number of cells that were not protected significantly decreased, while the modified cells survived longer. They could even be detected in the blood several months after the trial.

It is hypothesized that by keeping these cells in the body, the immune system improves and the patient can control the HIV virus.

The test was designed to test the safety and feasibility of the method.

This is a step towards finding strategies that do not require antiretroviral therapy for a functional cure for HIV infection .In other words, that patients are can be healthy without taking HIV medicines .

The Berlin Patient

It is estimated that 1% of the world population is resistant to HIV, and science tries to replicate this natural immunity to treatments.

The first person to recover from HIV worldwide was Timothy Ray Brown in 2007 , who was left without an immune system during treatment for leukemia after he underwent a bone marrow transplant from a donor with natural mutation resistant virus .

Researchers in Pennsylvania are trying to adapt the immune system of patients to have the defense that the donor gave Ray Brown.

The ultimate goal is to control the AIDS virus without having to administer medication.

This treatment, although it may be long term, is not forever. Cells die and scientists would have to re- inject a modified infusion into the patient to maintain virus -resistant cells .

This will not be permanent until stem cells can be genetically modified so that all the progeny of these cells lack the protein to prevent HIV.

For this research the mature lymphocytes were modified .

This is the first time a study in which the ZFN technology is applied in humans is published .