A first attempt was made to cure the Severe Immunodeficiency Syndrome in newborns, disease caused by the absence of the enzyme adenosine deaminase, which causes failures in the immune response, leading to death.
The gene coding for this enzyme has been successfully cloned and injected into leukocytes taken from affected children. Then these white cells were reinjected into the children's organism. The results are encouraging, however, bumping into one particularity - white blood cells have short life and for this reason gene therapy needs to be constantly repeated.
Gene therapy is one of the hopes of scientists in terms of cure and / or treatment for AIDS, a disease that, like the one mentioned above, affects the immune system of affected patients.
An example of success
American scientists say they are closer to curing color blindness using gene therapy, according to a study in the journal Nature (09/2009).
The University of Washington and Florida team was able to repair the ability to perceive color in adult scent monkeys (Saimiri sciureus).
The species is already born without the ability to distinguish between red and green because total vision depends on two versions of a gene called opsin, loaded on the X chromosome - one version brings the red-sensitive photoreceptor and the other green. Because male monkeys are born with only one X chromosome, they are colorblind and unable to distinguish between the two colors.
The team led by Professor Jay Neitz was able to introduce the human opsin gene which detects the red color in the light receptor cells behind the cornea of adult monkeys.
To test the effectiveness of gene therapy, scientists tested the Dalton and Sam monkeys. During the test, the animals had to identify colors in computerized images and received a prize - a glass of juice - when they got it right.
Results indicate that the treatment was successful. The monkeys that underwent the process had the necessary photopigments to see all the colors and were able to distinguish green and red.
According to Neitz, the improvements made by treatment two years ago remain stable, but scientists will continue to monitor the effects of treatment to assess the long-term impact.
Although further studies are still needed, Neitz believes the results offer a positive perspective that the same treatment may be applied to colorblind humans. Until now, scientists have believed that it would not be possible to manipulate the adult brain in this way.
It was believed that adding visual receptors needed for perfect vision could be done only in the early years when the brain is still considered more malleable.
Winfried Amoaku, an ophthalmologist at the University of Nottingham in England, believes the research could eventually benefit about 7% of men and 1% of women born with color deficiency in color visualization.
The research appears to be the first in primates to study visual color deficiency and indicates that it is possible to modify cells in their perception of color, "he said.
"More research is needed, however, before human trials and clinical treatments are started," he warned.