A gene therapy for children-bubbles tested in the United States

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In the United States, gene therapy has been tested in eight children with severe immunodeficiency. The treatment restored immunity in these young patients who could not benefit from a bone marrow transplant.

Severe combined immunodeficiency associated with X, or X-SCID, is a genetic disease characterized by the possibility of their transmission to the offspring of the affected individual (vertical transmission).
There are monogenic diseases, that is to say, which are associated with dysfunction … "data-url =" / sante / definitions / medicine-disease-genetics-5117 / "data-more =" Read more " >genetic disease rare and serious in which the immune cells that are supposed to fight infections do not develop or function properly. As a result, the patient develops severe respiratory infections. According to the website of Genethonthis disease affects one in 200,000 births.

The disease that manifests itself in the first months of life is often fatal in the first two years. One treatment option is to perform a graft of bone marrow a compatible donor, such as a brother or sister. But, many patients do not have a compatible donor in their environment. For them, the genetical therapy can therefore represent a hope.

This new experimental treatment was developed by NIH scientists (National Institutes of Health). To restore the immune system young patients, scientists have come up with a genetical therapy with a normal copy of The nucleus of the cell is "…" data-url = "/ health / definitions / genetics-gene-151 /" data-more = "Read more">gene IL2R. The eight children of theclinical test, aged between 2 and 14 months, did not have a sibling compatible with a transplant stem cells.

First, researchers retrieved blood stem cells in the bone marrow of patients. Then, they used a lentivirus harmless as a vector to bring cells the right version of the gene IL2R. Lentiviruses are virus at RNA structure
RNA is a molecule consisting of a sequence of ribonucleotides (adenine, cytosine, guanine, uracil) linked together … "data-image =" https://fr.cdn.v5.futura-sciences.com/ buildsv6 / images / midioriginal / f / 6 / a / f6aa50645c_50034152_arnt-yikrazuul-cc.jpg "data-url =" / health / definitions / genetics-arn-97 / "data-more =" Read more ">RNA whose most famous is the HIV. Then the cells were given back to patients who also received a small dose of chemotherapy (busulfan) to help the modified stem cells toimplant and to produce blood cells. The children were followed for one duration median of 16 months.

Gene therapy corrects the immune system

After three to four months, seven of the eight children had normal levels of lymphocyte
Lymphocytes are part of the family of leukocytes (white blood cells). They take the appearance of small round cells (about 7 micrometers in diameter) and have a nucleus. We have them … "data-image =" https://www.cdn.v5.futura-sciences.com/buildsv6/images/midioriginal/b/6/0/b60ee437ba_50034172_lymphocyte-triche-nci.jpg "data-url = "/ health / definitions / medecine-lymphocyte-187 /" data-more = "Read more">lymphocytes T, B and NK cells (natural killer). In the eighth child, T cell levels were initially low, but their numbers increased significantly after a second injection of modified stem cells.

Viral and bacterial infections that children had before therapy have dissipated. The children seemed to be growing normally. Some patients have had side effects, with a level of platelets low, but overall the technique seemed safe. These results appear in the journal New England Journal of Medicine.

According to the NIH press releasethis treatment would be safer and more effective than other gene therapies already tested against this disease, which used other vectors and other chemotherapies. In particular, these old therapies failed to restore all immune cells such as B cells, the cells that produce the structure of an antibody
An antibody is a protein complex. If every body with an immune system codes for billions of different antibodies, they all have the same overall characteristics. These are … "data-image =" https://www.cdn.v5.futura-sciences.com/buildsv6/images/midioriginal/a/5/4/a543c37e56_50034150_antibody-yohan-gfld.jpg "data-url = "/ health / definitions / medecine-antibodies-93 /" data-more = "Read more">antibody. Here, four children were able to stop infusions intravenous antibody; three of them responded well to the principles of the vaccine
It involves injecting into the body an infectious agent (virus or bacteria), in a harmless form but stimulating the immune response of the body. The immune system has … "data-image =" https://www.cdn.v5.futura-sciences.com/buildsv6/images/midioriginal/d/7/7/d77c1cf78f_50038307_pasteur-joseph-meister.jpg "data -url = "/ health / definitions / medicine-vaccination-11858 /" data-more = "Read more">vaccinations. Finally, in other gene therapies, there could be a risk of leukemia because of the vector used, which does not seem to be the case with lentivirus.

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Gene therapy could be an effective treatment option for infants with this extremely serious condition

For Anthony S. Fauci, director of the National Institute of Causes of … "data-image =" https://www.cdn.v5.futura-sciences.com/buildsv6/images/midioriginal/9/1/ 2 / 9122e6917c_88466_shutterstock-piotr-marcinski.jpg "data-url =" / health / definitions / medecine-allergy-2956 / "data-more =" Read more ">allergies and infectious diseases (Niaid) of the NIH, "These exciting new findings suggest that gene therapy may be an effective treatment option for infants with this condition. disease extremely serious, especially those who do not have an optimal donor for stem cell transplantation. This breakthrough offers them the hope of developing a fully functional immune system and the chance to lead a healthy and full life. "

What you must remember

  • Eight babies were treated with gene therapy for severe immunodeficiency.
  • Their genetic disease is linked to a deficiency of an X chromosome gene.
  • The normal gene was provided to blood stem cells by a lentivirus.
  • Lymphocyte levels have improved in patients.

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