P2 is only 18 years old and has received monthly blood transfusions since he was 3 years old, due to the disease beta thalassemia. But for the past 21 months, he hasn't needed them. An international team of scientists succeeded in partially correcting the genetic defect, allowing him independence. This is a major victory for gene therapy, the act of editing faulty genes inside living cells in order to treat disease.

A new study published in the journal Nature On September 16, 2010, brought the story of patient P2's gene therapy from beta-thalassemia disease. Beta thalassemia is a recessive genetic disease, which means that you have to inherit two defective copies of the disease, one from each parent, in order for it to be manifested. In this disease the red blood cells are formed with defective hemoglobin. Hemoglobin is a protein found inside the red blood cells and it allows them to carry oxygen from the lungs to the rest of the body. Hemoglobin consists of two subunits, alpha globin and beta globin, which are produced by different genes. In beta thalassemia, the production of beta globin is affected. Patients with beta thalassemia suffer from acute and life-threatening anemia because they do not produce enough normal red blood cells. The only way to keep them alive is multiple blood transfusions, because the red blood cells live only three months. The only current cure is a bone marrow stem cell transplant from a relative. This option is not always available, and even when it is available it is dangerous and does not guarantee success.
Marina Cavazzana-Calvo and Emmanuel Payen chose a different approach. They tried to directly correct the problematic genes behind the disease. Working with a large international team, they took some stem cells from the bone marrow (where the blood cells are made) from P2 and infected them with a virus that contained a normal copy of the gene for beta globin.
The virus they used is a lentivirus (lentivirus) capable of inserting its genome into the genome of the cells it infects. The AIDS virus also belongs to this family, but the viruses that use gene therapy have undergone a treatment that prevents them from reproducing on their own and their sole purpose is to serve as a transport vehicle to introduce the desired genes into the cells. As an added safety factor, the virus is programmed to disable itself after transferring the information to the genome.
Before receiving the new blood-producing stem cells, P2 underwent a round of chemotherapy to clear his body of the existing damaged blood cells. It is not a simple process but it prepares the body to receive the repaired cells, which were inserted into his body three years ago on June 7, 2007. After a year P2 received his last blood transfusion. He did not need another transfusion for the next two years. He still suffers from mild anemia but his quality of life is good.
This new success comes after a lot of hard work. The method successfully tested in mice In 2000 and past upgrades during the following years. This case is the first in which the reimplantation of the repaired cells was successful. The repaired cells constitute only a ninth of the total red blood cells of P2, and the repaired beta globin molecules are only one third of these. Although not the majority, they are enough to ensure that he has enough normal copies of hemoglobin to allow him independence.
The success of gene therapy comes with a cautionary note. There is no way to know where the correct copy of the gene will be inserted within the genome. This point may lead to impairment of the function of another gene, even though then there is a second copy of the same gene that will continue to function properly. The scenario that is particularly feared is the case where the insertion of the copy disrupts a step in the control of the cellular division process and leads to a cancerous growth, as has already happened in gene therapy cases in the past.
3 תגובות
I did not find the names of the investigators, in my opinion something illogical.
So my proposal is this to solve the problem of genes that are not well positioned.
1. Replicate a single cell after undergoing a gene transplant, keep some of the replications and use the others for genetic sequencing (I understand that they are destroyed in the process)
2. Once the correct genetic sequence has been identified, use the cells we saved to carry out the healing process.
3. If there is no normal genome, repeat the gene transplant with the help of the virus until there is a normal genome.
I understand that the bottleneck here is the non-invention of a quick and cheap gene sequencer and the process today can be expensive and long
Then someone will come and say that animals are being abused.
It should be understood that experimenting on animals is a necessary step in inventing a medicine that can save both boys and animals