Gene Therapy
- Revolution of Medicine -
History of Gene Therapy
In the early 1970’s scientists began to propose an idea for treating inherited diseases that are caused by abnormal genes which was called “gene surgery”. The purpose of proposing this idea was to be able to take out the disease-causing gene, and then surgically implant a certain gene that functions properly. However, due to the lack of biological knowledge, scientists needed much expertise to perform this type of surgery on the human body. Around 1983, scientists from Baylor College of Medicine in Houston, Texas,proposed that gene therapy can be helpful for treating the Lesch-Nyhan disease. Experiments were made by injecting an enzyme-producing gene into a group of cells for replication, so that it may correct the disease. With the experiments, scientists then speculated that by injecting cells into people who carry the disease, it can correct the genetic defect that caused the disease to begin with. Throughout the 1980’s, as the science of genetics progressed, medical scientists believed that gene therapy could be a promising method for treating genetic based diseases.Due to the fact that scientists were able to identify specific genetic defects that cause inherited diseases, the growth and research of gene therapy escalated.
Making Mark on History
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On September 14,1990, the first person to undergo the process of gene therapy was a four- year old girl, Ashanti DeSilva, who was suffering from a genetic disorder that prevented her body from producing the enzyme: adenosine deaminase (ADA).This caused her body to have a weak immune system, making her extremely vulnerable to both minor and dangerous infections. Dr. W. French Anderson of the National Heart, Lung and Blood Institute, and Dr. Michael Blaese and Dr. Kenneth Kulver, both from the National Cancer Institute, performed gene therapy on Ashanti at the National Institutes of Health’s Clinical Center in Bethesda, Maryland. They took white bloods cells (which are necessary for the immune system to function properly) from the girl, and inserted ADA producing genes into the white blood cells, which they then transfused the cells back into Ashanti. As a result, Ashanti’s cells were able to produce the enzyme ADA.
Before and after pictures of Ashanti Desilva. On the left, Ashanti is with Dr.W.French Anderson. On the right, this is Ashanti after the procedure. She is all grown up and healthy!
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After the 1990’s the excitement from Ashanti DeSilva’s success story resulted in a new hope for other patients and families. Another patient, around the month of September, 1999, Jesse Gelsinger decided to give gene therapy a try, in hopes of not only finding a cure to his disease, Ornithine Transcarbamylase Deficiency (OTC) a rare metabolic disease that causes a build-up of ammonia in the body, but also in his determination to perhaps help others who happen to be tackling the same disease. He wasn’t a “sick” patient, since his disorder was controlled under a low-protein diet, as well as on medication of 32 pills a day. However, unlike Ashanti, his story turned to create the biggest negative impact on Gene Therapy field, because to everyone’s dismay, Jesse died four days after starting his treatment of multiple organ failure, which was thought to be caused due a severe immune response to the adenovirus carrier which was the vector that was used to transfer the genes to his liver. This caused a lot of issues around the field due to the fact that a lot of money was being put into researching Gene Therapy, which now only seemed to be a idea that only looked great on its surface, however lacked in its depth to achieve. Doctors such as Dr. Harold Varmus, director of National Institutes Health criticized the idea of gene therapy by stating that this field happened to only be a “mistaken widespread perception of success”. Due to this failure, Gene Therapy happened to lost its faith by people, however obstacles didn’t stop scientists and doctors in their own faith in this field. So they then took upon this failure as a lesson to be learned, and continued their research.
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Later in 2000, Dr. Alain Fischer of the Necker Hospital in Paris and his colleagues treated two infant boys for their Severe Combined Immunodeficiency (SCID) disorder, which causes a lack of a working immune system. Patients with this usually try to live out their lives by living in a sterile “bubble” since they aren’t immune to infections, thus why they were given the name “Bubble Boys”. Fischer was able to cause this success by taking “bone marrow cells from the boys and purified out the stem cells, which they nursed these cells along in a special cocktail of compounds meant to help the stem cells thrive and multiply and also to make them more amenable to genetic engineering”. Within 15 days of insertion of these new cells, the researchers saw results! Both of the boys had started producing immune cells and chemicals. They also then had “normal levels of T, B, and natural killer immune cells” and were also “vaccinated against tetanus, diphtheria, and polio”. Before this treatment, vaccination would have don’t anything at all for the boys. This thus gave hope back again with this field due to its success, because after failure, Gene Therapy was showing promises that it had failed before years back.
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A few more years later in 2007, Timothy Brown became to be the first person in the world to be cured of HIV, a feat considered impossible. His success story proved many who thought otherwise, that the impossible had now become the possible, by using Gene Therapy! Not only did Timothy was diagnosed with HIV, he also had acute myeloid leukemia, cancer of the blood. To combat his HIV, his doctor specifically chose a donor that happened to have a mutation in both copies of the CCR5 gene. This gene “encodes an HIV co-receptor carried on the surface of T cells to which HIV usually must bind in order to enter the cells”. Through this treatment doctors were unable to find any traces of HIV virus in his system. Brown no longer had to take medications for his HIV, and thus began to live HIV-free!
