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Binoculars whose DNA had been tampered with in a controversial effort in China to make them resistant to HIV infection could still contract the virus that causes AIDS.
Some relatively uncommon strains of HIV could enter their cells if the girls came into contact with contaminated tissues or fluids, said Robin Shattock, president of Mucosal Infection and Immunity to HIV. 39 Imperial College London, UK.
He Jiankui, the researcher who used a technique called Crispr to manipulate the DNA of twins when they were in the embryonic stage, faces criticism for exposing girls to potential risks for life that scientists are just beginning to understand. Other widely used prevention approaches would be more reliable and less risky than using unproven technique to alter their genomes, Shattock said.
"It's a totally ridiculous and unnecessary approach" to preventing infections, he said during a phone interview. "It is the shady ethical aspect."
Crispr allows scientists to eliminate or replace specific genes in living organisms. Although the treatment of many DNA-related diseases is promising, scientists are currently studying whether this affects the risks of cancer or other disorders in people. Many governments have restricted or banned its use in human embryos because modified traits can be passed on to future generations with unknown consequences.
Based at the Southern University of Science and Technology in Shenzhen, China, he announced his work in a YouTube video and spoke Wednesday at a conference in Hong Kong, where he announced that a second modified pregnancy is in progress.
The university said in a statement that she was "shocked" by the actions of Mr. He, the National Health Commission of China asked for an investigation, and a group of 122 Chinese scientists issued a joint statement decrying work as "madness".
"I understand that my work will be controversial, but I believe that families need this technology and I am willing to accept criticism of them," the researcher said in the video.
According to the World Health Organization, nearly 37 million people worldwide are living with HIV, although the infection rate in China is among the lowest. He, who was trained in the United States, said that the girl's father was infected and that he wanted to protect them from HIV.
The transmission of a parent to a child can be blocked by the appropriate use of antivirals, Shattock said. A diet called PrEP can also prevent people at high risk of contagion from being infected with other pathways.
Daily antiviral treatment presents its own risks, and HIV still kills about 1 million people each year, he said in a separate video. Gene editing, "even if it does not apply to the general public, can be helpful in helping some affected families at very high risk to protect their children from the same fate," he said in the video. .
Working with a small team, he has modified a gene that makes a protein called the CCR5 receptor, which HIV uses to enter the cell. People born with a mutated CCR5 receptor are much less likely to get HIV than those with a normal version.
However, HIV has another way to get into the cells, via another receptor called CXCR4, said Shattock. While this version is rarer than those using CCR5, CXCR4-dependent strains could be involved in up to 5% of infections in some parts of the world, he said. A 2012 Botswana study of 148 infected women in Botswana found that 15% had both types of HIV, while the others had only the CCR5-dependent virus.
"It's very unlikely, but it can not be ruled out that an infected person via a strain using CXCR4 enters the cells," he said.
The genes come in pairs – one from each parent. In one of the twins, only one of the two copies was successfully changed, he told the Associated Press. This could mean that the child is not protected against HIV infection, said Ewan Birney, director of the European Institute of Bioinformatics.
Companies and laboratories have long considered modifying the CCR5 receptor to prevent or slow down HIV. Medications such as Pfizer Inc.'s Selzentry cover the receptor, thus blocking access to HIV, although its effectiveness diminishes when HIV mutates to use the other receptor.
Scientists continue to look for ways to safely modify the CCR5 gene in people at high risk of contracting HIV, said Daniel Kuritzkes, an infectious disease specialist at Harvard Medical School, but there is no evidence reason to think that twins face such dangers. Making genetic changes – even in adults – presents dangers that require researchers to demonstrate that patients subject to such experimental procedures are likely to generate benefits, and experience offers them none at all. -he declares.
"I can not understand the justification for that," Kuritzkes said. "I can not imagine how that adds up in any way.
© 2018 Bloomberg LP
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