US ethicists and medical experts say the use of gene editing to make babies resistant to HIV infection goes too far and could be a step backward for genetic science.
The news revealed on Monday morning that Chinese scientist He Jiankui had modified the genetic code of two embryos to make them resistant to HIV, then transferred them to a woman who had subsequently given birth to two daughters – twin sisters.
Although his claims have not yet been verified, he claims that a baby has two sets of the modified CCR5 gene, which, he hopes, will prevent HIV from entering his cells if he ever had to come into contact with the virus. The other baby seems to have only one altered CCR5 gene set, which may not completely protect her from HIV infection, but may prolong her life if she were to have her own life. infect.
As he tries to present his findings as a boon to the HIV community, researchers and bioethicists in the United States say the announcement has left them perplexed and worried.
HIV researchers are interested in gene editing, but not in its own way, said Paul Volberding, co-director of the AIDS Research Center at the University of California at San Francisco Gladstone. .
We do not know the risks yet and we use healthy, uninfected people here.
Paul Volberding, co-director of the University of California, Gladstone Center for AIDS Research in San Francisco
"I am very interested in the different ways in which gene editing could be used to try to cure HIV infection, but its use for the prevention of infection seems seriously flawed, "said Volberding. "HIV infection can be easily prevented with antiretrovirals."
And since treatments and therapies already exist to prevent the transmission of HIV from a parent to a child, he finds it "very troubling" for scientists to subject these babies to these untested methods.
"We do not know the risks yet, and we use uninfected and healthy people here," Volberding said.
Some of these risks include the still unknown consequences of permanent modification of a gene, which would then be passed on to subsequent generations. For example, the Associated Press, who broke the story, observes that people with abnormal CCR5 genes are more likely to die of influenza and contracting West Nile virus.
Scientists around the world agree that even though the editing of "germinal" genes – changes in gamete cells or embryos that will be passed on to future generations – might one day be part of of our society, it would be irresponsible to use it in man the techniques were deemed safe and effective, and until there is a "broad consensus of society" on how to use them
These principles were outlined at the first World Summit on Human Gene Publishing, which was held in 2015, and they generally allowed to comply with the laws of other countries on the planet. 39, gene editing. In the United States, Congress has banned the use of federal funds for gene editing experiments on human embryos, and the FDA does not have the right to approve clinical trials involving them.
Nita Farahany, bioethicist and director of the Duke Initiative for Science and Society, is not surprised to learn that a scientist has flouted international conventions calling for the advent of genetic modification of healthy embryos to create pregnancies and births.
However, like Volberding, she is surprised that HIV is the first application of germline gene editing, given the treatments already available to suppress virus levels and help people live longer and healthier lives.
"You would think that the first application of CRISPR-cas9 for gene editing would be more fatal genetic variations," said Farahany, referring to the tool allowing scientists to cut sections of a genome and replace them with something else. "Things that cause great physical suffering or death in children," such as the infant Tay-Sachs, a serious condition that can cause a child to lose sight, hearing, and the ability to move before causing death to children. the age of 4 or 5 years. .
In addition to the medical redundancy of its experience, experts are also concerned that its results actually perpetuate the stigmatization of HIV-positive people in a country where people are already facing serious consequences if others discover their HIV status.
Ann Mongoven, associate director of health care ethics at the Markkula Center for Applied Ethics at Santa Clara University, notes that the story of the PA that announced the news raises troubling questions about whether scientists have exploited HIV-related stigma to encourage parents to participate in research.
The AP reports that of the seven couples who agreed to do experimental in vitro fertilization with He, all men were HIV-positive, but all of them had suppressed their levels of the virus with standard anti-HIV drugs. This suppression, combined with basic infection control measures, such as the use of condoms throughout pregnancy, would have prevented them from transmitting the virus to their partners and unborn children.
Still, the article says that they wanted to participate in what he called an "AIDS vaccine development" program aimed at protecting their future children from an HIV / AIDS vaccine. "Similar fate". It is not learned that a child whose father is HIV-positive will contract the virus themselves.
"The real question is whether the fear of AIDS and the stigma of AIDS has become a way to recruit parents for this research," she said.
Mongoven fears that once the news of the twins has spread, it could fuel the misperception of how HIV is transmitted. About half a million people are living with HIV in China.
Not the "best first case"
Bioethician Arthur Caplan, of the New York University School of Medicine, says that genetic engineering of human beings is inevitable and that even though parents are afraid to create "designer babies" by giving priority to surface features, such as color and eye height, scientists in technology for the prevention and treatment of diseases – much like the experience It.
Ultimately, he predicts, once gene editing becomes a reliable tool to help prevent disease and other undesirable traits, parents might actually be considered careless if they choose not to use these tools.
"There are many cultures around the world, including the United States, which are highly competitive and market-oriented companies in which individuals are looking for their children in particular to gain an advantage and benefit," he said. -he declares. "This idea that we will not do gene editing when it is about to improve or improve, I find it silly and a kind of head trick -headed."
Indeed, a recent Pew survey of about 2,500 Americans found that 72% believe that gene assembly to treat a congenital anomaly or critical illness is an appropriate use of the technology, while 60% believe that It should also be used to reduce the risk of serious illness that may occur during the course of life.
But until gene editing becomes safe and standardized, experts know clearly where the boundaries are. The experts we spoke to are deeply disappointed that his experience was the first to demonstrate the potential of CRISPR-cas9 in the world.
Volberding is excited about the promise that genetic modification holds for HIV – but only to cure those already infected and not to prevent it in healthy people. Farhany, too, thinks that genetic publishing is very promising for relieving human suffering – but only after a large number of studies on animals and plants have proved that it was safe and effective.
"It's unfortunate that our first use of CRISPR in humans is so far removed from the type of use that most scientists could have done for a better first case," Mongoven said.