Back in the 18th century, British physician Dr Edward Jenner tested his hypothesis that harmless cowpox can prevent deadly smallpox disease on a young boy in exchange for a few coins to his poor parents. In 2018, a Chinese researcher Dr He Jiankui tested genome editing on human embryos in exchange for free IVF treatment. But that’s where the parallels end.
The sharpness of Jenner’s mind and his daring action brought us the concept of the vaccine, which has saved millions of people around the world. Can genome editing in embryos bring a new revolutionary technology to life and eradicate disease in human populations? Far from it. In fact, it is closer to nightmares of The Island of Dr Moreau or The Boys from Brazil.
Today, shortly before the start of an international conference on genome editing in Hong Kong, Dr He revealed to the Associated Press that his team edited the genome of human embryos resulting in the birth of two babies.
The genomes of the non-identical twin girls born this month in city of Shenzhen in China have been edited using CRISPR/Cas9 to delete the gene known as CCR5 (C-C motif chemokine receptor 5).
The CCR5 gene is expressed ubiquitously and it has a role in immune system activation. Mutations in the CCR5 gene are linked to resistance to HIV virus infection. Today, symptoms of HIV infection can be kept under control and millions of HIV-positive people worldwide live a normal life. If the amount of HIV virus in a blood sample is undetectable, the risk of transmission of HIV infection to babies is minimal, especially in case of HIV-positive men and HIV-negative mothers.
Furthermore, CCR5-linked resistance seems not to be absolute – isolated cases of HIV-positive patients that lack CCR5 have been reported. In one of the recently born twins only one copy of the gene was deleted, which does not protect the baby from HIV infection, it might result only in slower progress of the disease.
In addition, the editing has been done on ‘a few’ cells from five-day-old embryos, not the fertilised egg or all the cells. This means that both girls are likely to be chimeras – only a certain percentage of the cells in their bodies will carry the mutation, and they might not be resistant to HIV infection at all. Then, why has Dr He has done this? The first thing that comes in mind is to claim the fame of being the first.
According to the Associated Press report, the couples were recruited through Baihualin, a Beijing-based AIDS advocacy group, in exchange for free IVF treatment. In all couples, the men were HIV-positive but the women were not. All the men had the infection kept under control and the titre of HIV virus was undetectable, which means that risk of transmission of HIV infection to babies was negligible.
Dr He and Lin Zhitong, the head of the ethics committee at Shenzhen HarMoniCare Women and Children’s Hospital which approved the study, said that they helped families and their children and that this is ethical – medical staff handling the HIV-positive samples were aware of potential risk of being infected.
Dr He and his team edited 16 out of 22 embryos and 11 of them were used in six implant attempts before the twin pregnancy was achieved. What happened with the other nine? How far did they develop? Did they carry any malformations?
Although Dr He claims that the couples fully understood the risk and they were offered a choice between non-manipulated or manipulated embryos, it does not make sense that they really have comprehended the risks to which they were exposing their babies and themselves. The consent forms reportedly called the project an ‘AIDS vaccine development’ programme.
If this can be called ethical, then Dr He and his team’s perception of ethics is very different to that of the rest of the world. The institutions associated with Dr He and this work have already publicly denied any involvement in or knowledge of it.