In recent days, news of AIDS patients in the UK or being cured has been constantly being screened on major social networks and news sites.
When the world is boiling for the word cure, the question comes along: Is the therapy capable of extensive clinical trials, and is it equally applicable to Chinese patients? Science is not a child's play. How do we rationally look at this result in the face of voices and problems?
Talking about cure is too early
On the 5th, scholars from University College London, Cambridge University, and Imperial College of Science and Technology reported their latest treatments for AIDS in the British Nature Journal.
According to this, the British male patient who did not want to be named was found to be infected with HIV in 2003. He began receiving antiretroviral drugs in 2012 and was diagnosed with Hodgkin's lymphoma in the same year. In 2016, the patient underwent chemotherapy and hematopoietic stem cell transplantation, and 16 months of antiretroviral therapy continued. When he did not detect HIV in his body, the treatment team and the patient decided to stop antiretroviral treatment. In the 18 months after stopping this treatment, his condition continued to ease.
Although the researchers believe that it is still too early to say that he has cured, the results have been very encouraging.
The only AIDS patient recognized to be cured in the academic world is the Berlin patient Timothy Brown. Ten years ago, Brown suffered from both AIDS and leukemia. In 2007, he received radiation therapy and stem cell transplantation in Berlin. Both diseases disappeared. However, similar attempts to other patients have not been successful since then.
The HIV-infected person who was referred to by some scholars as a London patient and the Berlin patient of that year accepted a therapy involving stem cell transplantation. One thing that the two have received in common is that there is a rare variant of the stem cell donor's CCR5 receptor that can make the body resistant to HIV and prevent it from entering the host cell.
CCR5 is a major entry point for HIV to attack the human body. The researchers believe that the replacement of immune cells with cells without CCR5 receptors by stem cell transplantation may be the reason why HIV does not rebound in patients after stopping treatment.
To treat cancer, the two also received radiotherapy and chemotherapy. Researchers believe this may help eradicate HIV. However, there were significant differences in the treatment of these two cases – Berlin patients received two transplants and received whole body radiotherapy; London patients received only one transplant and relatively mild chemotherapy, and did not receive radiation. Researchers believe that the experience of London patients may be better promoted.
The report's lead author, Professor Lavindra Gupta of University College London, said: By using similar therapies to ease the condition of the second patient, we have shown that 'Berlin patients' are not unusual cases.
The team said that given the toxic side effects of chemotherapy, the above treatment is not suitable for standard HIV treatment, but it brings hope to researchers to find a cure strategy that can completely eliminate HIV.
Professor Jane Deton of the Queen Mary School of the University of London said that CCR5 has always been one of the important concerns in the field of AIDS treatment research. This report shows its key role. Future treatment strategies are likely to include CCR5 modifications or Knockout, it is necessary to carry out further follow-up studies on this case.
This therapy is not widely available
When the media are full of expectations around the cure, some insiders believe that this outcome must be treated with caution. So, how do you judge whether HIV-infected people are cured?
Li Taisheng, director of the Department of Infectious Diseases at Peking Union Medical College Hospital, said in an interview with Xinhua News Agency that the concept of AIDS radical cure is rarely mentioned in academic circles. It is usually mentioned that functional cure, that is, after stopping antiretroviral drugs 1 The virus does not rebound in the year, and it can be considered that a functional cure has been achieved. The author's intention is also expected to achieve a functional cure, as this patient has been discontinued for one and a half years.
Before the Berlin patients have been generally recognized as a cure - no HIV has been detected in the blood for several years after stopping the drug. Since then, many researchers have been working hard to replicate the success of Berlin patients, but they have not succeeded.
Li Taisheng believes that the biggest significance of this London patient is that bone marrow transplantation with CCR5Δ32 homozygous mutant gene in HIV-infected patients may achieve the near-radical effect of patients like Berlin. Although the papers published in the journal Nature are very scientific, they are too optimistic if they say that AIDS is about to be cured.
He said that the premise of this treatment is that HIV-infected patients with blood diseases are worthy of bone marrow stem cell transplantation. After all, the cost of transplantation is high and the risk is high, and HIV-infected people take the existing treatment through standardized treatment. The drug can effectively control the virus replication in the patient, so that the patient can basically live and work normally. Therefore, extensive bone marrow stem cell transplantation for HIV-infected patients is not worth promoting and is difficult to replicate. The donor of the transplant must have the corresponding gene deletion, and also need to match the match of the recipient. The two conditions are extremely unlikely to be met at the same time, and the CCR5Δ32 homozygous mutant gene is more common in the Chinese race than in the West. It is rare.
In addition, the previous research of the Li Taisheng team showed that the main epidemic among the HIV carriers in China was the AE recombinant subtype, nearly half of which was CXCR4 tropic, targeting CCR5Δ32 (homozygous). Bone marrow transplantation does not remove the CXCR4 tropic HIV virus and does not produce a therapeutic effect. Therefore, for millions of people living with HIV, bone marrow stem cell transplantation is only suitable for a very limited number of patients and is unlikely to be a realistic treatment option for most people.
The sensation brought about by the British patient case, Professor Sarah Federer of Imperial College of England also believes that although this new result is very meaningful, it cannot promote the research in this field significantly beyond the "Berlin patient" It was found that "the treatments received by patients in the new report are not safe and not scalable, and it is certainly not suitable as a program for HIV-infected people who have used retroviral therapy and achieved good results.
Reporter: Zhang Jiawei Lin Miaomiao