On February 16, the topic of #World's First Female AIDS Cured Person# quickly rushed to Weibo's hot search.
Screenshot of Weibo
AIDS is one of the insoluble diseases encountered by humans, and it is very difficult to treat, and the cure of this patient is undoubtedly a major advance in the field of AIDS treatment.
But does this mean that AIDS patients can be cured?
Why has AIDS always been an incurable disease?
Let's first look at how HIV infects humans and develops into AIDS.
After the human virus (HIV) enters the human body, it specifically attacks helper T cells, which are cells that are specifically designed to help everyone resist pathogen infection, and the human immune system will be gradually destroyed.
HIV is transmitted through blood and sexual contact, unprotected sex and contaminated needles are the main causes of transmission, fortunately, HIV cannot be transmitted through air, water, daily contact.
AIDS is divided into three phases: acute infection, asymptomatic and AIDS, and only patients in the final AIDS phase can be called AIDS patients.
The acute infection phase often occurs 2 to 4 weeks after infection, during which patients may have symptoms such as fever, fatigue, rash, and lymphadenopathy, and most patients have symptoms that are not severe.
This is where AIDS is cunning, HIV hurts immune cells, making patients more susceptible to other diseases, and it can be said that there are no specific clinical manifestations during the acute infection period, and patients seem to have just suffered from other diseases.
Because of the presence of the window period (the time when HIV infection has just occurred to the point where a patient's blood can be detected), testing during the acute infection phase does not necessarily detect HIV or antibodies.
This is followed by an asymptomatic period, silent and dangerous, often lasting 2 to 10 years and most patients with symptoms that are not easily detected or asymptomatic, but this time is also contagious.
The human body's immune system and the invading virus confront each other, our immune system, first recognize the invader, targeted training of "soldiers", and then quickly invest a large number of "soldiers" who can attack the invader, and finally achieve the purpose of eliminating the "invader" on the battlefield.
In this process, there are two points that can cause the immune system to fail.
1. The human body cannot identify the intruder in time
HIV is like a girl with a thousand faces, constantly appearing with new faces. In the fight of guerrilla warfare, a shot to another place, our immune system is always led by the nose, unable to completely annihilate all enemies.
2. HIV hides outside the battlefield
We can destroy the enemy on the battlefield, but we can't do anything about the virus hidden in our cells. The hepatitis B virus is smart enough to hide in the human nucleus, and HIV is even better, not only hiding in the nucleus, but also integrating itself directly into the host DNA.
Although there are now various drugs, some inhibiting viral replication, and some various antibody drugs, we still can't completely eliminate HIV.
That is why the emergence of AIDS curers has such a big impact.
As early as 10 years ago, the medical community has successfully cured an AIDS patient, in 2007, Timothy Ray Brown, a Berliner with leukemia and AIDS, received a bone marrow transplant when treating leukemia, in this process, the researchers just screened out the CCR5Δ32 bone marrow donor, and then cured aids.
What is CCR5Δ32?
This starts with a key gene called CCR5, which is a helper receptor for HIV to invade human immune cells, and when it has a specific mutation, the body may become immune to HIV.
And this specific mutation of the gene is the above mentioned CCR5Δ32. In 2016, a second patient appeared, similar to the previous Berliner.
The third patient, who announced his cure on Feb. 16, was diagnosed with AIDS in 2013 and, four years later, developed leukemia. In the process of treating leukemia, she performed haploid cord blood hematopoietic stem cell transplant (haplo-cord SCT), which also carries a mutant gene that prevents HIV virus from entering the cell, CCR5Δ32.
It is worth noting that, unlike the other 2 patients, this is the third CASE of AIDS cured worldwide, and she uses umbilical cord hematopoietic stem cells. The stem cells transplanted from the other 2 cured AIDS patients were all from bone marrow.
Compared with bone marrow transplantation, the use of cord blood transplantation can greatly increase the likelihood of patients finding suitable donors, establish multiple cord blood banks around the world, and expand the scope of screening through the donation of newborns.
At the same time, cord blood stem cells have lower requirements for matching and cause fewer complications.
Currently, multiple ultra-sensitive tests of the New York patient's immune cells have failed to detect signs of HIV replication, nor have they detected any HIV antibodies.
They took immune cells from the New York patient and tried to infect them with HIV in the lab, but thankfully nothing happened.
Does the cure of AIDS patients mean that AIDS patients around the world have hope of a cure?
Can AIDS be cured?
Unfortunately, the cures that have been successful so far are still not universal.
In simple terms, the current treatment method is to replace the immune system of others with the immune system of the patient, first use chemotherapy to destroy the immune system in the patient's body, including the diseased immune cells in the patient's body, and then transplant stem cells that can resist HIV to rebuild the patient's immune system.
There is a high risk of this process, with rejection occurring during treatment in the first two cured AIDS patients and experiencing life-threatening as a result.
On the other hand, it is also not easy to find someone who has CCR5Δ32 and is willing to donate. Even if found, the donor needs to be successfully matched with the patient, otherwise there will be a violent rejection reaction after the transplant.
In fact, the three patients who have been cured all have one thing in common, they are all in the process of treating cancer, treating AIDS, that is, they originally need to receive stem cell transplants.
At the same time, the huge cost of treatment is also one of the reasons why AIDS treatment is not universal.
How can AIDS be prevented?
Avoid possible contagious behavior
For example, having multiple sexual partners, not using condoms, sharing needles with others to inject drugs, and extracting teeth and getting tattoos in informal medical units (perhaps using utensils that are not strictly sterilized in the process).
If high-risk behavior is unavoidable, topical condoms, pre-exposure (post-exposure) oral medications can be effective in preventing HIV infection.
Take preventive medications
Taking PR prophylaxis strictly according to the regimen, the effectiveness of preventing HIV infection can reach more than 90%.
If the drug is started after exposure, the success rate of blocking HIV infection is more than 80%.
The success rate is related to the timeliness of the first dose and the compliance of the drug, the earlier the drug is taken after exposure, the higher the success rate of blockade, and the best medication is taken within 2 hours after exposure, and the longest should not exceed 72 hours. After the start of taking the drug, taking the drug regularly every day is better than the blocking effect of frequent missed doses.
It is believed that with the development of medical level, in the near future, the cure of AIDS will become a possibility.
(Popular Science China)