The third AIDS patient was "cured"! Can humans finally conquer AIDS?

On February 15, American researchers reported the world's first female AIDS "cure" at an academic conference. This patient is also the third HIV infection cure case. Academically speaking: After receiving treatment and stopping antiviral drugs, the patient's body has not been detected with HIV virus for more than 14 months, indicating that her infection has been completely relieved.

The key to the patient's recovery was hematopoietic stem cell transplantation: researchers first used chemotherapy drugs to kill the patient's own immune cells, and then transplanted new cells that would not be infected by HIV. The hematopoietic stem cells she received carried a gene mutation called "CCR5Δ32/Δ32", which can protect T cells from infection. This is because the CCR5 gene corresponds to a protein that HIV needs to bind to when entering cells, and the mutant version of the protein cannot bind to the virus.

HIV-infected T cells (electron microscope image) | NIAID

The innovation of this treatment is the use of umbilical cord blood stem cells. The previous two cured cases used hematopoietic stem cells from adult bone marrow. Umbilical cord blood stem cells are easier to obtain and have less stringent matching requirements, so they are expected to be used in more patients. In the future, researchers will further expand the sample size to verify the effectiveness and safety of this therapy.

However, it must be pointed out that the scope of application of this therapy is very limited. Stem cell transplantation faces considerable risks. If it is only used to treat AIDS, it has no advantages over antiviral drugs. Only when the patient happens to need hematopoietic stem cells to treat other diseases can this method be considered to eliminate HIV by the way - for example, this time the patient received a transplant for the treatment of acute leukemia.

In 2007, the first case of "AIDS cure" appeared, namely the "Berlin patient" Timothy Ray Brown. He was suffering from leukemia at the time, and after chemotherapy failed, he received a bone marrow transplant. The person who donated his bone marrow happened to have the CCR5Δ32 mutation.

Timothy Ray Brown

The Berlin patient was on the brink of death, but after he survived the transplant and severe complications, doctors discovered that the bone marrow transplant not only cured his leukemia, but also successfully suppressed HIV in his body. Later, he stopped taking anti-HIV drugs and remained healthy.

Many people wanted to replicate the success of the Berlin patient, but transplant cases have failed again and again. People once thought that the Berlin patient was just a fluke, or that perhaps one had to be extremely sick during the transplant process like the Berlin patient to survive.

It wasn't until 2019 that the second "London patient" appeared.

Ravindra Gupta, a virologist at University College London, said at an academic conference that the "London patient" was 36 years old and had Hodgkin's lymphoma. He received a bone marrow transplant with the CCR5Δ32 mutation in May 2016. The entire treatment process was relatively smooth and there were no unexpected situations.

A colored transmission electron micrograph of the HIV virus, in green, attaching to a white blood cell, in orange.CreditCreditNIBSC/Science Source

The London patient stopped taking anti-HIV drugs in September 2017, and by 2019, when the report was published, there was no detectable HIV virus in his blood.

The HIV antibodies are still there, but the levels are decreasing over time, similar to what happened in the Berlin patient.

At the time, according to media reports, there was another case of the "Düsseldorf patient" who also showed great promise. But there seemed to be no further news about him later.

Although there have been three cured cases, it cannot be used to treat all AIDS cases. Bone marrow transplantation is not a good choice for patients who are only infected with HIV. These three patients underwent bone marrow transplantation primarily to treat malignant tumors, and eliminating HIV infection can only be regarded as a side benefit. After all, transplantation is also a treatment method with relatively high costs and risks, and there are now many drugs that can control the HIV virus for a long time. For people who are simply infected with HIV, it may be more realistic to control it with medication.

Maybe there is hope for a cure for HIV

Indeed, gene therapy

Many teams are now studying how to precisely modify genes, such as changing the CCR5 gene in bone marrow cells without changing other cells. For bone marrow cells, only the CCR5 gene is precisely changed without changing other genes.

Image | pixabay

This level of precision is not currently achievable.

In addition, we should also pay attention to the X4 strain of HIV virus, which does not enter cells through the CCR5 protein, but through the CXCR4 protein. Therefore, modifying CCR5 cannot prevent this HIV strain. CCR5 mutations cannot resist all HIV viruses.

In any case, we are witnessing more and more good news. The first case of recovery may be just a miracle. But the second and third cases of recovery are science.

Author: Window Knocking Rain You Shiyou

Editor: Luna

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