40 million people have died from AIDS in 40 years. Can we cure AIDS?

Introduction

December 1st is the annual AIDS Day and the 36th "World AIDS Day". The theme is "Uniting social forces to fight AIDS together". While we call on the public to strengthen AIDS prevention, we also need to unite and jointly deal with this century-old disease for all mankind.

Since the first case of AIDS was reported in 1982, AIDS has spread all over the world in just over 40 years, with 80 million people infected with HIV and 40 million people dying from it. Everyone is afraid of AIDS. Even if the HIV virus in the body is controlled by drugs, many patients still survive in the cracks.

In February this year, good news came that the fifth AIDS patient was cured. Previously, four infected people were successfully cured. How did they cure AIDS? Is there any hope for other patients?

Deep into Science | Written by

At the beginning of 2023, the world's fifth "cured" AIDS patient appeared. After the patient underwent a hematopoietic stem cell transplant, even using the most accurate detection methods, the presence of HIV virus could not be detected in his body.

Therefore, he was considered to be "cured" of AIDS, and this news attracted widespread attention for a while.

Researchers published a paper in Nature Medicine, revealing the treatment of the fifth AIDS patient who was "cured"

Can HIV be cured? Why is it so difficult?

Today we will learn about AIDS, its treatment, and whether AIDS can be cured.

01Where did AIDS come from? Why does everyone “change color when talking about AIDS”?

Before talking about curing AIDS, we must first understand what AIDS is?

AIDS is known as acquired immunodeficiency syndrome (AIDS). As the name suggests, after contracting this disease, the body's immunity will be weakened. This is mainly caused by the human immunodeficiency virus, which we are familiar with as the human immunodeficiency virus (HIV). These viruses damage the human immune system, so that even when patients face common bacteria or viruses, they may cause fatal infections.

At present, the vast majority of AIDS patients cannot be completely cured. Once infected with HIV, they will carry the virus for life.

But fortunately, there are many retroviral drugs that can effectively control the HIV virus, and even carriers can live as long as ordinary people.

When it comes to HIV, we are curious about where it came from. The virus first appeared in a chimpanzee in Central Africa. In 2008, scholars at the University of Arizona pointed out that HIV had spread from chimpanzees to humans as early as the beginning of the 19th century.

Since then, HIV has gradually spread in Africa and eventually spread throughout the world.

In 1981, the American media reported the first case of AIDS, and since then everyone has been afraid of AIDS.

According to data from the World Health Organization, as of November 2021, more than 80 million people worldwide are infected with HIV, 40 million have died from AIDS-related illnesses, and nearly 40 million people are living with the disease.

For our country, the group of AIDS patients also needs attention.

According to data from the Chinese Center for Disease Control and Prevention, as of the end of 2020, there were more than 1.05 million people infected with HIV in my country, with a cumulative reported death toll of 351,000. The proportion of patients aged 50 and above is increasing, and the anti-AIDS situation is extremely stressful.

So, how to prevent and treat AIDS? Why is it possible to cure AIDS by transplanting stem cells?

First, let's talk about conventional treatments. Since the first case of AIDS appeared in 1981, as AIDS gradually came into the sight of scientists, a new antiretroviral therapy has been developed that can prolong the lives of people infected with AIDS. As of 2021, 25.4 million people have received antiretroviral therapy.

Later, researchers found that the combined use of three or more antiviral drugs to treat AIDS can reduce the resistance of a single drug, commonly known as "cocktail therapy."

02Bone marrow stem cell transplantation - the hope of curing AIDS

In recent years, hematopoietic stem cell transplantation has made breakthroughs in the treatment of AIDS, and five patients have been cured (Berlin patient, London patient, New York patient, City of Hope patient, Düsseldorf patient), which brings a ray of hope to other patients. Why can transplanted stem cells inhibit the reproduction of HIV virus in the body?

Stem cells are a type of cell with strong differentiation ability. Most tissues in the human body have corresponding stem cells. When cells age or die, stem cells differentiate to replenish these "lost" cells. The five AIDS patients we mentioned earlier are very special. They are HIV carriers and leukemia patients. The hematopoietic stem cell transplantation was originally used to treat leukemia, but in the end it also cured their AIDS. Why is this the case?

In fact, the reason why hematopoietic stem cell transplantation can treat AIDS is that when HIV invades human cells, it needs to bind to the CCR5 receptor of human cells. Blocking this receptor can prevent viral infection. The hematopoietic stem cells transplanted by the five patients mentioned above all have CCR5 gene mutations. Therefore, while curing leukemia, the HIV virus in the patient's body can no longer infect human cells. In this way, the residual HIV virus in the patient's body is slowly cleared and cannot be detected. In a sense, it is considered "cured."

It can be said that this ratio is quite low, but there are always a few lucky ones.

Next, we will introduce a typical example.

In 2006, German doctor Gero Huetter performed a hematopoietic stem cell transplant on an HIV-infected patient, the famous Berlin patient, Timothy Brown. The stem cells not only cured his leukemia, but also greatly reduced the level of HIV in his body, making it difficult to detect HIV in his body.

He was the first person in the world to be cured of AIDS.

Brown lived up to expectations and has since become an ambassador for the global fight against AIDS. His story of successfully fighting AIDS has inspired countless AIDS patients and allowed them to come out of the shadows, because maybe one day, they might also become that lucky person.

Whether it is the London patient, the New York patient, the City of Hope patient or the patient called the "Düsseldorf patient" we mentioned at the beginning, they are all lucky people.

Of course, there are certain limitations to hematopoietic stem cell transplantation for the treatment of AIDS. First, it has rejection. After receiving the transplant, the one-year survival rate is only about 60% due to rejection and other issues. Second, not every stem cell transplant recipient can obtain CCR5 mutated bone marrow, which is a very small probability event. Furthermore, this treatment is expensive, which is unaffordable for most AIDS patients.

At present, in addition to hematopoietic stem cell transplantation, scientists are also trying to use cutting-edge technologies such as gene therapy and mRNA to treat AIDS.

We look forward to more new technologies being used in the treatment of AIDS in the future, which will not only allow patients to return to normal life, but also cure more AIDS patients.

References

1.https://en.wikipedia.org/wiki/History_of_HIV/AIDS

2.https://www.sciencedaily.com/releases/2008/10/081001145024.htm

3.In-depth virological and immunological characterization of HIV-1 cure after CCR5Δ32/Δ32 allogeneic hematopoietic stem cell transplantation. nature medicine. 2023.

This article is a work supported by Science Popularization China Starry Sky Project

Team/Author: Deep Science

Reviewer: Tao Ning, Associate Researcher, Institute of Biophysics, Chinese Academy of Sciences

Produced by: China Association for Science and Technology Department of Science Popularization

Producer: China Science and Technology Press Co., Ltd., Beijing Zhongke Xinghe Culture Media Co., Ltd.