HIV is one of the most prevalent public health threats in the United States. More than 1.2 million people are currently living with the virus, and more than 35,000 new infections are reported each year. For decades, scientists from around the world have worked to find a cure with minimal success. However, a patient in Düsseldorf, Germany, has recently been cured of HIV with a stem cell transplant, making them the fifth person to be cured of HIV. The stem cell donor carried the HIV resistance genetic mutation known as CCRS-Δ32, which less than one percent of the population carries. This recent breakthrough in stem cell research has given medical professionals some level of hope in tackling the virus, but it simultaneously raises concerns regarding the effectiveness of the treatment. Considering these circumstances, the question must be asked: are stem cell transplants a truly safe and viable cure for people in the near future?
HIV (human immunodeficiency virus) is a virus that damages the body’s immune system, attacking white blood cells and rendering a person more susceptible to other illnesses and infections. It is transmitted through physical contact with an infected person’s bodily fluids, oftentimes during unprotected sex or through the sharing of equipment used for drug injection. Common symptoms of HIV include fevers, chills, rashes, swollen lymph nodes, and mouth ulcers. If the symptoms are left untreated after a certain period of time, the virus can develop into AIDS (acquired immunodeficiency syndrome). Beginning in 1983, the United States Congress funded governmental institutions such as the National Cancer Institute (NCI) and the National Institute of Allergy and Infectious Diseases (NIAID) to conduct most of the HIV/AIDS research. Although treatments like antiretroviral therapy (ART), which involves taking medicine that reduces the amount of HIV in the body, have been developed since then, no scientist has successfully made an approved cure for the virus.
Developing reliable cures for HIV is particularly challenging because of the way the virus operates in the body. According to the International AIDS Vaccine Initiative, HIV differs from other viruses when it comes to the vaccine development process. When a person is infected by viruses such as polio, smallpox, and influenza, the immune system identifies them as foreign pathogens. Afterwards, the immune system’s white blood cells split into cells that produce antibodies geared towards attacking the unfamiliar virus. This helps the body develop long-term immunity against another infection from the same virus. Vaccines work similarly by increasing the immune system’s antibody response to protect the individual in advance from any possible infection. HIV, however, hides itself from the immune system in two ways. First, HIV evades white blood cells, which prevents the immune system from fielding a strong enough antibody response that will effectively counter the infection. Secondly, HIV infects and destroys the CD4 T-lymphocytes, which are white blood cells that are instrumental in maintaining the healthy functioning of the immune system. Then, the HIV establishes a persistent infection in the T-lymphocytes, called viral reservoirs, allowing them to remain dormant in these cells along with other immune cells, until the virus can strike again without warning. From there, the chances for creating a vaccine to prevent an HIV infection or restrain the initial infection slim significantly. But this is where the possibility of using stem cell transplants as a viable treatment for HIV becomes relevant.
According to the New York Stem Cell Foundation, stem cells are unique cells that can become any cell type; for instance, they can be engineered into brain cells, blood cells, lung cells, etc. Blood cells, in particular, can turn into red blood cells, white blood cells, and platelets. Because of this, stem cell transplantations can be used to destroy unhealthy blood cells and replace them with stem cells made from bone marrow, making them vital for the treatment of certain types of cancer and blood-related diseases. In 2013, at the Düsseldorf University Hospital, an HIV-positive patient who underwent antiretroviral therapy (ART) received a stem cell transplant to treat both his HIV and acute myeloid leukemia (AML). The donor stem cells contained a rare mutation in the aforementioned CCR5 gene, known as the CCR5-Δ32 mutation, which is commonly found amongst people with European ancestry. The mutation resulted in the absence of a viral “safehouse” in the immune cells, where the virus could persist for an indefinite period of time, thus protecting the body against infection with HIV. Following the stem cell transplant, a team of doctors that treated the patient conducted tests to confirm whether any replication-capable HIV was left in his immune system. After four years of examining the patient, he was released from his ART, and to this day, he has not shown any signs of his HIV returning.
Still, stem transplants maintain many risks that prevent their broad implementation as treatment for HIV. According to the National Institutes of Health, since less than one percent of the population carries two copies of CCR5-Δ32, it limits the chances of finding a compatible donor, especially for non-White patients. Another challenge that comes along with stem cell transplants is the risk of obtaining graft-versus-host disease, a condition that causes transplanted immune cells to attack the patient’s body. Stem cell transplants aren’t a guaranteed cure for HIV, in view of the conditions required. Not to mention, stem cell transplants are never considered to treat HIV by itself. Consequently, in past cured HIV cases, patients often suffered from another life-threatening condition along with HIV, such as leukemia, that required a stem cell transplant. However, that’s not to say that stem cell transplants can’t become a reliable cure for HIV. The findings regarding the five cured cases of HIV suggest that stem cell transplants have considerable potential to completely heal patients suffering from HIV. Even when taking the procedure’s pitfalls into account, the future of HIV cure development looks optimistic with the arrival of this up-and-coming treatment.
