The science behind HIV & the potential for a cure

Human Immunodeficiency Virus, otherwise known as HIV, is a virus that is ubiquitous in social, political, and media-related contexts, yet is often poorly understood. Understanding the science behind HIV/AIDS is crucial to combating stigma as many negative misconceptions about the virus stem from a lack of knowledge about the biology that underlies HIV and AIDS, including their symptomatology, epidemiology and transmission. Gaps in public knowledge are often filled with misinformation shrouded in stigma, which is widely noted as being the biggest barrier to creating an AIDS-free generation. Stigma can foster a shameful environment in which individuals are often unwilling to get tested for HIV, disclose their positive status to potential sexual partners, or receive and take medication.

One of the most commonly stigmatized aspects of HIV/AIDS is the methods by which HIV is transmitted between HIV+ and HIV- individuals. HIV can only be transmitted when semen, blood, rectal fluid, pre-seminal fluid, vaginal fluids, or breast milk come in contact with a mucous membrane, which are located in the vagina, penis, rectum, and mouth. The most common methods of transmission are unprotected sexual intercourse, pregnancy, childbirth, and breastmilk, as well as the sharing of needles or syringes. HIV cannot be transmitted through saliva, kissing, touching, insect bites, sweat, sneezing, or coughing, all of which are common misconceptions associated with the transmission of the virus.

Though often erroneously used synonymously, AIDS, or Acquired Immunodeficiency Syndrome, is different than HIV. Left untreated, HIV can progress into AIDS, making it impossible to contract AIDS without first contracting HIV, which is why the two names are often used in conjunction with one another (e.g. HIV/AIDS). Often, HIV is asymptomatic. As such, it can remain dormant in the body and be undiagnosed for years. Once it reaches the bloodstream, HIV attacks the body’s immune system by targeting white blood cells known as CD4+ T-cells, which normally aid the body in fighting off infections and diseases. HIV is a retrovirus, meaning that it can write genetic code into the DNA of infected cells, effectively hijacking them and replicating within T-cells, thereby producing more cells with that same HIV+ genetic code and killing many disease-fighting cells in the process. This process can go on for several years, leaving the individual generally healthy and asymptomatic. As the virus remains in the body over time, T-cell counts can significantly diminish; when the T-cell count drops below 200, HIV has progressed to AIDS. This low T-cell count means that there are fewer cells protecting the body, making those living with AIDS extremely susceptible to infections and diseases that their bodies cannot adequately fight. Thus, patients do not die directly of AIDS, but rather of AIDS-related causes.

However, being HIV+ is far from a death sentence. The fact that there is no current cure for HIV should not discount the profoundly progressive strides the medical community has taken in creating treatments and preventative medicines, as well as conducting research that attempts to improve the lives of those currently living with HIV and AIDS. The most widely used treatment for HIV is currently a combination regimen of medicine known as ART, or Antiretroviral Therapy. Although ART does not cure HIV, it can reduce a patient’s viral load – the amount of detectable virus in the body – to a level that is undetectable. At this stage, the virus remains present in the body, but it cannot be transmitted to a partner. ART can also prevent perinatal transmission of HIV.

Recently, there has been a media frenzy of articles claiming that “A Cure for HIV is Here.” While titles like this are misleading, it is important to note the miraculous story of a man once diagnosed with HIV who now has no trace of the virus in his body. This patient, known as “The London Patient” received a bone-marrow transplant to treat his HIV-induced Hodgkin’s Lymphoma, which eliminated the virus from his body. This is the second known case of an HIV+ individual being “cured” of HIV/AIDS as the result a bone-marrow transplant. In both the case of “The London Patient” and the first known cured individual, Timothy Ray Brown (also known as “The Berlin Patient”), the bone-marrow transplant was not intended as a cure or even a treatment for AIDS, but rather as an attempt to rid the body of a chemotherapy-resistant cancer.

The two patients were “cured” because these transplants coincidentally had mutations in the CCR5 gene, which encodes a protein that HIV employs to enter the T-cells. Without this functional protein, the replication of HIV+ cells is halted. This genetic mutation is believed to impact 1% of Northern European populations and is hypothesized to have been introduced to the population by Vikings. This cure, while incredible and a huge medical advance, is not, however, accessible for the majority of the millions of infected individuals around the world. In addition to the procedure being expensive, difficult to achieve, and incredibly painful with harmful side effects, bone marrow transplants are often hard to come by and patients in need of a transplant can wait years before finding a match. Additionally, such procedures are largely unavailable and inaccessible to the majority of HIV+ individuals who often do not live in areas which can provide such medical treatment; nor do many of them have the financial means to cover the high costs of such a complex procedure. Though it is unlikely that the CCR5 gene will lead to an immediate and accessible cure for the virus, discoveries like this make it crucial to continue the production of new research and studies. There remains hope that a cure can be found, alongside treatments that both prevent and combat the virus as institutions such as the UCLA AIDS Institute, along with many others, continue to work towards creating an AIDS-free generation.

To learn more about the science behind HIV and AIDS you can visit: https://www.avert.org/professionals/hiv-science or http://scienceofhiv.org/.

Written by Isabella Goldsmith