AIDs changed the world. Now the world of AIDs is changing.

AIDs changed the world. Now the world of AIDs is changing.

Hannah Kitt explores the latest developments in fight against AIDS

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The now-infamous AIDS epidemic was first reported in June 1981. The Centers for Disease Control and Prevention reported an astonishing 774,467 cases of AIDS within the US between 1981 and 2001, with a mortality rate of over 50%.  Despite this clear global health issue, progress was slow. Funding into scientific research was limited, and it took 3 years for the World Health Organisation to recognise this global situation.

Nonetheless, advances were slowly made. It was discovered that AIDS results from infection by the HIV virus. The virus enters specific cells in the immune system, called CD4+ T cells. It hides inside these immune cells, making copies of itself before spreading even further within the immune system. As the virus replicates and spreads, its CD4+ host cells are destroyed. Eventually the amount of CD4+T cells becomes so low that the immune system shuts down, making the body vulnerable to any number of infections. The fact that the virus hides within our own cells makes it difficult to kill and develop an effective treatment.

The fact that the virus hides within our own cells makes it difficult to kill

Since these initial discoveries, scientific research has advanced in leaps and bounds. Since 2008, a 20 year old patient with a low viral load treated with antiretroviral therapies (ATRs) has a life expectancy of 78 years, only just falling short of the average life expectancy. ARTS usually consist of 3 different drugs, each blocking the progression of HIV. ARTs have been called ‘one of the greatest public health success stories of the past 40 years’. But they are not perfect. ARTs must be taken daily over the course of a lifetime, and can have serious side effects which vary between drug combinations, but can include: diarrhoea, vomiting, anaemia, and muscle aches.

Aids definition. Source: The blue diamond gallery

Ten years ago, the ‘Berlin patient’ appeared to have been cured of HIV in a stroke of serendipity. The Berlin patient underwent a bone marrow transplant (BMT) to treat his cancer. The donor bone marrow originated from a person with a genetic mutation in the CCR5 gene, which makes immune cells resistant to HIV. This was thought to explain how HIV was eradicated from the Berlin patient.

However, six more individuals who had BMTs to treat cancer appear to be cured from HIV. Of these six patients, only one received bone marrow from a donor with this CCR5 mutation, suggesting there must be another explanation. What all six patients have in common with each other, and with the Berlin patient, is that they all suffered from the same side effect of BMTs: graft vs host disease.

Image of HIV-infected cell (HIV shown in green) Source: wiki-commons

Graft vs host disease is a dangerous complication of BMTs where the donor immune cells attack the recipient’s immune cells. The recipient’s immune cells consequently die, along with the HIV hiding within them. Although inducing graft vs host disease is not a viable option, especially in people with a life expectancy of 78 years, research into these 6 BMT patients will provide more insight into the mechanisms of HIV.

A further trial started 3 years ago, involving 24 newly diagnosed HIV cases. Now, 5 of these participants have undetected levels of the virus in their system. Although they cannot be officially declared totally cured until more time has passed, it certainly looks promising.

if successful, science will have drastically changed the fate of an HIV positive diagnosis.

In this trial, another approach was taken. Participants were given 2 vaccines, with booster doses, and additional doses of romidepsin. The vaccines lead to production of proteins found in all different variants of HIV. The immune system develops the ability to recognise and destroy these proteins, so when the romidepsin flushes the dormant HIV out from the CD4+ T cells, the immune system can destroy the HIV.

This vaccine trial, if successful, has the potential to be applied on a much larger scale. And if successful, science will have drastically changed the fate of an HIV positive diagnosis.

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