At last, scientists discover why some Africans have lower HIV viral loads

Africans possess a rarefied genetic variant that only exists in their population and enables them to fight HIV naturally, a new groundbreaking research shows.

A team of scientists may have at last cracked the code as to why HIV viral loads are significantly lower in infected people of African ancestry.

Viral load is the level of the virus found in a HIV patient’s system.

Individuals with higher virus levels are characterised by speedy progression of the disease, which subsequently increases their transmission risk.

Several factors influence virus levels, which widely vary from one person living with HIV to the other. Genetic composition of an individual is one of the key determinants of virus levels.

Africans possess a diminished viral load, which minimises their virus transmission. As a result, this slows down the disease progression within their bodies, as illustrated by the revolutionary study published in the scientific journal Nature.

The research team comprised scientists from Canadian National Microbiology’s Public Health Agency, the department of Medicine at the University of Cambridge and London”s Imperial College.

The team racked their brains for nearly three decades to arrive at their findings, which are first of their kind.  “We have succeeded in identifying not only a new genetic variation but also one that exists only in this population and is associated with lower viral loads of HIV, by analysing a huge sample gathered from Africans,” explained the lead author from Public Health Agency Paul McLaren. 

Scientists are upbeat that the study could significantly impact spirited search for HIV cure, which has remained elusive. 

  HIV remains a major global public health issue, having claimed 40.4 million lives so far with ongoing transmission in all countries globally. Some countries are reporting increasing trends in new infections. There were an estimated 39.0 million people living with HIV at the end of 2022, two thirds of whom are in the WHO African Region, according to the World Health Organisation.

 Experts have decried the scanty information on the link between DNA and HIV among Africans.

Even though the African continent bears the brunt of HIV, a large chunk of studies focuses on European populations.

“The importance of better understanding the genetic role of HIV infection among African populations cannot be overemphasised. The continent, which is home to over 25 million people living with HIV,  is disproportionately affected by the virus,” stated the experts. 

“Africans bear the greatest burden of HIV infection but their under-representation in studies pertaining to human DNA still abounds.”

DNA samples of around 4,000 African individuals living with the most common virus strain, HIV-1, were analysed. Inside chromosome 1, the researchers noticed a variation which contained CHD1L gene.

This gene is linked to carriers with lower virus levels of the variant.

The role of CHD1L in repairing DNA that is damaged is widely known. However, scientists are still burning the midnight oil to establish why the variant should play a significant role in viral load reduction. The researchers estimate that between four per cent and 13 per cent of people of African ancestry carry this variant. 

The researchers used generated cell variants capable of being HIV infected using stem cells. This is because the virus attacks immune cells. They observed that CHD1L activity was either turned down or had been shut.

When the CHD1L was shut, HIV replication was seen to be better in macrophage — a type of immune cells. In an unprecedented twist, however, no effect was detected in another type of cell known as T cells.

Considering it is in T cells that most replication of HIV takes place, this was an unusual deviation.

Lead researchers André Lever and Dr Harriet Groom opined that “the gene seemed to play a vital role in controlling levels of the virus in African populations.

“Even though we are yet to ascertain how it does this, we discover a new thing each time regarding control of HIV. We not only learn a new thing about the virus but also a new thing about the cell as well.”

“This link between viral load and replication of HIV in macrophages is unexpected and particularly interesting,” said Dr Groom.

Prof Manjinder Sandhu, research co-author based at London’s Imperial College Faculty of Medicine,  notes that the fight against HIV is very far from over.

“We have not found a cure, we are yet to find a vaccine for infection prevention, and we are still seeing some individuals developing resistance to drugs. Clearly, there is still a long way to go in the fight against the virus considering we have over a million new infections reported yearly,” remarked Prof Sandhu.

He said understanding fully how HIV replication is controlled by the genetic variant should promptly follow.

The latest developments come even as the world is basking in optimism after yet another person was declared effectively cured of HIV in a major scientific breakthrough.

The Swiss national identified as the Geneva Patient brought to six the number of individuals ‘cured’ of the virus all from Western countries.

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