Major HIV concern: Drug therapy may reduce HIV to undetectable levels, but it is still growing

A new study, funded by the National Institutes of Health, has revealed that HIV infected patients may still be at risk of the infection even when undergoing antiretroviral therapy (ART). Drug therapy may reduce HIV in blood to undetectable levels but the virus replicates in lymphoid tissues such as lymph nodes that help maintain reservoirs of the virus.

According to the study researchers, a deeper understanding of how HIV virus persists inside the body of the infected is essential for development of strategies. This can eliminate even the undetectable viral reservoirs. This will only be a prerequisite for achieving a HIV cure.

ART may quickly suppress the HIV virus in blood to undetectable levels but they are ineffective in destroying the viral reservoirs in the tissue. Health experts have long debated why these reservoirs are maintained.

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In a bid to get a valid answer, the investigators sequenced viral DNA from blood cells and lymph nodes collected from three HIV infected patients. The data was collected before and during the first six months of ART. They found out that the virus evolved over time showing ongoing replication.

However, they did not accumulate mutations presenting drug resistance. The researchers also demonstrated continuous HIV replication in lymphoid tissue sanctuaries led to refilling of viral reservoirs in those on ART even when their blood does not show HIV virus presence.

Northwestern University's Steven Wolinsky, M.D., and colleagues also developed a mathematical model for explaining how the virus evolves during ART without the appearance of highly drug-resistant strains.

The calculations based on the model revealed drug-resistant strains are dominated by drug-sensitive HIV strains when effective drug concentration is low in the body. However, at intermediate concentrations, the drug-resistant strains start dominating and during high concentrations, HIV cannot grow.

The findings can be extremely useful in devising strategies that can deliver clinically effective drug concentrations throughout lymphoid tissue compartment. It may pave way for a promising HIV cure in future, reports EurekAlert.