London: Casting doubts on finding a cure for HIV anytime soon, British researchers have found that the virus can grow 'silently' in patients who are thought to be responding well to treatment.
Advances in anti-retroviral therapy given to HIV patients over the past 30 years mean that most patients can have their virus suppressed to almost undetectable levels and live a long and healthy life.
It had been thought that after many years of successful treatment, the body would naturally purge itself of the virus.
"This research shows that sadly, the HIV virus has found yet another way to escape our treatments,” said lead researcher Anna Maria Geretti, professor at University of Liverpool.
For the study, the researchers followed patients undergoing uninterrupted treatment for up to 14 years.
"The good news is that we did not see any worsening over time, but the bad news is that these findings really cast doubt over whether HIV can be 'cured' by increasing immune cell responses against it - a strategy that now looks like it will eventually fail," Geretti noted.
The researchers found that during treatment for HIV the virus hides in blood cells that are responsible for the patient's immune response.
The virus does this by inserting its own genetic information into the DNA of the blood cells, called CD4 Tlymphocytes.
The study measured the levels of integrated HIV in the CD4 cells of patients undergoing uninterrupted treatment for up to 14 years, and compared patients receiving treatment for different lengths of time.
The researchers discovered that the amount of HIV found to be integrated in the CD4 cells was undiminished from year one to year 14.
The research demonstrates that whenever a CD4 cell multiplies to produce more cells, it copies itself and also copies the HIV genes.
This process - a sort of silent HIV replication - means the virus does not need to copy itself, produce new virus particles, and infect new CD4 cells - but is automatically incorporated at the birth of the cell, the study noted.
The findings were published in the journal 'EbioMedicine'.