HIV RNA may persist in rectal tissue even after a person achieves viral suppression in plasma, a small study published in AIDS showed.
Viral loads in blood and rectal tissue were measured in 12 participants, six of whom are women, before they started antiretroviral therapy, and were measured again 2, 6 and 12 weeks into treatment. All volunteers started on a three-drug antiretroviral regimen that contained dolutegravir.
Every participant had an undetectable plasma viral load by week 6. However, only 27.3% (3 people) had an undetectable level of the virus in their rectum at any point during the study.
Baseline viral loads in both plasma and rectal tissue were lower in those who achieved rectal viral suppression than in the other participants. However, viral suppression in rectal tissue was independent of dolutegravir levels.
All three of the people with a suppressed rectal viral load in this study were women. This study was too small to determine why this might be so, but larger studies are planned that should elucidate potential sex differences in tissue viral load, study authors said.