Rectal cell-associated HIV-1 RNA: a new marker ready for the clinic.

Gut-associated lymphoid tissue is a huge reservoir for HIV-1. Developing new strategies to target "residual" HIV-1 in patients on effective therapy brings the need for an evaluation of tissue reservoirs in the clinic. We measured cell-associated HIV-1 RNA and DNA in blood and rectal biopsies from 23 patients, including 14 with undetectable viremia on HAART, by using an adaptation of commercially available tests. Rectal cell HIV-1 RNA was detected in all viremic patients, with median levels of 4.90 log(10) copies/million CD4. Although plasma viremia was found at a median of 3 copies/mL in "aviremic" patients, rectal cell HIV-1 RNA was detected in 28.5% with median levels of 5.17 log(10) copies/million CD4. Consequently, we propose to use this marker in future clinical trials targeting "residual" HIV-1 in patients with viremia below the detection limit.