amfAR, The Foundation for AIDS Research

Gut vs. Blood: Deeper States of HIV Latency

Jeffrey Laurence, M.D.

Earlier this year, we presented research by amfAR grantees investigating HIV latency in cells apart from CD4+ T cells of the blood. These reports included studies of specialized cells in the brain and vagina that may represent unrecognized reservoirs for latent HIV, and thus additional impediments to an HIV cure.

Dr. Steve YuklDr. Steve YuklWriting in the November issue of PLoS Pathogens, amfAR-funded scientists Steve Yukl and colleagues from the amfAR Institute for HIV Cure Research continue this work, exploring latency in cells of the intestine vs. the blood.

A technique known as “transcription profiling” was used to examine the initial steps of the viral life cycle in infected CD4+ T cells from the blood and cells extracted from rectal biopsies. Sixteen HIV-infected individuals were included; all but one were male. They were followed as part of two long-term studies, and all individuals had complete suppression of virus with ART—as assessed by blood tests—for a range of 2 to 10 years.

Yukl and colleagues found that CD4+ T cells from the rectum may be more vulnerable to latent infection compared with T cells isolated from the blood. This “deeper state of latency” in the gut suggests that it is maintained by different processes than in the blood. One such mechanism, a block in transcriptional initiation—the first step in the viral life cycle of infected cells—was particularly prominent in the gut. Whether this difference is due to special features of HIV viruses that infect gut tissues, or conditions peculiar to the gut, is being explored.

The authors conclude that “infected cells in the rectum may be less susceptible to agents designed to reverse latency. [Our studies] could help inform new therapies aimed at HIV cure.”

Dr. Laurence is amfAR’s senior scientific consultant.