HIV latency differs across tissues in the body

Available antiretroviral drugs significantly prolong life expectancy in people living with HIV. However, the virus can escape host defenses and drug treatment by establishing a reversibly silent infection in immune cells that produce a protein called CD4 (i.e., CD4+ T cells). This latent infection, which is characterized by inactivated HIV transcription, represents the major barrier to a cure. While much of the research to date has highlighted the importance of CD4+ T cells in the blood as reservoirs for latent HIV, it is becoming increasingly apparent that the gut may play an integral role as a major tissue reservoir for the virus. To compare the mechanisms that inhibit HIV transcription in the gut and blood, Yukl and his colleagues quantified HIV transcripts in cells from the blood and rectum of HIV-infected individuals effectively treated with antiretroviral drugs.

The researchers found that different mechanisms block HIV transcription and underlie HIV latency in CD4+ T cells in the blood and gut. Moreover, the findings suggest that the rectum may be enriched for latently infected cells, or cells in a deeper state of latency. These differences in the blocks to HIV transcription are important to consider in designing therapies that aim to disrupt HIV latency in all tissue compartments. In particular, infected cells in the rectum may be less susceptible to agents designed to reverse latency or may require different types of therapies.