This Week in HIV Research: Average Time Between Diagnosis and Linkage to Care

This week, a study finds that the average time it takes to for newly diagnosed patients to enter care in the U.S. is three months. Meanwhile, researchers presented an assay that can evaluate the ability of latency reversal agents to awaken dormant HIV. And another study finds that HIV can hide in hematopoietic stem and progenitor cells, which can provide more clues into cure research. To beat HIV, you have to follow the science!

Delay Between HIV Diagnosis and Linkage to Care Averages 3 Months in U.S.

People living with HIV in the U.S. enter care about three months on average after learning that they have seroconverted, a data analysis published in Journal of Acquired Immune Deficiency Syndrome found.

It takes an additional almost four months for them to receive their second set of lab tests, and a little over a year after that to achieve undetectable viral loads. Once achieved, people were virally suppressed for an average of 4.5 years. Combining the delays in each of the stages, people spend an average of 20 months between an HIV diagnosis and viral suppression. Between diagnosis and linkage to care, about 8% drop out of care. Between linkage to care and engagement in care, almost 6% drop out. And between engagement in care and achieving viral suppression, about 10% drop out.

The model assumed that those who left the care continuum did not return. It thus represents a worst-case scenario, but its insights "have policy implications that can be helpful to clinicians and program managers," study authors concluded.

Assay Evaluates Levels of HIV Expression Induced by Latency Reversal Agents

An assay that can evaluate latency reversal agents (LRA) against resting CD4+ cells was presented in EBioMedicine.

LRAs cause the dormant CD4+ cells to express the virus, which can then be targeted by antiretroviral drugs. The latency clearance assay (LCA) also includes immune effectors that can eliminate the infected cells that have been activated by the LRA, according to an associated press release.

Researchers tested the assay with vorinostat (VOR), an investigative LRA. They showed that VOR can induce sufficiently high viral protein levels on the cell's surface for the clearance process to work. Because the assay is labor- and time-intensive, and needs a large number of cells that it can test, it should only be used to evaluate very promising LRAs, study authors cautioned. However, the findings "underscore the potential value of evaluating latency reversing agents within the context of viral clearance ex vivo, prior to ultimate in vivo testing," they concluded.

HIV Hides Also in Hematopoietic Progenitor Cells

HIV can hide in hematopoietic stem and progenitor cells (HSPCs) and can be passed on to "daughter cells," researchers reported in PLOS Pathogens.

Identification of all cell types that can harbor dormant virus is important for research into curing HIV by activating and eradicating all virus in the body. Stem cells are the undifferentiated cells from which various cell types are formed. Progenitor cells are the intermediate form of the specific cells that make up our blood, tissue, muscles, etc. Study authors analyzed bone marrow from eight people living with HIV who have an undetectable viral load. They found that the viral genome in HSPCs can be passed down to different "daughter" blood cells generated from these HSPCs, and that it can be either CCR5- or CXCR4-tropic.

Previously, only CXCR4-tropic genomes were thought to be long-lived. Knowing that HIV can hide in hematopoietic stem and progenitor cells can lead to better treatment strategies. "Having established this, now we're poised to ask if we can treat HIV infection by targeting hematopoietic progenitor cells," said study author Kathleen Collins, M.D., Ph.D., in an associated press release.