Rajesh T. Gandhi, MD reviewing Descours B et al. Nature 2017 Mar 15.

A subpopulation of CD4 cells expressing CD32a is enriched for HIV in patients on antiretroviral therapy.

Antiretroviral therapy (ART) does not cure HIV infection, because the virus persists in a latent reservoir of resting memory CD4 cells that does not appreciably decay over time. Now, researchers have identified a cell surface marker that they propose may identify the HIV reservoir.

To find candidate markers, the investigators first developed an in vitro model by infecting resting CD4 cells with HIV. Of 103 genes that were induced in infected but not in uninfected cells, 16 encoded cell surface markers. Of the markers, HIV infection most specifically induced expression of CD32a, an immunoglobulin G Fc receptor.

The investigators then examined cells from 12 patients receiving ART. CD32a+ cells (0.012% of total CD4 cells) had 1000-fold higher levels of HIV DNA than CD4 cells without this receptor. On a viral culture assay, CD32a+ CD4 cells contained up to 3000-fold more replication-competent HIV than other cells. When CD32a+ CD4 cells were depleted from the virus culture assay from three patients, HIV growth was delayed — although virus was still recovered.

CITATION(S):

Descours B et al. CD32a is a marker of a CD4 T-cell HIV reservoir harbouring replication-competent proviruses. Nature 2017 Mar 15; [e-pub]. 

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