New assay could detect hidden viral reservoirs in HIV-infected patients

Researchers at the University of Pittsburgh (PA, USA) have created a new assay, known as TZA, which could potentially be sensitive enough to detect and quantify the latent reservoir of HIV that resides in infected individuals even after treatment.

This work, which was published in Nature Medicine, also suggested that the quantity of this latent reservoir in aviremic patients could be up to 70-fold larger than previous estimates.

Professor at the University’s Department of Infectious Diseases and Microbiology and senior author of this study, Phalguni Gupta, commented on the significance of this problem: “Globally there are substantial efforts to cure people of HIV by finding ways to eradicate this latent reservoir of virus that stubbornly persists in patients, despite our best therapies. But those efforts aren’t going to progress if we don’t have tests that are sensitive and practical enough to tell doctors if someone is truly cured.”

To allow scientists to quantify any ’hidden’ HIV reservoirs, this assay detects a gene that is only switched on in the presence of replicating HIV.

This novel assay could offer many advantages compared to other techniques, such as ‘quantitative viral outgrowth assay’ or Q-VOA, which is currently the best available assay for the task. TZA costs a third as much as Q-VOA and produces results in half the amount of time.  As well as also being less labour-intensive, significantly less blood is also required from the patient.

Gupta commented on the advantages of this new assay: “Using this test, we demonstrated that asymptomatic patients on antiretroviral therapy carry a much larger HIV reservoir than previous estimates—as much as 70 times what the Q-VOA test was detecting. Because these tests have different ways to measure HIV that is capable of replicating, it is likely beneficial to have both available as scientists strive toward a cure.”

These advantages suggest that this assay, TZA, could be utilized as a faster and more accurate method for quantifying latent reservoirs residing in infected individuals, hopefully helping further research which aims to eradicate this virus completely from the population.

Sources: Sanyal A, Mailliard RB, Rinaldo CR et al. Novel assay reveals a large, inducible, replication-competent HIV-1 reservoir in resting CD4+ T cells. Nat. Med. doi: 10.1038/nm.4347 (2017) (Epub ahead of print);


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