Impact of Collection Method on Assessment of Semen HIV RNA Viral Load

Brendan J W Osborne,Colin Kovacs,Prameet M Sheth,Rupert Kaul,Tony Mazzulli,Douglas F Nixon

doi:10.1371/journal.pone.0023654

Brendan J W Osborne, Colin Kovacs + Show 4 more

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https://doi.org/10.1371/journal.pone.0023654

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Abstract

BackgroundThe blood HIV RNA viral load is the best-defined predictor of HIV transmission, in part due to ease of measurement and the correlation of blood and genital tract (semen or cervico-vaginal) viral load, although recent studies found semen HIV RNA concentration to be a stronger predictor of HIV transmission. There is currently no standardized method for semen collection when measuring HIV RNA concentration. Therefore, we compared two collection techniques in order to study of the impact of antiretroviral therapy on the semen viral load.Methodology/Principal FindingsSemen was collected by masturbation from HIV-infected, therapy-naïve men who have sex with men (MSM) either undiluted (Visit 1) or directly into transport medium (Visit 2). Seminal plasma was then isolated, and the HIV RNA concentration obtained with each collection technique was measured and corrected for dilution if necessary. Collection of semen directly into transport medium resulted in a median HIV RNA viral load that was 0.4 log10 higher than undiluted samples.Conclusions/SignificanceThe method of semen collection is an important consideration when quantifying the HIV RNA viral load in this compartment.

Highlights

There were an estimated 2.6 million new HIV-1 (HIV) infections in 2009 [1], most acquired through sex
No participant had a prior history of an AIDS-defining illness, and no participant had syphilis, N. gonorrhea or C. trachomatis infection by nucleic acid amplification testing (NAAT), clinical urethritis, genital ulcer disease or leukocytes detected on dipstick of first void urine
This study demonstrates that the method of semen collection can have a substantial impact on semen HIV RNA VL measurements, and this should be an important consideration when performing and assessing studies of semen HIV RNA load

Summary

Introduction

There were an estimated 2.6 million new HIV-1 (HIV) infections in 2009 [1], most acquired through sex. The blood HIV RNA viral load is the best defined predictor of HIV transmission [2], probably because it is measured and tends to correlate with the genital tract (semen or cervico-vaginal) viral load [3]. A significant minority of individuals continue to have detectable levels of viral RNA in semen despite an undetectable HIV RNA blood VL, sometimes at very high levels [6] Whether this phenomenon underpins the inability of ART to completely prevent HIV transmission is not clear. The blood HIV RNA viral load is the best-defined predictor of HIV transmission, in part due to ease of measurement and the correlation of blood and genital tract (semen or cervico-vaginal) viral load, recent studies found semen HIV RNA concentration to be a stronger predictor of HIV transmission. We compared two collection techniques in order to study of the impact of antiretroviral therapy on the semen viral load

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Conclusion