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AASLD 2013: HCV Levels in Semen May Correspond to Blood Viral Load

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HIV positive men with higher hepatitis C virus (HCV) RNA levels in their blood during acute infection were more likely to have HCV in their semen as well, which may raise the risk of sexual transmission, researchers reported last month at the 64thAASLD Liver Meeting in Washington, DC.

Since the early 2000s clinicians have reported outbreaks of apparently sexually transmitted HCV among HIV positive men who have sex with men. Transmission has been associated with a variety of factors including anal sex, fisting, non-injection recreational drug use, and presence of other sexually transmitted infections, but the precise mechanism of sexual transmission remains unclear. HCV is transmitted efficiently through blood, but studies of HCV in semen have yielded conflicting results

Daniel Bradshaw from the Kirby Institute of the University of New South Wales and colleagues measured HCV RNA levels in blood plasma and semen of HIV positive men with acute or chronic hepatitis C, hypothesizing that sexual transmission in this population may be fueled by high HCV levels in semen during acute or recent infection.

According to the poster abstract, the analysis included 53 men with hepatitis C recruited in Sydney; the median age was 50 years. Of these, 13 (24%) were HIV positive with acute HCV (less than 12 months), 19 (36%) were HIV positive with chronic HCV (more than 12 months), and 21 (40%) had chronic HCV monoinfection.

Men with acute HCV had a 5-month median duration of infection, with 38% infected less than 3 months. HCV genotype 1a was most common (57%), followed by 3a (28%), 1b (8%), and 4 (8%). Most HIV positive men were on antiretroviral therapy with undetectable HIV viral load and the median CD4 T-cell count exceeded 600 cells/mm3.

The researchers measured HCV in paired blood plasma and semen samples using the Abbott M200 RT-PCR assay, optimized for quantification of HCV RNA in semen, with a lower limit of detection of 60 IU/mL.

Results

  • Overall, 43% of men had detectable HCV in their semen.
  • Median blood plasma HCV RNA viral load was 6.1 log IU/mL, with no significant difference between the 3 groups.
  • When detectable, median semen HCV RNA was 1.9 log IU/mL -- 4.2 log lower than plasma levels.
  • There were no significant differences in the proportion with detectable semen HCV between men with acute and chronic hepatitis C (46% vs 43%), nor between HIV positive and HIV negative men (41% vs 48%).
  • Overall, there was a trend toward higher median plasma HCV RNA in men with detectable compared with undetectable semen HCV RNA (6.2 vs 5.9 log IU/mL), but this did not reach statistical significance.
  • Among HIV positive men with acute HCV, however, median plasma HCV RNA was significantly higher among those with detectable vs undetectable semen HCV RNA (6.2 vs 4.8 log IU/mL).

"For men with acute HCV/HIV coinfection, detectable HCV RNA in semen was more likely with a higher plasma HCV RNA, implying a possible relationship between viral dynamics in plasma and semen in the acute phase of HCV," the researchers concluded. "If, as previously described, HIV coinfected individuals in the early acute phase of HCV have a higher plasma HCV RNA and lower HCV clearance, this could lead to increased semen HCV RNA, facilitating sexual transmission."

12/18/13

Reference

D Bradshaw, F Lamoury, B Catlett, M Danta, et al. Seminal HCV RNA level may mirror dynamics of plasma HCV RNA in HIV-positive men with acute infection. 64th Annual Meeting of the American Association for the Study of Liver Diseases (AASLD 2013). Washington, DC, November 1-5, 2013. Abstract 1453.