Hepatitis C viral load in semen of HIV-positive men during acute and chronic hepatitis C infection

BACKGROUND: Acute hepatitis C infection (HCV) in MSM is well described. Sexual transmission of HCV is suspected, but the excess among HIV- positive men remains unexplained. One factor may be a higher concentration of HCV virus in body fluids in HIV-co-infection, particularly during acute infection, as described for HIV itself. HCV is present in the extracellular fluid of semen (seminal plasma). In HIV co-infection up to 40% of HCV viraemic patients have HCV RNA detectable in seminal plasma. We hypothesised that HIV- positive men with acute HCV infection were more likely to have detectable HCV in seminal plasma than those with chronic HCV infection and that the viral load may be higher. METHODS: Paired blood and semen samples were collected from each man at presentation of acute HCV (defined as HCV-RNA positive/anti- HCV negative with follow up confirming acute infection or HCV RNA positive with previous negative within 6 months and >10× rise in ALT), with repeat samples at 1 and 6 months. For the control group (HCV infection for > 6 months and not on HCV treatment), paired samples were taken at baseline (recruitment), 1 and 6 months. HCV RNA quantification on plasma and seminal plasma was performed using an automated nucleic acid extraction with amplification and detection by TaqMan PCR. HCV VL lower limit of detection is 10 IU/ml. RESULTS: To date, 5 acute HCV cases and 9 chronic HCV cases have been recruited. At baseline 0/5 acute and 2/9 chronic cases had detectable HCV RNA in semen. Of all samples tested 2/10 (20%) of acute cases and 4/23 (17%) of chronic cases (NS) had detectable HCV RNA in semen. In all, HCV RNA viral loads were < 30 IU/ml (acute cases) and < 230 IU/ml (chronic cases). HCV RNA in semen did not correlate with plasma HCV viral load. CONCLUSION: In this study there was no evidence that seminal HCV RNA viral loads were higher in acute HCV infection. The majority of HCV seminal viral loads were undetectable and when present, were in very low quantities. This suggests that the quantity of seminal HCV virus is not a significant factor in determining the rate of HCV transmission. Recruitment to the study is ongoing.