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HCV antibody testing may miss recent infections in gay men living with HIV
Michael Carter, 2014-09-23 08:00:00
testing should be used to diagnose acute hepatitis C virus (HCV) infections in
gay men living with HIV, Dutch research published in the online edition of Clinical Infectious Diseases shows. HCV
antibodies only developed a median of 74 days after infection with the virus. Over
half of people who had a successful response to HCV therapy lost their HCV
antibodies during follow-up. However, there was a high rate of re-infection,
and these could be reliably diagnosed using antibody testing.
acute HCV is…preferably performed using nucleic acid testing instead of
anti-HCV testing,” write the authors.
sexually transmitted HCV have been observed among HIV-positive gay and other
men who have sex with men (MSM) in several European and US cities. Routine
HIV care for people at risk of HCV should include regular HCV screens,
including testing for HCV RNA and HCV antibody testing.
But the utility of
antibody testing – especially for the diagnosis of acute infections – is open
to question. People with HCV mono-infection typically develop antibodies
within 30-70 days of infection, but there have been reports of a delayed
antibody response in people with HIV co-infection.
Amsterdam therefore designed a study to examine the HCV antibody dynamics in
gay men living with HIV with an estimated date of HCV infection. Their aims were
to determine time to emergence of antibodies following infection; antibody
response to spontaneous clearance or successful therapy; and antibody activity
following HCV re-infection.
The study sample
comprised 63 MSM. Most received care after 2009 and retrospective testing
of stored blood samples gave a firm date of primary infection with HCV.
Follow-up lasted four years.
All participants in the study
developed HCV antibodies. The median time between infection and the emergence
of antibodies was 74 days. Just over half (59%) had antibodies within three
months of infection, 73% within four months and 98% at twelve months.
subjects (27%) in our study, no anti-HCV antibodies were detected four months
after the estimated date of HCV infection,” comment the researchers. They
believe this shows the importance of using HCV RNA testing to detect recent
infections. But they also note that the median time to the emergence of
antibodies – 74 days – was comparable to that observed in some research
involving people with HCV mono-infection.
Overall, 36 participants cleared their infection, 31 after HCV therapy. A decrease, but not
complete loss of HCV antibodies, was observed in people with spontaneous
clearance. The cumulative incidence of loss of antibodies was 37% within three
years of their initial appearance, and 51% within three years of a successful
treatment response. Lower peak HCV viral load was associated with disappearance
A total of 21
re-infections were observed in 18 people who cleared the virus. Peak HCV
antibody levels were significantly higher following re-infection compared to
primary infection (p = 0.014). Disturbances in liver function were less
pronounced following re-infection compared to primary infection (median ALT, 66
vs. 119 u/l), suggesting that monitoring liver function may not pick-up all
“Our main findings
were that (1) the seroconversion window in this population was comparable to
the seroconversion window reported among HIV-uninfected subjects, (2)
seroreversion was very common following successful antiviral treatment, and (3)
after an initial decrease in anti-HCV levels following SVR, levels increased
following reinfection to levels reached during primary infection or higher,” comment
“monitoring antibody dynamics following SVR could thus be a useful and
inexpensive alternative or additional tool for evaluation and diagnosis of HCV
reinfection in the HIV-infected MSM population.”
But Dr Thomas Reiberger of the HIV and Liver Study Group, Medical University of Vienna, author of an
editorial that accompanies the study emphasises that acute HCV infections could be missed if only antibody testing was used. Early detection is important for prevention of onward transmission and also for provision of treatment - HCV is more likely to be cleared by interferon-based treatment during acute infection. He concludes that the study’s
findings support “broader use of sensitive quantitative PCR-based HCV-RNA
testing in this high-risk population.”