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Vertical HCV transmission fundamentally different according to maternal coinfection status

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November 3, 2018

Maternal neutralizing antibody responses have a role in preventing vertical transmission of hepatitis C virus, but not among women coinfected with HIV, according to study findings published in The Journal of Infectious Diseases.

The findings suggest that the mechanism for vertical transmission of HCV may be different between monoinfected women and coinfected women, said Hugo Soudeyns, PhD, professor and chair of the department of microbiology, infectiology and immunology at the University of Montreal, and colleagues.

“It is established that the rate of vertical HCV transmission is augmented significantly when the mother is coinfected with human immunodeficiency virus type 1 (HIV-1),” they wrote. “We and others have proposed that inhibition by HIV-1 of maternal HCV-specific immune responses could be responsible for this increased transmission risk, but there is little direct experimental evidence in support of that hypothesis.”

Their investigation of vertical HCV transmission included 17 pregnant women with HCV monoinfection and 15 with HCV/HIV-1 coinfection, including seven cases of vertical HCV transmission.

“We found that quasispecies diversity was strongly correlated with selective pressure directed against [hypervariable region 1 (HVR1)]” — a target for humoral immunity — “and neutralizing activity in both monoinfected and coinfected women,” they wrote. “These results suggest that HCV quasispecies diversity in pregnancy results from immune pressure exerted on HVR1 by maternal neutralizing antibody responses regardless of coinfection status.”

According to Soudeyns and colleagues, the results also showed an association between the diversity of HCV quasispecies during pregnancy and the risk for vertical HCV transmission in monoinfected women, but not in coinfected women, “suggesting an important role of maternal neutralizing antibody response in limiting vertical HCV transmission. Our findings also imply that in presence of maternal coinfection, effective neutralizing activity, although coercing the virus to evolve, is insufficient to prevent vertical transmission.”

“Our results clearly argue in favor of the mechanisms involved in vertical HCV transmission being fundamentally different according to maternal coinfection status,” the authors concluded. “Results of this study could inform future management strategies for HCV-infected women willing to become pregnant and encourage treatment with direct-acting antiviral agents in women presenting with a low HCV quasispecies diversity in the preconception or early pregnancy periods.” – by Caitlyn Stulpin

Disclosures: The authors report no relevant financial disclosures.