MONTREAL, April 7, 2020 – A research team from CHU Sainte-Justine and the Centre hospitalier de l'Université de Montréal (CHUM) has been studying the mother-child dynamics of human papillomavirus (HPV) antibody transmission in order to examine the natural immunology associated with the virus. Until now, very little data on the behaviour of these antibodies have been available. The results of this study are presented today in the journal EClinicalMedicine published by The Lancet.

HPV is one of the most common sexually transmitted infections in Canada and around the world. Although we know that it is not common for a pregnant woman to transmit HPV to her infant, there is little information on the natural immunity associated with HPV and the mother-child dynamics of antibodies.

HPV, a virus like no other!

"HPV behaves differently than other known viruses. For example, natural HPV infection does not induce a phase of viral presence in the bloodstream. As a result, the immune response to natural infection is often slow and characterized by a very low level of antibodies that have little chance of protecting the host from subsequent infection. This phenomenon is counter-intuitive since, in other viruses, natural infection normally produces high levels of antibodies, even more than vaccination," explains Professor Helen Trottier, a researcher at CHU Sainte-Justine and a professor at Université de Montréal.

"Here, we have been studying whether the behaviour of the virus also differs in the transmission of antibodies from mother to child," she adds.

HERITAGE cohort

The HERITAGE cohort, including HPV-positive pregnant woen, provided important data that have aided in correlating HPV antibody levels between mothers and newborns at birth and describing the dynamics of antibodies in children during the first two years of life.

"We collected blood samples from participants in the first trimester of pregnancy, then from the children at birth, and at 6, 12 and 24 months. In our analyses, the correlation between maternal and neonatal HPV antibodies suggested a vertical transfer. In addition, we found that most children eliminated the antibodies within 6 to 12 months following birth, which is similar to what happens with other viral infections," says Monica Zahreddine, the study's first author.

"It is important to understand the behaviour of HPV-related antibodies in order to shed light on the immunology of this particular virus. We already know that childhood immunization is generally less effective when maternal antibodies are still present in the child's body," adds Ms. Zahreddine. "Our data are reassuring because HPV antibodies transmitted during pregnancy appear to work in the same way as antibodies associated with other viruses, even for women who have been vaccinated." 

Cutting-edge expertise

In 2018, CHU Sainte-Justine announced the creation of the very first Mother and Child Infectious Diseases Center in North America whose purpose was to provide even more effective support to women, children and adolescents who are at risk or fighting against viruses or bacteria.

"Although antibodies to HPV are detectable in newborns and seem to wane from the age of 6 months, we must continue our research to determine whether or not these antibodies have a protective effect on the child," concludes Professor Trottier. "We want to increase our knowledge in the field of mother-child infectiology for the benefit of patients." 

About the study

The article "Antibodies to human papillomavirus types 6, 11, 16 and 18: vertical transmission and clearance in children up to two years of age" was published on April 7, 2020 in the journal EClinicalMedicine. The first author is Monica Zahreddine, MSc, a laboratory staff member under the direction of Helen Trottier. The principal author is Helen Trottier, PhD, Associate Professor at the School of Public Health of Université de Montréal (ESPUM) and researcher at CHU Sainte-Justine Research Center. The study was supported by the Canadian Institutes of Health Research (CIHR).

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