New York- Covid-19 infection during pregnancy leads to distinct immune changes in mothers and babies, according to a study.
The researchers found that Covid-19 dysregulates maternal immune response, with different immune signatures between mothers with asymptomatic and severe disease.
"We know that pregnancy increases maternal risk for Covid-19, but relatively little is known about the long-term consequences of in-utero exposure for infants," said Jae Jung, Director of the Cleveland Clinic Global Center for Pathogen & Human Health Research.
The study highlights "how important it will be for long-term follow-up after pregnancy to catch and hopefully prevent any unforeseen long-term health conditions related to prenatal infection,"Jung added.
For the study, published in the journal Cell Reports Medicine, the team involved 93 mothers with Covid-19 and 45 of their infant children who were exposed to SARS-CoV-2, the virus that causes Covid-19.
The research team studied immune profiles for more than 1,400 cytokines and other inflammatory proteins collected from peripheral and cord blood samples.
The researchers compared maternal blood specimens collected close to the initial detection of SARS-CoV-2 and at different time points throughout pregnancy and delivery.
They found that compared to mild or moderate disease, pregnant women with severe Covid-19 exhibited significantly more inflammation and elevated levels of a protein called IFNL1 (interferon lambda 1) and the receptor it binds with, IFNLR1, which plays a critical role in protecting against viruses.
"This increase in interferon lambda signaling may help explain why we see relatively little direct transmission of Covid-19 between mother and baby during the period right before or after birth -- what we call vertical transmission," explained Suan-Sin (Jolin) Foo, a research associate in Dr. Jung's lab and co-first author on the paper.
Despite the lack of evidence for robust vertical transmission, the researchers found that SARS-CoV-2 infection alters maternal immunity at delivery and that gestational SARS-CoV-2 exposure alters infant immunity at birth.
At delivery, the women exhibited dysregulated levels of several cytokines that are associated with pregnancy complications, including MMP7, MDK, ESM1, BGN and CD209.
Among infants, prenatal exposure induced the expression of cytokines related to T cells, which are a type of immune cell involved in recognising and attacking specific antigens.
The majority of births within the cohort were healthy, but there was a high incidence of some complications, including preeclampsia and foetal growth restriction.
More research will be necessary to understand the extent to which the observed immune changes are related to these clinical outcomes, the team said.
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