COVID-19 may cause fetal inflammation even in absence of placental
infection, researchers report

Date:
January 18, 2022
Source:
Wayne State University - Office of the Vice President for Research
Summary:
Researchers have found that SARS-CoV-2, the virus that causes
COVID-19, may cause fetal inflammation even in the absence of
placental infection.



FULL STORY ========================================================================== Researchers at the Wayne State University School of Medicine and the
National Institutes of Health's Perinatology Research Branch in Detroit
have found that SARS-CoV-2, the virus that causes COVID-19, may cause
fetal inflammation even in the absence of placental infection.


========================================================================== Pregnant women have a higher risk of severe illness if infected with
COVID-19.

Infection increases the risk of preterm birth, stillbirth and
preeclampsia.

"Maternal-fetal immune responses in pregnant women infected with
SARS-CoV-2," published today in the journal Nature Communications, reports
that COVID-19 infection during pregnancy may cause inflammatory immune responses in the fetus, even if the virus does not infect the placenta.

The study, conducted by Nardhy Gomez-Lopez, Ph.D., associate professor of
the WSU Department of Obstetrics and Gynecology, and section head of the Maternal- Fetal Immunobiology Unit, and Roberto Romero, M.D., D.Med.Sci.,
chief of the NIH's Perinatology Research Branch, based at the Wayne State University School of Medicine, and professor of Molecular Obstetrics and Genetics at the WSU School of Medicine, details changes in antibodies,
immune cell types and inflammatory markers in maternal blood, umbilical
cord blood and placental tissues.

"We found that in pregnant mothers who contract the virus, SARS-CoV-2
induces a fetal immune response even in the absence of placental
infection or symptoms in the newborn. The potential long-term effects
of this inflammatory process on infants requires further study,"
Dr. Gomez-Lopez said.

The researchers evaluated 23 pregnant women. Twelve tested positive for
SARS- CoV-2, and of those, eight were asymptomatic, one had mild symptoms
and three had severe COVID-19. After delivery, the researchers compared
immune responses between mothers and their newborns by comparing maternal
blood and umbilical cord blood. Inflammatory immune responses triggered
by the virus were observed in women, their newborns and placental tissues regardless of whether the mothers displayed symptoms.

The study team described the following observations:
* Pregnant women with SARS-CoV-2 had a reduction in an immune
cell type
called T-cells, which helps drive antiviral responses.

* Infected mothers developed antibodies against the virus whether
or not
they had symptoms, and some of these antibodies were found in the
umbilical cord blood.

* Infected mothers had a higher level of immune activity markers
(i.e.,
cytokines) in blood regardless of symptoms. The elevated cytokines
are interleukin-8, interleukin-15 and interleukin-10.

* Infants born to infected mothers, even if the mother had no
symptoms, had
an inflammatory response reflected by higher levels of
interleukin-8.

This elevation was observed even though the fetus presumably did
not have COVID-19.

* While the virus was absent in placentas, the placentas from infected
mothers had altered ratios of immune cell types. The researchers
also found altered immune activity (measured by changes in RNA
transcripts) in the placenta and cord blood of infants born to
infected mothers. These findings indicate that the neonatal immune
system is affected by maternal infection by SARS-CoV-2 even if
the virus is not detected in the placenta.

"This study provides insight into the maternal-fetal immune responses
triggered by SARSCoV-2 and emphasizes the rarity of placental infection,"
Dr. Romero said. "Most pregnant women with SARS-CoV-2 infection are asymptomatic or only experience mild symptoms. Regardless, in the first
six months of the COVID-19 pandemic, it was documented that infected
pregnant women are at an increased risk for hospitalization, mechanical ventilation, intensive care unit admission and preterm birth, but rates
of maternal mortality were reported to be similar between pregnant
and non-pregnant women. More recently, it has been clearly shown that
pregnant women are at high risk for severe disease and death, as well
as preterm birth. Investigating host immune responses in pregnant
women who are infected, even if they are asymptomatic, is timely."
These latest findings will help researchers better understand COVID-19
during pregnancy. The authors noted that the potential long-term effects
of this inflammatory process on infants requires further study.

This research was supported by the Perinatology Research Branch,
Division of Obstetrics and Maternal-Fetal Medicine, Division of
Intramural Research, Eunice Kennedy Shriver National Institute of
Child Health and Human Development, National Institutes of Health,
U.S. Department of Health and Human Services (NICHD/NIH/DHHS) under
Contract No. HHSN275201300006C. This research was also supported by the
Wayne State University Perinatal Initiative in Maternal, Perinatal and
Child Health.

========================================================================== Story Source: Materials provided
by Wayne_State_University_-_Office_of_the_Vice_President_for
Research. Note: Content may be edited for style and length.


========================================================================== Journal Reference:
1. Valeria Garcia-Flores, Roberto Romero, Yi Xu, Kevin R. Theis, Marcia
Arenas-Hernandez, Derek Miller, Azam Peyvandipour, Gaurav Bhatti,
Jose Galaz, Meyer Gershater, Dustyn Levenson, Errile Pusod,
Li Tao, David Kracht, Violetta Florova, Yaozhu Leng, Kenichiro
Motomura, Robert Para, Megan Faucett, Chaur-Dong Hsu, Gary Zhang,
Adi L. Tarca, Roger Pique- Regi, Nardhy Gomez-Lopez. Maternal-fetal
immune responses in pregnant women infected with SARS-CoV-2. Nature
Communications, 2022; 13 (1) DOI: 10.1038/s41467-021-27745-z ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2022/01/220118162448.htm

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