Researchers from RMIT University and collaborating institutions have discovered a key reason why influenza can lead to severe complications during pregnancy. Their study, published in Science Advances, identifies a viral sensor called TLR7 that becomes overly active in pregnant women, causing inflammation and potentially fatal effects on both mother and fetus.
Using animal models, the team found that during flu infection, this sensor triggers an immune response that extends beyond the lungs into the bloodstream. This overreaction can disrupt vascular function and lead to severe maternal and fetal complications.
"Previously, we thought that influenza directly harmed babies in the womb," said Dr. Stella Liong from RMIT's School of Health and Biomedical Sciences. "But our research shows that it’s actually an exaggerated immune response by the mother that causes harm."
The study suggests that blocking TLR7 could help prevent these dangerous effects. By targeting this sensor, treatments might be developed to reduce inflammation during flu infection in pregnant women.
"Future therapies could focus on dampening down the overactive maternal immune system rather than attacking the virus itself," explained Professor Stavros Selemidis, co-lead author of the study. "This shift in understanding opens up new avenues for treatment and prevention."
Dr. Gemma Trollope, a first author on the research who is now at the Olivia Newton-John Cancer Research Institute, emphasized the importance of vaccination: "The best defense against maternal flu complications is immunization. We hope this finding leads to stronger health messaging about the safety and efficacy of flu vaccines during pregnancy."
Previous studies have shown that severe flu in pregnancy can affect babies' brain development by inflaming blood vessels and reducing oxygen and nutrient flow from mother to baby. The new research identifies TLR7 as a key player in these complications, offering hope for targeted treatments.
"This discovery redefines how we think about infection during pregnancy," said Dr. Liong. "With this information, we can develop more effective strategies to protect both mothers and their unborn children."
The team is planning further studies to explore how to block TLR7 safely and effectively in pregnant women. As the research progresses, it could lead to new treatments that specifically target the immune system's overreaction during flu infection.
"Understanding these mechanisms will be crucial for developing safer therapies and improving maternal health outcomes," added Professor Selemidis.
