A domestic research team has revealed for the first time the principle by which inflammation during pregnancy causes allergies in the fetus. This research result is expected to lead to methods for early prediction and prevention of allergic diseases such as pediatric asthma.
KAIST announced on 4th that a research team led by Dr. Kwon Myung-seung from the Graduate School of Medical Science at Konyang University Hospital and Professor Lee Heung-kyu from the Department of Life Science has identified that inflammation occurring during pregnancy affects the fetal stress response regulation system through the placenta, thereby potentially intensifying allergic reactions.
The research team confirmed in mouse experiments that inflammation during pregnancy increases the survival and memory capacity of later-acquired immune cells known as T cells. They induced inflammation by injecting lipopolysaccharide (LPS), a known representative substance that induces inflammatory responses, into pregnant mice.
As inflammation occurred in the placenta, the signaling substance tumor necrosis factor-alpha (TNF-α) increased. The research team confirmed that this substance activated a type of white blood cell known as neutrophils, causing inflammatory damage to the placenta. This damage led to the excessive secretion of glucocorticoids, a stress hormone, in the fetus, resulting in significant changes in the immune system.
Ultimately, the fetal immune cells, T cells, survived longer and exhibited stronger memory functions. The stress induced by inflammation strengthened the immune response. When the later-born mice were exposed to antigens, the T cells reacted excessively, leading to allergic reactions. In fact, when house dust mites were injected into the mice's airways, immune cells increased, causing excessive inflammation and immune responses.
Professor Lee Heung-kyu noted, "This research result is the first in the world to elucidate how the mother's inflammatory response during pregnancy affects the fetal allergic immune system through the placenta," adding, "In the future, this will provide crucial scientific evidence for the development of biomarkers for early prediction of pediatric allergic diseases and the establishment of prevention strategies."
This research result was published in the international journal 'Mucosal Immunology' on July 1.
References
Mucosal immunology(2025), DOI: https://doi.org/10.1016/j.mucimm.2025.06.006