Aditi Kaveti ’23
It is estimated that anywhere from 10 to 30 percent of the world’s population is affected by allergies, with thousands more learning to manage their new condition every week. These allergies occur when the immune system, in response to a foreign substance, produces antibodies that bind to cells, which release chemicals that trigger a reaction. Many infants experience allergic responses closely linked with the mother’s allergic responses in specific ways that suggest the transfer of allergies is due to more than just genetics.
Dr. Florent Ginhoux, Senior Principal Investigator at A*STAR’s Singapore Immunology Network (SIgN), has been studying mast cells in the developing fetus. His team focuses on how this cell, one of the first lines of defence in the fetus’s immune system, becomes sensitized to antibodies and releases chemicals that trigger allergic reactions. Researchers exposed mice to a common allergen, ragweed pollen, prior to pregnancy. This allergen induced a sensitivity in certain mice that passed it onto their offspring. The experimental results were supported by cellular tests and imaging.
The most important discovery in Ginhoux’s study was that immunoglobulin E (IgE), a key antibody responsible for allergic reactions, is able to cross the placenta and enter the fetus. IgE then binds to fetal mast cells, causing degranulation, the release of chemicals that triggers an allergic reaction. This mother-to-child transfer of allergies is allergen-specific, as the offspring only showed a sensitivity to ragweed pollen and not to any other common allergen. Additionally, the team noticed that the neonatal Fc receptor (FcRN) is required for IgE to enter the placenta.
This predilection for a certain allergen is not permanent in the infant, however. The study suggested that while there is a transfer of sensitivity from mother to offspring, this sensitivity appears to fade over time. The newborn mice that were highly susceptible to allergic reactions at 4 weeks old displayed little to no sensitivity a mere two weeks later.
In the future, the team will use the findings of this study to research new intervention strategies to minimize the occurrence of neonatal allergies. They hope to focus their efforts to attempt to reduce the high incidence of eczema in children of mothers with the clinically proven disease.
 Duke-NUS Medical School, Mothers pass on allergies to offspring. ScienceDaily, (2020).
 Image retrieved from: https://pixabay.com/photos/blossom-bloom-pollen-dandelion-5031482/