Mariam Malik ’22
Anaphylaxis is the biological reaction of the body to an allergy, in which airways are constricted and blood pressure suddenly drops. Anaphylactic shock can result from various allergies, including food and insect stings. Previous research has shown that during an allergic reaction, the immune system releases high levels of high-affinity Immunoglobin (IgE) antibodies, which then strongly bind to allergens to form an allergic reaction. Although past research has resulted in an abundance of new information, it was still unknown what cell actually caused such an allergic reaction. But researchers at Yale University in Connecticut have discovered an immune cell subtype in mice responsible for triggering allergic reactions.
At the Jackson Laboratory for Genomic Medicine, head researchers Uthaman Gowthaman and Jennifer Chen first bred mice that possessed DOCK8 immunodeficiency syndrome, a rare genetic disease. This disease,when possessed by humans, causes ongoing viral contamination of the skin, severe allergies and asthma. The mice were found to have a large quantity of T follicular helper 13 (Tfh13) cells, uncommon for normal mice. In general, T helper cells produce cytokines, a type of chemical messenger that sends signals to mediate immunity, inflammation, and hematopoiesis, or the making of blood cellular components. Additionally, another group of normal mice were then sensitized with respiratory and food allergens to stimulate intense allergic reactions and eventually anaphylaxis. When both groups were assessed, Tfh13 cells were absent in the non-allergic mice, while both IgE and Tfh13 cells were present in the allergic mice.
To evaluate whether or not the same discovery could apply to humans, researchers drew blood samples from people who had either peanut or respiratory allergies and from those with no allergies. The team of researchers found that participants with allergies and the IgE connected to them had higher levels of Tfh13 cells as well. The evidence found in mice and human blood samples show that Tfh13 cells most likely direct the B cells in our immune systems to produce IgE that have a strong tendency to bind to allergens.
The new discovery, as the researchers add, brings hope into possible treatments and/or prevention of allergy-related illnesses. By focusing on the Tfh13 cells and learning how they thrive, medical assistance could be provided to prevent Tfh13 from binding. However, the team does include that the discovery will most likely not be a substitute for an epipen. The epinephrine in an epipen is life-saving once anaphylaxis occurs, but researchers hope that by focusing on Tfh13 cells, a possible treatment could be found that would prevent the onset of anaphylaxis.
- U. Gowthaman, et al., Identification of a T follicular helper cell subset that drives anaphylactic IgE. Science 365, (2019). Doi: 10.1126/science.aaw6433
- Image retrieved from: https://en.wikipedia.org/wiki/Milk_allergy#/media/File:Skin_prick_testing_for_allergies.jpg