JUST THE BASICS

Eosinophils (the pink guys in the car) are a type of white blood cell whose main job is to fight parasites (a good thing). However, eosinophils can also cause allergic inflammation (a bad thing). Because eosinophils help us fight infections, they can be found hanging out in many places throughout the body. An interesting exception to this is the esophagus - eosinophils do not normally go to the esophagus! If they are found there on, say, a biopsy, it suggests that a medical problem is causing inflammation. This cartoon likens the esophagus to a speakeasy - off limits for “Eos” unless they know the password to get in.

TELL ME SOMETHING NERDY

The password, calpain, is a protein that is found in the esophagus and may play a role in eosinophilic esophagitis, an allergic disease that causes inflammation of the esophagus. This cartoon also contains a lot of immunology easter eggs tucked into the background. The taxi is called Eotaxi 3, a nod to the chemokine Eotaxin-3, which stimulates eosinophils to migrate throughout the body. Hanging off the rear-view mirror is a Charcot-Leyden crystal, which can be found in tissues where eosinophils are causing inflammation. Finally, one of the bumper stickers says, “I love IL-5”, which is a signal molecule that stimulates and activates eosinophils!

Published in January 2023 Annals of Allergy, Asthma & Immunology: https://doi.org/10.1016/j.anai.2022.09.025