Some hairy cells in the nose may trigger sneezing and allergies to dust mites, mold and other substances, new work with mice suggests.

When exposed to allergens, these “brush cells” make chemicals that lead to inflammation, researchers report January 17 in Science Immunology. Only immune cells previously were thought to make such inflammatory chemicals — fatty compounds known as lipids. The findings may provide new clues about how people develop allergies.

Brush cells are shaped like teardrops topped by tufts of hairlike projections. In people, mice and other animals, these cells are also found in the linings of the trachea and the intestines, where they are known as tuft cells (SN: 4/13/18). However, brush cells are far more common in the nose than in other tissues, and may help the body identify when pathogens or noxious chemicals have been inhaled, says Lora Bankova, an allergist and immunologist at Brigham and Women’s Hospital in Boston.

Bankova and her colleagues discovered that, when exposed to certain molds or dust mite proteins, brush cells in mice’s noses churn out inflammation-producing lipids, called cysteinyl leukotrienes. The cells also made the lipids when encountering ATP, a chemical used by cells for energy that also signals when nearby cells are damaged, as in an infection. Mice exposed to allergens or ATP developed swelling of their nasal tissues. But mice that lacked brush cells suffered much less inflammation.

Such inflammation may lead to allergies in some cases. The researchers haven’t yet confirmed that brush cells in human noses respond to allergens in the same way as these cells do in mice.