Researchers in Switzerland reported preclinical evidence that chimeric allergen receptor regulatory T cells can suppress birch pollen-driven allergic asthma in mice. In work published in the Journal of Experimental Medicine, investigators at Lausanne University Hospital and the University of Lausanne developed CAR-like CAlleR Tregs that recognize a birch pollen allergen and reduce airway inflammation, preventing or reducing asthma symptoms in sensitized models. The team positioned the approach as a potential future option for severe allergic asthma, where allergen immunotherapy is typically not recommended. The findings are framed as proof-of-concept for redirecting immune tolerance mechanisms to soluble antigens.