From tissue adaptation to disease-associated eosinophil states

Eosinophils are highly adaptable immune cells whose phenotype and function are shaped by developmental, spatial, temporal, and inflammatory cues. Beyond their classical roles in type 2 immunity, eosinophils participate in chronic inflammation, fibrosis, metabolic disease, infection, and cancer. Here, we review how disease-associated eosinophil states emerge through perturbation of four interconnected determinants: eosinophil development, local tissue environment, tissue residency time, and inflammatory context. We discuss how disease can alter eosinophil development before tissue entry and reshape eosinophil adaptation within tissues, and how these processes may influence therapeutic responses. Together, these observations provide a framework for understanding disease-associated eosinophil diversity and for considering therapeutic strategies that preserve beneficial tissue-associated functions.