Rediscovering eosinophil identity through tissue adaptation

Eosinophils are now recognized as multifunctional immune cells that contribute to tissue homeostasis, repair, metabolism and host defense in addition to fulfilling their established roles in type 2 immunity and allergic disease. Substantial eosinophil heterogeneity is evident across tissues and inflammatory states, challenging the view that eosinophils are a uniform population of short-lived effector granulocytes. Here we discuss the current understanding of eosinophil development, tissue adaptation and functional specialization across organs and disease contexts. We propose an integrated framework in which eosinophil identity is shaped by four interdependent axes: differentiation and lineage commitment; local environmental cues; time of tissue residence; and inflammatory status. Together, these factors generate eosinophil states that are dynamic, context dependent and continuously tuned to their tissue environment. Viewing eosinophils through this multidimensional lens reframes these cells as adaptable participants in tissue physiology, rather than solely as terminal effectors of type 2 immunity.