IL5RA and Chronic Eosinophilic Leukemia, Not Otherwise Specified: We used EoL-1 human eosinophilic leukemia cell line as a model for the investigation of eosinophilic functions for four main reasons: (1) their rapid (within hours) responsiveness to broad range of stimuli, (2) their expression profile of PRRs whose roles in regulating eosinophilic responses are largely unknown, (3) their ability to express human eosinophilic pan markers, including Siglec-8 and IL5R [23, 24], and (4) eosinophils' sparsity in blood.