Eosinophils in Asthma — Closing the Loop or Opening the Door?

Although the origin of the concept that eosinophils are critical to asthma pathobiology remains controversial, there is consensus that Paul Ehrlich first identified a bilobed nucleated cell as an “eosin”-ophil in 1879 on the basis of the cell's granular uptake of his newly discovered dye. These cells were soon found in airway tissues and “catarrh” (sputum) of patients with asthma. Over the years, eosinophils were identified as a prominent cell type in asthma, yet their role as either an “effector” or “innocent bystander” was not confirmed until the publication of articles by Nair et al.1 and Haldar et al.2 in . . .