The use of GM-CSF receptor α (Csf2ra)-deficient mice illustrates that GM-CSF signaling, although not necessary for the development of eosinophils in normal mice, promotes eosinophil accumulation in the lungs and aggravates airway inflammation in the allergic asthma model; this may be associated with GM-CSF-induced chemotaxis and could promote eosinophil survival (71). Here, CSF2 is linked to allergic asthma.