Levels of BAL, lung, blood, and bone marrow eosinophils in Siglec-F deficient vs WT mice. Different groups of Siglec-F deficient or WT mice were subjected to chronic OVA challenge. Non-OVA challenged mice served as a control. Eosinophils in bronchoalveolar lavage (BAL), blood, and bone marrow were quantitated in cytospin slides stained with Wright-Giemsa, whereas eosinophils in lung sections were quantitated by immunostaining with an anti-MBP Ab. Chronic OVA challenge in WT mice induced a significant increase in BAL eosinophils (p < 0.0001*)(Fig 1A), peribronchial eosinophils (p < 0.0001*)(Fig 1B), and blood eosinophils (p < 0.003*)(Fig 1C)(WT no OVA vs WT OVA). Levels of eosinophils in OVA challenged Siglec-F deficient mice were significantly increased compared to WT mice challenged with OVA in the BAL (p < 0.001#)(Fig 1A), lung (p < 0.04#)(Fig 1B), blood (p < 0.003#)(Fig 1C), and bone marrow (p < 0.001#)(Fig 1D)(n = 16 mice/group).