CD24 and thrombocytosis disease: Restored clearance of senescent neutrophils in MPN mice prevented their abnormal interaction with megakaryocytes, as CD24 blockade decreased megakaryocyte emperipolesis of neutrophils (Figure 5I-L); consequently, thrombocytosis developed only in MPN mice treated with control IgG, but not in those with CD24 blockade or deletion (Figure 5M-O).