As shown in Figure 6, S100A8 and S100A9 promote the apoptosis of eosinophils from HES subjects as well as CEL patients, which indicates that both proteins possess therapeutic potential for both diseases but may also induce unwanted and unrecognized side effects, including inflammation (Figures 3D, 6). This evidence concerns the gene S100A9 and Chronic Eosinophilic Leukemia, Not Otherwise Specified.