Neutrophils in CLL show aberrant function. (A) GSEA of the proteome of blood neutrophils indicated pathways with reduced expression of proteins of the secretory vesicles and granules. Detailed expression values are shown in supplemental Tables 9 and 10. (B) Analysis of the enrichment score indicated 48 significantly downregulated proteins of the pathway “secretory vesicle” and 35 proteins of the pathway “secretory granule”. The heatmap visualizes the expression intensities of proteins of both pathways (secretory vesicle and secretory granule) in blood neutrophils of CLL-bearing mice. (C) Expression intensity of ceruloplasmin on blood neutrophils determined by LC-MS/MS. (D) MPO expression in neutrophils from non-CLL and CLL-bearing mice were analyzed by FC. (E) Neutrophils from non-CLL and CLL-bearing mice were incubated with pH-sensitive E coli and then analyzed by FC to determine the level of the acidification of phagolysosomes postphagocytosis of the bacteria. **P < .01, ***P < .001. Data represent mean ± SEM. (A-C) Non-CLL, n = 6; CLL, n = 12. (D) Non-CLL, n = 5; CLL, n = 6. (E) Non-CLL, n = 6; CLL, n = 6. CERU, ceruloplasmin; G, secretory granule pathway; V, secretory vesicle pathway.