Characteristics of neutrophils from healthy controls, untreated patients with SCA, patients with SCA treated with HU, patients with SCA in the ET program, and patients with SCA treated with both HU and ET therapy. Expression of (A) Mac-1 integrin (CD18/CD11b), (B) LFA-1 integrin (CD18/CD11a), (C) CD66a, and (D) CD162 adhesion molecules. (E) Population of aged CD62^low/CD184^high neutrophils. Plasma level of (F) elastase, (G) TNF-α, IL-8, and IL-1β in healthy controls (AA, n = 8), untreated patients with SCA (SS, n = 8), and patients with SCA in the ET program (SS-ET, n = 8). (H) Percentage of endothelial surface covered by adherent neutrophils after flow adhesion experiments performed on whole blood from healthy controls (AA, n = 3), untreated patients with SCA (SS, n = 3), patients with SCA treated with HU (SS + HU, n = 3), patients with SCA undergoing erythrocytapheresis (SS + ET, n = 3), and patients with SCA in the ET program and treated with HU (SS + ET + HU, n = 3). Representative images of the flow adhesion assay of whole blood on endothelial cells with fluorescent labeling of neutrophils (in green). Data for patients in panels A-H are from healthy controls (AA, n = 10), untreated patients with SCA (SS, n = 12), patients with SCA treated with HU (SS + HU, n = 12), patients with SCA on the ET program (SS + ET, n = 20), and patients with SCA treated with HU and on the ET program (SS + HU + ET, n = 20). The Mann-Whitney t test was used for the statistical comparison within 2 groups. ∗P < .05; ∗∗P < .01; ∗∗∗P < .001. ns, not significant (P > .05).