Defective in vitro granulocytic differentiation and maturation in patient primary cells. A, May-Grünwald Giemsa (MGG) staining of representative cytospins from the index patient (P) and an unrelated healthy control (HC) monitoring in vitro differentiation of CD34+ cells on day 4 (D4) to day 14 (D14) as indicated. Blast-like cells are marked by the symbol ∗, differentiating cells are marked by the symbol #, and terminally differentiated cells are marked by the symbol ∗∗. Magnification, ×100. (B) Graphic representation of the different stages of differentiation quantified by expert cytologic evaluation of cytospins in (A). (C) Mean fluorescence index (MFI) of CXCR2 gated on CD66b+CD16+ neutrophils isolated from whole blood or bone marrow (BM) from the HC and the patient. Unpaired t test. (D) MFI of CD10 on CD66b+CD16+ neutrophils isolated from whole blood or BM from the HC and the P. Unpaired t test. (E) Flow cytometry plot showing CD62L and CD16 expression gated on live CD66b+CD16med-high cells. (F) Representative MGG staining of peripheral blood smears from the HC and the patient. Magnification, ×50.