Increased expression of SRP54 during granulocyte differentiation. CD34⁺ cells from healthy donors (controls) or patients were cultured for 21 days in serum free-medium with SCF, IL-3, and G-CSF. (A) May-Grünwald Giemsa was performed to determine the purity and stages of differentiation at days (D) 7, 14, and 21. The expression levels of (B) SRP54, (C) CSF3R, and (D) SRP72 were quantified by quantitative reverse transcription polymerase chain reaction (qRT-PCR) related to PPIA and HPRT at days (D) 0, 7, 14, 21. Results are the mean ± SEM of 4 to 8 control samples performed in triplicate. Student t test: *P < .05; **P < .01; ***P < .001. (E) The expression level of SRP54 was quantified by qRT-PCR related to PPIA and HPRT in CD34⁺ progenitors, CD36⁺GPA⁺ erythroblasts, and CD41⁺CD42⁺ megakaryocytes. Results are the mean ± SEM of 4 to 8 control samples performed in triplicate. (F) The expression level of SRP54 was quantified by qRT-PCR related to PPIA and HPRT in granulocytic precursors at days 7 and 14 in both controls (n = 5) and patients (n = 5). Results are the mean ± SEM performed in triplicate. (G) The expression level of SRP54 protein was evaluated by western blot analysis on day 10 granulocytic precursors in controls (n = 2) and patients (n = 2), using specific antibodies.