Bortezomib-induced neutropenia in G913X Elane mice. Mice (n = 3-6) were treated with a single subcutaneous injection of bortezomib (1 mg/kg) and at the indicated times, the number of B lymphocytes in the blood (A) and neutrophils in the blood and bone marrow (B) were measured. (C) Granulocytic (Gr-1⁺) cells were harvested from the bone marrow at the indicated times after treatment with bortezomib, and real-time RT-PCR for Hsap5 performed. RNA expression relative to β-actin is shown. Data represent the means ± SEM of 3-7 samples. (D) Granulocytic (Gr-1⁺) cells were harvested from the bone marrow 30 hours after treatment with bortezomib or saline alone, and real-time RT-PCR for Chop performed. RNA expression relative to β-actin is shown. Data represent the means ± SEM of 3 samples. *P < .05 compared with wild-type (WT) mice in the same treatment group; ^#P < .05 compared with saline-treated cells of the same genotype.