Immunocytochemical detection of Bim in normal bone marrow cells and mast cells. (A) Mononuclear cells obtained from normal bone marrow (BM); (B) neoplastic mast cells (MCs) obtained from the BM of a patient with ASM; and (C) neoplastic MCs obtained from the BM of a patient with MCL. Immunocytochemistry was performed using an antibody against Bim. (D) Wright-Giemsa staining of neoplastic MCs in a patient with MCL. (E-F) Cord blood–derived cultured MCs were kept in SCF, 100 ng/mL (E) or were starved from SCF (F) for 5 days (37°C). Then, cells were harvested, spun on cytospin slides, and stained with an anti-Bim antibody. (G-H) Tryptase stain (G) and Wright-Giemsa stain (H) of cultured cord blood–derived MCs kept in SCF. Figures shown in panels A through H (magnification, ×400 each) were prepared using an Olympus DP11 camera connected to an Olympus BX50F4 microscope equipped with 100×/1.35 UPlan-Apo objective lens (Olympus). Images were prepared using Adobe Photoshop CS2 software Version 9.0 (Adobe Systems) and processed with PowerPoint software (Microsoft). (I) Real-time PCR performed on cultured cord blood–derived mast cells kept in medium with (+SCF) or without (−SCF) SCF for 2 days. PCR was performed using primers specific for Bim and ABL. Expression of Bim mRNA is expressed as percentage of control (= ABL mRNA levels = 100%) and represents the mean ± SD of 6 independent experiments. *P < .05. (J) Apoptosis-inducing effect of SCF starvation on cultured cord blood–derived MCs. MCs were kept in the presence (+SCF, left panel) or absence (−SCF, right panel) of 100 ng/mL SCF for 5 days, and then were subjected to annexin V staining and flow cytometry.