Expression of surface CD30 on neoplastic MCs. (A) BM cells of patients with ISM ([#1], left panel), ASM ([#32], middle panel), or MCL ([#39], right panel) were stained with antibodies against CD34, CD45, CD38, CD117, and CD30. After erythrocyte lysis, expression of CD30 on CD117⁺⁺ (CD45⁺/CD34⁻) MCs was analyzed by flow cytometry on a FACSCantoII (BD Biosciences). The black open histograms show the isotype control and the red histograms represent CD30 expression on CD117⁺⁺ MCs. Patients [#] refer to the numbers in Table 1. (B) HMC-1.1 cells, HMC-1.2 cells (top panel), MCPV-1.1 cells, MCPV-1.4 cells (middle panel), and C2 cells (bottom panel) were first incubated with Fc-blocking reagent and then with PE-labeled antibody Ber-H2 directed against CD30. After incubation for 15 minutes, expression of CD30 was analyzed by flow cytometry on a FACSCalibur (BD Biosciences). Black open histograms show the isotype-matched control antibody, and red histograms reactivity with the CD30 antibody.