Detection of HDC mRNA expression in primary CML cells by Northern blotting and RT-PCR. (A) Northern blot analysis of HDC mRNA expression in PBMCs obtained from 3 patients with accelerated-phase CML (nos. 1-3), 3 with chronic-phase CML (no. 4-6), and 2 donors with normal bone marrow (NM). Total RNA was isolated and subjected to Northern blot analysis using an HDC-specific cDNA probe. β-actin served as loading control. (B) RT-PCR analysis of HDC mRNA expression in purified CD203c⁺-sorted basophils (purity > 98%) obtained from 2 patients (nos. 1, 2) with accelerated-phase CML, and in KU812 cells. (C) RT-PCR analysis of basophil-depleted (CD203c-negative) CML cells using primers specific for HDC or β-actin. The RT omission controls (-RT) are also shown. (D) Northern blot analysis of expression of HDC mRNA in various myeloid cell lines (K562, KU812, KG1a, HL60) and human lung fibroblasts (LUFs) using cDNA probes specific for HDC and β-actin (loading control).