CD34 and Splenomegaly: After a median follow-up of 77 months (IQR, 36–150 months), 364 subjects (43%) developed a hemoglobin concentration <100 g/L, 42% splenomegaly >10 cm below the left costal margin, 41%, a WBC > 12 × 109/L, 30% platelet concentration <150 × 109/L, 15%, a WBC < 4 × 109/L, and 34%, blood CD34-positive cells >100 × 106/L.