Patients with idiopathic myelofibrosis show increased CD34+ cell concentrations in peripheral blood compared to patients with polycythaemia vera and essential thrombocythaemia

Abstract

The aim of the present work was to compare the results for some haematological variables in 12 patients with idiopathic myelofibrosis (IMF) with those of 21 patients with polycythaemia vera (PV), 22 patients with essential thrombocythaemia (ET) and 10 healthy control subjects. In each patient and control subject peripheral blood was used for analysis of flow cytometric measurement of CD34‐positive (CD34⁺) cells, in vitro colony growth and plasma erythropoietin (EPO) concentration. The mean concentration of CD34⁺ cells in the IMF group was 568±686×10³ mL, which significantly (P3 mL, 3.0±3.7×10³ mL and 1.9±0.8×10³ mL, respectively). The mean number of EPO‐independent erythroid colonies (EEC) was 110±215 colonies per10⁵ cells for the IMF patients. In comparison with the means for PV and ET patients (40±140 and 12±27 colonies per 10⁵ cells, respectively) the difference did not reach statistical significance. The mean EEC for IMF patients was, however, significantly higher compared with the mean for the control subjects (PP+ cell concentration in peripheral blood is progenitor cells of extra‐medullar origin.