GATA-1 Protein Levels Are Not Altered and Are Correlated to the Jak-2 Mutation Status in Patients with Idiopathic Myelofibrosis (IMF).

GATA-1 is important in megakaryocytopoiesis, and the fact that GATA-1^low mice eventually develop myelofibrosis indicates that GATA-1 is important in the pathogenesis of idiopathic myelofibrosis (IMF). Previous study has shown that GATA-1 levels were lower in protein content in CD61⁺ cells of patients with IMF (Vannucci et al., Am J Pathol 167:849 2005). But the study was done with pooled protein from only three patients. We used ELISA assay (GATA-1 ELISA kit, Panomics, CA) to assay the protein content from nuclear extracts of blood hematopoietic progenitor cells (CD34⁺cells) and megakaryocytes (CD61⁺ cells) from patients with IMF and compared the results with those of patients with other myeloproliferative disorders and with controls. CD 61⁺ cells were obtained from 10-day cultures of blood CD34⁺ cells in serum-free culture medium with thrombopoietin and stem cell growth factor as described. The results are shown in Table 1. No statistical difference was found in the GATA-1 content in the nuclear extracts in CD34⁺ or CD61⁺ cells. We further analyze the GATA-1 levels in relation to the JAK2 status and significant correlation between the levels of GATA-1 levels and positive JAK2 nutation were found in blood CD34⁺ cells (p=0.01) and subsignificant in CD61⁺cells (p=0.08) (Table2) .These preliminary results suggest that GATA-1 protein contents are not altered and higher GATA-1 levels are seen in JAK-2 mutation positive patients with IMF.