Iron Chelation Therapy and Mobilization of Hematopoietic Peripheral Progenitors in Patients with β-Thalassemia Major

Abstract 5178

Several reports established an association between iron chelation therapy with deferasirox and hematopoietic improvement in patients with myelodysplastic syndromes. Data in β-thalassemia major (TM) patients is absent. We evaluated levels (frequency and aboslute number) of several hematopoietic peripheral progenitors (HPP: Colony Forming Unit-Granulocyte/Macrophage [CFU-GM], Erythroid Burst-Forming Unit [BFU-E], Colony Forming Unit-Granulocyte, Erythrocyte, Macrophage, Megakaryocyte [CFU-GEMM], and Long Term Culture-Initiating Cells [LTC-IC]) in 26 TM patients (median age 28. 5 years, 42. 3% males) and 12 age-matched controls. All TM patients had to be using the same iron chelator for at least 6 months with >80% compliance. The levels of all HPP were significantly higher in TM patients than controls, and varied between splenectomized and nonsplenectomized patients (lower CFU-GM and BFU-E, and higher LTC-IC in splenectomized patients). Patients using deferasirox (n=9) showed significantly higher levels of BFU-E compared with both deferoxamine (n=10) and deferiprone (n=7) treated patients (p<0. 01). After adjusting for age, sex, splenectomy status, serum ferritin changes, the association between higher BFU-E levels and deferasirox compared with deferoxamine or deferiprone therapy remained statistically significant (R²=0. 698, p=0. 006). Mobilization of BFU-E in TM patients receiving regular iron chelation therapy depends on the type of chelator used, independent of iron status.