Hematopoietic peripheral circulating blood stem cells as an independent marker of good transfusion management in patients with β-thalassemia: results from a preliminary study

BACKGROUND Beyond hemoglobin (Hb) levels and performance status, further surrogate markers of appropriate transfusion management should improve the quality of thalassemia care. We investigated the levels of peripheral circulating CD34+ stem cells as an independent marker of appropriate hematopoietic balance in patients with thalassemia. STUDY DESIGN AND METHODS Peripheral circulating CD34+ stem cells, colony‐forming unitgranulocyte, erythrocyte, macrophage, magakaryocyte (CF‐GEMM), colony‐forming unitgranulocyte/macrophage (CFU‐GM), and erythroidburst‐forming units (BFU‐E) were assayed, according to standard procedures. Patients with thalassemia major (TM) and thalassemia intermedia (TI) were tested and compared to healthy controls. Demographic and clinical data were recorded. RESULTS Overall, 56 patients with TM (median age, 35 years; range, 13‐52 years) and 13 with TI (median age, 44 years; range, 27‐67 years) were evaluated. Annual red blood cell (RBC) transfusion requirements ranged from 10 to 65 units in all patients except four nontransfused cases. A significant increase in peripheral circulating stem cells was observed in patients, in comparison with healthy controls. Nontransfused patients showed the mean highest levels of stem cells (CD34, 32.5 ± 14.8/μL; BFU‐E, 41.3 ± 22.8/mL; CFU‐GM, 19.6 ± 5.6/mL; CFU‐GEMM, 9.0 ± 6.1/mL). CD34+ cell count was 6.9 ± 4.5/μL in TM (p = 0.014) and 11.8 ± 14.8/μL (p = 0.051) in TI. Furthermore, only in patients with TI was a significant increase in CFU‐GEMM (3.0 ± 4.8 vs. 0.75 ± 2.05/mL, p = 0.0001) observed. At multivariate analysis, peripheral circulating CD34+ stem cells did not correlate with age, sex, smoking habit, number of RBCs units transfused, Hb levels, iron chelation therapy, history of splenectomy, and hypothyroidism. CONCLUSION Circulating peripheral CD34 + stem cells are increased in β‐thalassemia, in particular in nontransfused patients, compared to healthy controls.