Transfusion‐associated iron overload as a predictive factor for poor stem cell mobilization in patients with haematological malignancies

Abstract

Summary Transfusion‐associated iron overload is often observed in patients with haematological malignancies. We analysed the effect of iron overload, indicated by high serum ferritin level, on the mobilization of CD34⁺ peripheral blood stem cells (PBSCs). We evaluated the association between the serum ferritin level prior to PBSC collection and the number of CD34⁺ cells collected through leukapheresis in 51 patients with various haematological malignancies. Patients with serum ferritin level over 1000 ng mL⁻¹ were defined as high‐ferritin group. Comparing the good (≥1 × 10⁶ per kg CD34⁺ cells) and poor (6 per kg CD34⁺ cells) mobilizing groups, there was no difference in disease status, previous chemotherapies and white blood cell count at the first day of apheresis. However, there was a significant difference in the median units of red blood cell transfused between the good and poor mobilizer (2 vs. 8 units; P = 0·012). Serum ferritin level was notably higher in the poor mobilizer (1670 ± 1320 ng mL⁻¹) compared with the good mobilizer (965 ± 705 ng mL⁻¹, P = 0·035). The cumulative number of CD34⁺ cells per kg collected during the whole procedure was significantly lower in the high‐ferritin group (5·5 ± 4·7 × 10⁶ per kg vs. 13·1 ± 9·1 × 10⁶ per kg, P = 0·01). Multivariate analysis revealed that serum ferritin level remained as an independent predictive factor for poor PBSC mobilization. Our study indicated that transfusion‐associated iron overload is a predictive factor for poor PBSC mobilization. Iron chelation therapy prior to apheresis may be required to collect sufficient numbers of PBSCs in the iron overload patients.