Phlebotomy as an Effective Treatment for Iron Overload after Allogeneic Hematopoietic Cell Transplantation: Iron Depletion Kinetics Are Influenced by the Donor Hemochromatosis (HFE) Genotype.

Introduction: Iron metabolism plays an important role in hematopoiesis and immune response. In the present project, body iron stores and factors affecting iron storage such as HFE genotype and the number of blood transfusions were evaluated in patients after allogeneic hematopoietic cell transplantation (HCT). In patients with iron overload, the effect of phlebotomy (PT) on iron stores was analysed in correlation to HFE mutations.

Patients and methods: Serum ferritin was measured in 201 consecutive patients transplanted from January 2001 to December 2004 at the University of Leipzig. After excluding patients with normal body iron (serum ferritin levels between 30–400 ng/ml) and patients surviving less than 4 months after HCT, 61 patients (31 males/30 females; median age 48 y) treated with PT were evaluated. Diagnoses included acute leukemias (n=29; 48%), chronic leukemias (n=15; 24%), MDS (n=8; 13%) and others (n=9; 15%). 33 patients (54%) were conditioned with Cyclophosphamid 120 mg/kg and 12 Gy TBI. Patients with unrelated donors received ATG 15 mg/kg/day for 3 days. The remaining patients (n=28; 46%) were treated with Fludarabin 30 mg/m²/day for 3 days and TBI 2 Gy applied once. Donors were matched related in 21 (34%) and matched unrelated in 40 (66%) patients. HFE genotype of patients and donors were analysed by real time PCR using a LightCycler, Roche. The effectiveness of PT was assessed by serum ferritin and liver function test evaluation.

Results: The majority of patients after HCT (n=172; 86%) had iron overload with a median ferritin of 1697 ng/ml. From these, 61 patients received PT. These patients received a median of 28 (range 2–102) units of blood transfusions. Acute GvHD ≥ grade II was present in 25 (41%) and chronic GvHD in 19 (31%) patients. Elevated SGPT/SGOT and AP were detected in 34 (56%) and 39 (64%) patients respectively. Mutations in the HFE gene were found in 14 (25%) prior to HCT: heterozygosity (het) for H63D (n=10), for C282Y (n=3) and homozygosity for H63D (n=1). Similarly, 22 donors (40%) showed het. for H63D (n=12), for C282Y (n=4) and for S65C (n=4). Two donors were homozygous for S65C. After HCT, all pts expressed donor HFE genotype. PT was performed every 2 weeks with a median of 200 ml blood removed in one session. Interestingly, median Hemoglobin (Hb) rose under PT (p<0.0001). PT resulted in a significant depletion of iron stores (p<0.0001), improvement in SGPT/SGOT (p=0.002), bilirubin (p<0.0001), and AP (p=0.01). In multivariate analysis, a slower rate of iron depletion significantly correlated with mutated donor HFE genotype (p=0.002). In such patients less iron/ml blood were removed per PT and more often PT were required compared to patients with wildtype HFE donors.

Conclusions: Iron overload is a frequent complication after HCT. PT is highly effective in removing excess iron and improving Hb and liver function associated with iron overload after HCT. Patients transplanted from a donor with a mutant HFE gene showed slower iron depletion kinetics by PT compared to patients transplanted from donors with wildtype HFE. The role of donor HFE genotype is currently being analysed in patients after HCT.