Transfusional iron burden and liver toxicity after bone marrow transplantation for acute myelogenous leukemia and hemoglobinopathies

Iron Overload in Children with Acute Lymphoblastic and Acute Myeloblastic Leukemia-Experience of One Center

Transfusions of packed red blood cells (PRBCs), given due to an oncological disease and its acute complications, are an indispensable part of anticancer therapy. However, they can lead to post-transfusion iron overload. The study aim was to evaluate the role of ferritin as a nonspecific marker of leukemic growth and marker of transfusion-related iron overload. We performed a longitudinal study of PRBC transfusions and changes in ferritin concentrations during the oncological treatment of 135 patients with childhood acute lymphoblastic and acute myeloblastic leukemia (ALL and AML, median age 5.62 years). At the diagnosis, 41% of patients had a ferritin level over 500 ng/mL, and 14% of patients had a ferritin level over 1000 ng/mL. At the cessation of the treatment, 80% of the children had serum ferritin (SF) over 500 ng/mL, and 31% had SF over 1000 ng/mL. There was no significant difference between SF at the beginning of the treatment between ALL and AML patients, but children with AML finished treatment with statistically higher SF. AML patients had also statistically higher number of transfusions. We found statistically significant positive correlations between ferritin and age, and weight and units of transfused blood. Serum ferritin at the moment of diagnosis can be a useful marker of leukemic growth, but high levels of SF are connected with iron overload in both AML and ALL.

Supportive care during pediatric hematopoietic stem cell transplantation: beyond infectious diseases. A report from workshops on supportive care of the Pediatric Diseases Working Party (PDWP) of the European Society for Blood and Marrow Transplantation (EBMT)

Hematopoietic stem cell transplantation (HSCT) is currently the standard of care for many malignant and nonmalignant blood diseases. As several treatment-emerging acute toxicities are expected, optimal supportive measurements critically affect HSCT outcomes. The paucity of good clinical studies in supportive practices gives rise to the establishment of heterogeneous guidelines across the different centers, which hampers direct clinical comparison in multicentric studies. Aiming to harmonize the supportive care provided during the pediatric HSCT in Europe, the Pediatric Diseases Working Party (PDWP) of the European Society for Blood and Marrow Transplantation (EBMT) promoted dedicated workshops during the years 2017 and 2018. The present paper describes the resulting consensus on the management of sinusoidal obstructive syndrome, mucositis, enteral and parenteral nutrition, iron overload, and emesis during HSCT.

Serum ferritin is not a reliable predictor to determine iron overload in thalassemia major patients post-hematopoietic stem cell transplantation

OBJECTIVE

Iron overload (IO) in transfusion-dependent anemia persists after hematopoietic stem cell transplantation (HSCT) and can cause long-term organ damage. In many studies, the diagnosis of IO before and after HSCT is based on serum ferritin (SF) levels rather than on assessment of liver iron concentration (LIC) by MRI or SQUID.

METHOD

In a retrospective multicenter study, we analyzed the concordance for indication of iron depletion therapy and correlation between LIC and SF of 36 thalassemia patients after HSCT. LIC was determined either by MRI-R2 (FerriScan®) or SQUID.

RESULTS

The concordance between LIC and SF varies over time after transplant (P = 0.011). The correlation between SF and LIC was strong in the first year (Spearman's rho 0.75; P < 0.001). In agreement, the concordance between SF and LIC concerning indication for treatment was close to 1 with an overall error rate ca. of 10%. In particular in the first year after HSCT, SF underestimates the degree of iron overload. However, in the longitudinal analysis since the second year post-HSCT onward no association was found between LIC and SF (P = 0.217). Furthermore, in the second year after HSCT, the overall error rate was 35%, whereas in the 3rd, 4th, and >4th year, it was 58%, 60%, and 25%, respectively.

CONCLUSIONS

Our data suggest serum ferritin is not a reliable predictor to determine iron overload in thalassemia patients after HSCT.

Allogeneic hematopoietic stem cell transplantation in congenital hemoglobinopathies with myeloablative conditioning and rabbit anti-thymocyte globulin

Background

Allogeneic hematopoietic stem cell transplantation (HSCT) is a curative therapy for β-thalassemia major (TM) and sickle cell disease (SCD) in children. Graft-versus-host disease (GVHD) and treatment-related mortality (TRM) remain significant challenges to improving survival after HSCT. Here, we analyzed the outcome of TM and SCD patients, who received allogeneic HSCT with myeloablative conditioning at our institution.

Methods

Twenty-two patients (15 TM, 7 SCD), with a median age of 9 years (range, 1.6–16.9), underwent allogeneic HSCT using busulfan, cyclophosphamide and rabbit anti-thymocyte globulin-based conditioning. Cells were derived from either the bone marrow (8 patients), or peripheral blood stem cells (14 patients). The majority of patients received HSCT from a matched sibling donor (N=18). GVHD prophylaxis included cyclosporine and short course methotrexate.

Results

All patients achieved donor engraftment. Two SCD patients died from TRM-related grade IV gut GVHD (N=1) or severe bronchiolitis obliterans (BO) (N=1). Cumulative incidence of acute and chronic GVHD was 36.4% and 32.7%, respectively. Veno-occlusive disease (VOD) occurred in 8 patients (36.4%), but resolved in all instances. Epstein-Barr virus (EBV)-related post-transplantation lymphoproliferative disease (PTLD) occurred in 1 patient. The overall survival (OS) was 90.9% (TM 100%, SCD 71.4%), with all patients achieving transfusion independence, while 8 achieved complete donor chimerism.

Conclusion

Busulfan, cyclophosphamide, and ATG-based conditioning for HSCT of TM and SCD patients did not result in graft failure, although modifications may be required to reduce VOD incidence. Further changes to donor type and cell source prioritization are necessary to minimize TRM and morbidity caused by GVHD.

Effect of pre-transplantation serum ferritin on outcomes in patients undergoing allogeneic hematopoietic stem cell transplantation: A meta-analysis

BACKGROUND

Pre-transplantation serum ferritin (SF) has been considered to be a potential prognostic biomarker in patients undergoing allogeneic hematopoietic stem cell transplantation (allogeneic HSCT), but this conclusion remains controversial. Thus, we performed a meta-analysis to investigate the prognostic significance of pre-transplantation SF in patients undergoing allogeneic HSCT.

METHODS

We systematically searched PubMed, Embase, and Web of Science up to September 2017, and finally identified a total of 25 eligible studies with 4545 patients.

RESULTS

The pooled results of our meta-analysis showed that high pre-transplantation SF was markedly related to worse overall survival (OS) [hazard ratio (HR) = 1.82; 95% confidence interval (95% CI): 1.47-2.26; P < .001], nonrelapse mortality (NRM) (HR = 2.28; 95% CI: 1.79-2.89; P < .001), and progression-free survival (PFS) (HR = 1.72; 95% CI: 1.27-2.33; P < .001). In addition, high pre-transplantation SF was closely associated with a lower incidence of chronic graft versus host disease (cGVHD) (OR = 0.74, 95% CI: 0.58-0.96; P < .05), and a higher incidence of blood stream infections (BSIs) (OR = 1.67, 95% CI: 0.93-3.01; P = .09). However, no significance relationship was found between elevated pre-transplantation SF and acute graft versus host disease (aGVHD) (OR = 1.08, 95% CI:.72-1.62; P = .70).

CONCLUSION

In patients undergoing allogeneic HSCT for hematological malignancies, elevated pre-transplantation SF was significantly associated with worse OS and PFS, higher incidence of NRM and BSI, and lower incidence of cGVHD, but it had no effect on aGVHD. Considering the limitations in our meta-analysis, more prospective and homogeneous clinical studies are needed to further confirm our findings.

[Assessment and management of post-transplant iron overload: Guidelines of the Francophone Society of Marrow Transplantation and Cellular Therapy (SFGM-TC)]

To harmonize clinical practice in hematopoietic stem cell transplantation, the Francophone Society of Bone Marrow Transplantation and Cell Therapy (SFGM-TC) set up the sixth annual series of workshops which brought together practitioners from all member centers and took place in September 2015 in Lille. The main aim of this session was to describe the impact, evaluation and treatment of post-transplant iron overload.

Prevalence and risk factors of iron overload after hematopoietic stem cell transplantation for childhood acute leukemia: a LEA study

Data on post-transplant iron overload (IO) are scarce in pediatrics. We conducted a prospective multicenter cohort study (Leucémie de l'Enfant et de l'Adolescent cohort) to determine the prevalence and risk factors of IO in 384 acute leukemia survivors transplanted during childhood. Prevalence of IO (ferritin level ⩾350 ng/mL) was 42.2% (95%CI 37.2-47.2%). Factors significantly associated with IO were: 1) in univariate analysis: older age at transplant (P<0.001), allogeneic versus autologous transplantation (P<0.001), radiation-based preparative regimen (P=0.035) and recent period of transplantation (P<0.001); 2) in multivariate analysis: older age at transplant in quartiles (Odds Ratio (OR)=7.64, 95% CI: 3.73-15.64 for age >12.7 years and OR=5.36, 95% CI: 2.63-10.95 for age from 8.2 to 12.7 years compared to age < 4.7 years), acute myeloid leukemia (OR=3.23, 95% CI: 1.47-7.13), allogeneic graft (OR=4.34, 95% CI: 2.07-9.12 for alternative donors and OR=2.53, 95% CI: 1.2-5.33 for siblings, compared to autologous graft) and radiation-based conditioning regimen (OR=2.45, 95% CI: 1.09-5.53). Graft-versus-host disease was an additional risk factor for allogeneic graft recipients. In conclusion, IO is a frequent complication in pediatric long-term survivors after transplantation for acute leukemia, more frequently observed in older children, those transplanted from alternative donors or with graft-versus-host disease.

Measurement of liver iron concentration by superconducting quantum interference device biomagnetic liver susceptometry validates serum ferritin as prognostic parameter for allogeneic stem cell transplantation

INTRODUCTION

There are conflicting data regarding the role of serum ferritin (SF) as surrogate parameter for iron overload as an independent prognostic factor for outcome after allogeneic stem cell transplantation (SCT). Superconducting quantum interference device (SQUID) biomagnetic liver susceptometry, a noninvasive measurement of iron overload, allows measurement of the interference of an exteriorly applied small but highly constant magnetic field by the paramagnetic liver storage iron. By measuring the true iron load of patients through SQUID, we wanted to assess the effect of iron overload on patients undergoing SCT.

METHODS

We conducted a single-center retrospective analysis (1994-2010), comparing the effect of SF and liver iron content measured by SQUID shortly before transplantation on overall survival (OS), event-free survival (EFS), and transplant-related mortality (TRM) in 142 patients (median age 54.5 yr, range 5.6-75 yr) undergoing SCT (80% reduced intensity regimen). Patients were subdivided into five groups: myelodysplastic syndrome, de novo acute myeloid leukemia (AML), secondary AML, primary myelofibrosis, and others.

RESULTS

Correlation between SF and SQUID was significant (r = 0.6; P < 0.001; log function). The chance of infection was increased 2.4-fold (95% CI 1.22-4.71) when SQUID values ranged ≥1000 μg Fe/g liver (P = 0.012). We found similar results for SF >1000 ng/mL (P = 0.003). A significant association between SQUID and fungal infection was also seen (P = 0.004). For patients with SQUID ≥1000, the risk of proven fungal infection was increased 3.08-fold (95% CI 1.43-6.63). A similar association between SF >1000 and fungal infection was shown (P = 0.01). In univariate analysis, age was a prognostic factor for TRM (P = 0.034, HR 1.04, CI 1.00-1.08). SF ≥1000 was associated with OS (P = 0.033, HR 2.09, CI 1.06-4.11) and EFS (P = 0.016, HR 2.15, 95% CI 1.15-4.10). In multivariate analysis on EFS, only age and SF >1000 remained as independent factors (HR 1.027, P = 0.040, 95% CI 1.001-1.054 and HR 2.058, P = 0.034, 95% CI 1.056-4.008, respectively). The multivariate analysis on TRM left age and SQUID values ≥1000 in the final model (HR 1.045, P = 0.041, 95% CI 1.002-1.090 and HR 2.110, P = 0.103, 95% CI 0.859-5.183, respectively).

CONCLUSION

Our data confirmed that SF ≥1000 increases the risk of infection, moreover fungal infection in transplant recipients. As SQUID values correlate well with SF, we could show that SF is indeed a good surrogate parameter for iron overload when measured shortly before SCT. Prospective trials are needed to investigate the effect of iron chelation before or during SCT on transplant outcome.

Iron Overload in Survivors of Childhood Cancer

Iron overload is a significant cause of morbidity and mortality for patients who require frequent transfusions. We completed a prospective, cross-sectional study to evaluate the prevalence of iron overload in previously transfused childhood cancer survivors. Survivors recruited from the University of Minnesota Long-Term Follow-Up Clinic were stratified into 3 groups: oncology patients not treated with hematopoietic stem cell transplantation (HSCT) (n=27), patients treated with allogeneic HSCT (n=27), and patients treated with autologous HSCT (n=9). Serum ferritin was collected and hepatic magnetic resonance imaging (FerriScan) was obtained for those with iron overload (defined as ferritin ≥1000 ng/mL). The prevalence of iron overload in subjects with a history of allogeneic HSCT was 25.9% (95% CI, 9.4%-42.5%) compared with only 3.7% (95% CI, 0%-10.8%) in subjects treated without HSCT and 0% in subjects treated with autologous HSCT. No association was found between serum ferritin levels and the presence of cardiac, liver, or endocrine dysfunction. The prevalence of iron overload in subjects who received no HSCT or autologous HSCT is low in our study. A higher prevalence was found in patients receiving allogeneic HSCT, reiterating the importance of screening these patients for iron overload in accordance with the current Children's Oncology Group Long Term Follow-Up Guidelines.

Hepatic veno-occlusive disease may develop in secondary iron overloaded mice after allogeneic hematopoietic stem cell transplantation with total body irradiation

BACKGROUND

The outcome of hematopoietic stem cell transplantation (HSCT) is poor in patients with secondary iron overload (SIO). We evaluated the relationship between SIO and veno-occlusive disease (VOD) in an animal model with radiation for HSCT.

METHODS

We used a 6-week-old female BDF1 (H-2(b/d)) and a male C57/BL6 (H-2(b)) as recipient and donor, respectively. Recipient mice were injected intraperitoneally with 10 mg of iron dextran (cumulative doses of 50 mg, 100 mg, and 200 mg). All mice received total body irradiation for HSCT. We obtained peripheral blood for alanine transaminase (ALT) and liver for pathologic findings, lipid hyperoxide (LH) as reactive oxygen species (ROS), and liver iron content (LIC) on post-HSCT day 1 and day 7. The VOD score was assessed by pathologic findings.

RESULTS

ALT levels increased depending on cumulative iron dose, with significant differences between days 1 and 7 for mice loaded with 200 mg of iron (P<0.01). LH levels significantly increased in mice loaded with 200 mg of iron compared to those in other groups (P<0.01). For mice loaded with 100 mg of iron, the LH level depended on the radiation dose (P<0.01). There was a statistically significant relationship among ALT, LH, and LIC parameters (P<0.05). Pathologic scores for VOD correlated with LIC (P<0.01).

CONCLUSION

Livers with SIO showed high ROS levels depending on cumulative iron dose, and correlations with elevated liver enzyme and LIC. The pathologic score for VOD was associated with the LIC. Our results suggest that SIO may induce VOD after HSCT with irradiation.

An assessment of iron overload in children treated for cancer and nonmalignant hematologic disorders

Our goal was to assess the natural fate of iron overload (IO) following transfusions of packed red blood cells (PRBCs) in children treated for cancer and nonmalignant disorders according to the intensity level of their treatment. Sixty-six children were followed up from February 2010 to March 2013. The transfusion burden was compared between three treatment intensity groups assigned according to the Intensity of Treatment Rating Scale 3.0 (ITR-3). IO was assessed by serial measurements of serum ferritin (SF) (n= 66) and quantification of tissue iron by magnetic resonance imaging (MRI) (n=12). Of the children studied, 36 % (24/66) received moderately intensive treatment (level 2), 21 % (14/ 66) received very intensive treatment (level 3), and 42 % (28/ 66) received the most intensive treatment (level 4). The number of PRBC (p=0.016), the total transfused volume (p= 0.026), and transfused volume adjusted to body weight (p= 0.004) were significantly higher in the level 4 group. By the median follow-up time of 35.5 months (range 8–133), 21– 29 % of patients (including level 2 and level 3 children) had SF >1,000 μg/l 1 year after cessation of transfusions. The slowest decrease of SF was observed in the level 4 group. Initial MRI examination demonstrated either mild or moderate IO in the liver and spleen. Repetitive MRI showed significant improvement in relaxation time between the initial and follow-up MRI performances in the liver (5.9 vs. 8.6 ms, p= 0.03) and the spleen (4.3 vs. 8.8 ms, p=0.03).

CONCLUSION

IO diminished over time, but in the level 4 patients, it was detectable for years after cessation of transfusions.

Characterization of transfusion-derived iron deposition in childhood cancer survivors

BACKGROUND

Childhood cancer survivors (CCS) receiving packed red blood cell (PRBC) transfusions may have increased risk for vital organ iron deposition causing serious late effects.

METHODS

This cross-sectional cohort study of a CCS cohort quantified organ iron content by magnetic resonance imaging. Iron status by serum markers and hemochromatosis gene mutation status were assessed.

RESULTS

Seventy-five patients who had received a range (0-392 mL/kg) of cumulative PRBC transfusion volumes were enrolled (median age 14 years, range 8-25.6 years at evaluation). Median follow-up time was 4.4 years, and median time since last transfusion was 4.9 years. Cancer diagnoses included acute lymphoblastic or myelogenous leukemia (ALL/AML; n = 33) and solid tumors (n = 42). Liver and pancreatic iron concentrations were elevated in 36 of 73 (49.3%) and 19 of 72 (26.4%) subjects, respectively. Cardiac iron concentration was not increased in this cohort. In multivariate analysis, cumulative PRBC volume (P < 0.0001) and older age at diagnosis (P < 0.0001) predicted elevated liver iron concentration.

CONCLUSIONS

Iron overload (IO) may occur in children and adolescents/young adults treated for cancer and is associated with cumulative PRBC transfusion volume and age at diagnosis.

IMPACT

These findings have implications for development of monitoring and management guidelines for cancer patients and survivors at risk for IO, exploration of the additive risk of liver/pancreatic damage from chemotherapeutic exposures, and health education to minimize further liver/pancreatic damage from exposures such as excessive alcohol intake and hepatotoxic medications.

Once-daily oral deferasirox for the treatment of transfusional iron overload

The increasing use of blood transfusions, combined with extended patient survival, has led to an increase in the number of patients at risk of developing transfusional iron overload. Clinical data have shown that the once-daily oral iron chelator deferasirox is effective in adults and children with various transfusion-dependent anemias, including β-thalassemia and the myelodysplastic syndromes. Deferasirox has a defined, clinically manageable safety profile. The most common treatment-related adverse events are mild gastrointestinal disorders, skin rash and mild, nonprogressive serum creatinine increases. The deferasirox clinical trial program is continuing in Phase II/III extension phases and Phase IV trials. Long-term data continue to support the efficacy and safety of deferasirox. Convenient, effective and tolerable chelation therapy with deferasirox is a significant development in the treatment of transfusional iron overload.

Risk factors for hyperferritinemia secondary to red blood cell transfusions in pediatric cancer patients

BACKGROUND

Transfusion of packed red blood cells is common in pediatric cancer patients who receive chemotherapy. This study was done to identify characteristics of pediatric cancer patients at risk of hyperferritinemia secondary to frequent transfusions.

PROCEDURE

In this retrospective chart review, all pediatric cancer patients who completed chemotherapy from January 2007 to January 2012 and had an assessment of serum ferritin 6 months after the end of treatment were included. Variables included: age, sex, type of cancer diagnosis, weight and body surface area (BSA) at the time of diagnosis, number of transfusions, total transfused volume (TTV), total transfused volume per body weight (TVPBW), and weight and BSA change from the time of diagnosis to the time of ferritin check.

RESULTS

Of 109 eligible patients, 85 (78%) received transfusions. Sixteen patients (14.7%) had ferritin levels > 200 µg/L and four (3.7%) had ferritin levels > 1,000 µg/L. Although age, weight and BSA at cancer diagnosis, number of transfusions and TVPBW were correlated with the level of ferritin, independent risk factors were TTV (range 1,961-30,090 ml in patients with hyperferritinemia, P < 0.001) and BSA change from the time of diagnosis to the time of ferritin check (range -0.15 to 0.31 m(2) in patients with hyperferritinemia, P < 0.001). Increase in BSA was correlated with reduction of hyperferritinemia in follow-up ferritin measurements (P = 0.049).

CONCLUSIONS

In addition to TTV, change in BSA is an independent predictor for the degree and possibly persistence of hyperferritinemia in pediatric cancer patients and should be considered in decisions to initiate interventions.

Association of iron overload with allogeneic hematopoietic cell transplantation outcomes: a prospective cohort study using R2-MRI-measured liver iron content

Using liver magnetic resonance imaging (R2-MRI) to quantify liver iron content (LIC), we conducted a prospective cohort study to determine the association between iron overload and adult allogeneic hematopoietic cell transplantation (HCT) outcomes. Patients received pretransplant ferritin measurements; patients with ferritin >500 ng/mL underwent R2-MRI. Patients were defined as no iron overload (N = 28) and iron overload (LIC >1.8 mg/g; N = 60). Median LIC in the iron-overload group was 4.3 mg/g (range, 1.9-25.4). There was no difference in the 1-year probability of overall survival, nonrelapse mortality, relapse, acute or chronic graft-versus-host disease, organ failure, infections, or hepatic veno-occlusive disease between groups. We also found no difference in the cumulative incidence of a composite end point of nonrelapse mortality, any infection, organ failure, or hepatic veno-occlusive disease (1-year cumulative incidence, 71% vs 80%; P = .44). In multivariate analyses, iron-overload status did not impact risks of overall mortality (relative risk = 2.3; 95% confidence interval, 0.9-5.9; P = .08). In conclusion, we found no association between pretransplant iron overload and allogeneic HCT outcomes. Future studies in this population should use LIC to define iron overload instead of ferritin.

Association of projected transfusional iron burden with treatment intensity in childhood cancer survivors

BACKGROUND

Packed red blood cell (PRBC) transfusion is a mainstay in childhood cancer treatment, but has potential for inducing iron overload. The purpose of this study was to determine whether treatment intensity is predictive of projected iron burden resulting from PRBC transfusions among survivors of several forms of childhood cancer.

PROCEDURE

This retrospective cohort study involved patients treated at Children's Hospital Los Angeles (CHLA) between June 1, 2004 and December 31, 2009. Clinical/demographic data were abstracted from medical records. Treatment Intensity Level was determined for each patient using a published scale. Adjusted cumulative PRBC transfusion volume for each patient (ml/kg) was used to compute the adjusted total iron burden (mg/kg) based upon the average hematocrit of the product.

RESULTS

Median age of the cohort (n = 214) was 7.9 years (range 0.2-20.2). One hundred and fourteen (53.3%) were male and 129 (60.3%) were Hispanic/Latino. Diagnoses included acute leukemia and six solid tumors, management of which represents a range of cancer treatment intensities. The number of transfusions, transfusion volumes, and projected iron burden were significantly increased and exceeded upper limits of normal among patients with higher treatment intensity. Multivariate analysis found younger age and lower hemoglobin at diagnosis to be associated with greater iron burden after adjusting for treatment intensity.

CONCLUSION

Greater treatment intensity is associated with need for more PRBC transfusions, and thus increased risk of iron overload among childhood cancer survivors. Iron overload may represent another clinically significant late effect following childhood cancer treatment.

The prognostic role of hemochromatosis H63D allele in allogeneic hematopoietic stem cell transplantation

Iron overload is considered as a significant cause of morbidity and mortality in hematopoietic stem cell transplant (HSCT) recipients. The presence of hemochromatosis gene (HFE) mutations might exacerbate iron toxicity in the post-transplant setting. This prospective study was planned to evaluate the genetic spectrum of HFE mutations in Turkish patients undergoing HSCT and the impact of HFE genotype on transplant morbidity and mortality. HFE genotypes of 102 patients [median age, 27.5 years (16-64 years); male/female, 73:29], who underwent allogeneic HSCT, were analyzed. Twenty-two patients were heterozygous and 1 patient was homozygous for the H63D mutation, while the C282Y mutation was observed in none of our patients. The frequency of invasive fungal infections (IFI) was significantly higher in H63D-mutated patients (p=0.004). H63D mutation was identified as an independent risk factor for the development of IFI (p=0.006, OR=0.554, SE=0.208), without an impact on overall survival and transplant-related mortality. The multifactorial iron-overloaded state in HSCT recipients might affect the phenotypic expression of HFE mutations and alter the severity of clinical presentation. The impact of HFE genotype on iron parameters and transplant-related morbidity and mortality should be validated with further studies.

Iron overload and allogeneic hematopoietic stem-cell transplantation

Iron overload is frequently observed in patients with hematologic diseases before and after allogeneic stem-cell transplantation because they usually receive multiple red blood cell transfusions. Elevated pretransplant serum ferritin levels, which are widely used as indicators of body iron status, are significantly associated with a lower overall survival rate and a higher incidence of treatment-related complications; for example, infections and hepatic veno-occlusive disease. As serum ferritin levels are affected, not only by iron loading but also by inflammation, imaging techniques to quantify tissue iron levels have been developed, for example, quantitative MRI using the transverse magnetic relaxation rate, and superconducting quantum interference devices. Iron chelators, such as deferasirox, a new oral iron-chelating agent, reduce iron load in transfusion-dependent patients. Iron-chelating therapy before and/or after transplantation is a promising strategy to improve the clinical outcomes of transplant patients with iron overload. However, further research is needed to prove the direct relationship between iron overload and adverse outcomes, as well as to determine the effects of treatment for iron overload on outcomes of allogeneic stem-cell transplantation.

Posttransplant oral iron-chelating therapy in patients with beta-thalassemia major

Allogeneic hematopoetic stem cell transplantation (HSCT) is the only radical cure of beta-thalassemia. However, iron overload remains a cause of morbidity and mortality in posttransplant period. The authors present 7 patients as a preliminary report who underwent bone marrow transplant (BMT) and received oral chelating therapy (deferasirox) because of poor compliance to phlebotomy and desferrioxamine. The patients investigated mainly for possible side effects of deferasirox. No negative effect was seen in aspartate aminotransferase (AST), alanine aminotransferase (ALT), hemoglobin (Hb), and donor chimerism of the patients while serum ferritin levels significantly reduced (P = .018). Although serum creatinin significantly increased (P = .034), it was in normal limits in all patients. The authors believe that this report shows promising findings to plan further studies to clarify clinical safety and efficacy of deferasirox in posttransplant period.

Hepatic veno-occlusive disease in children after hematopoietic stem cell transplantation: incidence, risk factors, and outcome

Four hundred and sixty-seven hematopoietic stem cell transplantations (HSCTs) (217 autologous and 250 allogeneic HSCT) were performed in 374 children at four pediatric HSCT centers in Korea from January 2005 to December 2007. Among 467 transplants, veno-occlusive disease (VOD) developed in 72 transplants (15.4%) at a median of 10 days after HSCT. Multivariate analysis showed that BU or TBI-containing regimen (P=0.002), VOD prophylaxis without lipo-prostaglandin E1 (PGE1) (P=0.012), number of previous HSCT (P=0.014), and pretransplant serum ferritin (P=0.018) were independent risk factors for developing VOD. Mean serum ferritin levels were significantly higher in HSCT with VOD (2109.6+/-2842.5 ng/ml) than in HSCT without VOD (1315.9+/-1094.4 ng/ml) (P<0.001). The relative risk of death within 100 days of HSCT in transplants with VOD compared with transplants without VOD was 3.39 (confidence interval: 1.78-6.45). Our results suggest that lipo-PGE1 might have a protective effect against the development of VOD, and pretransplant serum ferritin could act as a risk factor for VOD. A larger prospective study is needed to confirm a possible role of lipo-PGE1 and iron chelation therapy in reducing the incidence of VOD.

Absence of VOD in paediatric thalassaemic HSCT recipients using defibrotide prophylaxis and intravenous Busulphan

Hepatic veno-occlusive disease (VOD) is a common complication of haematopoietic stem cell transplantation (HSCT), with reported incidences of 5-40% in children. Recently, defibrotide (DF) has been successfully used as prophylaxis and treatment of VOD. This study reports data on 63 human leucocyte antigen-matched HSCT performed in 57 children affected by beta thalassemia at very high risk for developing VOD (liver fibrosis, iron overload, hepatitis C virus infections, busulphan-based conditioning, methotraexate + ciclosporine). All patients received a busulphan-based conditioning regimen, either orally (four HSCT) or intravenously (59 HSCT). All patients received oral DF (40 mg/kg per day, final dose) as VOD prophylaxis from median day -9 to median day +29. In order to overcome the lack of oral paediatric formulations, a galenic formulation was administered. DF was well tolerated. Only one patient fulfilled Seattle Criteria for VOD diagnosis. This patient had discontinued DF 6 d prior to VOD onset, due to high risk of haemorrhage. We concluded that oral defibrotide prophylaxis and i.v. busulphan safely abated VOD incidence in high-risk patients who had undergone HSCT. A galenic preparation of oral DF also permits this treatment in low-weight patients. Costs of DF prophylaxis are acceptable considering the reduced incidence of VOD.

Iron overload adversely affects outcome of allogeneic hematopoietic cell transplantation

Iron overload is common in patients undergoing allogeneic hematopoietic cell transplantation (HCT) for hematologic disorders. Serum ferritin, a marker of tissue iron overload, was measured immediately before transplant in adult patients undergoing myeloablative HCT from matched sibling or unrelated donors. The effect of elevated pretransplant ferritin (defined as ferritin >or=1000 ng/ml) on day 100 mortality, overall survival, acute GVHD and infectious complications was assessed. Data on 190 patients were analyzed. In univariate analysis, the high-ferritin group had increased day 100 mortality (20 vs 9%, P=0.038), decreased overall survival (log-rank test: P-value=0.004), increased acute GVHD/death (63 vs 43%, P=0.009) and increased incidence of blood stream infections (BSIs)/death (60 vs 44%, P=0.042). In a multivariate analysis, high ferritin was associated with increased risk of death (Cox model: hazard ratio=2.28, P=0.004), increased day 100 mortality (generalized linear model (GLM) odds ratio=3.82, P=0.013), increased incidence of acute GVHD/death (GLM odds ratio=3.11, P=0.001) and increased risk of BSI/death (GLM odds ratio=1.99, P=0.032). The results remained similar when serum ferritin was considered a continuous variable. Elevated serum ferritin adversely impacts on overall survival and increases the likelihood of acute GVHD and BSI after allogeneic HCT.

Recent advances in the understanding of inherited sideroblastic anaemia

Sideroblastic anaemia includes a heterogeneous group of rare conditions, characterized by decreased haem synthesis and mitochondrial iron overload, which are diagnosed by the presence of ringed sideroblasts in the bone marrow aspirate. The most frequent form is X-linked sideroblastic anaemia, caused by mutations of delta-aminolevulinic acid synthase 2 (ALAS2), the enzyme that catalyses the first and regulatory step of haem synthesis in erythroid precursors and is post-transcriptionally controlled by the iron regulatory proteins. Impaired haem production causes variable degrees of anaemia and mitochondrial iron accumulation as ringed sideroblasts. The heterogeneity and complexity of sideroblastic anaemia is explained by an increasing number of recognized molecular defects. New forms have been recognized as being linked to the deficient function of mitochondrial proteins involved in iron-sulphur cluster biogenesis, such as ABCB7 and GLRX5, which are extremely rare but represent important biological models. Local mitochondrial iron overload is present in all sideroblastic anaemias, whereas systemic iron overload occurs only in the forms because of primary or secondary deficiency of ALAS2.