Iron overload, hematopoietic cell transplantation, and graft-versus-host disease

Diagnosis and management of acquired aplastic anemia in childhood. Guidelines from the Marrow Failure Study Group of the Pediatric Haemato-Oncology Italian Association (AIEOP)

Acquired aplastic anemia (AA) is a rare heterogeneous disorder characterized by pancytopenia and hypoplastic bone marrow. The incidence is 2-3 per million population per year in the Western world, but 3 times higher in East Asia. Survival in severe aplastic anemia (SAA) has improved significantly due to advances in hematopoietic stem cell transplantation (HSCT), immunosuppressive therapy, biologic agents, and supportive care. In SAA, HSCT from a matched sibling donor (MSD) is the first-line treatment. If a MSD is not available, options include immunosuppressive therapy (IST), matched unrelated donor, or haploidentical HSCT. The purpose of this guideline is to provide health care professionals with clear guidance on the diagnosis and management of pediatric patients with AA. A preliminary evidence-based document prepared by a group of pediatric hematologists of the Bone Marrow Failure Study Group of the Italian Association of Pediatric Hemato-Oncology (AIEOP) was discussed, modified and approved during a series of consensus conferences that started online during COVID 19 and continued in the following years, according to procedures previously validated by the AIEOP Board of Directors.

Liver Pathology After Hematopoietic Stem Cell Transplantation

Hematopoietic stem cell transplantation is used to treat a variety of hematologic malignancies and autoimmune conditions. The immunosuppressive medications as well as other therapies used both before and after transplantation leave patients susceptible to a wide spectrum of complications, including liver injury. Causes for liver damage associated with stem cell transplantation include sinusoidal obstruction syndrome, graft-versus-host disease, iron overload, and opportunistic infection. Here, the authors review the clinical and pathological findings of these etiologies of liver injury and provide a framework for diagnosis.

Longitudinal proteomics study of serum changes after allogeneic HSCT reveals potential markers of metabolic complications related to aGvHD

Even though hematopoietic stem cell transplantation (HSCT) allows successful treatment for many malignant and non-malignant disorders, its curative potential remains limited by severe side effects, including infections and other transplant-related complications such as graft-versus-host disease (GvHD). This study examined changes in serum proteome via high-performance two-dimensional gel electrophoresis (2-DE) during HSCT to search for diagnostic biomarkers for post-HSCT complications. Longitudinal proteomic analysis revealed proteins related to metabolic complications and hemolytic anemia. Retinol-binding protein 4 (RBP4), a reliable marker of insulin resistance, was identified, and is possibly associated with the onset mechanism of acute graft-versus-host disease (aGvHD) and/or skin GvHD. Although the cause of insulin resistance is not fully understood, it is thought to be associated with adipocytes inflammation induced by RBP4, iron overload and hemolytic anemia after HSCT, as observed in this study. The present study has demonstrated that insulin resistance and metabolic complications could be immediate complications after transplantation and are associated with aGvHD. The biomarkers revealed in this study are promising tools to be used for improving the early diagnosis of HSCT-associated complications, especially aGvHD, possibly even before clinical manifestations.

In vivo imaging of invasive aspergillosis with 18F-fluorodeoxysorbitol positron emission tomography

Invasive aspergillosis is a critical complication in immunocompromised patients with hematologic malignancies or with viral pneumonia caused by influenza virus or SARS‑CoV‑2. Although early and accurate diagnosis of invasive aspergillosis can maximize clinical outcomes, current diagnostic methods are time-consuming and poorly sensitive. Here, we assess the ability of 2-deoxy-2-¹⁸F-fluorosorbitol (¹⁸F-FDS) positron emission tomography (PET) to specifically and noninvasively detect Aspergillus infections. We show that ¹⁸F-FDS PET can be used to visualize Aspergillus fumigatus infection of the lungs, brain, and muscles in mouse models. In particular, ¹⁸F-FDS can distinguish pulmonary aspergillosis from Staphylococcus aureus infection, both of which induce pulmonary infiltrates in immunocompromised patients. Thus, our results indicate that the combination of ¹⁸F-FDS PET and appropriate clinical information may be useful in the differential diagnosis and localization of invasive aspergillosis.

Cellular Therapy in Pediatric Hematologic Malignancies

Advances in cellular therapies for pediatric patients have created many opportunities for improved survival with reduced morbidity. This article reviews current cellular therapies in pediatric hematological malignancy, including the most updated practices in hematopoietic stem cell transplant and the use of chimeric antigen receptor (CAR) therapy in T cells. Hematopoietic stem cell transplant has evolved with improvements in chemotherapy regimens, immunosuppression, and donor-matching options. Novel therapies in development which will likely further improve the options for patients are reviewed including Natural Killer, Regulatory T-cells and αβ depletion.

Analysis of determinant factors of liver fibrosis progression in ex-thalassemic patients

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) potentially renders thalassemia patients disease-free with presumably cessation of associated complications. This study analyzes the liver fibrosis status and the determinants of its progression in ex-thalassemic patients. The liver fibrosis status of 108 pediatric transfusion-dependent β-thalassemia major patients was evaluated before and one year after allo-HSCT using transient elastography (TE). All patients achieved normal hematopoiesis. In univariate analyses, not in all, but in patients developing significant post-HSCT iron overload or hepatic graft-versus-host disease (GvHD), as well as recipients of bone marrow stem cells (BMSC), significant TE increment occurred. In multivariable analyses, through a model with large effect size (Adj.R² = 26%, F_(3,104) = 13.53, P < 0.001), post-HSCT serum ferritin and hepatic GvHD were ascertained as independent determinants of significant TE increase, and the effect of stem cell graft source approached the level of significance. Excluding the patients with intermediate/high Lucarelli risk classes, the TE increase was significantly greater only in BMSC recipients (P = 0.033). Although the risk impact of allograft source on liver fibrosis progression requires further evaluation; hepatic status of ex-thalassemic patients can be preserved after HSCT, if hepatic GvHD is controlled and adequate post-transplantation iron depletion is ensured.

Retrospective Evaluation of Relationship Between Iron Overload and Transplantation Complications in Pediatric Patient Who Underwent Allogeneic Stem Cell Transplantation Due to Acute Leukemia and Myelodysplastic Syndrome

BACKGROUND

Hematopoietic stem cell transplantation (HSCT) is a curative therapy option for hematologic malignancies. Iron overload is common in this patient group and can impact short-term and long-term nonrelapse mortality.

STUDY DESIGN

Retrospective observational cohort study.

AIMS

To evaluate the effect of iron load on early and late HSCT outcomes in patients with acute leukemia and myelodysplasia to assess the necessity of reducing iron load.

PATIENTS AND METHODS

Sixty patients who underwent HSCT in pediatric stem cell transplantation unit between 2000 and 2012 were evaluated retrospectively. The patients were divided into those with pretransplantation serum ferritin levels above and below the median value of 1299 ng/mL.

RESULTS

Forty-two (70%) of the patients were male, mean ages of the low and high ferritin groups were 85.43±9.42 and 118.56±10.04 months, respectively. Acute graft-versus-host disease (GVHD) within the first 100 days and acute liver GVHD were significantly more common in the high ferritin group (P<0.011 for both). Ferritin level was not associated with rates of engraftment syndrome, veno-occlusive disease, early/late infection, relapse, or overall and disease-free survival.

CONCLUSIONS

In our study, significant result especially in terms of acute liver GVHD, was important to emphasize the need to be more careful in terms of acute liver GVHD risk in early liver pathologies in patients with high levels of ferritin after transplantation. In future large studies may be helpful to explain the relationship between acute liver GVHD and high ferritin levels.

Therapeutic use of transferrin to modulate anemia and conditions of iron toxicity

As the main iron transporter, transferrin delivers iron to target tissues like the bone marrow for erythropoiesis. Also, by binding free iron, transferrin prevents formation of reactive oxygen species. Transferrin deficiency due to congenital hypotransferrinemia is characterized by anemia as well as oxidative stress related to toxic free iron. Transferrin supplementation may be beneficial in two ways. First, transferrin can correct anemia by modulating the amount of iron that is available for erythropoiesis. This is obvious for patients that suffer from hypotransferrinemia, but may also have beneficial effects for β-thalassemia patients. Second, under conditions of iron overload, transferrin reduces oxidative stress by binding free iron in the circulation and in tissues. Hereby, transferrin protects the host against the reactive oxygen species that can be formed as a consequence of free iron. This beneficial effect is shown in hematological patients undergoing chemotherapy and stem cell transplantation. Transferrin may also be beneficial in lung injury, ischemia-reperfusion injury and hypomyelination. This review summarizes the preclinical and clinical data on the efficacy of exogenous transferrin administration to modulate certain forms of anemia and to prevent the toxic effects of free iron. Thereby, we show that transferrin has promising therapeutic potential in a wide variety of conditions.

Allogeneic transplantation using CD34+ selected peripheral blood progenitor cells combined with non-mobilized donor T cells for refractory severe aplastic anaemia

Allogeneic haematopoietic stem cell transplantation is curative for severe aplastic anaemia (SAA) unresponsive to immunosuppressive therapy. To reduce chronic graft-versus-host disease (GVHD), which occurs more frequently after peripheral blood stem cell (PBSC) transplantation compared to bone-marrow transplantation (BMT), and to prevent graft rejection, we developed a novel partial T-cell depleted transplant that infuses high numbers of granulocyte colony-stimulating factor-mobilized CD34⁺ selected PBSCs combined with a BMT-equivalent dose of non-mobilized donor T-cells. Fifteen patients with refractory SAA received cyclophosphamide, anti-thymocyte globulin and fludarabine conditioning, and were transplanted with a median 8 × 10⁶ CD34⁺  cells/kg and 2 × 10⁷ non-mobilized CD3⁺ T-cells/kg from human leucocyte antigen-matched sibling donors. All achieved sustained engraftment with only two developing acute and two developing chronic GVHD. With a 3·5-year median follow-up, 86% of patients survived and were transfusion-independent. When compared to a retrospective cohort of 56 bone-marrow failure patients that received the identical transplant preparative regimen and GVHD prophylaxis with the exception that the allograft contained unmanipulated PBSCs, partial T-cell depleted transplant recipients had delayed donor T-cell chimerism and relative reduction of 75% in the incidence of acute grade II-IV GVHD (13% vs. 52%; P = 0·010) and of 82% in chronic GVHD (13% vs. 72%; P = 0·0004). In multivariate analysis, partial T-cell depleted transplants remained significantly associated with a reduced risk of GVHD. In conclusion, for patients with refractory SAA, this novel transplant strategy achieves excellent engraftment and survival when compared to unmanipulated PBSC transplants and dramatically reduces the incidence of both acute and chronic GVHD.

[Effects of iron chelation therapy on allogeneic hematopoietic stem cell transplantation in myelodysplastic syndrome patients with iron overload]

OBJECTIVE

To investigate the effects of iron chelation therapy on hematopoietic reconstitution and related complications of allogeneic hematopoietic stem cell transplantation (allo-HSCT) in patients with myelodysplastic syndrome (MDS).

METHODS

Various clinical parameters were analyzed retrospectively in 57 MDS patients with iron overload who received allo-HSCT. According to the level of serum ferritin (SF) before transplantation divided patients into two groups: the effective treatment group (SF<1 000 μg/L) and iron overload group (SF≥1 000 μg/L).

RESULTS

①30/57 cases were received iron chelation treatment, 27/57 patients didn' t received iron chelating therapy before transplantation. 19/30 cases were in the effective treatment group, and the median SF level before transplantation was 561 (223-846) μg/L. 11/30 cases were in the iron overload group, and the median SF level before transplantation was 1 262 (1 100-2 352) μg/L. The median SF level was 1 540 (1 320-3 112) μg/L of 27 patients didn't received iron chelating therapy before transplantation. ② The rate of fully-engraftment in the effective treatment group and iron overload group was 19 cases (100.0% ) and 34 cases (89.5% ), myeloid reconstitution of 12(10-18) and 12(11-30) days respectively (P=0.441), and platelet reconstitution of 13(12-30) and 15 (10-32) days respectively (P=0.579). ③The infection risk rate of the effective treatment group was less than iron overload group [36.8% (7/19) vs 82.4% (28/34), P=0.002]. ④The incidence of aGVHD in effective treatment group was less than iron overload group [26.3%(5/19) vs 64.7%(22/34), P= 0.010]. All patients of the effective treatment group were Ⅰ/Ⅱ degree. 16 cases were Ⅰ/Ⅱ degree and 6 cases were Ⅲ/Ⅳ degree in the iron overload group. ⑤ 6 cases of iron overload group accepted iron chelation treatment early post-transplantation, and SF level decreased from 2 870 (2 205-3 580) μg/L to 1 270 (1 020-1 650) μg/L. ⑥The difference of median disease-free survival time between the effective treatment group and iron overload group was not statistically significant [28.9 (0.3-89.5) months vs 21.2(0.1-81.0) months, χ(2)=3.751, P=0.053].

CONCLUSIONS

Iron overload obviously increased transplant-related complications, and effective iron chelation therapy before transplantation significantly decreased the incidence of infection and degree of aGVHD, thereby reduced the non-relapse mortality in patients with MDS.

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.

Association between Plasma Endothelin-1, Transforming Growth Factor-β, Fibroblast Growth Factor, and Nitric Oxide Levels and Liver Injury in Hematopoietic Stem Cell Transplantation Recipients with Persistent Iron Overload after Transplantation

Graft-versus-host disease, iron overload, and infections are the major causes of liver dysfunction in allogeneic hematopoietic stem cell transplantation (AHSCT) recipients. We investigated the relationship between serum iron parameters and the levels of transforming growth factor-β (TGF-β), fibroblast growth factor (FGF), endothelin-1 (ET-1), and nitric oxide (NO) as predictors of chronic liver injury in 54 AHSCT recipients who survived at least a year after transplantation. Serum samples from patients were obtained for the evaluation of ET-1, TGF-β, FGF, NO, and nontransferrin bound iron at the first year follow-up visit using commercially available ELISA kits. Patients were categorized depending on serum ferritin and transferrin saturation levels. The parameters were compared between the groups, and survival analysis was also performed. Most of the AHSCT recipients (81.5%) were in complete remission during the study. After a median follow-up time of 73 months (range, 13 to 109 months), 72.2% of the patients were alive. Mean serum levels of ET-1, NO, TGF-β, and FGF were 81.54 ± 21.62 μmol/mL, 31.82 ± 26.42 μmol/mL, 2.56 ± 0.77 ng/mL, and 50.31 ± 32.69 pg/mL, respectively. Nineteen patients (35.2% of the cohort) had serum ferritin levels higher than 1000 ng/mL. Mean serum levels of ET-1, NO, TGF-β, and FGF were similar in patients with serum ferritin levels below or above 1000 ng/mL (P > .05). Serum ferritin levels were positively correlated with serum alanine aminotransferase (r = .284, P = .042) and γ-glutamyl transferase (r = .271, P = .05) levels and were negatively correlated with serum albumin levels (r = .295, P = .034). There was a significant positive correlation between serum transferrin saturation and alanine aminotransferase levels (r = .305, P = .03). Serum ET-1 level was positively correlated with alkaline phosphatase levels (r = .304, P = .026). In univariate Cox regression analysis serum levels of iron parameters, ET-1, NO, TGF-β, and FGF did not have an impact on overall survival (P > .05). The probability of progression-free survival was also similar in patients with ferritin levels above or below 1000 ng/mL (P = .275). The probability of survival was similar in patients with transferrin saturation ≥70% and <70% (P > .05). Serum iron parameters showed a positive correlation with liver injury. However, there was no correlation between fibrogenic cytokines and liver transaminases. Our results suggest that iron overload at least with the current levels of ferritin might have a relatively benign course. Prospective randomized trials will guide the actual role of iron chelation in the post-transplantation setting.

Rapid donor T-cell engraftment increases the risk of chronic graft-versus-host disease following salvage allogeneic peripheral blood hematopoietic cell transplantation for bone marrow failure syndromes

The risk of graft-rejection after allogeneic hematopoietic cell transplantation using conventional cyclophosphamide-based conditioning is increased in patients with bone marrow failure syndromes (BMFS) who are heavily transfused and often HLA-alloimmunized. Fifty-six patients with BMFS underwent fludarabine-based reduced-intensity conditioning and allogeneic peripheral blood progenitor cell (PBPC) transplantation at a single institution. The conditioning regimen consisted of intravenous cyclophosphamide, fludarabine, and equine antithymocyte globulin. Graft-versus-host disease (GVHD) prophylaxis included cyclosporine A alone or in combination with either mycophenolate mofetil or methotrexate. To reduce the risk of graft-rejection/failure, unmanipulated G-CSF mobilized PBPCs obtained from an HLA-identical or single HLA-antigen mismatched relative were transplanted rather than donor bone marrow. Despite a high prevalence of pretransplant HLA-alloimmunization (41%) and a heavy prior transfusion burden, graft-failure did not occur with all patients having sustained donor lympho-hematopoietic engraftment. The cumulative incidence of grade II-IV acute-GVHD and chronic-GVHD was 51.8% and 72%, respectively; with 87.1% surviving at a median follow-up of 4.5 years. A multivariate analysis showed pretransplant alloimmunization and rapid donor T-cell engraftment (≥95% donor by day 30) were both significantly (P < 0.05) associated with the development of chronic-GVHD (adjusted HR 2.13 and 2.99, respectively). These data show fludarabine-based PBPC transplantation overcomes the risk of graft-failure in patients with BMFS, although rapid donor T-cell engraftment associated with this approach appears to increase the risk of chronic-GVHD. (Clinicaltrials.gov identifier: NCT00003838).

Efficacy and safety of oral deferasirox treatment in the posttransplant period for patients who have undergone allogeneic hematopoietic stem cell transplantation (alloHSCT)

Iron overload is considered to be associated with various complications in patients who undergo both allogeneic (allo) and autologous hematopoietic stem cell transplantation (HSCT). A total of 23 alloHSCT recipients who started deferasirox treatment due to hyperferritinemia (ferritin ≥1,000 ng/mL) were analyzed retrospectively. The demographic characteristics, data about deferasirox treatment, and history of phlebotomy were obtained from the patients' files. The reduction in posttreatment ferritin levels was found statistically significant compared with pretreatment ferritin levels in both def+phlebotomy and def+nonphlebotomy groups (p = 0.025 and 0.017, respectively). The liver enzymes, especially ALT and bilirubins, were significantly reduced after the treatment (p < 0.05). The deferasirox treatment reduced pretreatment ferritin levels below the level of 1,000 ng/mL in a median period of 94 days, and these data were found to be statistically significant (p < 0.05). The median treatment duration time with deferasirox was 94 days (72-122). The most common adverse effects were nausea and vomiting, which occurred in three of the patients (13%). In conclusion, our data suggest that oral deferasirox treatment may be used as a safe and effective alternative method for reducing iron overload in alloHSCT recipients, whether combined with or without phlebotomy.

Preclinical evaluation of two 68Ga-siderophores as potential radiopharmaceuticals for Aspergillus fumigatus infection imaging

Purpose

Invasive pulmonary aspergillosis is mainly caused by Aspergillus fumigatus, and is one of the major causes of morbidity and mortality in immunocompromised patients. The mortality associated with invasive pulmonary aspergillosis remains high, mainly due to the difficulties and limitations in diagnosis. We have shown that siderophores can be labelled with ⁶⁸Ga and can be used for PET imaging of A. fumigatus infection in rats. Here we report on the further evaluation of the most promising ⁶⁸Ga-siderophore candidates, triacetylfusarinine (TAFC) and ferrioxamine E (FOXE).

Methods

Siderophores were labelled with ⁶⁸Ga using acetate buffer. Log P, protein binding and stability values were determined. Uptake by A. fumigatus was studied in vitro in cultures with high and low iron loads. In vivo biodistribution was determined in normal mice and an infection model was established using neutropenic rats inoculated with A. fumigatus. Static and dynamic μPET imaging was performed and correlated with CT images, and lung infection was evaluated ex vivo.

Results

⁶⁸Ga-siderophores were labelled with high radiochemical purity and specific activity. ⁶⁸Ga-TAFC and ⁶⁸Ga-FOXE showed high uptake by A. fumigatus in iron-deficient cultures. In normal mice, ⁶⁸Ga-TAFC and ⁶⁸Ga-FOXE showed rapid renal excretion with high metabolic stability. In the rat infection model focal lung uptake was detected by μPET with both compounds and increased with severity of the infection, correlating with abnormal CT images.

Conclusion

⁶⁸Ga-TAFC and ⁶⁸Ga-FOXE displayed excellent in vitro stability and high uptake by A. fumigatus. Both compounds showed excellent pharmacokinetics, highly selective accumulation in infected lung tissue and good correlation with severity of disease in a rat infection model, which makes them promising agents for A. fumigatus infection imaging.

Electronic supplementary material

The online version of this article (doi:10.1007/s00259-012-2110-3) contains supplementary material, which is available to authorized users.

Comorbidities and hematopoietic cell transplantation outcomes

Conventional allogeneic hematopoietic cell transplantation (allo-HCT) is a potentially curative treatment option for various hematological diseases due, in part to high-dose conditioning and, in part, to graft-versus-tumor effects. Reduced-intensity or non-myeloablative conditioning regimens have relied mostly on graft-versus-tumor effects for disease control, and their advent has allowed relatively older and medically infirm patients to be offered allo-HCT. However, both HCT modalities have been associated with organ toxicities and graft-versus-host disease, resulting in substantial non-relapse mortality. It has become increasingly important to optimize pre-transplant risk assessment in order to improve HCT decision making and clinical trial assignments. Single-organ comorbidity involving liver, lung, heart, or kidney before HCT has been traditionally found to cause organ toxicity after HCT. Recent efforts have resulted in the advent of a weighted scoring system that could sensitively capture multiple-organ comorbidities prior to HCT. The HCT-comorbidity index (HCT-CI) has provided better prediction of HCT-related morbidity and mortality than other non-HCT-specific indices. Subsequent studies, with the exception of a few studies with modest numbers of patients, have confirmed the prognostic importance of the HCT-CI. Further, the HCT-CI has been consolidated with various disease-specific and patient-specific risk factors to refine assignments of patients to the appropriate HCT setting. Ongoing studies are addressing prospective validation of the HCT-CI, furthering our understanding of biological aging, and enhancing the applicability of the HCT-CI comorbidity coding. Future knowledge of the impacts of multiple comorbidities on post-HCT toxicities might guide new prophylactic and therapeutic interventions to lessen the procedure's mortality.