Increased Bone Marrow Iron Scores Are Strongly Correlated With Elevated Serum Ferritin Levels and Poorer Survival in Patients With Iron Overload That Underwent Allogeneic Hematopoietic Stem Cell Transplantation: A Single Center Experience

Impact of iron overload in hematopoietic stem cell transplantation

Iron overload (IOL) is a common condition in patients with hematological malignancies(HMs) undergoing hematopoietic stem cell transplantation (HSCT). Pathophysiologically, IOL results in iron-induced toxicity in HSCT by producing reactive oxygen species (ROS), which leads to detrimental effects on hematopoiesis, clonal evolution, and immunosuppression. IOL, therefore, may have a negative impact on the clinical outcomes of HSCT. For patients at a higher risk of developing IOL before HSCT, it is necessary to monitor red blood cell transfusion units, serum ferritin (SF) levels and MRI image of organs, and initiate iron removal therapy as soon as possible. Iron chelating therapy (ICT) might be safe and efficient in the post-HSCT period. We provide an overview of results from experimental and clinical evidence on the current understanding of IOL in patients with HMs undergoing HSCT, involving the underlying pathophysiological and clinical impact of IOL, as well as the significance of iron reduction therapy.

PROGNOSIS OF ACUTE LEUKEMIA DEPENDING ON THE IRON METABOLISM PARAMETERS IN CHILDREN AFTER CHORNOBYL NUCLEAR POWER PLANT ACCIDENT

OBJECTIVE

To determine the influence of iron metabolism on the prognosis of acute lymphoblastic (ALL) and (AML)myeloblastic leukemia at the different phases of chemotherapy in children after Chоrnobyl accident.

MATERIALS AND METHODS

333 children (295 - ALL, 38 - AML) were examined at the stages of chemotherapy. Thecomparison group included 93 children without leukemia. Acute leukemia variants, patients survival, relapses, thenature of disease (live child or died), iron methabolism (morphometric parameters of erythrocytes, SI, SF, STf, TS),manifestations of dyserythropoiesis, bone marrow sideroblast and patients radiation dose were taken into account.

RESULTS

In 295 patients with ALL the following variants of leukemia were established: pro-B-ALL in 23, «common»type of ALL in 224, pre-B-ALL in 29, T-ALL in 19. Thirty eight patients were diagnosed with AML (11 - M1, 19 - M2,8 - M4). Doses of radiation in patients with AL were (2.78 ± 0.10) mSv and they did not correlate with clinical andhematological parameters, disease variant. Relapse rates and shorter survival were in patients with T-ALL, pro-B-ALLand AML with SF levels > 500 ng/ml (p < 0.05). The amount of children with normochromic-normocytic anemias andmanifestations of dysplasia of erythroid lineage elements was greater in the AML than in ALL. SF content in patientswas elevated during chemotherapy and was lower than the initial one only in the remission period. Transferrin wasreliably overloaded with iron: TS (70.2 ± 2.3) % compared with the control group (32.7 ± 2.1) %. Correlationbetween TS and survival of patients was detected (rs = -0.45). Direct correlation between the number of iron granules in erythrocariocytes and SF level (rs = 0.43) was established, indicating the phenomena of ineffective erythropoiesis.

CONCLUSIONS

The negative influence of iron excess in the patients body on the hemopoiesis function, manifestations of ineffective erythropoiesis and the course of acute leukemia in children have been established. Changes inferrokinetic processes in children can be the basis of leukemоgenesis development.

Iron overload as a risk factor for poor graft function following allogeneic hematopoietic stem cell transplantation

Hematological malignancies are increasingly treated with allogeneic hematopoietic stem cell transplantation (allo-HSCT). Unfortunately, iron overload is a frequent adverse effect of allo-HSCT and is associated with poor prognosis. In the present study, we investigated hematopoiesis in iron-overloaded mice and elucidated the effects of iron overload on the bone marrow (BM) microenvironment. Iron-overloaded BALB/C mice were generated by injecting 20 mg/mL saccharated iron oxide intraperitoneally. Hematoxylin-eosin staining was performed to evaluate the effects of an iron overload in mice. BM cells obtained from C57BL/6 mice were transplanted into irradiated BALB/C mice (whole-body irradiation of 4 Gy, twice with a 4-hours interval) by tail vein injection. Two weeks after allo-HSCT, the hematopoietic reconstitution capacity was evaluated in recipients by colony-forming assays. Histopathological examinations showed brown-stained granular deposits, irregularly arranged lymphocytes in the liver tissues, and blue-stained blocks in the BM collected from mice received injections of high-dose saccharated iron oxide (20 mg/mL). Iron-overloaded mice showed more platelets, higher-hemoglobin (HGB) concentration, fewer granulocyte-macrophage colony-forming units (CFU-GM), erythrocyte colony-forming units (CFU-E), and mixed granulocyte/erythrocyte/monocyte/megakaryocyte colony-forming units (CFU-mix) than healthy mice. Iron-overloaded recipients presented with reduced erythrocytes and HGB concentration in peripheral blood, along with decreased marrow stroma cells, CFU-GM, CFU-E, and CFU-mix relative to healthy recipients. Taken together, our findings demonstrate that iron overload might alter the number of red blood cells after transplantation in mice by destroying the BM microenvironment, thereby affecting the recovery of BM hematopoietic function.

Iron Overload Is Associated with Delayed Engraftment and Increased Nonrelapse Mortality in Recipients of Umbilical Cord Blood Hematopoietic Cell Transplantation

The negative impact of iron overload (IO) on outcomes of allogeneic hematopoietic cell transplantation (HCT) is well recognized, but its impact on umbilical cord blood (UCB) transplant outcome is unknown. We retrospectively analyzed outcomes of 150 patients who received UCB-HCT at our institution, stratified by pre-HCT serum ferritin (SF) level of 2000 ng/mL. Two-year overall survival rate among patients with SF >2000 and ≤2000 ng/mL was 26.1% (95% CI, 10.6% to 44.7%) and 52.1% (95% CI, 40.1% to 62.8%), respectively; hazard ratio (HR) = 2.26 (95% CI, 1.28 to 4.00, P = .005). Two-year nonrelapse mortality rate was higher among patients with SF >2000 ng/mL (56.5%; 95% CI, 33.3% to 74.4%) compared to SF ≤2000 ng/mL (30.1%; 95% CI, 20.0% to 40.9%); HR = 2.18 (95% CI, 1.10 to 4.31, P = .025). Neutrophil engraftment at 42 days was 78.3% (95% CI, 53.5% to 90.8%) in patients with SF >2000 ng/mL versus 91.8% (95% CI, 82.1% to 96.4%) in patients with SF ≤2000 ng/mL; HR = 0.58 (95% CI, 0.35 to 0.96, P = .034). A significant difference in platelet engraftment at 3 months was also observed: 52.2% (95% CI, 29.4% to 70.8%) for SF >2000 ng/mL versus 80.8% (95% CI, 69.5% to 88.3%) for SF ≤2000 ng/mL; HR = 0.48 (95% CI, 0.23 to 0.98, P = .044). In conclusion, IO defined by SF of 2000 ng/mL is a strong adverse prognostic factor for UCB-HCT and should be considered when UCB is chosen as the graft source for patients without a fully matched donor.

Bone marrow iron score as an indicator for secondary iron overload in acute myeloid leukemia patients

OBJECTIVES

Secondary iron overload due to red blood cell transfusions (RBCT) is associated with increased morbidity and mortality. However, attention for secondary iron overload and its side effects in patients with hematological malignancies may need improvement. The aim of this study was to determine the number of transfused RBCT needed to reach a maximum bone marrow iron score (BMIS).

METHODS

Bone marrow iron score was independently assessed by two researchers on consecutive bone marrow samples of 35 acute myeloid leukemia (AML) patients. The slides were blinded to both researchers to prevent bias. A Kaplan-Meier survival analysis was performed for estimation of the proportion of patients reaching a maximum BMIS.

RESULTS

In total, 141 bone marrow specimens from 35 patients were included. The median number of RBCT to reach a maximum was 20 units (range 6-42, IQR 15-26), after a mean of 1.64 chemotherapy courses (SD 0.99).

CONCLUSIONS

In conclusion, the cumulative RBCT number is associated with BMIS. Due to the considerable variation in number of RBCT to reach a maximum BMIS, BMIS instead of only considering the cumulative RBCT number may be a valuable indicator of secondary iron overload in AML patients. BMIS could guide iron-lowering therapy and/or transfusion strategies in an early stage.

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.

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.