Severe Beta-thalassemia Research Articles

Cross-sectional study on the impact of cardiac and hepatic iron overload, as measured by MRI T2*, on the quality of life in children with severe beta-thalassemia major.

A cross-sectional study to explore the correlation between cardiac and hepatic iron overload and its impact on the quality of life in children diagnosed with severe beta-thalassemia major (β-TM). A cohort of 55 pediatric patients with β-TM, diagnosed via genetic testing at the Affiliated Hospital of Guangdong Medical University from January 2015 to January 2022, was included in this study. The assessment of cardiac and hepatic iron overload was conducted using the magnetic resonance imaging T2* technique. The Chinese version of the Pediatric Quality of Life Inventory (PedsQL) 4.0. Pearson correlation analysis was utilized to assess the relationships between the cardiac and hepatic T2* values and between these T2* values and the total scores of PedsQL 4.0. Analysis showed no significant correlation between cardiac and hepatic T2* values. However, a significant relationship was observed between cardiac T2* values and PedsQL 4.0 total scores (r = 0.313, P < .05), indicating that cardiac, but not hepatic, iron overload is associated with the quality of life. This study highlights the absence of correlation between cardiac and hepatic iron overload levels and demonstrates a significant impact of cardiac iron overload on the quality of life in children with β-TM. These findings suggest the need for a focused approach to cardiac health in managing β-TM.

Rare coinheritance of hemoglobin vancleave with severe beta-thalassemia mutation in a patient with secondary erythrocytosis

Hemoglobin (Hb) Vancleave (NM_000518.5:c.431 A > T; dbSNP: rs33918338) is an extremely rare structural hemoglobin variant worldwide, and studies are limited. This report describes the case of a 16-year-old male patient who presented with secondary erythrocytosis. The diagnosis of Hb Vancleave, in combination with codon 41/42 (-TTCT) (NM_000518.5:c.126_129del; dbSNP: rs80356821), was confirmed by direct sequencing. This report highlights the importance of sequencing in the differential diagnosis of beta-thalassemia syndrome in Malaysia.

Hypoparathyroidism and Hypothyroidism Secondary to Hemochromatosis in Beta Thalassemia Major

Hemochromatosis, an iron metabolism disorder caused by iron overload, often runs in families. It leads to various issues like cardiomyopathy, liver cirrhosis, and hormonal imbalances. This article presents a unique case of secondary hemochromatosis resulting from repeated transfusions. A 15-year-old boy with severe beta-thalassemia major received about 600 units of packed red blood cells over nine years. This led to clinical hypoparathyroidism and subclinical hypothyroidism, affecting multiple organs. Elevated ferritin and transferrin levels confirmed iron buildup, visible on MRI scans in the liver, pancreas, skeleton, heart, and thyroid gland. Such widespread organ involvement due to transfusion-related hemochromatosis is rare and makes this case noteworthy, especially considering the scarcity of similar reports in Pakistan.

Retracted: Clinical Study of Mobile Application- (App-) Based Family-Centered Care (FCC) Model Combined with Comprehensive Iron Removal Treatment in Children with Severe Beta Thalassemia.

[This retracts the article DOI: 10.1155/2022/4658709.].

Myocardial infarction in patients with severe beta thalassaemia: a case series

BackgroundCardiac disease remains a dominant if not the most important cause of morbidity and mortality in patients with thalassaemia, particularly in those with thalassaemia major. Myocardial infarction and coronary artery disease however are rarely reported.Case presentationsThree older patients with three distinct thalassaemia syndromes presented with acute coronary syndrome. Two were heavily transfused whilst the other was a minimally transfused patient. Both heavily transfused patients had ST-elevation myocardial infarctions (STEMI) while the minimally transfused patient had unstable angina. Coronary angiogram (CA) was normal in two patients. One patient who developed a STEMI had a 50% plaque. All three were managed as standard ACS, although the aetiology appeared non-atherogenic.ConclusionsThe exact etiology of the presentation, remains a mystery and therefore the rational use of thrombolytic therapy, carrying out angiogram in the primary setting, using and continuing antiplatelet and high dose statins all remains unclear in this sub group of patients.

Is the Role of Hepcidin and Erythroferrone in the Pathogenesis of Beta Thalassemia the Key to Developing Novel Treatment Strategies?

Thalassemia is a disease of erythrocytes that varies largely on its genetic composition and associated clinical presentation. Though some patients may remain asymptomatic, those with a complicated course may experience severe anemia early in childhood, carrying into adulthood and requiring recurrent blood transfusions as a pillar of symptom management. Due to the consequences of ineffective erythropoiesis and frequent transfusions, patients with severe beta thalassemia may be subsequently susceptible to hemochromatosis. In light of the established role of hepcidin and erythroferrone in the pathogenesis of beta thalassemia, this review aims to discuss current clinical trials and studies in the field while presenting clinical implications of the HAMP gene polymorphisms and novel treatments. Research suggested incorporating erythroferrone and serum hepcidin testing as a part of routine workups for beta thalassemia, as they could be a predictive tool for early iron accumulation. Furthermore, ameliorating low hepcidin and high erythroferrone appeared to be crucial in treating beta thalassemia and its complications due to iron overload. Currently, hepcidin-like compounds, such as minihepcidins, LJPC-401, PTG-300, VIT-2763, and agents that promote hepcidin production by inhibiting TMPRSS6 expression or erythroferrone, were shown to be effective in restoring iron homeostasis in preliminary studies. Moreover, the natural bioactives astragalus polysaccharide and icariin have been recently recognized as hepcidin expression inductors.

Clinical Study of Mobile Application- (App-) Based Family-Centered Care (FCC) Model Combined with Comprehensive Iron Removal Treatment in Children with Severe Beta Thalassemia.

Methods A retrospective study was conducted on the clinical records of 148 children diagnosed with severe beta thalassemia who were admitted to our hospital between October 2018 and September 2021. The patients were separated into two groups, a control group and an intervention group, with 74 cases in each group, according to the various care approaches. The basic treatment regimen was given to all of the children: deferoxamine mesylate combined with deferiprone. During treatment, the control group received routine care, and the intervention group adopted the FCC model based on a mobile app. The quality of life scale for children and adolescents (QLSCA) score, the family assessment device (FAD) score, the exercise of self-care agency scale (ESCA) score, and the medication compliance scale score were compared between the two groups. Results The QLSCA score, ESCA score, and medication compliance scale score of the intervention group were significantly higher than those of the control group and showed a significant difference (intergroup effect: F = 198.400, 259.200, and 129.800, all P < 0.001). Scores in both groups increased over time (time effect: F = 19.350, 40.830, and 12.130, all P < 0.001), and there was an interaction effect between grouping and time (interaction effect: F = 3.937, 12.020, and 5.028). The P values were 0.020, <0.001, and 0.007. The FAD score of the intervention group was significantly lower than that of the control group (intergroup effect: F = 177.200, P < 0.001). The FAD scores of both groups decreased over time (time effect: F = 7.921, P = 0.005). There was an interaction effect between groups and time (interaction effect: F = 5.206, P = 0.006). Conclusion The application effect of the mobile app-based FCC model combined with the comprehensive iron removal treatment program in children with severe beta thalassemia is significant, which can significantly improve the quality of life, family function, self-care ability, and medication compliance of children, and has high clinical application value.

Leg Ulcers: A Report in Patients with Hemoglobin E Beta Thalassemia and Review of the Literature in Severe Beta Thalassemia

Background: Leg ulcers are a frequent complication in patients with the inherited hemoglobin disorders. In thalassemia, the literature is limited, and factors associated with the development of leg ulcers in hemoglobin E (HbE) beta thalassemia, the most common form of severe beta-thalassemia worldwide, have not previously been reported. Methods: We reviewed all available medical records of patients with HbE beta thalassemia to document the onset of leg ulcers at the 2 largest treatment centers in Sri Lanka. We reviewed the literature to identify studies reporting outcomes of interventions for ulcers in severe thalassemia. Results: Of a total of 255 actively registered patients with HbE thalassemia in the 2 centers, 196 patient charts were evaluable. A leg ulcer with a documented date of onset was recorded in 45 (22%) of 196 evaluable patients, aged (mean ± SEM) 22.2 ± 1.4 years. Most had been irregularly transfused; steady-state hemoglobin was 6.4 ± 0.2 g/dL. Treatment achieving healing in 17 patients included transfusions, antibiotics, oral zinc, wound toileting, and skin grafting. Conclusion: Leg ulcers may be more common in HbE beta thalassemia than in other forms of thalassemia. A systematic approach to treatment will be needed to document the prevalence and factors placing such patients at risk for leg ulcers. Controlled trials to evaluate the optimal treatment of this common complication are indicated.

Lentiviral globin gene therapy with reduced intensity conditioning in adults with severe beta-thalassemia

Lentiviral globin gene therapy with reduced intensity conditioning in adults with severe beta-thalassemia

Immune recovery after in vivo T-cell depletion myeloablative conditioning hematopoietic stem cell transplantation in severe beta-thalassemia children.

The clinical outcome of hematopoietic stem cell transplantation (HSCT) in those with severe beta-thalassemia (β-TM) is closely related to post-transplantation immune reconstitution (IR). However, the data on the IR in these settings are scarce. A prospective analysis of the clinical outcome and IR in 47 children with severe β-TM who underwent in vivo T-cell depletion myeloablative conditioning and matched sibling donor HSCT was performed. Immune reconstitution, including immune cell subset counts, as well as the generation of new T and B cells assays after HSCT, was measured. In the first year after HSCT, bacterial infections and cytomegalovirus (CMV) reactivation were observed in 70.2% and 36.2% of the patients, respectively. In the same period, poor CD4+ T-cell recovery was observed. The B cells recovered within 6months. Natural killer (NK) cells recovered as early as 1month, but their function was defective. Cord blood and bone marrow (CB+BM) group had slower T-cell recovery, and higher B cells and NK cells in comparison with peripheral blood and bone marrow (PB+BM) group. The high incidence of infection within 1year afterin vivo T-cell depletion myeloablative conditioning HSCT in severe β-TM was consistent with poor IR.

Global analysis of erythroid cells redox status reveals the involvement of Prdx1 and Prdx2 in the severity of beta thalassemia.

β-thalassemia is a worldwide distributed monogenic red cell disorder, characterized by an absent or reduced beta globin chain synthesis. The unbalance of alpha-gamma chain and the presence of pathological free iron promote severe oxidative damage, playing crucial a role in erythrocyte hemolysis, exacerbating ineffective erythropoiesis and decreasing the lifespan of red blood cells (RBC). Catalase, glutathione peroxidase and peroxiredoxins act together to protect RBCs from hydrogen peroxide insult. Among them, peroxiredoxins stand out for their overall abundance and reactivity. In RBCs, Prdx2 is the third most abundant protein, although Prdxs 1 and 6 isoforms are also found in lower amounts. Despite the importance of these enzymes, Prdx1 and Prdx2 may have their peroxidase activity inactivated by hyperoxidation at high hydroperoxide concentrations, which also promotes the molecular chaperone activity of these proteins. Some studies have demonstrated the importance of Prdx1 and Prdx2 for the development and maintenance of erythrocytes in hemolytic anemia. Now, we performed a global analysis comparatively evaluating the expression profile of several antioxidant enzymes and their physiological reducing agents in patients with beta thalassemia intermedia (BTI) and healthy individuals. Furthermore, increased levels of ROS were observed not only in RBC, but also in neutrophils and mononuclear cells of BTI patients. The level of transcripts and the protein content of Prx1 were increased in reticulocyte and RBCs of BTI patients and the protein content was also found to be higher when compared to beta thalassemia major (BTM), suggesting that this peroxidase could cooperate with Prx2 in the removal of H2O2. Furthermore, Prdx2 production is highly increased in RBCs of BTM patients that present high amounts of hyperoxidized species. A significant increase in the content of Trx1, Srx1 and Sod1 in RBCs of BTI patients suggested protective roles for these enzymes in BTI patients. Finally, the upregulation of Nrf2 and Keap1 transcription factors found in BTI patients may be involved in the regulation of the antioxidant enzymes analyzed in this work.

Genetic determinants related to pharmacological induction of foetal haemoglobin in transfusion-dependent HbE-β thalassaemia.

Thalassaemia are the most common inherited autosomal recessive single gene disorders characterized by chronic hereditary haemolytic anaemia due to the absence or reduced synthesis of one or more of the globin chains. Haemoglobin E-β thalassaemia is the genotype responsible for approximately one half of all severe beta-thalassaemia worldwide. This study proposes to evaluate the effect of various molecular parameters on the response of hydroxyurea. Hydroxyurea was started at an initial dose of 10mg/kg of body weight/day on 110 transfusion-dependent HbE-β thalassaemia patients. HbF level was measured by HPLC analysis. β-Thalassaemia mutations, XmnI and five other SNPs, and α-globin gene deletions and triplications were detected by ARMS-PCR, RFLP-PCR and Gap-PCR, respectively. Based on the factors for evaluating hydroxyurea-response, 42 patients were responders as they showed an increment of Hb from a mean baseline value of 6.45g/dl (± 0.70) to 7.78g/dl (± 0.72) post-therapy. Based on increase in HbF above the median value (14.72%) post-therapy, 78 patients were found to be responders. All the 78 responders showed mean decrease in transfusion of 74.26% (± 8.32) with a maximum decrease of 98.43%. There was a significant correlation between decrease in transfusion and increase in HbF level for all 78 responders. XmnI polymorphism showed the strongest association (p < 0.0001) with increase in HbF levels and Hb levels. Patients with α-globin gene deletions were better responders. It was concluded that hydroxyurea treatment is effective in transfusion-dependent HbE-β thalassaemia patients and the response is best in patients having both XmnI polymorphism and α-deletion.

Genotype-phenotype correlation among beta-thalassemia and beta-thalassemia/HbE disease in Thai children: predictable clinical spectrum using genotypic analysis.

IntroductionBeta-thalassemia is a group of inherited hemolytic anemias and one of the most common genetic disorders in Thailand. The clinical spectrum of beta-thalassemia disease ranges from mild to severe clinical symptoms including mild beta-thalassemia intermedia (TI) and severe beta-thalassemia major (TM).ObjectiveThis study aimed to determine the correlation between beta-globin gene (HBB) mutations and their phenotypic manifestations by evaluating patients’ clinical characteristics, transfusion requirements, growth and hematologic parameters, and hemoglobin typing among pediatric patients treated at Phramongkutklao Hospital.Materials and methodsSeventy beta-thalassemia patients, including 63 with beta-thalassemia/hemoglobin E (HbE) and 7 with either homozygous or compound heterozygous beta-thalassemia, were enrolled in this study. Their clinical presentation, growth parameters and laboratory findings were reviewed and analyzed. The mean follow-up time was 10.52±5.62 years. Mutation analysis in each individual was performed using multiplex amplification refractory mutation system (M-ARMS), direct DNA sequencing of beta-globin gene and gap PCR for 3.4 kb deletion detection.ResultsAll 7 homozygous and compound heterozygous beta-thalassemia patients were classified in TM. Among 63 patients with beta-thalassemia/HbE, 58 were classified in TM and 4 were classified in TI. Mean age at diagnosis was 0.8±0.49 years for homozygous or compound heterozygous beta-thalassemia and 3.43±3.5 years for beta-thalassemia/HbE. The most common HBB mutation was HBB:c.126_129delCTTT [codon 41/42 (-TCTT)] found in 34 alleles (48.6%). The height for age was also lower in homozygous beta-thalassemia patients (<3rd percentile) compared to compound heterozygous beta-thalassemia patients (25–50th percentile).ConclusionThis study revealed a genotype–phenotype correlation of the most prevalent beta-thalassemia in Thai children using diagnostic capacity in genotypic analysis of HBB mutation. Our findings can provide a better prediction of clinical manifestation and severity by early identification of the type of the HBB mutations.

Alteration of HSC Functions in Thalassemia

Beta-thalassemia represents one of the most globally widespread monogenic disorders and is characterized by significantly reduced or absent synthesis of hemoglobin beta-chains. In its severe form the insufficient production of adult hemoglobin results in altered erythropoiesis, hemolytic anemia, bone marrow (BM) hematopoietic hyperplasia and splenomegaly often associated with extramedullary hematopoiesis, requiring regular blood transfusions and iron chelation treatment. Over the last two decades many progresses were made in the field of allogeneic bone marrow (BM) transplantation to definitively cure beta-thalassemia. In parallel, experimental autologous transplantation protocols were developed to correct the disease by gene therapy also in patients lacking a compatible donor. Both in the allogeneic and autologous setting, thalassemic hematopoietic stem cells (HSCs) and the BM niche represent central elements.Although many aspects of the pathophysiology of thalassemia have been extensively investigated, the HSC and its niche have never been explored. In thalassemia, the BM is a stressed environment, characterized by the compensatory expansion of erythroid progenitors secondary to ineffective erythropoiesis. Whether other hematopoietic subpopulations, such as primitive progenitors and/or HSCs, might be affected by such an altered hematopoietic microenvironment is unknown.We investigated the frequency of hematopoietic progenitors in a murine model of severe beta-thalassemia intermedia. Immunophenotypic analyses revealed no differences in MEP, GMP, CMP, LMPP and MPP committed precursor subpopulations, whereas a significantly lower frequency of HSCs (Lin- Sca-1+ c-kit+ CD48- CD150+) was observed in thalassemic mice, as compared to age-matched wild-type controls. Competitive transplantation experiments revealed a disadvantage in the engraftment capacity of thalassemic HSCs, which was substantiated by the preliminary results from in vitro and in vivo cell cycle analyses suggesting an accelerated HSC exhaustion. Analyses of other cellular components, such as BM stroma and differentiated hematopoietic cells, revealed that additional elements are altered in the thalassemic BM microenvironment. The cellular and molecular bases of HSC-niche interaction in this pathological condition are under investigation.Our results uncover a previously ignored defect of HSCs in beta-thalassemia. The investigation of cellular and molecular players that might affect in trans HSC functions in the complexity of this altered microenvironment is ongoing. DisclosuresNo relevant conflicts of interest to declare.

Alpha hemoglobin stabilizing protein: Its causal relationship with the severity of beta thalassemia.

Thalassemia major is characterized by anemia, iron overload and cellular damage. The severity of symptoms correlates with the alpha/non-alpha globin imbalance and is proportional to the magnitude of alpha chain excess. Alpha hemoglobin stabilizing protein (AHSP), the erythroid specific alpha globin chaperone, stabilizes free alpha chains, and prevents the formation of reactive oxygen radicals. Though AHSP expression has been linked to the severity of beta thalassemia, its role as a probable genetic modifier of disease severity, has still not been unequivocally established. In the present study, the level of the chaperone has been seen to vary in regularly transfused beta thalassemia patients, being underexpressed in 64% of cases, upregulated in 16% and comparable to controls in 20% of the cases. This discrepancy may be attributed to the degree of DNA damage, % HbF, and the number of nucleated RBCs in the peripheral blood of these patients. Results reveal that a decrease in the free alpha chain pool, and hence the repertoire of unbound iron, due to elevated HbF and/or the presence of nucleated RBCs in the peripheral blood results in the upregulation of the AHSP gene.

Molecular analysis of beta-globin gene mutations among Thai beta-thalassemia children: results from a single center study

BackgroundBeta-thalassemia is one of the most common genetic disorders in Thailand. Clinical phenotype ranges from silent carrier to clinically manifested conditions including severe beta-thalassemia major and mild beta-thalassemia intermedia.ObjectiveThis study aimed to characterize the spectrum of beta-globin gene mutations in pediatric patients who were followed-up in Phramongkutklao Hospital.Patients and methodsEighty unrelated beta-thalassemia patients were enrolled in this study including 57 with beta-thalassemia/hemoglobin E, eight with homozygous beta-thalassemia, and 15 with heterozygous beta-thalassemia. Mutation analysis was performed by multiplex amplification refractory mutation system (M-ARMS), direct DNA sequencing of beta-globin gene, and gap polymerase chain reaction for 3.4 kb deletion detection, respectively.ResultsA total of 13 different beta-thalassemia mutations were identified among 88 alleles. The most common mutation was codon 41/42 (-TCTT) (37.5%), followed by codon 17 (A>T) (26.1%), IVS-I-5 (G>C) (8%), IVS-II-654 (C>T) (6.8%), IVS-I-1 (G>T) (4.5%), and codon 71/72 (+A) (2.3%), and all these six common mutations (85.2%) were detected by M-ARMS. Six uncommon mutations (10.2%) were identified by DNA sequencing including 4.5% for codon 35 (C>A) and 1.1% initiation codon mutation (ATG>AGG), codon 15 (G>A), codon 19 (A>G), codon 27/28 (+C), and codon 123/124/125 (-ACCCCACC), respectively. The 3.4 kb deletion was detected at 4.5%. The most common genotype of beta-thalassemia major patients was codon 41/42 (-TCTT)/codon 26 (G>A) or betaE accounting for 40%.ConclusionAll of the beta-thalassemia alleles have been characterized by a combination of techniques including M-ARMS, DNA sequencing, and gap polymerase chain reaction for 3.4 kb deletion detection. Thirteen mutations account for 100% of the beta-thalassemia genes among the pediatric patients in our study.

Identification of candidate genes involved in clinical variability among Tunisian patients with β-thalassemia

The short tandem repeats (STR) are undoubtedly the most used molecular markers in genetic diversity studies. β-thalassemia is a hereditary hemolytic anemia which is a common health problem all over the world. The disease has two main clinical forms: the severe form or β-thalassemia major (TM) and the moderate form or β-thalassemia intermedia (TI). To help understand this inconsistency, five STR have been studied in a group of 27 β-thalassemic patients divided into 15 (TM) and 12 (TI).For each STR, the distribution of alleles, has been compared among patients with β-thalassemia major (TM) and those with β-thalassemia intermedia (TI).The comparison has shown, for the STR D14S72, one specific allele to (TM) and for the STR D14S990 and D14S68, two specific alleles to TI patients. The combination of these alleles with severe beta-thalassemia genotypes leads to the phenotype of beta-thalassemia intermedia even though there are no any attenuating factors such as XmnI Gg polymorphism at position −158 of the HBG2 promotor or the alpha-globin defects. This suggests that these alleles are associated with factors reducing β-thalassemia clinical effects. One of this STR is located in the 5′UTR of the CEBPε gene which incodes a transcription factor expressed in the myeloid lineage.Thus, the involvement of the transcription factor CEBPε in the myeloid cells suggests that CEBPε is a candidate gene involved in the modulation of the β-thalassemia expression through immune system reactions.

Hematopoietic Cell Mobilization for Gene Therapy of Adult Patients with Severe Beta-Thalassemia: The Challenge of Splenectomy and the Role of Plerixafor

Abstract 166▪FN2▪This icon denotes a clinically relevant abstractIn preparation for a trial for gene therapy of thalassemia, we investigated the safety and efficacy of stem cell mobilization in adult patients with severe thalassemia using either GCSF or Plerixafor. We first assessed mobilization with G-CSF or G-CSF following pretreatment with Hydroxyurea (HU). HU was used in non splenectomized patients in order to reduce extramedullary hemopoiesis in spleen and the splenic size and in splenectomized patients in order to decrease the high number of platelets and mainly WBCs before G-CSF, so as to reduce the chance of complicated leukocytosis during mobilization. We present data on 23 patients from the G-CSF study (EudraCT number 2005-000315-10, NCT00336362) and on 14 patients from the Plerixafor study (EudraCT number 2009–014136-37, NCT01206075). The bulk of the CD34+cell enriched leukaphereses product in either study was cryopreserved for the future gene therapy trial. Mobilization with G-CSF was safe and effective in non-splenectomized patients (CD34+cellsX106/kg/2aphereses: 6.67±2.87, n=6). HU+G-CSF-treated subjects (n=4), mobilized successfully only when an optimal wash out period of approximately two weeks was maintained before G-CSF administration (CD34+cellsX106/kg/2aphereses: 7.34±1.19 vs 1.86±0.76, respectively, p=0.03). HU reduced the spleen size before G-CSF (376±96cm3 vs 556±218cm3) and resulted in less splenic enlargement during mobilization as compared to non-HU pretreated subjects (26.8% vs 60%, p=0.1), although this difference did not reach statistical significance. Splenectomized patients responded excessively to G-CSF by developing early hyperleukocytosis (day 3 mean WBCs: 80.0±7.5×103/μl) without a corresponding rise in blood CD34+cells. This necessitated a significant G-CSF dose reduction or hold resulting in poor yields in the majority of cases (CD34+cells/kg/2aphereses: 2.0±1.7, n=4). One-month HU-pretreatment (n=9), prevented the G-CSF-associated hyperleukocytosis during mobilization (mean WBCs: 60.4±20.8×103/μl) allowing for safe and successful CD34+cell collections (CD34+cells/kg/2aphereses: 6.6±2.3, p=0.02 vs G-CSF-alone), but again, only when an optimal 2-week wash out period was maintained. Despite the safe and effective mobilization with the optimal HU+G-CSF combination of splenectomized patients, HU pretreatment significantly prolonged the mobilization procedure. Plerixafor induced a rapid and effective mobilization in both the splenectomized and non-splenectomized patients (CD34+celsX106/kg/1 or 2 aphereses: 7.29±1.82, n=8 and 5.38±1.99, n=6, respectively) and it was very well tolerated. In SPL subjects, the mean yield per apheresis with plerixafor was higher, with a trend to significance, over its G-CSF counterpart and similar to the mean yield obtained by the optimally HU+G-CSF-treated patients in the G-CSF study (CD34+cells/kgX106/apheresis: 4.19±3.13 vs 1.01±0.85 vs 3.32±1.16, p=0.06 and p=0.6 respectively). One patient who was remobilized with the combination of G-CSF+plerixafor due to previous failure to collect 32×106/kg/2aphereses with G-CSF-alone, yielded 6.5χ10^6 CD34+cells/kg by one apheresis. Importantly also for the non-SPL patients treated with plerixafor, a mean increase of splenic volume of 10.9±14.3% was encountered which was significantly lower than the 60% mean spleen volume increase during G-CSF mobilization (p=0.03). There was no significant difference in the clonogenic capacity (CFU-GM, BFU-E) of CD34+cells mobilized by G-CSF, HU+G-CSF or Plerixafor. However, there was a trend for Plerixafor to mobilize more primitive HSC subpopulations (CD34+/CD38−, CD34+/CD38−/HLADR−) as compared to HU+G-CSF- or G-CSF-alone-mobilized cells.These results suggest that either G-CSF or Plerixafor could be used for mobilizing non-splenectomized patients. Plerixafor seems to represent the agent of choice for mobilization of splenectomized patients with thalassemia. Disclosures:Off Label Use: Plerixafor is used off-label for mobilization of thalassemic subjects.

Hematopoietic stem cell mobilization strategies for gene therapy of beta thalassemia and sickle cell disease

Effective gene therapy for hemoglobinopathies will require high numbers of autologous gene-engineered hematopoetic stem cells to be reintroduced into the patients. Stem cell mobilization using G-CSF is the most convenient and effective approach to achieve this goal, but it can have severe side effects in sickle cell anemia and be potentially harmful in the case of severe thalassemia. Hence, the optimal way of collection of hematopoetic stem cells from patients with thalassemia and sickle cell disease needs to be determined. In this paper, we review the possible risks of G-CSF mobilization in hemoglobinopathies and we outline the approaches used in an on-going clinical trial in which pretreatment with hydroxyurea is used to reduce potential risks of G-CSF administration to patients with severe beta thalassemia.

Thalassemia major: A report of two cases with severe skeletal involvement

Beta thalassemia major is rare in Serbia. Previously incurable, affected patients now live to adulthood with regular blood transfusions. The improvement in supportive treatment over recent decades has given rise to many more patients suffering from the associated metabolic complications of anaemia and iron overload, such as osteopenia and other skeletal changes. We present two patients with severe beta thalassemia major from early childhood, who encountered pathological long-bone fractures during the clinical course of their disease. One suffered a distal femoral diaphyseal fracture, and the second a distal tibia fracture. Both fractures occurred in osteopenic bone and were managed non-operatively due to the patients' general medical condition. Despite intense medical intervention, both patients died from disease progression within one year of their fractures, aged 23 and 24 years. As life expectancy rises it is anticipated that an increased number of beta thalassemia major patients will suffer pathological long-bone and other osteoporotic fractures. These fractures appear to both herald and contribute to a general clinical deterioration of this disease. Advances in stem-cell technology may hold the key for a definitive cure.