Recent advances in bone marrow transplantation in hemoglobinopathies

Long-Term Follow-Up of Patients Undergoing Thalidomide Therapy for Transfusion-Dependent β-Thalassaemia: A Single-Center Experience

Objective

We evaluated the long-term safety and efficacy of thalidomide in the treatment of transfusion-dependent β-thalassemia (TDT).

Methods

Fifty patients with TDT were treated with thalidomide and followed-up for 5 years. Thalidomide at a 50 mg dose was administered once a day after dinner. The dose was increased to 150 mg/d after 3 d if well tolerated. After 1 year of treatment, the hemoglobin (Hb) level was stabilized at its maximum, and thalidomide was gradually reduced and maintained at the minimum dose. The hematological response, transfusion dependence, and haemolytic indicators were assessed.

Results

At 9 month of follow-up, 38 (76%) patients achieved an excellent response, 1 (2%) a good response, 4(8%) a minor response, and 7(14%) did not show a response. The overall response rate was 86%. At 9 months, the Hb level increased from 79.0 ± 13.2 g/L at baseline to 99.0 ± 13.7g/L (P<0.001). Patients who achieved excellent response continued to show an increase in Hb levels during follow-up. At 48 months, the mean Hb level was 98.99 ± 10.3g/L; 21 patients (84.0%) became transfusion independent. Thalidomide was reduced and maintained to 25 mg/d in three of these patients. Moreover, five patients completed 60 months of follow-up, and with a mean Hb level of 99.8 ± 6.7g/L. During follow-up, grade 1-2 adverse drug reactions were noted; however, no grade 3 or higher adverse event was reported. However, no decrease in hemolytic indicators was observed.

Conclusion

Thalidomide was well tolerated in the long term, while it significantly improved Hb levels and reduced the transfusion burden.

Identification of two novel β-globin gene mutations HBB: exon3del, HBB: c.-81A>C

BACKGROUND

β-thalassemia is a common inherited hemolytic disorder caused by mutations in the HBB gene. Genetic analysis of 2 new beta-thalassemia patients with deletion mutations in the HBB gene and their family members.

METHODS

Their clinical presentation and blood phenotypic tests were analyzed. We detected the approximate degree of deletion of these two new HBB gene deletion mutants and analyzed their specific deletion locations by multiplex ligation-dependent probe amplification (MLPA), reverse breakpoint polymerase chain reaction (GAP-PCR), and sanger DNA sequencing.

RESULTS

Two new deletion mutants of the HBB gene were identified. First, a 49% decrease in the expression of the third exon of the HBB gene was detected by MLPA testing, and then proband 1 and her mother were found to have HBB: exon3del and proband 2 and her mother to have HBB: c.-81A > C by GAP-PCR and sanger sequencing.

CONCLUSION

When the blood phenotype and clinical manifestations do not match the genotype, the presence of new mutants should be considered, and attention should be paid to further testing to avoid missing the diagnosis, which can help in clinical diagnosis and treatment, prenatal diagnosis and genetic counseling.

Therapy Development by Genome Editing of Hematopoietic Stem Cells

Accessibility of hematopoietic stem cells (HSCs) for the manipulation and repopulation of the blood and immune systems has placed them at the forefront of cell and gene therapy development. Recent advances in genome-editing tools, in particular for clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein (Cas) and CRISPR/Cas-derived editing systems, have transformed the gene therapy landscape. Their versatility and the ability to edit genomic sequences and facilitate gene disruption, correction or insertion, have broadened the spectrum of potential gene therapy targets and accelerated the development of potential curative therapies for many rare diseases treatable by transplantation or modification of HSCs. Ongoing developments seek to address efficiency and precision of HSC modification, tolerability of treatment and the distribution and affordability of corresponding therapies. Here, we give an overview of recent progress in the field of HSC genome editing as treatment for inherited disorders and summarize the most significant findings from corresponding preclinical and clinical studies. With emphasis on HSC-based therapies, we also discuss technical hurdles that need to be overcome en route to clinical translation of genome editing and indicate advances that may facilitate routine application beyond the most common disorders.

Consensus Predictive Model for Human K562 Cell Growth Inhibition through Enalos Cloud Platform

β-Thalassemia is an inherited hematologic disorder caused by various mutations of the β-globin gene, thus resulting in a significant decrease in adult hemoglobin (HbA) production. An increase in fetal hemoglobin (HbF) levels by drug molecules is considered of great potential in β-thalassemia treatment and is expected to counterbalance the impaired production of HbA. In this work, based on a set of 129 experimentally tested biological inhibitors, we developed and validated a computational model for the prediction of K562 functional inhibition, possibly associated with HbF induction. To facilitate future advancements in the field, we incorporated our model into Enalos Cloud Platform, which enabled online access to our computational scheme (http://enalos.insilicotox.com/K562) through a user-friendly interface. This web service is offered to the wider community to promote in silico drug discovery through fast and reliable predictions.

Genetic disruption of the KLF1 gene to overexpress the γ-globin gene using the CRISPR/Cas9 system

BACKGROUND

β-thalassemia comprises a major group of human genetic disorders involving a decrease in or an end to the normal synthesis of the β-globin chains of hemoglobin. KLF1 is a key regulatory molecule involved in the γ- to β-globin gene switching process directly inducing the expression of the β-globin gene and indirectly repressing γ-globin. The present study aimed to investigate the ability of an engineered CRISPR/Cas9 system with respect to disrupting the KLF1 gene to inhibit the γ- to β-hemoglobin switching process in K562 cells.

METHODS

We targeted three sites on the KLF1 gene, two of which are upstream of codon 288 in exon 2 and the other site being in exon 3.

RESULTS

The average indel percentage in the cells transfected with CRISPR a, b and c was approximately 24%. Relative quantification was performed for the assessment of γ-globin expression. The levels of γ-globin mRNA on day 5 of differentiation were 8.1-, 7.7- and 1.8-fold in the cells treated with CRISPR/Cas9 a, b and c, respectively,compared to untreated cells. The measurement of HbF expression levels confirmed the same results.

CONCLUSIONS

The findings obtained in the present study support the induction of an indel mutation in the KLF1 gene leading to a null allele. As a result, the effect of KLF1 on the expression of BCL11A is decreased and its inhibitory effect on γ-globin gene expression is removed. Application of CRISPR technology to induce an indel in the KLF1 gene in adult erythroid progenitors may provide a method for activating fetal hemoglobin expression in individuals with β-thalassemia or sickle cell disease.

Function and Safety of Lentivirus-Mediated Gene Transfer for CSF2RA-Deficiency

Hereditary pulmonary alveolar proteinosis (hPAP) is a rare disorder of pulmonary surfactant accumulation and hypoxemic respiratory failure caused by mutations in CSF2RA (encoding the granulocyte/macrophage colony-stimulating factor [GM-CSF] receptor α-chain [CD116]), which results in reduced GM-CSF-dependent pulmonary surfactant clearance by alveolar macrophages. While no pharmacologic therapy currently exists for hPAP, it was recently demonstrated that endotracheal instillation of wild-type or gene-corrected mononuclear phagocytes (pulmonary macrophage transplantation [PMT]) results in a significant and durable therapeutic efficacy in a validated murine model of hPAP. To facilitate the translation of PMT therapy to human hPAP patients, a self-inactivating (SIN) lentiviral vector was generated expressing a codon-optimized human CSF2RA-cDNA driven from an EF1α short promoter (Lv.EFS.CSF2RAcoop), and a series of nonclinical efficacy and safety studies were performed in cultured macrophage cell lines and primary human cells. Studies in cytokine-dependent Ba/F3 cells demonstrated efficient transduction, vector-derived CD116 expression proportional to vector copy number, and GM-CSF-dependent cell survival and proliferation. Using a novel cell line constructed to express a normal GM-CSF receptor β subunit and a dysfunctional α subunit (due to a function-altering CSF2RAG196R mutation) that reflects the macrophage disease phenotype of hPAP patients, it was demonstrated that Lv.EFS.CSF2RAcoop transduction restored GM-CSF receptor function. Further, Lv.EFS.CSF2RAcoop transduction of healthy primary CD34+ cells did not adversely affect cell proliferation or affect the cell differentiation program. Results demonstrate Lv.EFS.CSF2RAcoop reconstituted GM-CSF receptor α expression, restoring GM-CSF signaling in hPAP macrophages, and had no adverse effects in the intended target cells, thus supporting testing of PMT therapy of hPAP in humans.

Target-based drug discovery for [Formula: see text]-globin disorders: drug target prediction using quantitative modeling with hybrid functional Petri nets

Recent molecular studies provide important clues into treatment of [Formula: see text]-thalassemia, sickle-cell anaemia and other [Formula: see text]-globin disorders revealing that increased production of fetal hemoglobin, that is normally suppressed in adulthood, can ameliorate the severity of these diseases. In this paper, we present a novel approach for drug prediction for [Formula: see text]-globin disorders. Our approach is centered upon quantitative modeling of interactions in human fetal-to-adult hemoglobin switch network using hybrid functional Petri nets. In accordance with the reverse pharmacology approach, we pose a hypothesis regarding modulation of specific protein targets that induce [Formula: see text]-globin and consequently fetal hemoglobin. Comparison of simulation results for the proposed strategy with the ones obtained for already existing drugs shows that our strategy is the optimal as it leads to highest level of [Formula: see text]-globin induction and thereby has potential beneficial therapeutic effects on [Formula: see text]-globin disorders. Simulation results enable verification of model coherence demonstrating that it is consistent with qPCR data available for known strategies and/or drugs.

The Intravenous Route of Injection Optimizes Engraftment and Survival in the Murine Model of In Utero Hematopoietic Cell Transplantation

In utero hematopoietic cell transplantation (IUHCT) has the potential to treat a number of congenital hematologic disorders. Clinical application is limited by low levels of donor engraftment. Techniques that optimize donor cell delivery to the fetal liver (FL), the hematopoietic organ at the time of IUHCT, have the potential to enhance engraftment and the clinical success of IUHCT. We compared the 3 clinically applicable routes of injection (intravenous [i.v.], intraperitoneal [i.p.], and intrahepatic [i.h.]) and assessed short- and long-term donor cell engraftment and fetal survival in the murine model of IUHCT. We hypothesized that the i.v. route would promote direct donor cell homing to the FL, resulting in increased engraftment and allowing for larger injectate volumes without increased fetal mortality. We demonstrate that the i.v. route results in (1) rapid diffuse donor cell population of the FL compared with delayed diffuse engraftment after the i.p. and i.h. routes; (2) higher FL and spleen engraftment at early prenatal time points; (3) enhanced stable long-term peripheral blood donor cell engraftment; and (4) improved survival at higher injectate volumes, allowing for higher donor cell doses and increased long-term engraftment. These findings support the use of an i.v. route for clinical protocols of IUHCT.

Hemopoietic stem cell transplantation in thalassemia: a report from the European Society for Blood and Bone Marrow Transplantation Hemoglobinopathy Registry, 2000-2010

Allogeneic hemopoietic stem cell transplantation (HSCT) is the only method currently available to cure transfusion-dependent thalassemia major that has been widely used worldwide. To verify transplantation distribution, demography, activity, policies and outcomes inside the European Group for Blood and Marrow Transplantation (EBMT), we performed a retrospective non-interventional study, extracting data from the EBMT hemoglobinopathy prospective registry database. We included 1493 consecutive patients with thalassemia major transplanted between 1 January 2000 and 31 December 2010. In total, 1359 (91%) transplants were performed on patients <18 years old, 1061 were from a human leukocyte Ag-identical sibling donor. After a median observation time of 2 years, the 2-year overall survival (OS) and event-free survival (EFS; that is, thalassemia-free survival) were 88 ± 1% and 81 ± 1%, respectively. Transplantation from a human leukocyte Ag-identical sibling offered the best results, with OS and EFS of 91 ± 1% and 83 ± 1%, respectively. No significant differences in survival were reported between countries. The threshold age for optimal transplant outcomes was around 14 years, with an OS of 90-96% and an EFS of 83-93% when transplants were performed before this age. Allogeneic HSCT for thalassemia is a curative approach that is employed internationally and produces excellent results.

Development and characterization of K562 cell clones expressing BCL11A-XL: Decreased hemoglobin production with fetal hemoglobin inducers and its rescue with mithramycin

Induction of fetal hemoglobin (HbF) is considered a promising strategy in the treatment of β-thalassemia, in which production of adult hemoglobin (HbA) is impaired by mutations affecting the β-globin gene. Recent results indicate that B-cell lymphoma/leukemia 11A (BCL11A) is a major repressor of γ-globin gene expression. Therefore, disrupting the binding of the BCL11A transcriptional repressor complex to the γ-globin gene promoter provides a novel approach for inducing expression of the γ-globin genes. To develop a cellular screening system for the identification of BCL11A inhibitors, we produced K562 cell clones with integrated copies of a BCL11A-XL expressing vector. We characterized 12 K562 clones expressing different levels of BCL11A-XL and found that a clear inverse relationship does exist between the levels of BCL11A-XL and the extent of hemoglobinization induced by a panel of HbF inducers. Using mithramycin as an inducer, we found that this molecule was the only HbF inducer efficient in rescuing the ability to differentiate along the erythroid program, even in K562 cell clones expressing high levels of BCL11A-XL, suggesting that BCL11A-XL activity is counteracted by mithramycin.

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K562 clones were described with integrated copies of a BCL11A-XL expressing vector.

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B-Cell lymphoma/leukemia 11A-XL (BCL11A-XL) levels inversely correlate with the extent of hemoglobin induction.

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Mithramycin induces γ-globin genes even in K562 clones expressing high levels of BCL11A-XL.

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K562(BCL11A-XL) clones might be useful in identifying fetal hemoglobin inducers acting on BCL11A.

Reproductive issues in sickle cell disease

As medical advances improve survival, reduce disease-related morbidity, and improve quality of life, reproductive issues will take higher priority in the sickle cell disease (SCD) community. A wide variety of topics are addressed in this chapter, including fertility, gonadal failure, erectile dysfunction, and menstrual issues in SCD. Etiologies of impaired male fertility are multifactorial and include hypogonadism, erectile dysfunction, sperm abnormalities, and complications of medical therapies. Much less is known about the prevalence and etiology of infertility in women with SCD. Other reproductive issues in women included in this review are pain and the menstrual cycle, contraception, and preconception counseling. Finally, long-term therapies for SCD and their impact on fertility are presented. Transfusional iron overload and gonadal failure are addressed, followed by options for fertility preservation after stem cell transplantation. Focus is placed on hydroxyurea therapy given its benefits and increasing use in SCD. The impact of this agent on spermatogenesis, azoospermia, and the developing fetus is discussed.

Reproductive issues in sickle cell disease

As medical advances improve survival, reduce disease-related morbidity, and improve quality of life, reproductive issues will take higher priority in the sickle cell disease (SCD) community. A wide variety of topics are addressed in this chapter, including fertility, gonadal failure, erectile dysfunction, and menstrual issues in SCD. Etiologies of impaired male fertility are multifactorial and include hypogonadism, erectile dysfunction, sperm abnormalities, and complications of medical therapies. Much less is known about the prevalence and etiology of infertility in women with SCD. Other reproductive issues in women included in this review are pain and the menstrual cycle, contraception, and preconception counseling. Finally, long-term therapies for SCD and their impact on fertility are presented. Transfusional iron overload and gonadal failure are addressed, followed by options for fertility preservation after stem cell transplantation. Focus is placed on hydroxyurea therapy given its benefits and increasing use in SCD. The impact of this agent on spermatogenesis, azoospermia, and the developing fetus is discussed.

A mindfulness-based program for improving quality of life among hematopoietic stem cell transplantation survivors: feasibility and preliminary findings

Health-related quality of life (HRQoL) is often substantially reduced among individuals who have undergone hematopoietic stem cell transplantation (HSCT), and incidences of depression, fatigue, and anxiety are elevated. We examined effects of a mindfulness-based intervention (MBI) compared to psycho-oncological telephone consultation upon HRQoL, depression, anxiety, and fatigue among HSCT survivors. Sixty-two medically stable patients participated in the study; they had completed HSCT ≥6 months previously. Thirty-two were randomly assigned to intervention arms, and 30 were offered their treatment preference. MBI consisted of a structured 8-week program of mindfulness training. Assessments were made at baseline, post-intervention and 3 months follow-up. Primary outcome was HRQoL. Depression, fatigue, anxiety, and personal goal attainment were secondary measures. Non-completion of interventions was low in both groups (9 %, MBI; 7 % control). Employing intention-to-treat analysis, MBI, compared with comparison procedure, improved HRQoL and reduced depression and anxiety at post-intervention (p's < 0.05); Cohen's d effect sizes, 0.6-0.7; 3-month follow-up benefits were modest. These findings demonstrate broad feasibility and acceptance of, as well as satisfaction and adherence with, a program of mindfulness training for HSCT survivors; findings also suggest improved HRQoL and well-being as a consequence of MBI. Nevertheless, this is a preliminary study; a larger trial with more prolonged intervention phase is warranted.

Recent trends for novel options in experimental biological therapy of β-thalassemia

INTRODUCTION

β-thalassemias are caused by nearly 300 mutations of the β-globin gene, leading to low or absent production of adult hemoglobin. Achievements have been recently obtained on innovative therapeutic strategies for β-thalassemias, based on studies focusing on the transcriptional regulation of the γ-globin genes, epigenetic mechanisms governing erythroid differentiation, gene therapy and genetic correction of the mutations.

AREAS COVERED

The objective of this review is to describe recently published approaches (the review covers the years 2011 - 2014) useful for the development of novel therapeutic strategies for the treatment of β-thalassemia.

EXPERT OPINION

Modification of β-globin gene expression in β-thalassemia cells was achieved by gene therapy (eventually in combination with induction of fetal hemoglobin [HbF]) and correction of the mutated β-globin gene. Based on recent areas of progress in understanding the control of γ-globin gene expression, novel strategies for inducing HbF have been proposed. Furthermore, the identification of microRNAs involved in erythroid differentiation and HbF production opens novel options for developing therapeutic approaches for β-thalassemia and sickle-cell anemia.

Docosahexaenoic and eicosapentaenoic acid supplementation does not exacerbate oxidative stress or intravascular haemolysis in homozygous sickle cell patients

We investigated whether or not Omega-3 long-chain polyunsaturated fatty acid (omega-3 LCPUFA) supplementation exacerbates oxidative stress in homozygous sickle cell patients aged 2 to 14 years. Depending on their age, they received between one and three omega-3 (277.8mg DHA and 39.0mg EPA/capsule) or placebo (high oleic acid sunflower seed oil) capsules for one year. Supplementation increased significantly the levels of the two fatty acids in red cell phosphatidylcholine and phosphatidylethanolamine (p<0.001). The patients who received omega-3 LCPUFA compared with their placebo-taking counterparts had a higher concentration of plasma vitamin E at one year (14.3±2.8 versus 12.3±2.8µmol/l; p<0.001). The two groups had comparable concentrations of the vitamin at six month intervention (10.8±2.2 versus 10.7±2.9µmol/l; p>0.05) and baseline (10.7±3.1 versus 10.7±2.8µmol/l; p>0.05). After six month of intervention, the patients on omega 3 fatty acids had lower GPx-1 (33.5±13.4 versus 46.6 ±17.6, p<0.01) and Cu/Zn-SOD (1070±600 versus 1470±690 p<0.05) activities than at baseline. GPx-1 (33.5±17.6IU/g Hb versus 43.7±13.2IU/g Hb; p<0.01) and Cu/Zn-SOD (1070±600IU/g Hb versus 1360±920IU/g Hb; p>0.05) activities were reduced in the omega 3 compared with the placebo at six month intervention. There was no difference in the activity of either of the enzymes between baseline and six month intervention in the placebo group (p>0.05). This study demonstrates; DHA and EPA supplementation, rather than exacerbating the inherent oxidative stress associated with the disease, seems to provide an antioxidant protection. Hence, it will be safe to provide omega-3 LCPUFA to sickle cell patients to help ameliorate vaso-occlusive and haemolytic crises and membrane fatty acid abnormality.

Stem cell and genetic therapies for the fetus

The prenatal diagnosis and management of congenital disease has made significant progress over the previous decade. Currently, fetal therapy (including open surgery and fetoscopic intervention) provides therapeutic options for a range of congenital anomalies; however, it is restricted to the treatment of fetal pathophysiology. Improvements in prenatal screening and the early diagnosis of genetic disease allow for preemptive treatment of anticipated postnatal disease by stem cell or genetic therapy. While currently awaiting clinical application, in utero stem cell therapy has made significant advances in overcoming the engraftment and immunologic barriers in both murine and pre-clinical large animal models. Likewise, proof in principle for fetal gene therapy has been demonstrated in rodent and large animal systems as a method to prevent the onset of inherited genetic disease; however, safety and ethical risks still need to be addressed prior to human application. In this review, we examine the current status and future direction of stem cell and genetic therapy for the fetus.

The switch from fetal to adult hemoglobin

The fetal-to-adult hemoglobin switch and silencing of fetal hemoglobin (HbF) have been areas of long-standing interest among hematologists, given the fact that clinical induction of HbF production holds tremendous promise to ameliorate the clinical symptoms of sickle cell disease (SCD) and β-thalassemia. In this article, we discuss historic attempts to induce HbF that have resulted in some therapeutic approaches to manage SCD and β-thalassemia. We then go on to discuss how more recent molecular studies that have identified regulators, including BCL11A, MYB, and KLF1, hold great promise to develop targeted and more effective approaches for HbF induction. We go on to discuss strategies by which such approaches may be developed. Older studies in this field can provide important lessons for future studies aimed at developing more effective strategies for HbF induction, and we therefore chronologically cover the work accomplished as this field has evolved over the course of the past four decades.

Bone marrow transplant options and preferences in a sickle cell anemia cohort on chronic transfusions

BACKGROUND

Bone marrow transplantation (BMT) using human leukocyte antigen (HLA)-matched sibling donors can be curative for children with sickle cell anemia (SCA). However, minimal data exist regarding availability of HLA-identical matched siblings for transplant-eligible children, and family interest in pursuing transplantation.

METHODS

We retrospectively analyzed a pediatric SCA cohort receiving chronic transfusions between July 2004 and January 2011. Data were analyzed regarding the number of full siblings and half-siblings, availability, and family interest in HLA testing the full siblings, and interest in proceeding with HLAmatched transplantation.

RESULTS

Among 113 patients, 46 (41%) had at least 1 full sibling and 40 (35%) had an unaffected full sibling who could serve as a BMT donor. The families of 23 of these patients (58%) agreed to HLA-type sibling, 8 of whom (35%) were matched. Transfusion indications for families agreeing to HLA typing included stroke (46%) abnormal TCD (29%), acute chest syndrome (21%), and other CNS reasons (4%). Common reasons to decline HLA typing or transplantation included fear of the process, toxicities of the procedure, and comfort with current quality of life on transfusions. Only 8 of 113 (7%) were eligible for matched BMT, and only 3 (3%) underwent HLA-matched transplantation. Two unmatched children received haploidentical transplantation.

CONCLUSIONS

Most families of children with SCA on chronic transfusions choose to proceed with HLA typing. However, when a matched sibling was identified, most families declined to proceed with matched-sibling transplantation. Discussing BMT as a treatment option, offering HLA typing and identifying barriers may improve acceptance of this treatment modality.

Analysis of 120 pediatric patients with nonmalignant disorders transplanted using unrelated plasma-depleted or -reduced cord blood

BACKGROUND

Unrelated cord blood (CB) is an important stem cell source for unrelated hematopoietic cell transplantation (HCT) of patients with nonmalignant disorders. Processing methods to prepare red blood cell-reduced CB units incur significant nucleated cell loss. In contrast, plasma depletion or reduction (PDR) processing of CB units entails the removal of only a portion of the plasma with minimal nucleated cell loss. However, there are relatively limited data regarding outcomes of CB transplants using units processed by PDR.

STUDY DESIGN AND METHODS

A Center for International Blood and Marrow Transplant Research (CIBMTR)-audited analysis was performed on 120 pediatric patients with nonmalignant disorders transplanted between November 2001 and January 2008 at 29 US and 17 international centers using PDR CB units from two CB banks.

RESULTS

Transplant characteristics were as follows: median age, 3.5 years (range, 0.1-14 years); median patient weight, 15 kg (range, 4-61 kg); 58% male; HLA matches (intermediate-resolution HLA-A and HLA-B and high-resolution HLA-DRB1) of the units used in these patients six of six in 26, five of six in 48, four of six in 47, and three of six or two of six in 6; median prefreeze total nucleated cell dose, 10.5×10(7)/kg; median prefreeze CD34+ dose, 3.7×10(5)/kg; and nonmyeloablative regimen in 24%. The median times to myeloid and platelet engraftment were 21 and 49 days, respectively. The cumulative incidence of reported Grade II to IV acute graft-versus-host disease (aGVHD) was 38±5%, and 19±4% had Grade III to IV aGVHD. The Kaplan-Meier estimates of 3-year transplant-related mortality, overall survival, and disease-free survival were 20±4, 79±4, and 70±6%, respectively.

CONCLUSION

These data demonstrate the effectiveness of PDR CB units for HCT.

Self-reported level of and factors influencing the compliance to desferrioxamine therapy in multitransfused thalassaemias

AIM

To analyse the self-reported degree of and factors influencing the compliance to desferrioxamine (DFO) therapy in children with transfusion-dependent thalassaemia major in Malaysia.

METHODS

A cross-sectional study was conducted on all children with thalassaemia major on DFO attending Likas Hospital, Sabah, in September 2008. Patients or carer-providers were interviewed to report on the degree of compliance as either highly (administering >90% of DFO), moderately (51-90%), poorly (1%-50%) or non-compliant (0%) to DFO in the preceding month. The latest serum ferritin levels were noted.

RESULTS

The median (range) age at first blood transfusion of these 139 (73 males, median (range) age at interview: 9.0 years (2-16 years)) patients were 1.0 year (2 months to 10 years). The median (range) duration of regular DFO therapy was 2 years (2 months to 10 years). Forty-three (31%) of the patients reported themselves to be highly compliant, 70 (50%) moderately and 26 (19%) poorly or non-compliant. Multivariate analysis showed that a lower family income negatively affected the degree of compliance, while family support positively affected the degree of compliance to DFO. No correlation existed between self-reported degree of compliance and latest serum ferritin level (6444 ± µmol/L; P = 0.186).

CONCLUSION

The self-reported compliance to DFO therapy was moderate in this cohort of patients with thalassaemia major in Malaysia. The serum ferritin level was high, possibly because of the relatively short duration of DFO therapy and compliance. Oral iron chelator should be considered to improve the compliance to iron chelation.

Purified hematopoietic stem cell transplantation: the next generation of blood and immune replacement

Replacement of disease-causing stem cells with healthy ones has been achieved clinically via hematopoietic cell transplantation (HCT) for the last 40 years, as a treatment modality for a variety of cancers and immunodeficiencies with moderate, but increasing, success. This procedure has traditionally included transplantation of mixed hematopoietic populations that include hematopoietic stem cells (HSC) and other cells, such as T cells. This article explores and delineates the potential expansion of this technique to treat a variety of inherited diseases of immune function, the current barriers in HCT and pure HSC transplantation, and the up-and-coming strategies to combat these obstacles.

Targeted therapeutic strategies for fetal hemoglobin induction

Increased levels of fetal hemoglobin (HbF) can ameliorate the severity of the β-hemoglobin disorders, sickle cell disease (SCD) and β-thalassemia, which are major sources of morbidity and mortality worldwide. As a result, there has been a longstanding interest in developing therapeutic approaches for inducing HbF. For more than 3 decades, the majority of HbF inducers developed were based on empiric observations and have had limited success. Recently, human genetic approaches have provided insight into previously unappreciated regulators of the fetal-to-adult hemoglobin switch and HbF silencing, revealing molecular targets to induce HbF. This article reviews these developments and discusses how molecules including BCL11A, KLF1, MYB, SOX6, miRNAs 15a and 16-1, and histone deacetylase 1 and 2 (HDAC1/2) could be important targets for HbF induction in humans. The current understanding of how these molecules function and the benefits and drawbacks of each of these potential therapeutic targets are also examined. The identification of these regulators of HbF expression is extremely promising and suggests that rationally designed approaches targeting the very mechanisms mediating this switching process could lead to better, less toxic, and more effective strategies for HbF induction.

Purified hematopoietic stem cell transplantation: the next generation of blood and immune replacement

Replacement of disease-causing stem cells with healthy ones has been achieved clinically via hematopoietic cell transplantation (HCT) for the last 40 years, as a treatment modality for a variety of cancers and immunodeficiencies with moderate, but increasing, success. This procedure has traditionally included transplantation of mixed hematopoietic populations that include hematopoietic stem cells (HSC) and other cells, such as T cells. This article explores and delineates the potential expansion of this technique to treat a variety of inherited diseases of immune function, the current barriers in HCT and pure HSC transplantation, and the up-and-coming strategies to combat these obstacles.

Pulmonary hypertension in thalassemia

Pulmonary hypertension (PH) is common in thalassemia and contributes to mortality. Advancing age and a history of splenectomy are major risk factors in this population. The etiology of PH is multifactorial, involving a complex interaction of platelets, the coagulation system, erythrocytes, and endothelial cells along with inflammatory and vascular mediators. The long-term effect of splenectomy, red cell membrane pathology, coagulation abnormalities, low nitric oxide (NO) bioavailability, excess arginase activity, platelet activation, oxidative stress, iron overload, and chronic hemolysis play a role. The process of hemolysis disables the arginine-NO pathway through the simultaneous release of erythrocyte arginase and cell-free hemoglobin. Both NO and its obligate substrate arginine are rapidly consumed. The biological consequences of hemolysis on NO bioavailability ultimately translate into the clinical manifestations of PH. Guidelines for the management of PH in thalassemia have not yet been established; however, clinical trials are ongoing in an effort to guide future therapy.

Sickle cell disease in the United States: looking back and forward at 100 years of progress in management and survival

The past 100 years since James Herrick's first description of sickle cell disease in the United States have been characterized by the gradual development of management strategies. We review the progress in sickle cell disease management in the United States over the past 100 years, with emphasis on the diverse forces surrounding advances in disease management. Mortality and survival data are presented chronologically, with an attempt to highlight improvements in survival associated with specific advancements for pediatric and adult care. Finally, the future course for sickle cell disease management is explored, given the continued work in advancing the field.

Trends of hematopoietic stem cell transplantation in the third millennium

PURPOSE OF REVIEW

Hematopoietic stem cell transplantation (HSCT) has evolved into an accepted therapy for many congenital or acquired disorders of the hematopoietic system. It has seen major changes in indications and use of transplant techniques. HSCT is a high cost procedure and requires investments; information on trends is essential for patient counselling and healthcare planning.

RECENT FINDINGS

HSCT rates have increased worldwide. Increase is constant and predictable; the reasons therefore are manifold. Introduction of reduced intensity conditioning regimens has opened access to patients at older age and with comorbidities. Higher numbers of unrelated volunteer donors and cord blood products give access to HSCT for patients without family donors. For some well defined indications, HSCT has become the most cost efficient therapy in countries with limited resources. Use of HSCT is under discussion for nonhematopoietic indications, as is the use of nonhematopoietic stem cells for organ repair.

SUMMARY

HSCT is likely to continue to increase for currently established indications. Indications and technologies will vary between countries with limited or nonrestricted resources. The most cost effective approach might not be the same everywhere. Novel indications will emerge but time will be needed to confirm their benefit. Close observation of global trends will become an essential tool for healthcare agencies in order to provide the necessary infrastructure in time.