Overview on practices in thalassemia intermedia management aiming for lowering complication rates across a region of endemicity: the OPTIMAL CARE study. Blood. 2010;115:1886-1892. [PMID: 20032507 DOI: 10.1182/blood-2009-09-243154]

Non-transfusion-dependent thalassemias

Non-transfusion-dependent thalassemias include a variety of phenotypes that, unlike patients with beta (β)-thalassemia major, do not require regular transfusion therapy for survival. The most commonly investigated forms are β-thalassemia intermedia, hemoglobin E/β-thalassemia, and α-thalassemia intermedia (hemoglobin H disease). However, transfusion-independence in such patients is not without side effects. Ineffective erythropoiesis and peripheral hemolysis, the hallmarks of disease process, lead to a variety of subsequent pathophysiologies including iron overload and hypercoagulability that ultimately lead to a number of serious clinical morbidities. Thus, prompt and accurate diagnosis of non-transfusion-dependent thalassemia is essential to ensure early intervention. Although several management options are currently available, the need to develop more novel therapeutics is justified by recent advances in our understanding of the mechanisms of disease. Such efforts require wide international collaboration, especially since non-transfusion-dependent thalassemias are no longer bound to low- and middle-income countries but have spread to large multiethnic cities in Europe and the Americas due to continued migration.

The spectrum of ocular alterations in patients with β-thalassemia syndromes suggests a pathology similar to pseudoxanthoma elasticum

PURPOSE

To determine the prevalence and spectrum of ocular fundus abnormalities in patients with β-thalassemia and to investigate risk factors for their development.

DESIGN

Cross-sectional, observational study.

PARTICIPANTS

A total of 255 patients with β-thalassemia major (TM) and β-thalassemia intermedia (TI) were consecutively recruited and investigated.

METHODS

Patients underwent best correct visual acuity, indirect ophthalmoscopy, and fundus photography, including fundus autofluorescence (FAF) and near-infrared reflectance imaging using a confocal scanning laser ophthalmoscope (cSLO). Hematologic parameters were determined, including mean ferritin levels, aspartate amino transferase, alanine amino transferase, calcium, pre-transfusion hemoglobin, history of splenectomy, and liver iron concentration. Factors associated with the ocular phenotype were assessed using logistic regression.

MAIN OUTCOME MEASURES

Ocular phenotype as determined by clinical examination and used multimodal imaging.

RESULTS

A total of 153 patients (60.0%) affected by TM and 102 patients (40.0%) affected by TI participated, of whom 216 (84.7%) were receiving iron-chelating therapy. Ocular fundus abnormalities characteristic of pseudoxanthoma elasticum (PXE) were detected by cSLO in 70 of 255 patients (27.8%) and included peau d'orange (19.6%), angioid streaks (12.9%), pattern dystrophy-like changes (7.5%), and optic disc drusen (2.0%). Pseudoxanthoma elasticum-like changes were more frequent in patients with TI (P<0.001). Patients with PXE-like fundus changes were older than patients without these fundus changes (P<0.001). In both patients with TI and TM, age (P = 0.001) and splenectomy (P = 0.001) had the strongest association with presence of PXE-like fundus changes in multivariate analyses. A total of 43 of 255 patients (16.9%) showed increased retinal vascular tortuosity independently of the PXE-like fundus changes, which was associated with aspartate amino transferase (P = 0.036), hemoglobin (P = 0.008), and ferritin levels (P = 0.005).

CONCLUSIONS

Pseudoxanthoma elasticum-like fundus changes are a frequent finding in patients with β-thalassemia. In TI, these changes increase with duration or severity of the disease. This particular ocular phenotype suggests an ocular pathology similar to PXE. Retinal vascular tortuosity may be an additional disease manifestation independent of the PXE-like syndrome. Patients with long-standing disease requiring iron-chelating treatment and a history of splenectomy need regular ophthalmic checkups because they are at risk of developing PXE-like fundus changes and potentially of subsequent choroidal neovascularization.

Quantification of HBG mRNA in primary erythroid cultures: prediction of the response to hydroxyurea in sickle cell and beta-thalassemia

BACKGROUND AND OBJECTIVE

Increased expression of fetal hemoglobin (HbF) may ameliorate the clinical course of hemoglobinopathies like sickle cell disease (SCD) and β-thalassemia. Hydroxyurea (HU) can stimulate HbF production in these diseases but the response is highly variable indicating the utility of developing an in vitro test to predict the patient's response to HU. We assessed whether the HbF response of patients with SCD and thalassemia intermedia (TI) to HU correlates with HBG (both γ-globin genes) expression in their cultured erythroid progenitors following exposure to HU.

PATIENTS AND METHODS

We exposed primary erythroid cultures from peripheral blood mononuclear cells from 30 patients with SCD and 15 with TI to HU and measured HBG mRNA by real-time quantitative PCR. The same patients were then treated with HU and their HbF response after treatment with a stable dose of HU was compared with the mRNA results in cultured cells.

RESULTS AND CONCLUSION

The fold increase in HBG mRNA in erythroid progenitors was similar to the fold increase in HbF in vivo. Quantification of HBG mRNA in erythroid progenitor cell cultures from patients with SCD and TI is predictive of their clinical response to HU.

Pulmonary hypertension associated with chronic hemolytic anemia and other blood disorders

Pulmonary hypertension (PH) has emerged as a major complication of several hematologic disorders, including hemoglobinopathies, red cell membrane disorders, chronic myeloproliferative disorders, and splenectomy. With the exception of sickle cell disease, there are a limited number of studies systematically evaluating the prevalence of PH using the gold standard right heart catheterization in these disorders. The cause of the PH in patients with hematologic disorders is multifactorial, and a thorough diagnostic evaluation is essential. More importantly, there are virtually no high-quality data on the safety and efficacy of PH-targeted therapy in this patient population.

Deferasirox for the treatment of iron overload in non-transfusion-dependent thalassemia

Non-transfusion-dependent thalassemia (NTDT) defines a group of patients who do not require regular transfusions for survival, but are at significant risk of iron accumulation from underlying disease-related mechanisms distinct from transfusional iron overload. Management of iron overload in NTDT has received little attention compared with that of β-thalassemia major, despite evidence of significant iron-induced complications with advancing age. The efficacy and safety of the iron chelator deferasirox in NTDT has been evaluated in two pilot studies and the first prospective, randomized, placebo-controlled study (THALASSA) of any chelator in NTDT. Treatment with deferasirox for up to 2 years yielded a sustained reduction in iron burden, with a clinically manageable safety profile. Following these trial data, deferasirox is the first iron chelator approved for use in NTDT patients, and with NTDT guidelines now available, physicians are better equipped to achieve effective monitoring and management of iron burden in NTDT.

Thalassemia and the hypercoagulable state

Thalassemia, an inherited hemolytic disorder, is associated with a high incidence of thrombosis. The major mechanisms underlying thromboembolism (TE) are an abnormal red blood cell surface, platelet activation and endothelial cell activation. A higher risk of TE is found in splenectomized patients due to thrombocytosis and increased abnormal RBCs in the circulation. Regular RBC transfusions can reduce the proportion of abnormal RBCs and suppress erythropoiesis. Regular transfusion may also reduce levels of circulating coagulation markers and reduce elevated pulmonary artery pressure. To prevent thromboembolic events, aspirin is now recommended for splenectomized patients with thrombocytosis.

Iron overload in β-thalassemia intermedia: an emerging concern

PURPOSE OF REVIEW

The aim is to overview recent evidence on consequences, assessment, and management of iron overload in transfusion-independent patients with β-thalassemia intermedia.

RECENT FINDINGS

Despite their transfusion-independence, β-thalassemia intermedia patients can still accumulate iron due to increased intestinal absorption. Recent observational studies show that iron burden in this group of patients can ultimately reach considerably high thresholds, and leads to a variety of serious morbidities involving the liver, endocrine glands, and arguably the vascular system. The diagnosis of iron overload in this patient population can follow established guidelines from β-thalassemia major patients, although with careful interpretation of spot serum ferritin levels. Data from a recent randomized clinical trial demonstrated the efficacy and safety of iron chelation therapy in decreasing liver iron concentration in this group of patients, which may ultimately help in reducing morbidity risk.

SUMMARY

Iron overload in transfusion-independent patients with β-thalassemia intermedia deserves careful attention, and prompt diagnosis and management are recommended.

Sickle cell disease and venous thromboembolism: what the anticoagulation expert needs to know

Venous thromboembolism (VTE) is common in patients with sickle cell disease (SCD). The etiology of increased risk of VTE in SCD patients is multifactorial and is related to both traditional factors and SCD-specific factors. Traditional risk factors such as central venous catheters, frequent hospitalization, orthopedic surgeries for avascular necrosis, and pregnancy may lead to increased incidence of VTE in the SCD population. In addition, SCD itself appears to be a hypercoagulable state, and many SCD-specific factors such as thrombophilic defects, genotype and splenectomy may modify the risk of VTE. SCD complications such as acute chest syndrome and pulmonary hypertension may also be related to VTE. Anticoagulation experts should be aware of these factors to help inform prophylaxis and treatment decisions.

β- and α-Thalassemia intermedia in Basra, Southern Iraq

Hemoglobinopathies are common in Iraq and β-thalassemia major (β-TM) is a leading health problem in Basra, Southern Iraq. However, β- and α-thalassemia intermedia (β- and α-TI) have not been so well studied. This is a descriptive study of 152 consecutive β- and α-TI patients registered at the Centre for Hereditary Blood Diseases (CHBD) in Basra, Southern Iraq from October 1 2010 through June 30 2012 including age at diagnosis, blood transfusions and complications. β-Thalassemia intermedia was found in 80 (52.6%) patients with a mean age at diagnosis of 7.10 ± 8.0 years. This was significantly different from that of Hb H (β4) disease (12.95 ± 14.8 years), p <0.05. Patients with β-TI received significantly more blood transfusions (3.39 ± 3.85)/year compared to those with Hb H disease (1.07 ± 1.39)/year, p <0.05. Short stature, extramedullary erythropoiesis, pulmonary hypertension and iron overload were significantly higher among patients with β-TI compared to those with Hb H disease, p <0.05. Iron overload is a significant risk factor for growth retardation among patients with Hb H and β-TI. While age is a significant risk factor for osteoporosis in both types of thalassemia intermedia. Both α- and β-thalassemia (α- and β-thal) have been reported in Basra. Although β-TI is associated with a more severe disease than α-TI, both are associated with considerable complications. Thus, genetic studies are needed to determine the types of mutation producing β-TI and the exact α-thal determinants producing Hb H disease as they are important in the prediction of the phenotype severity.

Health of adults living with a clinically significant haemoglobinopathy in New South Wales, Australia

AIM

To comprehensively review the health needs of patients living with clinically significant haemoglobinopathies (thalassaemia and sickle-cell disease (SCD)) in New South Wales, Australia.

METHODS

A survey-based health needs assessment was undertaken in outpatients cared for at five tertiary institutions in metropolitan and regional centres. Sixty-three of 121 adults (approximately 80-90% of adult patients with transfusion-requiring haemoglobinopathies in New South Wales) completed an in-house and commercial health-related quality assessment survey (SF-36v2).

RESULTS

Subjects came from more than eight world regions, with those with SCD being more likely to be born outside of Australia than subjects with thalassaemia (P < 0.001, likelihood ratio 20.64) as well as more likely to have been refugees (26% vs 2%). The population contained socially disadvantaged subjects with 13 subjects (20.6%) having incomes below the Australian poverty line. Complications of thalassaemia were comparable to previous international reports although our subjects had a high rate of secondary amenorrhea (>12 months = 27%) and surgical splenectomy (55.6%). Use of hydroxyurea in SCD was less than expected with only 46.6% of subjects having prior use. Lack of universal access to magnetic resonance imaging-guided chelation (international best practice) was evident, although 65.5% had been able to access magnetic resonance imaging through clinical trial, or self-funding.

CONCLUSIONS

Patients with SCD and thalassaemia experience considerable morbidity and mortality and require complex, multidisciplinary care. This study revealed both variance from international best practice and between specialist units. The results of this research may provide the impetus for the development of clinical and research networks to enable the uniform delivery of health services benchmarked against international standards.

Pulmonary hypertension in β thalassaemia

Pulmonary hypertension is one of the leading causes of morbidity and mortality in patients with haemolytic disorders and is a frequent finding in echocardiographic screening of patients with β thalassaemia. Substantial progress has been made in understanding of the multifactorial pathophysiology of pulmonary hypertension in β thalassaemia. Haemolysis, reduced nitric oxide bioavailability, iron overload, and hypercoagulopathy are among the main pathogenetic mechanisms. Various disease-directed therapeutic methods, such as transfusion, chelation, and splenectomy, have important roles in the development of pulmonary hypertension in β thalassaemia. Studies investigating the prevalence of pulmonary hypertension in β thalassaemia are mostly based on echocardiographic findings, and are thus limited by the scarcity of information derived from right heart catheterisation. Invasive pulmonary haemodynamic data are needed to clarify the true prevalence of pulmonary hypertension in β thalassaemia, to better understand the underlying pathophysiology and risk factors, and to define the optimum therapy for this devastating complication.

Serum ferritin in thalassemia intermedia

Serum ferritin is a useful monitoring tool for iron overload in thalassemia major. In resource poor settings access to modalities for assessment of iron overload are limited. This study was undertaken to assess the efficiency and usefulness of serum ferritin level in thalassemia intermedia (TI) patients. This was a cross sectional observational study. Seventy seven TI patients attending the pediatric hematology clinic were included. Fasting blood sample was taken from each patient in iron free vials for iron studies. Serum ferritin was estimated by immunometric enzyme immunoassay using Orgentec GmbH kits. Mean age of patients evaluated was 10.9 ± 5.03 (3-26) years. The mean age at diagnosis was 4.21 ± 2.3 (0.8-11) years. Mean serum ferritin was 486.54 ± 640.0 ng/ml (15-4,554). Thirty two (41.5 %) patients had a ferritin value of ≥500 ng/ml. Nine patients had a serum ferritin of ≥1,000 ng/ml. Three of the subjects with a ferritin >1,000 ng/ml had never received a blood transfusion (BT) and in the other six, the number of BTs ranged from 1 to 8. Serum ferritin did not correlate with age, total number of BTs splenectomy status or BT in last one year (p > 0.05). In 41.5 % of TI patients, serum ferritin was ≥500 ng/ml. Age, BT and splenectomized status did not affect ferritin level. We postulate interplay of other biological factors like HFE gene mutation, ferroportin, etc. to contribute to ferritin level and hence iron load in TI patients. Ferritin can possibly be used as screening and monitoring tool for iron load in TI patients when other modalities to assess iron overload are not easily available.

Pulmonary hypertension risk in patients with hemoglobin h disease: low incidence and absence of correlation with splenectomy

Pulmonary hypertension (PHT) is a common complication for patients with β thalassemia intermediate (TI), especially splenectomized patients. However, the frequency and risk factors of PHT in patients with hemoglobin H (HbH) disease is unknown. The purpose of this study was to identify the prevalence of PHT risk manifested as tricuspid regurgitant jet velocity (TRV) ≥2.5 m/s in patients with HbH disease and its correlation with splenectomy. One hundred and ninety-eight patients with HbH disease who visited the 303rd Hospital of the People's Liberation Army (Nanning, China) were investigated. Thirteen subjects (6.5%) were diagnosed as having a risk of PHT. Regression analyses showed that the prevalence of PHT risk was correlated only with age (r = 0.195, p = 0.006) and not with splenectomy. The risk of PHT in patients older than 35 years was 5.7 times (range 1.8-18.6) greater than that for patients younger than 35 years. For splenectomized patients compared to those with HbH disease, patients with TI had a higher frequency of PHT risk, higher nucleated red blood cell counts (46.03 ± 41.11 × 10(9)/l vs. 0.18 ± 1.19 × 10(9)/l, p < 0.001) and a higher platelet counts (837.6 ± 178.9 × 10(9)/l vs. 506.7 ± 146.2 × 10(9)/l, p < 0.001). PHT risk is low in patients with HbH disease and does not correlate with splenectomy. Patients older than 35 years should be monitored regularly.

Treating iron overload in patients with non-transfusion-dependent thalassemia

Despite receiving no or only occasional blood transfusions, patients with non-transfusion-dependent thalassemia (NTDT) have increased intestinal iron absorption and can accumulate iron to levels comparable with transfusion-dependent patients. This iron accumulation occurs more slowly in NTDT patients compared to transfusion-dependent thalassemia patients, and complications do not arise until later in life. It remains crucial for these patients' health to monitor and appropriately treat their iron burden. Based on recent data, including a randomized clinical trial on iron chelation in NTDT, a simple iron chelation treatment algorithm is presented to assist physicians with monitoring iron burden and initiating chelation therapy in this group of patients. Am. J. Hematol. 88:409–415, 2013. © 2013 Wiley Periodicals, Inc.

Flow cytometric assessment of circulating platelet and erythrocytes microparticles in young thalassemia major patients: relation to pulmonary hypertension and aortic wall stiffness

Heart disease is the leading cause of mortality and morbidity in β-thalassemia major (β-TM). Aggregability of abnormal red cells and membrane-derived microparticles (MPs) stemming from activated platelets and erythrocytes are responsible for thrombotic risk. We measured platelet and erythrocyte MPs (PMPs and ErMPs) in 60 young β-TM patients compared with 40 age- and sex-matched healthy controls and assessed their relation to clinicopathological characteristics and aortic elastic properties. Patients were studied stressing on transfusion history, splenectomy, thrombotic events, chelation therapy, hematological and coagulation profiles, flow cytometric measurement of PMPs (CD41b(+) ) and ErMPs (glycophorin A(+) ) as well as echocardiographic assessment of aortic elastic properties. Aortic stiffness index and pulmonary artery pressure were significantly higher, whereas aortic strain and distensibility were lower in TM patients than controls (P < 0.001). Both PMPs and ErMPs were significantly elevated in TM patients compared with controls, particularly patients with risk of pulmonary hypertension, history of thrombosis, splenectomy or serum ferritin >2500 μg/L (P < 0.001). Compliant patients on chelation therapy had lower MPs levels than non-compliant patients (P < 0.001). PMPs and ErMPs were positively correlated to markers of hemolysis, serum ferritin, D-dimer, vWF Ag, and aortic stiffness, whereas negatively correlated to hemoglobin level and aortic distensibility (P < 0.05). We suggest that increased MPs may be implicated in vascular dysfunction, pulmonary hypertension risk, and aortic wall stiffness observed in thalassemia patients. Their quantification could provide utility for early detection of cardiovascular abnormalities and monitoring the biological efficacy of chelation therapy.

A randomized phase I/II trial of HQK-1001, an oral fetal globin gene inducer, in β-thalassaemia intermedia and HbE/β-thalassaemia

β-thalassaemia intermedia (BTI) syndromes cause haemolytic anaemia, ineffective erythropoiesis, and widespread complications. Higher fetal globin expression within genotypes reduces globin imbalance and ameliorates anaemia. Sodium 2,2 dimethylbutyrate (HQK-1001), an orally bioavailable short-chain fatty acid derivative, induces γ-globin expression experimentally and is well-tolerated in normal subjects. Accordingly, a randomized, blinded, placebo-controlled, Phase I/II trial was performed in 21 adult BTI patients (14 with HbE/β(0) thalassaemia and seven with β(+)/β(0) thalassaemia intermedia, to determine effective doses for fetal globin induction, safety, and tolerability. HQK-1001 or placebo were administered once daily for 8 weeks at four dose levels (10, 20, 30, or 40 mg/kg per day), and subjects were monitored for laboratory and clinical events. Pharmacokinetic profiles demonstrated a t(1/2) of 10-12 h. Adverse events with HQK-1001 treatment were not significantly different from placebo treatment. The 20 mg/kg treatment doses increased median HbF above baseline levels by 6·6% and 4·4 g/l (P < 0·01) in 8/9 subjects; total haemoglobin (Hb) increased by a mean of 11 g/l in 4/9 subjects. These findings identified a safe oral therapeutic which induces fetal globin in BTI. Further investigation of HQK-1001 with longer dosing to definitively evaluate its haematological potential appears warranted.

Clinical experience with fetal hemoglobin induction therapy in patients with β-thalassemia

Recent molecular studies of fetal hemoglobin (HbF) regulation have reinvigorated the field and shown promise for the development of clinical HbF inducers to be used in patients with β-thalassemia and sickle cell disease. However, while numerous promising inducers of HbF have been studied in the past in β-thalassemia patient populations, with limited success in some cases, no universally effective agents have been found. Here we examine the clinical studies of such inducers in an attempt to systematically review the field. We examine trials of agents, including 5-azacytidine, hydroxyurea, and short-chain fatty acids. This review highlights the heterogeneity of clinical studies done on these agents, including both the patient populations examined and the study end points. By examining the published studies of these agents, we hope to provide a resource that will be valuable for the design of future studies of HbF inducers in β-thalassemia patient populations.

Glomerular hyperfiltration and proteinuria in transfusion-independent patients with β-thalassemia intermedia

BACKGROUND/AIMS

Renal manifestations have been described in β-thalassemia major and were attributed to transfusional iron overload and chelation therapy. Patients with the milder phenotype, β-thalassemia intermedia (TI), remain largely transfusion and iron chelation independent while enduring a chronic hemolytic anemia and primary iron overload. Data on renal function in patients with TI is lacking.

METHODS

In this cross-sectional study of 50 TI patients, we evaluated the association of estimated glomerular filtration rate (eGFR) and urinary protein to creatinine (UPr/UCr) ratio with relevant patient, disease and laboratory indices.

RESULTS

The median age of patients was 28 years (44% males). The eGFR was >90 ml/min/1.73 m(2) in all patients, with a median value of 142.3 ml/min/1.73 m(2). The median UPr/UCr ratio was 213.2 mg/g. There was a negative correlation between age and eGFR, while the UPr/UCr ratio correlated positively with markers of anemia, hemolysis and iron overload. A total of 24 (48%) patients had evidence of glomerular hyperfiltration, while 7 (14%) had proteinuria (UPr/UCr ratio >500 mg/g). Patients with proteinuria were characterized by elevated liver iron concentration (>7 mg Fe/g dry weight), non-transferrin-bound iron levels and nucleated red blood cell counts.

CONCLUSIONS

A considerable proportion of TI patients show evidence of abnormally elevated eGFR, with a declining trend towards advancing age. The occurrence of proteinuria is associated with anemia, hemolysis and iron toxicity.

Oxidative damage and genotoxicity biomarkers in transfused and untransfused thalassemic subjects

Chronic anemia and tissue hypoxia increase intestinal iron absorption and mitochondrial impairment in thalassemic patients. Regular blood transfusions improve hemoglobin levels but determine an iron overload that induces reactive oxygen species (ROS) overproduction. The aim of this study was to assess cellular oxidative damage by detection of ROS, lipid peroxidation, 8-oxo-dG, and mitochondrial transmembrane potential (Δψ(m)) in transfused and untransfused thalassemic patients. We have also evaluated genotoxicity by CBMN and comet assay. Our data show that ROS and lipid hydroperoxides are significantly higher in thalassemic patients than in controls, especially in untransfused thalassemia intermedia patients. Moreover, the latter have a significant decrease in Δψ(m) that highlights the energetic failure in hypoxic state and the ROS overproduction in the respiratory chain. 8-OHdG levels are higher in thalassemics than in controls, but do not differ significantly between the two patient groups. Both genotoxicity biomarkers highlight the mutagenic potential of hydroxyl radicals released by iron in the Fenton reaction. Values for percentage of DNA in the comet tail and micronuclei frequency, significantly higher in transfused patients, could also be due to active hepatitis C virus infection and to the many drug treatments. Our biomonitoring study confirms the oxidative damage in patients with thalassemia major and shows an unexpected cellular oxidative damage in untransfused thalassemic patients. In addition to iron overload, the results highlight the important role played by hypoxia-driven mitochondrial ROS overproduction in determining oxidative damage in β-thalassemias.

T2* MRI in regularly transfused children with thalassemia intermedia: serum ferritin does not reflect liver iron stores

Nontransfused patients with thalassemia intermedia (TI) accumulate iron due to increased gastrointestinal absorption of iron. Recent studies using T2* MRI revealed that serum ferritin does not reflect the severity of iron overload in nontransfused TI patients. We evaluated the iron overload status in TI children on monthly transfusion. Based on serum ferritin levels, 11 such patients (mean age 13.18 ± 4.09 years), were classified into two groups, group 1 (six patients) and group 2 (five patients) with serum ferritin levels below and above 1000 ng/mL, respectively. T2* MRI assessments were done for evaluation of hepatic and cardiac iron status. Group 1 and group 2 had mean serum ferritin levels of 817.300 ± 244.690 ng/mL and 1983.80 ± 662.862 ng/mL, respectively (P = .003). T2* MRI showed comparable moderate to severe hepatic iron overload status in both. None of the patients had myocardial iron deposition. We conclude that serum ferritin does not reflect the hepatic iron overload status in our patients with TI on regular transfusion.

Reawakening fetal hemoglobin: prospects for new therapies for the β-globin disorders

The level of fetal hemoglobin (HbF) modifies the severity of the common β-globin disorders. Knowledge of the normal mechanisms that repress HbF in the adult stage has remained limited until recently despite nearly 3 decades of molecular investigation, in part because of imperfect model systems. Recent studies have provided new insights into the developmental regulation of globin genes and identified specific transcription factors and epigenetic regulators responsible for physiologic silencing of HbF. Most prominent among these regulators is BCL11A, a transcriptional repressor that inhibits adult-stage HbF expression. KLF1 and c-Myb are additional critical HbF-regulating erythroid transcription factors more broadly involved in erythroid gene expression programs. Chromatin modifiers, including histone deacetylases and DNA methyltransferases, also play key roles in orchestrating appropriate globin gene expression. Taken together, these discoveries present novel therapeutic targets for further consideration. Although substantial hurdles remain, opportunities are now rich for the rational design of HbF inducers.

β-thalassemia intermedia: a clinical perspective

Our understanding of the molecular and pathophysiological mechanisms underlying the disease process in patients with β-thalassemia intermedia has substantially increased over the past decade. Earlier studies observed that patients with β-thalassemia intermedia experience a clinical-complications profile that is different from that in patients with β-thalassemia major. In this article, a variety of clinical morbidities are explored, and their associations with the underlying disease pathophysiology and risk factors are examined. These involve several organs and organ systems including the vasculature, heart, liver, endocrine glands, bone, and the extramedullary hematopoietic system. The effects of some therapeutic interventions on the development of clinical complications are also discussed.

Short- and long-term risks of splenectomy for benign haematological disorders: should we revisit the indications?

Splenectomy has represented a key treatment option in the treatment of many benign haematological diseases, including immune thrombocytopenia (ITP) and disorders associated with ongoing haemolysis (thalassaemia major and intermedia, sickle cell disease, and hereditary or acquired haemolytic anaemias). Improvements in surgical techniques have reduced perioperative complications and mortality. Preventive measures (new protein conjugate vaccines, antibiotic prophylaxis, and increased vigilance) are thought to greatly reduce the risk of overwhelming post-splenectomy infection (OPSI), although their implementation is inconsistent. Nevertheless, there is increasing documentation of the short- and long-term risks of splenectomy, which vary according to the underlying indication. Splenectomized patients are at increased risk of venous thromboembolism, particularly within the splenoportal system. The long-term thromboembolic risk is higher in haematological disorders associated with ongoing haemolysis, particularly in thalassaemia intermedia, which has led to a more conservative approach. In comparison, patients with ITP appear to be at lower risk of adverse effects of splenectomy, which maintains its place as the potentially most curative and safe second-line treatment. However, a splenectomy-sparing approach is also emerging for ITP, and recent guidelines recommend that this procedure is deferred until ≥ 12 months from ITP diagnosis, to allow sufficient time for possible remission.

D-dimer and portal vein status in splenectomized Egyptian β-thalassemia major patients: a prospective single-thalassemia center experience

Splenectomy is a recognized cause of portal vein thrombosis. Thirty-six β-thalassemia major (β-TM) patients were followed up for 36 months to evaluate changes in D-dimer levels (as a possible marker for thrombosis development) and portal vein status (by portal duplex ultrasound) at both early and late postlaparoscopic splenectomy periods. They were classified into group I if they were splenectomized in the study period (n = 12), or group II if they were splenectomized during the 5 years preceding the period (n = 24). In group I, D-dimer was measured 5 times: 1 day presplenectomy, the 1st week, 6th week, and 6th month postsplenectomy, and at the study end, whereas in group II, D-dimer was measured twice: at the study entry and end. Portal duplex was done 1 week postsplenectomy (group I) and at study end in both groups. Presplenectomy D-dimer levels in group I were significantly higher compared with the 6th month (P = .042) and study end (P = .03), whereas 1st week (postsplenectomy) D-dimer levels had a high mean of 3497.3 ng/mL, lowered at the 6th week (P = .017), at the 6th month (P = .008), and at study end (P = .005). D-dimer levels in group II showed no difference between study entry and end (P = .104). Portal vein "diameter and flow" were within normal findings in both groups. In this 3-year prospective study, a subclinical hypercoagulable state was detected 1 day prior to splenectomy and in the early postsplenectomy period, as evidenced by high D-dimer levels. Laparoscopic splenectomy was not associated with portal venous thrombosis either clinically or by duplex sonography.

Brain magnetic resonance angiography in splenectomized adults with β-thalassemia intermedia

BACKGROUND

 Hypercoagulability and venous thromboembolism are common in patients with β-thalassemia intermedia (TI), especially in the splenectomized adult. Although arterial involvement is not commonly reported, we have recently observed a high prevalence (60%) of silent brain infarction on brain MRI in 30 splenectomized adults with TI. The pathophysiology of these white matter lesions remains unknown.

METHODS

In this prospective work, we evaluated magnetic resonance angiography (MRA) scans of the same cohort of 30 patients. Data collected were the presence or absence of vascular lesions, their locations, and severity. Correlations between MRA abnormality and patients/disease characteristics were evaluated. Comparisons between MRA and previous MRI findings were made.

RESULTS

Of 29 evaluable patients, 8 (27.6%) had evidence of arterial stenosis on MRA. The majority of lesions had mild narrowing and mostly involved the internal carotid artery. Five patients (17.2%) had evidence of aneurysms. Low total hemoglobin and high non-transferrin-bound iron levels independently characterized patients with evidence of stenosis on MRA. Among the 18 patients with silent brain infarction on MRI, three had evidence of stenosis on MRA with only one patient having lesions that could explain the silent infarcts.

CONCLUSIONS

Cerebral vasculopathy is common in splenectomized adults with TI. However, large-vessel disease does not explain the occurrence of silent brain infarction. The combined use of MRA and MRI better identifies splenectomized TI adults with neuroimaging abnormalities.

Clinicopathological and radiological study of Egyptian β-thalassemia intermedia and β-thalassemia major patients: relation to complications and response to therapy

The clinico epidemiological characteristics, frequency of complications, and response to various therapeutic modalities in 80 Egyptian β-thalassemia intermedia (β-TI) patients were compared with 70 β-thalassemia major (β-TM) patients. β-Thalassemia intermedia patients had a higher incidence of left atrium dilatation, right ventricular dilatation and pulmonary hypertension, whereas, β-TM patients showed a higher incidence of left ventricular (LV) dilatation, restrictive LV filling and impaired LV contractility, with an overall higher incidence of heart disease (p <0.001). Short stature, delayed puberty, osteoporosis, bone fractures, diabetes mellitus and viral hepatitis was frequently observed in β-TM patients compared with β-TI patients (p <0.05). Administration of hydroxyurea (HU) alone was associated with significant improvement in hematological parameters and quality of life for β-TI patients. In conclusion, the risk of complications still burdens the life of Egyptian thalassemia patients and their frequency varies between β-TI and β-TM. We provide evidence that calls for the use of HU in β-TI patients.

Risk factors for pulmonary hypertension in patients with β thalassemia intermedia

BACKGROUND

Pulmonary hypertension (PHT) is a common yet poorly understood complication of β thalassemia intermedia (TI).

METHODS

We herein evaluated risk factors for PHT in TI, through comparing 64 TI patients with evidence of PHT by symptomatology and echocardiography (Group I) to age- and sex-matched TI patients without PHT (Group II). Retrieved data included demographics, laboratory parameters, clinical characteristics, and received treatments that may influence PHT development; and reflected the period prior to PHT occurrence in Group I.

RESULTS

The mean age of Group I patients at development of PHT was 37.3±10.6years; with 44% being males. Among studied parameters, Group I patients were more likely to be splenectomized (4.9-times), transfusion-naive (3.5-times); hydroxyurea-naive (2.6-times), or iron chelation-naive (2.3-times); and have nucleated red blood cell count ≥300×10(6)/l (2.59-times) or a previous history of thromboembolic events (3.69-times).

CONCLUSION

TI patients who eventually develop PHT may be identified early on by being splenectomized, having high nucleated red blood cell counts and a previous history of thromboembolism. Prospective clinical trials that evaluate the efficacy, safety, and cost effectiveness of transfusion, iron chelation, and hydroxyurea therapy in preventing PHT in TI are invited.

Fetal hemoglobin levels and morbidity in untransfused patients with β-thalassemia intermedia

To evaluate the association between fetal hemoglobin (HbF) levels and morbidity in β-thalassemia intermedia (TI), we analyzed data from 63 untransfused patients who had also never received HbF induction therapy. Patient records were reviewed for any history of 10 predefined morbidities. Laboratory measurements for markers of ineffective erythropoiesis were also obtained. The mean age of patients was 32.1 years, 47.6% were males, and the median HbF level was 37.2%. HbF levels correlated positively with total hemoglobin, yet negatively with growth differentiation factor-15 and non-transferrin-bound iron levels. Median HbF levels were significantly lower in patients with the majority of evaluated morbidities than in those without. There was a strong negative adjusted linear correlation between the HbF level and the total number of morbidities (R(2) = 0.825, P < .001). The HbF threshold of 63.7% had 95.5% sensitivity and 100% specificity for ensuring absence of morbidity. There exists a strong association between HbF levels and morbidity in the subset of untransfused patients with TI.

How I treat thalassemia

The purpose of this article is to set forth our approach to diagnosing and managing the thalassemias, including β-thalassemia intermedia and β-thalassemia major. The article begins by briefly describing recent advances in our understanding of the pathophysiology of thalassemia. In the discussion on diagnosing the condition, we cover the development of improved diagnostic tools, including the use of very small fetal DNA samples to detect single point mutations with great reliability for prenatal diagnosis of homozygous thalassemia. In our description of treatment strategies, we focus on how we deal with clinical manifestations and long-term complications using the most effective current treatment methods for β-thalassemia. The discussion of disease management focuses on our use of transfusion therapy and the newly developed oral iron chelators, deferiprone and deferasirox. We also deal with splenectomy and how we manage endocrinopathies and cardiac complications. In addition, we describe our use of hematopoietic stem cell transplantation, which has produced cure rates as high as 97%, and the use of cord blood transplantation. Finally, we briefly touch on therapies that might be effective in the near future, including new fetal hemoglobin inducers and gene therapy.

Thrombosis in thalassemia: why are we so concerned?

Although life expectancy of thalassemia patients has markedly improved over the last few decades, patients still suffer from many complications of this congenital disease. The presence of a high incidence of thromboembolic events (TEE), mainly in β-thalassemia intermedia (β-TI), has led to the identification of a hypercoagulable state in these patients. In this review, the molecular and cellular mechanisms leading to hypercoagulability in thalassemia are highlighted, with a special focus on thalassemia intermedia being the group with the highest incidence of thrombotic events as compared to other types of thalassemia. Clinical experience and available clues on optimal management are also discussed.

Levels of growth differentiation factor-15 are high and correlate with clinical severity in transfusion-independent patients with β thalassemia intermedia

Transfusion-independent patients with β thalassemia intermedia (TI) experience a variety of clinical complications attributed to the underlying ineffective erythropoiesis and subsequent anemia, hemolysis, and iron overload. Growth differentiation factor-15 (GDF-15) was recently investigated as a marker of ineffective erythropoiesis in several anemias. In this work, we evaluated GDF-15 levels in 55 patients with TI. The mean GDF-15 level was 25,197.8±16,208.9pg/ml which is lower than values reported for patients with thalassemia major, yet considerably higher than those reported in patients with other congenital and acquired anemias. GDF-15 levels were significantly higher in splenectomized compared to non-splenectomized patients and correlated with anemia, markers of iron overload, and a pre-defined clinical severity score. Further studies are needed to determine the practical utility of GDF-15 measurement and its potential to reflect the severity of the clinical course in TI patients.

Elevated liver iron concentration is a marker of increased morbidity in patients with β thalassemia intermedia

BACKGROUND

Patients with β thalassemia intermedia can have substantial iron overload, irrespectively of their transfusion status, secondary to increased intestinal iron absorption. This study evaluates whether iron overload in patients with β thalassemia intermedia is associated with morbidity.

DESIGN AND METHODS

This was a cross-sectional study of 168 patients with β thalassemia intermedia treated at two centers in Lebanon and Italy. Data on demographics, splenectomy status, transfusion status, and presence of co-morbidities were retrieved. Laboratory values of serum ferritin, fetal and total hemoglobin levels, as well as platelet and nucleated red blood cell counts were also obtained. Iron burden was determined directly by measuring liver iron concentration using magnetic resonance imaging. Patients were subdivided according to transfusion and splenectomy status into groups with phenotypes of different severity.

RESULTS

The mean age of the patients was 35.2 ± 12.6 years and 42.9% of them were male. The mean liver iron concentration was 8.4 ± 6.7 mg Fe/g dry weight. On multivariate logistic regression analysis, after adjusting for age, gender, splenectomy status, transfusion status, and laboratory indices, an increase in 1 mg Fe/g dry weight liver iron concentration was independently and significantly associated with higher odds of thrombosis, pulmonary hypertension, hypothyroidism, osteoporosis, and hypogonadism. A liver iron concentration of at least 7 and at least 6 mg Fe/g dry weight were the best thresholds for discriminating the presence and absence of vascular and endocrine/bone morbidities, respectively (area under the receiver-operating characteristic curve: 0.72, P<0.001). Elevated liver iron concentration was associated with an increased rate of morbidity in patients with phenotypes of all severity, with a steeper increase in the rate of vascular morbidity being attributed to aging, and an earlier appearance of endocrine and bone disease.

CONCLUSIONS

Elevated liver iron concentration in patients with β thalassemia intermedia is a marker of increased vascular, endocrine, and bone disease.

Risk factors and mortality associated with an elevated tricuspid regurgitant jet velocity measured by Doppler-echocardiography in thalassemia: a Thalassemia Clinical Research Network report

An elevated tricuspid regurgitant jet velocity (TRV) is associated with hemolysis and early mortality in sickle cell disease, yet risk factors, clinical parameters, and mortality associated with this biomarker in thalassemia are poorly defined. This report summarizes the prevalence of an elevated TRV in 325 patients screened by Doppler echocardiography in the Thalassemia Clinical Research Network. A documented TRV was reported in 148 of 325 (46%) of patients. Average age was 25.9 years (range, 5-56 years) and 97% were transfusion-dependent. Mean TRV was 2.3 ± 0.4 m/s (range, 0.2-3.5 m/s). An abnormal TRV ≥ 2.5 m/s was identified in 49 of 148 (33%) of patients with a documented TRV, 5% (8/148), with a TRV ≥ 3.0 m/s, suggesting significant PH risk. Older age was strongly associated with a high TRV; however, 16% of children had a TRV ≥ 2.5 m/s. A history of splenectomy, hepatitis C, smoking, or high white blood cell count was associated with TRV elevation. In summary, an elevated TRV is noted in one-third of transfusion-dependent thalassemia patients with a documented value and develops in both children and adults. Age, splenectomy, hepatitis C, and smoking are significant univariate risk factors, with splenectomy surfacing as the dominant risk factor over time. Mortality was low in this cohort. Prospective longitudinal studies are needed. This study is registered at http://www.clinicaltrials.gov as NCT00661804.

β-thalassemia: a model for elucidating the dynamic regulation of ineffective erythropoiesis and iron metabolism

β-thalassemia is a disease characterized by anemia and is associated with ineffective erythropoiesis and iron dysregulation resulting in iron overload. The peptide hormone hepcidin regulates iron metabolism, and insufficient hepcidin synthesis is responsible for iron overload in minimally transfused patients with this disease. Understanding the crosstalk between erythropoiesis and iron metabolism is an area of active investigation in which patients with and models of β-thalassemia have provided significant insight. The dependence of erythropoiesis on iron presupposes that iron demand for hemoglobin synthesis is involved in the regulation of iron metabolism. Major advances have been made in understanding iron availability for erythropoiesis and its dysregulation in β-thalassemia. In this review, we describe the clinical characteristics and current therapeutic standard in β-thalassemia, explore the definition of ineffective erythropoiesis, and discuss its role in hepcidin regulation. In preclinical experiments using interventions such as transferrin, hepcidin agonists, and JAK2 inhibitors, we provide evidence of potential new treatment alternatives that elucidate mechanisms by which expanded or ineffective erythropoiesis may regulate iron supply, distribution, and utilization in diseases such as β-thalassemia.