Complications and treatment of patients with β-thalassemia in France: results of the National Registry

Guidelines for the Standard Monitoring of Patients With Thalassemia: Report of the Thalassemia Longitudinal Cohort

Chronic transfusion therapy has played a central role in extending life expectancy for patients with hemoglobinopathies such as thalassemia. However, this life-saving therapy is associated with numerous complications that now comprise the bulk of management considerations for patients with thalassemia. This review reports on the experience of the Thalassemia Longitudinal Cohort and reviews available literature to establish guidelines for the management of patients with thalassemia.

Review of Endocrine Complications in Adult Patients with β-Thalassaemia Major

Endocrine abnormalities are amongst the most common complications of β-thalassaemia major (TM). This is an overview of endocrinopathies of adult patients with β-thalassaemia major, excluding osteoporosis and fertility issues. This review will focus on emerging evidence in the last 5 years with regards to endocrinopathies in patients with TM.

Red blood cell antibodies in thalassemia patients in northern India: risk factors and literature review

Study of the factors responsible for red cell alloimmunization can help in adopting appropriate strategy to minimize alloimmunization. However data for thalassemia patients from our region is limited. Therefore, a study was conducted to find out the frequency and the factors associated with red cell allo and autoimmunization in thalassemia patients at our center so as to enable us to take appropriate action to reduce alloimmunization. Clinical, demographic, allo and autoantibody and transfusion records of 280 thalassemia patients at our hospital were studied. Patients with and without alloantibodies were compared to find significant differences for age, gender, race, age at start of regular transfusions and splenectomy. Red cell antigen frequencies in thalassemia patients and published antigen frequencies in blood donors from the same center were compared to look antigen differences as a risk factor for alloimmunization. Twenty four thalassemia patients (8.6 %) developed 28 clinically significant alloantibodies. 18 (65 %) of the alloantibodies were of Rh system. The three most common antibodies detected was anti E (11, 39.3 %) followed by anti K (6, 21.4 %) and anti c (10.8 %). Five (1.8 %) of the 280 patients developed autoantibodies. Patient age was found to be significantly higher in alloimmunized patients than in non alloimmunized patients. Red cell antigen frequencies between blood donor and recipient populations were found to be homogenous for most of the relevant RBC antigens. The frequency of red cell alloimmunization in thalassemia patients from our center is moderate. In this setting of red cell phenotype concordant donor-recipient population requirement of extended phenotype matched transfusions may not be cost effective.

[Evaluation of transfusion hemochromatosis prevalence, SFVTT-01 study: preliminary results of the SFVTT working group]

RATIONAL

Although notification of post-transfusion hemosiderosis is mandatory since 1994 among the French hemovigilance network, it is so far largely under reported.

PATIENTS AND METHODS

We screened 42,443 patients hospitalized for blood diseases in France in 2009 and 2010 and determined which patients had received more than 20 PRC. Among them, we selected those having at least one measure of serum ferritin, and subsequently those which ferritin was greater than or equal to 1000 ng/mL.

RESULTS

Three thousand eight hundred and twelve patients (9%) received more than 20 PRC, 1935 (4.5%) had a ferritin assay, which was increased in 1216 patients (2.9%). Eight hundred and eighty-one patients underwent an hemovigilance report form. Forty-nine percent had low-risk myelodysplasia or acute leukemia, 7% hemoglobinopathies. Hemosiderosis was asymptomatic for 680 patients (77%), serious 188 (88%) and life-threatening for 11 (1%). Two patients died of terminal heart failure. The most severe hemosiderosis (≥ grade 2) were low-risk myelodysplasia and idiopathic aplastic anemia. Ninety-two percent of thalassemia patients and 46% of sickle cell anemia patients received an iron chelator. For low-risk myelodysplastic syndromes and idiopathic aplastic anemia, 228 of the 317 patients whose treatment is known and who could benefit from iron chelation (72%) have not received it.

CONCLUSION

These results encourage seeking optimal transmission of information (over 20 CGR) to the clinician, and prolonging hemovigilance action towards a more comprehensive statement of post-transfusion hemochromatosis.

KLF1 mutations are relatively more common in a thalassemia endemic region and ameliorate the severity of β-thalassemia

Mutations in human Krüppel-like factor 1 (KLF1) have recently been reported to be responsible for increased fetal hemoglobin (HbF) and hemoglobin A2 (HbA2). Because increased HbF and HbA2 levels are important features of β-thalassemia, we examined whether there is any relationship between KLF1 mutation and β-thalassemia in China. To do this, we first studied the incidence of KLF1 mutations in 2 Chinese populations: 3839 individuals from a thalassemia endemic region in south China and 1190 individuals from a non-thalassemia endemic region in north China. Interestingly, we found that the prevalence of KLF1 mutations is significantly higher in the thalassemia endemic region than that in non-thalassemia endemic region (1.25% vs 0.08%). Furthermore, we identified 7 functional variants including 4 previously reported (p.Gly176AlafsX179, p.Ala298Pro, p.Thr334Arg, and c.913+1G>A) and 3 novel variants (p.His299Asp, p.Cys341Tyr, and p.Glu5Lys) in southern China. The 2 most common mutations, p.Gly176AlafsX179 and p.His299Asp, accounted for 90.6% of the total. We found that zinc-finger mutations in KLF1 were selectively represented in 12 β-thalassemia intermedia patients and resulted in significantly different transfusion-free survival curves. Our findings suggest that KLF1 mutations occur selectively in the presence of β-thalassemia to increase the production of HbF, which in turn ameliorates the clinical severity of β-thalassemia.

Thalassemias

The thalassemia syndromes are hemoglobin disorders that result from significantly reduced or absent synthesis of either the α- or β-globin chains. The result is a chronic hemolytic anemia with ineffective erythropoiesis and bone marrow overstimulation. This article reviews current diagnostic approaches, complications, and disease management of thalassemia.

Assessment and management of iron overload in β-thalassaemia major patients during the 21st century: a real-life experience from the Italian WEBTHAL project

We conducted a cross-sectional study on 924 β-thalassaemia major patients (mean age 30·1 years) treated at nine Italian centres using the WEBTHAL software, to evaluate real-life application of iron overload assessment and management standards. Serum ferritin <2500 ng/ml was a risk factor for never having liver iron concentration (LIC) measurement, while absence of cardiac disease and siderosis were risk factors for a delay in LIC measurement >2 years. Patients who never had a cardiac MRI (CMR) T2* measurement were <18 years, had iron intake ≤0·4 mg/kg per day, or a serum ferritin <2500 ng/ml. A history of normal CMR T2* was the main risk factor for a delay in subsequent assessment of >2 years. Deferoxamine (22·8%) was more commonly used in patients with Hepatitis C Virus or high serum creatinine. Deferiprone (20·6%) was less commonly prescribed in patients with elevated alanine aminotransferase; while a deferoxamine + deferiprone combination (17·9%) was more commonly used in patients with serum ferritin >2500 ng/ml or CMR T2* <20 ms. Deferasirox (38·3%) was more commonly prescribed in patients <18 years, but less commonly used in those with heart disease or high iron intake. These observations largely echoed guidelines at the time, although some practices are expected to change in light of evolving evidence.

The impact of migrations on the health services for rare diseases in Europe: the example of haemoglobin disorders

Migration from different parts of the world to several European countries leads to the introduction of haemoglobinopathy genes into the population, which creates several demanding needs for prevention and treatment services for Hb disorders. In this paper we examined the degree to which European health services have responded to such challenges and in particular to health services necessary to address the needs of patients with thalassaemia and sickle cell disease (SCD). Information on available services was obtained from international organizations, collaborated European project, and the Thalassaemia International Federation (TIF) Databases, which include information from published surveys, registries, field trips, and delegation visits to countries and regions by expert advisors, local associations, and other collaborators' reports. Results show that countries with traditional strong prevention and treatment programs are well prepared to face the above challenges, while others are urgently needed to address these problems in a systematic way. The Thalassaemia International Federation (TIF) is committed to monitor the progress, raise awareness, and support the promotion of more immigrant-oriented health policies to ensure their integration in society and their access to appropriate, adequate, and timely health services.

Cross-talk between available guidelines for the management of patients with beta-thalassemia major

Efforts to optimize the management of patients with β-thalassemia major (TM) continue to expand. Evidence from biomedical research evaluating safe and careful processing measures of blood products, the efficacy and safety of oral iron chelators, and noninvasive techniques for the assessment of iron overload are translated into better patient outcomes. The construction of TM management guidelines facilitated the incorporation of such evidence into practice. However, as several aspects of the management of TM remain controversial or governed by resource availability, a concern regarding potential variations in recommendations made by the different guidelines becomes rational, especially for physicians treating TM patients outside countries where the guidelines were constructed. In this work, we overview currently available guidelines for the management of TM and explore apparent similarities and differences between them. The evaluated guidelines included the Thalassaemia International Federation, US, Canadian, UK, Italian and Australian guidelines. We noted a general consensus for most aspects of management, although some guidelines provided more comprehensive and contemporary recommendations than others. We did not identify differences warranting concern, although minor differences in iron overload assessment strategy and more notable variations in the recommendations for iron chelation therapy were observed.

Post-transfusional iron overload in the haemoglobinopathies

In this report, we review the recent advances in evaluation and treatment of transfusional iron overload (IO). Results of the French thalassaemia registry are described. According to the disease, thalassaemia major or sickle cell anaemia, mechanisms and toxicity of iron overload, knowledge about IO long-term outcome and chelation treatment results, respective value of IO markers, differ. The recent tools evaluating organ specific IO and the diversification of iron chelator agents make possible to individualize chelation therapy in clinical practice. The severity of IO and the level of transfusional iron intake, the preferential localization of IO (heart/liver) as well as the tolerance and adherence profiles of the patient can now be taken into account. Introduction of cardiac magnetic resonance imaging for the quantification of myocardial iron and use of oral chelators have already been reported as decreasing the cardiac mortality rate related to IO in thalassaemia major patients. Long-term observation of patients under oral chelators will show if morbidity is also improving via a more continuous control of toxic iron and/or a better accessibility to cellular iron pools.

Challenges of alloimmunization in patients with haemoglobinopathies

Red blood cell (RBC) transfusions can be life-sustaining in chronic inherited anaemias, such as thalassaemia, and the indications for blood transfusions in patients with sickle cell disease continue to expand. Complications of transfusions, such as allosensitization, can create significant medical challenges in the management of patients with haemoglobinopathies. This review summarizes key findings from the medical literature related to alloimmunization in haemoglobinopathies and examines potential measures to mitigate these risks. Areas where future studies are needed are also addressed.

French multicenter 22-year experience in stem cell transplantation for beta-thalassemia major: lessons and future directions

Although hematopoietic stem cell transplantation (HSCT) offers curative potential for beta-thalassemia major (beta-TM), it is associated with a variable but significant incidence of graft rejection. We studied the French national experience for improvement over time and the potential benefit of antithymocyte globulin (ATG). Between December 1985 and December 2007, 108 patients with beta-TM underwent HSCT in 21 different French transplantation centers. The majority of patients received a matched sibling transplant (n = 96) and a busulfan- and cyclophosphamide-based conditioning regimen (n = 95), also with ATG in 57 cases. Ninety-five of the 108 patients survived, with a median follow-up of 12 years. Probabilities of 15-year survival and thalassemia-free survival after first HSCT were 86.8% and 69.4%, respectively. Graft failure occurred in 24 patients, 11 of whom underwent a second HSCT. The use of ATG was associated with a decrease in rejection rate from 35% to 10%. Thalassemia-free survival improved significantly with time, reaching 83% in the 54 patients undergoing HSCT after 1994 (median time of HSCT). In view of the increased risk of graft rejection after matched sibling HSCT, current French national guidelines recommend, for all children at risk for beta-TM, the systematic addition of ATG to the myeloablative conditioning regimen and special attention to optimize transfusion and chelation therapy in the pretransplantation period.

Treatment and complications of thalassemia major in Guangxi, Southern China

BACKGROUND

β-Thalassemia is extremely prevalent in Guangxi province, Southern China. However, little is known about the treatment and complications of patients with thalassemia major (TM) in Guangxi. The first thalassemia center in China was opened in Guangxi in 2003. Since that time, more than 400 patients have been enrolled.

PROCEDURE

From December 2009 to February 2010, data was collected from TM patients visiting the thalassemia center including the circumstances of diagnosis, biological and clinical data, markers of iron overload and treatment.

RESULTS

Data on 231 patients (median age, 5 years; range, 5 months to 21 years) were recorded. Only 44.6% of patients maintained their hemoglobin levels >9.0 g/dl. In 186 patients with ferritin levels >1,000 ng/ml, an iron chelator was used regularly in 44.6%, irregularly in 26.9%, and was not used in 28.5%. The mean serum ferritin level was 3,143 ng/ml and levels increased with age. Height and weight retardation were found in 48.3% and 11.1% patients, respectively. Compared to patients treated outside of the center, patients completing treatment in the thalassemia center had a higher hemoglobin level before transfusion, higher height and weight SD score, and less splenomegaly, but a similar ratio of regular or irregular iron chelation. Six (18.2%) of 33 patients >10 years of age (14.3 ± 2.8 years; range, 11-19 years) were diagnosed as hypothyroid.

CONCLUSIONS

Although survival status of patients with TM in Guangxi has improved since the opening of the thalassemia center, TM complications remain high and with an early onset.

Management of transfusional iron overload - differential properties and efficacy of iron chelating agents

Regular red cell transfusion therapy ameliorates disease-related morbidity and can be lifesaving in patients with various hematological disorders. Transfusion therapy, however, causes progressive iron loading, which, if untreated, results in endocrinopathies, cardiac arrhythmias and congestive heart failure, hepatic fibrosis, and premature death. Iron chelation therapy is used to prevent iron loading, remove excess accumulated iron, detoxify iron, and reverse some of the iron-related complications. Three chelators have undergone extensive testing to date: deferoxamine, deferasirox, and deferiprone (although the latter drug is not currently licensed for use in North America where it is available only through compassionate use programs and research protocols). These chelators differ in their modes of administration, pharmacokinetics, efficacy with regard to organ-specific iron removal, and adverse-effect profiles. These differential properties influence acceptability, tolerability and adherence to therapy, and, ultimately, the effectiveness of treatment. Chelation therapy, therefore, must be individualized, taking into account patient preferences, toxicities, ongoing transfusional iron intake, and the degree of cardiac and hepatic iron loading.

Variants in genetic modifiers of β-thalassemia can help to predict the major or intermedia type of the disease

A cohort of 106 patients included in the French National Registry for Thalassemia were genotyped for 5 genetic modifiers of severity: i) β-thalassemia mutations; (ii) the XmnI SNP; (iii) the -3.7 kb α-thal deletion; (iv) the tag-SNP rs 11886868 in BCL11A exon 2; and (v) the tag-SNP rs9399137 in the HBSB1L-cMYB inter-region. Multivariate analysis was performed to study the risk of thalassemia Intermedia phenotype associated with the different combinations of alleles. The presence or absence of the favorable alleles could accurately predict the type of thalassemia in 83.2% of the cases. The percentage of correct predictions made from the β-thalassemia mutations and the XmnI SNP alone were significantly improved by the adjustment with the 3 other modifiers; from 73.6% to 83.2% (P<0.001). In this study, we showed that predictions based on genetic modifiers can foresee the Major or Intermedia type of β-thalassemia, even in cohorts of patients with various β-globin genotypes.