Hepatocellular carcinoma in thalassemia: A critical review

Disease burden, management strategies, and unmet needs in α-thalassemia due to hemoglobin H disease

Alpha-thalassemia is an inherited blood disorder caused by impaired α-globin chain production, leading to anemia and other complications. Hemoglobin H (HbH) disease is caused by a combination of mutations generally affecting the expression of three of four α-globin alleles; disease severity is highly heterogeneous, largely driven by genotype. Notably, non-deletional mutations cause a greater degree of ineffective erythropoiesis and hemolysis, higher transfusion burden, and increased complication risks versus deletional mutations. There are limited treatment options for HbH disease, and effective therapies are needed. This review discusses the pathophysiology of HbH disease, current management strategies, unmet needs, and emerging treatment options.

Thalassemia and malignancies: Updates from the literature

Thalassemia management has undergone significant development with the advancement in iron chelation therapy, which has led to a prolonged life expectancy. This has been accompanied by the emergence of several new morbidities and chronic diseases, including cancer. Over the years, multiple cases of solid and hematologic malignancies in thalassemia patients have been reported in the literature, with no clear mechanism for the development of cancer in these patients despite a number of potential mechanisms. However, the results of many studies have been contradictory regarding the risk of development of malignancies in thalassemia. The present review aims to discuss the available data on cancer and thalassemia in the literature, with the latest updates regarding possible malignancy development mechanisms, risks, and the most commonly reported types.

Clinical Complications and Their Management

The diversity of disease-related complications among patients with β-thalassemia is complicated by the wide spectrum of genotypes and clinical risk factors. The authors herein present the different complications seen in patients with β-thalassemia, the pathophysiology underlying these complications and their management.

Isolated focal intrahepatic extramedullary hematopoiesis mimicking hepatocellular carcinoma in a cirrhotic patient with secondary hemochromatosis from thalassemia

Extramedullary hematopoiesis is a common complication of ineffective erythropoiesis and bone marrow replacement disorders. Because of its nonspecific presentation and radiological appearance, diagnosing focal intrahepatic extramedullary hematopoiesis is challenging and often misdiagnosed as a hepatic tumor. Herein, we describe the case of a 48-year-old male with thalassemia and AE Bart's disease with secondary hemochromatosis and cirrhosis who developed focal intrahepatic extramedullary hematopoiesis mimicking hepatocellular carcinoma. After hepatic resection, extramedullary hematopoiesis was not observed at any site, including in the remaining liver, at the 4-year follow-up.

Iron overload disorders

Iron overload disorders represent a variety of conditions that lead to increased total body iron stores and resultant end-organ damage. An elevated ferritin and transferrin-iron saturation can be commonly encountered in the evaluation of elevated liver enzymes. Confirmatory homeostatic iron regulator (HFE) genetic testing for C282Y and H63D, mutations most encountered in hereditary hemochromatosis, should be pursued in evaluation of hyperferritinemia. Magnetic resonance imaging with quantitative assessment of iron content or liver biopsy (especially if liver disease is a cause of iron overload) should be used as appropriate. A secondary cause for iron overload should be considered if HFE genetic testing is negative for the C282Y homozygous or C282Y/H63D compound heterozygous mutations. Differential diagnosis of secondary iron overload includes hematologic disorders, iatrogenic causes, or chronic liver diseases. More common hematologic disorders include thalassemia syndromes, myelodysplastic syndrome, myelofibrosis, sideroblastic anemias, sickle cell disease, or pyruvate kinase deficiency. If iron overload has been excluded, evaluation for causes of hyperferritinemia should be pursued. Causes of hyperferritinemia include chronic liver disease, malignancy, infections, kidney failure, and rheumatic conditions, such as adult-onset Still's disease or hemophagocytic lymphohistiocytosis. In this review, we describe the diagnostic testing of patients with suspected hereditary hemochromatosis, the evaluation of patients with elevated serum ferritin levels, and signs of secondary overload and treatment options for those with secondary iron overload.

Current status of beta-thalassemia and its treatment strategies

Background

Thalassemia is an inherited hematological disorder categorized by a decrease or absence of one or more of the globin chains synthesis. Beta‐thalassemia is caused by one or more mutations in the beta‐globin gene. The absence or reduced amount of beta‐globin chains causes ineffective erythropoiesis which leads to anemia.

Methods

Beta‐thalassemia has been further divided into three main forms: thalassemia major, intermedia, and minor/silent carrier. A more severe form among these is thalassemia major in which individuals depend upon blood transfusion for survival. The high level of iron deposition occurs due to regular blood transfusion therapy.

Results

Overloaded iron raises the synthesis of reactive oxygen species (ROS) that are noxious and prompting the injury to the hepatic, endocrine, and vascular system. Thalassemia can be analyzed and diagnosed via prenatal testing (genetic testing of amniotic fluid), blood smear, complete blood count, and DNA analysis (genetic testing). Treatment of thalassemia intermediate is symptomatic; however; it can also be accomplished by folic supplementation and splenectomy.

Conclusion

Thalassemia major can be cured through regular transfusion of blood, transplantation of bone marrow, iron chelation management, hematopoietic stem cell transplantation, stimulation of fetal hemoglobin production, and gene therapy.

Evidence-based medicine and Management of Hepatocellular Carcinoma in Thalassemia

Background

Hepatocellular carcinoma as a complication is linked to improved outcomes of thalassemia.

Main body

Published data suggest an incidence of HCC in thalassemia of about 2%. However, since thalassemia is endemic in many under-developed countries where patients have not probably been screened for HCC yet, the burden of the disease could be higher. Prevention of HCV infection through blood transfusion, HCV treatment and adequate iron chelation are all tools to prevent HCC in thalassemia. In presence of risk factors, HCC screening seems appropriate for thalassemia. Management of HCC should not be different from that indicated for non thalassemics. However, liver transplantation can be challenging and should be reserved to highly selected cases, due to coexistence of relevant comorbidities. Decisions in the management of HCC in thalassemia should follow a multidisciplinary effort. Moreover, due to the paucity of published data about the issue, future multicenter international studies will be helpful.

Short conclusion

In BMC Gastroenterology results of a commendable effort to guidelines for the management of HCC in thalassemia are reported by an Italian panel of experts. However, due to the paucity of published data about the topic, some conclusions rely on grey areas and are reason of debate.

Gene therapies for transfusion dependent β-thalassemia: Current status and critical criteria for success

Thalassemia is one of the most prevalent monogenic diseases usually caused by quantitative defects in the production of β-globin leading to severe anemia. Technological advances in genome sequencing, stem cell selection, viral vector development, transduction and gene editing strategies now allow for efficient exvivo genetic manipulation of human stem cells that can lead to production of hemoglobin, leading to a meaningful clinical benefit in thalassemia patients. In this review, the status of the gene-therapy approaches available for transfusion dependent thalassemia are discussed, along with the critical criteria that affect efficacy and lessons that have been learned from the early phase clinical trials. Salient steps necessary for the clinical development, manufacturing, and regulatory approvals of gene therapies for thalassemia are also highlighted, so that the potential of these therapies can be realized. It is highly anticipated that gene therapies will soon become a treatment option for patients lacking compatible donors for hematopoietic stem cell transplant and will offer an alternative for definitive treatment of β-thalassemia.

Characteristics and Prognosis of Hepatocellular Carcinoma in Multi-Transfused Patients with β-Thalassemia. Experience of a Single Tertiary Center

Background/Aim

The incidence of hepatocellular carcinoma (HCC) in patients with transfusion dependent thalassemia (TDT) has been increasing, where viral hepatitis and iron overload are the two established HCC risk factors. The aim of this study was to investigate the etiological factors of HCC development and to evaluate the possible factors associated with survival in our cohort of TDT patients with HCC.

Methods

Records of patients with TDT diagnosed with HCC from 2008 to 2018 were reviewed. Liver iron concentration (LIC) has been assessed by the signal-intensity-ratio MRI. The diagnosis of HCC was made by a 3-phase contrast magnetic resonance imaging (MRI) and patients were staged and treated for HCC according to Barcelona Clinic Liver Cancer (BCLC) grading system.

Results

Forty-two TDT patients with HCC have been included. Most of them (78.5%) were anti-HCV positive, 59.5% HCV-RNA positive, and 16.5% had serological markers of resolved HBV infection. Patients with HCV infection have been treated successfully with either Peg-IFNa±Ribavirin or with the new direct antivirals (DAAs). At the time of HCC diagnosis, all patients with chronic HCV infection were HCV-RNA negative, 78.5% had underlying cirrhosis, and the vast majority (98%) had average or mild elevated LIC values. According to the BCLC system, patients were classified as 0-A: 28.5%, B: 57% and C-D: 14.5%. HCC has been treated with loco-regional treatment in 78.5% of our patients, while the rest have received sorafenib. Twenty-eight patients (66.5%) died due to HCC with a median survival time of 6 months (range: 2-60). Using the Cox proportional hazard model, the only factors associated with poor survival were BCLC stages C and D.

Conclusions

In conclusion, BCLC staging is the main prognostic factor of survival in patients with TDT who develop HCC.

Antibodies against the erythroferrone N-terminal domain prevent hepcidin suppression and ameliorate murine thalassemia

Erythroferrone (ERFE) is produced by erythroblasts in response to erythropoietin (EPO) and acts in the liver to prevent hepcidin stimulation by BMP6. Hepcidin suppression allows for the mobilization of iron to the bone marrow for the production of red blood cells. Aberrantly high circulating ERFE in conditions of stress erythropoiesis, such as in patients with β-thalassemia, promotes the tissue iron accumulation that substantially contributes to morbidity in these patients. Here we developed antibodies against ERFE to prevent hepcidin suppression and to correct the iron loading phenotype in a mouse model of β-thalassemia [Hbb(th3/+) mice] and used these antibodies as tools to further characterize ERFE's mechanism of action. We show that ERFE binds to BMP6 with nanomolar affinity and binds BMP2 and BMP4 with somewhat weaker affinities. We found that BMP6 binds the N-terminal domain of ERFE, and a polypeptide derived from the N terminus of ERFE was sufficient to cause hepcidin suppression in Huh7 hepatoma cells and in wild-type mice. Anti-ERFE antibodies targeting the N-terminal domain prevented hepcidin suppression in ERFE-treated Huh7 cells and in EPO-treated mice. Finally, we observed a decrease in splenomegaly and serum and liver iron in anti-ERFE-treated Hbb(th3/+) mice, accompanied by an increase in red blood cells and hemoglobin and a decrease in reticulocyte counts. In summary, we show that ERFE binds BMP6 directly and with high affinity, and that antibodies targeting the N-terminal domain of ERFE that prevent ERFE-BMP6 interactions constitute a potential therapeutic tool for iron loading anemias.

Increased Bone Marrow 18F-Choline Uptake in a Patient with Hepatocellular Carcinoma and Thalassemia Intermedia

A 57-year-old male with history of thalassemia intermedia and hepatocellular carcinoma underwent a positron emission tomography/computed tomography (PET/CT) scan with ¹⁸F-choline before radioembolization procedure with ⁹⁰Y-microspheres. The PET/CT scan with ¹⁸F-choline demonstrated highly increased tracer incorporation within a gross lesion in the hepatic dome coupled with diffuse activity in bone marrow, this latter aspect was probably due to the compensatory hematopoiesis stimulation induced by chronic hemolysis. This pattern of skeletal ¹⁸F-choline uptake should be considered as a peculiar PET/CT finding in thalassemic patients.

Thalassemia and hepatocellular carcinoma: links and risks

The increased survival and lifespan of thalassemia patients, in the setting of better iron overload monitoring and chelation, have also however increased the incidence of diseases and complications, which were less likely to develop. Among these, one of the most worrying in recent years is hepatocellular carcinoma (HCC). Due to blood transfusions, many patients with thalassemia are or have been infected with hepatitis C virus (HCV) or hepatitis B virus (HBV), especially those born before the 1990s or in countries in which universal HBV vaccination and safe blood programs are still not completely implemented. However, HCC has also been described in nontransfused patients and in those who are HCV- and HBV-negative. Therefore, other risk factors are involved in hepatocarcinogenesis in thalassemia. The following review analyzes recent literature on the role of different risk factors in the progression of liver disease in thalassemia as well as the importance of surveillance. Treatment of HCC in thalassemia is still highly debated and requires further studies.

Hepatic iron overload identified by magnetic resonance imaging-based T2* is a predictor of non-diagnostic elastography

Background

Magnetic resonance elastography (MRE) is a non-invasive test used to assess liver stiffness and fibrosis in chronic liver disease, which includes systemic iron overload. However, iron deposition by itself is associated with technical failure of MRE of the liver which necessitates the use of invasive liver biopsy as an alternative monitoring method for these patients. T2*-weighted magnetic resonance imaging (T2*) is a reliable modality to asses for hepatic as well as total body iron overload. Therefore, we aimed to determine a cutoff value on the T2* reading at which MRE would no longer provide accurate stiffness measurements in patients with iron overload.

Methods

Ninety-five patients with iron overload who underwent MRE at our institution, between 2010 and 2017 were reviewed retrospectively. We compared T2* values between patients with adequate elastography (N=63) versus those with non-diagnostic elastography (N=32). We additionally examined the ability of T2* to predict the likelihood of non-diagnostic elastography by estimating area under the ROC curve (AUC).

Results

T2* was significantly different between patients with and without an adequate elastography (P<0.0001) and predicted occurrence of non-diagnostic elastography with an AUC of 0.95. All patients with a non-diagnostic elastography had a T2* value below 20 milliseconds (ms), and correspondingly 55% of the patients with a T2* value below 20 ms had a non-diagnostic elastography. The subgroups of patients with a T2* value ≤10, ≤8, and ≤6 ms, had a higher likelihood of non-diagnostic elastography (87%, 92%, and 95%, respectively).

Conclusions

T2* can be used to accurately predict which patients are most likely to have a non-diagnostic elastography reading. T2* of 20 ms or lower reflects a higher likelihood of non-diagnostic elastography.

Hepatocellular Carcinoma in β-Thalassemia Patients: Review of the Literature with Molecular Insight into Liver Carcinogenesis

With the continuing progress in managing patients with thalassemia, especially in the setting of iron overload and iron chelation, the life span of these patients is increasing, while concomitantly increasing incidences of many diseases that were less likely to show when survival was rather limited. Hepatocellular carcinoma (HCC) is a major life-threatening cancer that is becoming more frequently identified in this population of patients. The two established risk factors for the development of HCC in thalassemia include iron overload and viral hepatitis with or without cirrhosis. Increased iron burden is becoming a major HCC risk factor in this patient population, especially in those in the older age group. As such, screening thalassemia patients using liver iron concentration (LIC) measurement by means of magnetic resonance imaging (MRI) and liver ultrasound is strongly recommended for the early detection of iron overload and for implementation of early iron chelation in an attempt to prevent organ-damaging iron overload and possibly HCC. There remain lacking data on HCC treatment outcomes in patients who have thalassemia. However, a personalized approach tailored to each patient’s comorbidities is essential to treatment success. Multicenter studies investigating the long-term outcomes of currently available therapeutic options in the thalassemia realm, in addition to novel HCC therapeutic targets, are needed to further improve the prognosis of these patients.

Hepatic iron overload in the portal tract predicts poor survival in hepatocellular carcinoma after curative resection

BACKGROUND & AIMS

Hepatic iron overload is associated with liver injury and hepatocarcinogenesis; however, it has not been evaluated in patients with hepatocellular carcinoma (HCC) in Asia. The aim of this study was to clarify the degree and distribution of intrahepatic iron deposition, and their effects on the survival of HCC patients.

METHODS

Intrahepatic iron deposition was examined using non-tumorous liver tissues from 204 HCC patients after curative resection, and they were scored by 2 semi-quantitative methods: simplified Scheuer's and modified Deugnier's methods. For the Scheuer's method, iron deposition in hepatocytes and Kupffer cells was separately evaluated, while for the modified Deugnier's method, hepatocyte iron score (HIS), sinusoidal iron score (SIS) and portal iron score (PIS) were systematically evaluated, and the corrected total iron score (cTIS) was calculated by multiplying the sum (TIS) of the HIS, SIS, and PIS by the coefficient.

RESULTS

The overall prevalence of hepatic iron was 40.7% with the simplified Scheuer's method and 45.1% with the modified Deugnier's method with a mean cTIS score of 2.46. During a median follow-up of 67 months, the cTIS was not associated with overall survival. However, a positive PIS was significantly associated with a lower 5-year overall survival rate (50.0%) compared with a negative PIS (73.7%, P = .006). In the multivariate analysis, a positive PIS was an independent factor for overall mortality (hazard ratio, 2.310; 95% confidence interval, 1.181-4.517).

CONCLUSIONS

Intrahepatic iron deposition was common, and iron overload in the portal tract indicated poor survival in curatively resected HCC patients.

Hepatocellular Carcinoma in a β-Thalassemia Intermedia Patient: Yet Another Case in the Expanding Epidemic

The incidence of hepatocellular carcinoma (HCC) in patients with thalassemia is increasing, the two well recognized HCC risk factors in thalassemia being iron overload and chronic hepatitis C. The carcinogenicity of iron is related to its induction of oxidative damage, whereas chronic hepatitis leads to necroinflammation that can accelerate progression to HCC. We hereby report the case of a non transfused, hepatitis C-negative, β-thalassemia intermedia (β-TI) patient from our practice who had evidence of significant iron overload, suggesting the importance of increased iron burden as a HCC risk factor in this patient population. As such, screening thalassemia patients using magnetic resonance imaging (MRI)-based liver iron concentration (LIC) measurement and liver ultrasound is strongly recommended for early detection of iron overload and HCC, respectively. Data appears to be lacking on HCC treatment outcomes in patients who have thalassemia, but an approach tailored to each patient's comorbidities is key to treatment success. The prognosis of these patients can be improved by multicenter studies investigating novel HCC therapeutic targets in the thalassemia realm.

Thalassemia Major: Transplantation or Transfusion and Chelation

Thalassemia is the most common monogenic hematologic disease that affects millions in the world and kills thousands of patients every year. Without transfusion or transplantation, patients with thalassemia major are expected to die within months of diagnosis. However, long-term transfusion and chelation therapy is highly challenging for many developing countries where the disease is prevalent, representing a major and unsustainable health burden. Stem cell transplantation is the only cure for thalassemia. It has witnessed major developments that have made it less toxic, more successful, and feasible for a larger number of patients with diverse comorbidities and from a wider range of donors. Advances in human leukocyte antigen typing have greatly refined alternate donor selection with results of matched unrelated donors similar to matched sibling donors. Novel strategies such as haploidentical and cord blood transplantation have increased the possibility of patients with no healthy donor to get a better opportunity to survive and avoid chronic transfusion complications. Cost-effectively, transplantation should be considered the primary treatment of choice in the presence of a suitable related or unrelated donor and at centers with a satisfactory experience in the field of transplantation and particularly, in managing those with thalassemia. Despite some complications such as graft-versus-host disease and late conditioning effects, the overall improvement in the quality of life of thalassemia is difficult to deny. Unfortunately, the number of transplants for thalassemia represents only a minority of all transplants conducted globally and the essential requirement for transplants for thalassemia in limited-resources countries should mandate the transplant societies, including Worldwide Network for Blood and Marrow Transplantation, to collaborate to help initiate and support specialized transfusion and transplant programs for managing thalassemia.

Successful Treatment of Hepatocellular Carcinoma Complicated by Fanconi Anemia

A 42-year-old woman with liver tumors was referred to our hospital. Her condition was complicated by Fanconi anemia, and she had undergone total laryngectomy 8 years ago. On admission, contrast-enhanced computed tomography revealed hypervascular tumors in the right hepatic lobe. Ultrasound-guided tumor biopsy revealed that the tumor comprised moderately differentiated hepatocellular carcinoma. Although the patient exhibited preserved liver function (Child-Pugh A), complete blood count revealed severe pancytopenia. Eventually, the tumor was successfully treated by transcatheter arterial embolization (TAE). Both platelet transfusion and systemic administration of antibiotics were performed. She was discharged 35 days after TAE.

Hepatocellular carcinoma as an emerging morbidity in the thalassemia syndromes: A comprehensive review

The incidence of hepatocellular carcinoma (HCC) in patients with thalassemia is on the rise. The 2 well recognized HCC risk factors in thalassemia are iron overload and chronic viral infection with hepatitis C. The carcinogenicity of iron is related to its induction of oxidative damage, which results in genotoxicity, and to immunologic dysregulation, which attenuates cancer immune surveillance. Chronic hepatitis B and C infections lead to necroinflammation, which can prompt progression to HCC, but an independent role of hepatitis B virus in hepatic carcinogenesis among patients with thalassemia has not been demonstrated. Screening patients who have thalassemia using magnetic resonance imaging-based liver iron concentration measurement and liver ultrasound is recommended for early detection of iron overload and HCC, respectively. Prevention primarily resides in hepatitis B vaccination, donor blood screening, hepatitis treatment, and iron chelation. Although solid data is lacking on the outcomes of HCC treatment in patients with thalassemia, a personalized approach tailored to the individual patient's comorbidities remains necessary for treatment success. Treatment modalities for HCC include surgical resection, chemoembolization, and liver transplantation, among others. Multicenter studies are needed to better explore therapeutic targets that can improve the prognosis of these patients. Cancer 2017;123:751-58. © 2016 American Cancer Society.

Management of Liver Complications in Haemoglobinopathies

Liver complications in haemoglobinopathies (thalassaemia and sickle cell disease) are due to several factors, dominated (beside chronic viral infections, not considered here) by chronic iron overload, biliary obstruction and venous thrombosis. Whereas the latter two factors can cause acute hepatic syndromes, all three mechanisms - when becoming chronic- can produce fibrosis and cirrhosis and even, in thalassaemia, hepatocellular carcinoma. These chronic hepatic complications are an indirect consequence of the significant improvement in life expectancy due to the overall amelioration of disease management. The diagnostic approach has benefited from non invasive (biochemical and imaging) approaches which have considerably reduced the indication of liver biopsy. The therapeutic management involves relatively efficient curative medical, endoscopic or surgical methods, but should rest primarily on preventive measures focused on the haematological causative factors but also on hepatic co-morbidities. This chapter will focus on hepatic complications in thalassaemia and sickle cell disease (SCD), without considering the complications related to virus B or C infections which will be described in another chapter.

Multidisciplinary Care in Haemoglobinopathies

While most complications are related to haemoglobinopathies and their treatment, it is also possible to observe substantial differences in comorbidities’ onset and seriousness which depend also to the different HPs genotypes. These differences should be carefully considered when health authorities set up and manage adequate care systems and treatments plans. We describe services organisation in Italy including the availability of multispecialty care and tools, in the HPs units participating to the HTA-THAL Multiregional Registry, with the aim to derive the impact of the services and multispecialty care availability on the management of the disease and on the patients wellbeing. The high dispersion and heterogeneity of services demonstrated, exposes the Italian system to a high risk of: (a) inappropriate use of economical and medical resources, (b) limited access to multidisciplinary care of some patients with apparent inequality among different centres, and (c) low patients satisfaction with the services provided. The identification of a ‘standard for HPs services’ is necessary not only at national but also at interventional level in order to implement collaborative research and the identification and networking of reference’ centres worldwide. Following the big efforts provided in the last years here there is a new challenging mission for the TIF.

Hepatocellular Carcinoma and Liver Transplantation: State of the Art

Hepatocellular carcinoma (HCC) is an aggressive tumor that often occurs in chronic liver disease and cirrhosis. The incidence of HCC is growing worldwide. With respect to any other available treatment for liver cancer, liver transplantation (LT) has the highest potential to cure. LT allows for removal at once of both the tumor ("seed") and the damaged-hepatic tissue ("soil") where cancerogenesis and chronic liver disorders have progressed together. The Milan criteria (MC) have been applied worldwide to select patients with HCC for LT, yielding a 4-year survival rate of 75%. These criteria represent the benchmark for patient selection and are the basis for comparison with any other suggested criteria. However, MC are often considered to be too restrictive, and recent data show that between 25% and 50% of patients with HCC are currently transplanted beyond conventional indications. Consequently, any unrestricted expansion of selection criteria will increase the need for donor organs, lengthen waiting periods, increase drop-out rates, and impair outcomes on intention-to-treat analysis. Management of HCC recurrence after LT is challenging. There are a few reports available regarding the safety and efficacy of sorafenib for HCC recurrence after LT, but the data are heterogeneous. A multi-center prospective randomized controlled trial comparing placebo with sorafenib is advised. Alternatively, a meta-analysis of patient survival with sorafenib for HCC recurrence after LT could be helpful to characterize the therapeutic benefit and safety of sorafenib. Here, we review the use of LT for HCC, with particular emphasis on the selection criteria for transplantation in patients with HCC and management of HCC recurrence after LT.

Use of magnetic resonance imaging to monitor iron overload

Treatment of iron overload requires robust estimates of total-body iron burden and its response to iron chelation therapy. Compliance with chelation therapy varies considerably among patients, and individual reporting is notoriously unreliable. Even with perfect compliance, intersubject variability in chelator effectiveness is extremely high, necessitating reliable iron estimates to guide dose titration. In addition, each chelator has a unique profile with respect to clearing iron stores from different organs. This article presents the tools available to clinicians to monitor their patients, focusing on noninvasive magnetic resonance imaging methods because they have become the de facto standard of care.

Novel approach to reactive oxygen species in nontransfusion-dependent thalassemia

The term Nontransfusion dependent thalassaemia (NTDT) was suggested to describe patients who had clinical manifestations that are too severe to be termed minor yet too mild to be termed major. Those patients are not entirely dependent on transfusions for survival. If left untreated, three main factors are responsible for the clinical sequelae of NTDT: ineffective erythropoiesis, chronic hemolytic anemia, and iron overload. Reactive oxygen species (ROS) generation in NTDT patients is caused by 2 major mechanisms. The first one is chronic hypoxia resulting from chronic anemia and ineffective erythropoiesis leading to mitochondrial damage and the second is iron overload also due to chronic anemia and tissue hypoxia leading to increase intestinal iron absorption in thalassemic patients. Oxidative damage by reactive oxygen species (generated by free globin chains and labile plasma iron) is believed to be one of the main contributors to cell injury, tissue damage, and hypercoagulability in patients with thalassemia. Independently increased ROS has been linked to a myriad of pathological outcomes such as leg ulcers, decreased wound healing, pulmonary hypertension, silent brain infarcts, and increased thrombosis to count a few. Interestingly many of those complications overlap with those found in NTDT patients.

Pathophysiology and Clinical Manifestations of the β-Thalassemias

The β-thalassemia syndromes reflect deficient or absent β-globin synthesis usually owing to a mutation in the β-globin locus. The relative excess of α-globin results in the formation of insoluble aggregates leading to ineffective erythropoiesis and shortened red cell survival. A relatively high capacity for fetal hemoglobin synthesis is a major genetic modifier of disease severity, with polymorphisms in other genes also having a significant role. Iron overload secondary to enhanced absorption and red cell transfusions causes an increase in liver iron and in various other tissues, leading to endocrine and cardiac dysfunction. Modern chelation regimens are effective in removing iron and preserving or restoring organ function.

Iron overload in non-transfusion-dependent thalassemia: a clinical perspective

Iron overload due to increased intestinal iron absorption represents an important clinical problem in patients with non-transfusion-dependent thalassemia (NTDT), particularly as they advance in age. Current models for iron metabolism in patients with beta (β)-thalassemia intermedia (TI) suggest that suppression of serum hepcidin results in increased iron absorption and release of iron from the reticuloendothelial system, leading to depletion of macrophage iron, relatively low levels of serum ferritin, and liver iron loading. The clinical consequences of iron overload in patients with NTDT are multifactorial and include endocrinopathy, bone disease, thromboembolism, pulmonary hypertension, cerebrovascular and neuronal damage, liver fibrosis or cirrhosis, and increased risk of hepatocellular carcinoma. Although serum ferritin levels correlate with liver iron concentration (LIC), they underestimate iron load in these patients compared with transfusion-dependent patients with equivalent LIC. Therefore, direct measurement of LIC is recommended with chelation therapy as indicated.

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.