Hydroxyurea can eliminate transfusion requirements in children with severe beta-thalassemia

Overview on practices in thalassemia intermedia management aiming for lowering complication rates across a region of endemicity: the OPTIMAL CARE study

Despite recent advances in understanding the pathophysiologic mechanisms behind the thalassemia intermedia (TI) phenotype, data on the effects of treatment are deficient. To provide such data, we evaluated 584 TI patients for the associations between patient and disease characteristics, treatment received, and the rate of complications. The most common disease-related complications were osteoporosis, extramedullary hematopoeisis (EMH), hypogonadism, and cholelithiasis, followed by thrombosis, pulmonary hypertension (PHT), abnormal liver function, and leg ulcers. Hypothyroidism, heart failure, and diabetes mellitus were less frequently observed. On multivariate analysis, older age and splenectomy were independently associated with an increased risk of most disease-related complications. Transfusion therapy was protective for thrombosis, EMH, PHT, heart failure, cholelithiasis, and leg ulcers. However, transfusion therapy was associated with an increased risk of endocrinopathy. Iron chelation therapy was in turn protective for endocrinopathy and PHT. Hydroxyurea treatment was associated with an increased risk of hypogonadism yet was protective for EMH, PHT, leg ulcers, hypothyroidism, and osteoporosis. Attention should be paid to the impact of age on complications in TI, and the beneficial role of splenectomy deserves revisiting. This study provides evidence that calls for prospective evaluation of the roles of transfusion, iron chelation, and hydroxyurea therapy in TI patients.

Thalassaemia intermedia: an update

Our understanding of the molecular and pathophysiological mechanisms underlying the disease process in patients with thalassaemia intermedia (TI) has substantially increased over the past decade. TI encompasses a wide clinical spectrum of beta-thalassaemia phenotypes. Some TI patients are asymptomatic until adult life, whereas others are symptomatic from as young as 2 years of age. A number of clinical complications commonly associated with TI are rarely seen in thalassaemia major, including extramedullary hematopoiesis, leg ulcers, gallstones, thrombosis and pulmonary hypertension. There are a number of options currently available for managing patients with TI, including transfusion therapy, iron chelation therapy, modulation of foetal haemoglobin production and haematopoietic stem cell transplantation. However, at present, there are no clear guidelines for an orchestrated optimal treatment plan.

Effect of wheat grass therapy on transfusion requirement in beta-thalassemia major

OBJECTIVE

To assess the efficacy of wheat grass juice on transfusion requirement in patients with beta thalassemia major.

METHODS

Fifty-three patients of thalassemia major with a median age of 16 years were given wheat grass juice tablets.

RESULTS

The Mean pre and post wheat grass therapy, the pack cell requirement was 288.06 +/- 53.25 gm/Kg/year and 301.25 +/- 54.86 gm/Kg/year (p =0.054) respectively. No adverse effects were noted.

CONCLUSION

We conclude that wheat grass therapy for one year is not effective in reducing the transfusion requirement in transfusion dependent thalassemia.

Effect of hydroxyurea on extramedullary haematopoiesis in thalassaemia intermedia: case reports and literature review

Extramedullary haematopoiesis (EH) is the production of blood cell precursors outside the bone marrow that occurs in various disorders, such as thalassaemia, sickle cell anaemia, hereditary spherocytosis, polycythaemia vera, myelofibrosis and other haematological diseases. In chronic anaemia, it is a physiological response to increased erythropoietin. In some other conditions, such as myeloid metaplasia, polycythaemia vera or chronic myeloid leukaemia, EH is due to a clonal disorder of haematopoiesis that enables progenitor cells to escape from the marrow and lodge in other organs. EH usually involves the liver, spleen and lymph nodes or it can be paravertebral, intrathoracic, pelvic. It is often asymptomatic but can sometimes lead to symptomatic tumour-like masses. Treatment options are still controversial and limited, including hypertransfusion regimen, surgical treatment, radiotherapy and hydroxyurea (HU). We describe intrathoracic and symptomatic pelvic EH masses in a 48-year-old woman and intrathoracic bilateral masses causing respiratory insufficiency with pleural effusion in a 42-year-old male, both affected by thalassaemia intermedia. Both patients showed a clinical improvement with hydroxyurea therapy and occasional blood transfusions.

Hydroxyurea or chronic exchange transfusions in patients with sickle cell disease: role of transcranial Doppler ultrasound in stroke prophylaxis

Hydroxyurea is increasingly used in patients with sickle cell disease and acts by several underlying mechanisms. Its usage has been reported to eliminate transfusion needs in children with beta-thalassemia major. It has also been used in sickle cell disease patients on stroke prophylaxis with exchange transfusions who develop transfusional iron overload and is now being considered as a possible alternative to chronic transfusions for secondary stroke prophylaxis. Our case demonstrates a pitfall when using hydroxyurea without monitoring intracranial cerebral vessels for vasculopathic changes; presence of which can predict stroke risk and alert the need for chronic blood transfusions as primary stroke prophylaxis. Transcranial Doppler is a crucial investigation that can reveal elevated cerebral arterial flow velocities.

Fetal hemoglobin chemical inducers for treatment of hemoglobinopathies

The switch from fetal ((G)gamma and (A)gamma) to adult (beta and delta) globin gene expression occurs at birth, leading to the gradual replacement of HbF with HbA. Genetic regulation of this switch has been studied for decades, and the molecular mechanisms underlying this developmental change in gene expression have been in part elucidated. The understanding of the developmental regulation of gamma-globin gene expression was paralleled by the identification of a series of chemical compounds able to reactivate HbF synthesis in vitro and in vivo in adult erythroid cells. Reactivation of HbF expression is an important therapeutic option in patients with hemoglobin disorders, such as sickle cell anemia and beta-thalassemia. These HbF inducers can be grouped in several classes based on their chemical structures and mechanisms of action. Clinical studies with some of these agents have shown that they were effective, in a part of patients, in ameliorating the clinical condition. The increase in HbF in response to these drugs varies among patients with beta-thalassemia and sickle cell disease due to individual genetic determinants.

Hydroxycarbamide-induced changes in E/beta thalassemia red blood cells

In thalassemia, fetal hemoglobin (HbF) augmentation with hydroxycarbamide (also known as hydroxyurea) is not always successful. The expected parallel effects on red cell (RBC) membrane deformability, cell hydration, and membrane phospholipid organization, all important for extending RBC life span and increasing Hb, have been infrequently examined. We analyzed these characteristics in 15 nontransfused E/beta(0) thalassemia patients treated with HU (mean 10.2 months). Membrane deformability and cell hydration mildly improved in association with increased HbF levels approaching statistical significance (r = 0.51, P = 0.06). All measures improved considerably in splenctomized patients. These findings underscore the disappointing results of hydroxyurea treatment in clinical trials and the importance of examining the effect on RBC characteristics for the development and understanding of HbF-enhancing agents.

Can homeopathy bring additional benefits to thalassemic patients on hydroxyurea therapy? Encouraging results of a preliminary study

Several homeopathic remedies, namely, Pulsatilla Nigricans (30th potency), Ceanothus Americanus (both mother tincture and 6th potency) and Ferrum Metallicum (30th potency) selected as per similia principles were administered to 38 thalassemic patients receiving Hydroxyurea (HU) therapy for a varying period of time. Levels of serum ferritin (SF), fetal hemoglobin (HbF), hemoglobin (Hb), platelet count (PC), mean corpuscular volume (MCV), mean corpuscular hemoglobin concentration (MCHC), mean corpuscular hemoglobin (MCH), white blood cell (WBC) count, bilirubin content, alanine amino transferase (ALT), aspartate amino transferase (AST) and serum total protein content of patients were determined before and 3 months after administration of the homeopathic remedies in combination with HU to evaluate additional benefits, if any, derived by the homeopathic remedies, by comparing the data with those of 38 subjects receiving only HU therapy. Preliminary results indicated that there was a significant decrease in the SF and increase in HbF levels in the combined, treated subjects. Although the changes in other parameters were not so significant, there was a significant decrease in size of spleen in most patients with spleenomegaly and improvement in general health conditions along with an increased gap between transfusions in most patients receiving the combined homeopathic treatment. The homeopathic remedies being inexpensive and without any known side-effects seem to have great potentials in bringing additional benefits to thalassemic patients; particularly in the developing world where blood transfusions suffer from inadequate screening and fall short of the stringent safety standards followed in the developed countries. Further independent studies are encouraged.

Histone deacetylase inhibitors and hemoglobin F induction in beta-thalassemia

Epigenomic modifiers, such as histone deacetylase inhibitors, are compounds that regulate gene expression by interfering with the enzymatic machinery that maintains the proper chromatin structure of the nucleus. These compounds are at the forefront of novel therapeutic agents for the treatment of several diseases including cancer and genetic disorders such as beta-thalassemia and sickle cell disease. Here we review the current understanding of the mechanism of action of epigenomic modifiers in the treatment of beta-thalassemia and sickle cell anemia. We also discuss how the lessons learned from the study of the effects of these compounds on the beta-globin locus, one of the best characterized regions of the human genome, might contribute to the understanding of the mechanism of action of these same compounds in cancer, where the specific regions of the genome that are responsible for the pathophysiology of the disease are often poorly defined.

Response to hydroxyurea therapy in beta-thalassemia

Although a relatively small number of previous studies suggest a modest response to hydroxyurea (HU) therapy in beta-thalassemia, more recent investigations have revealed that some transfusion-dependent patients can become transfusion-independent following HU therapy. Patients with Ggamma XmnI polymorphism, several beta-globin mutations, and alpha-thalassemia deletions were inconsistently reported to have significant responses to HU therapy. To better predict who may respond, we retrospectively evaluated the clinical response and the molecular background of 18 beta-thalassemia patients treated with HU for a mean of 46 months. The majority of transfusion-dependent patients responded to HU therapy with 9 out of 11 (82%) becoming transfusion-independent. Five thalassemia intermedia (TI) patients receiving occasional blood transfusion did not require any additional transfusions following therapy and two TI patients who had never received transfusions had a 2 g/dl increase in their hemoglobin level. The majority of beta-thalassemia major patients who became transfusion-independent (7/9) were either homozygous (5) or heterozygous (2) for the XmnI polymorphism. No correlation was identified between response to therapy and the presence of specific beta-thalassemia mutations or alpha-globin deletions. We conclude that further analysis of the degree of response of transfusion-dependent beta-thalassemia patients to HU therapy, as well as, the impact of their genetic background on this response is required to identify patients likely to have significant response.

Fetal Hemoglobin Inducers from the Natural World: A Novel Approach for Identification of Drugs for the Treatment of {beta}-Thalassemia and Sickle-Cell Anemia

The objective of this review is to present examples of lead compounds identified from biological material (fungi, plant extracts and agro-industry material) and of possible interest in the field of a pharmacological approach to the therapy of beta-thalassemia using molecules able to stimulate production of fetal hemoglobin (HbF) in adults. Concerning the employment of HbF inducers as potential drugs for pharmacological treatment of beta-thalassemia, the following conclusions can be reached: (i) this therapeutic approach is reasonable, on the basis of the clinical parameters exhibited by hereditary persistence of fetal hemoglobin patients, (ii) clinical trials (even if still limited) employing HbF inducers were effective in ameliorating the symptoms of beta-thalassemia patients, (iii) good correlation of in vivo and in vitro results of HbF synthesis and gamma-globin mRNA accumulation indicates that in vitro testing might be predictive of in vivo responses and (iv) combined use of different inducers might be useful to maximize HbF, both in vitro and in vivo. In this review, we present three examples of HbF inducers from the natural world: (i) angelicin and linear psoralens, contained in plant extracts from Angelica arcangelica and Aegle marmelos, (ii) resveratrol, a polyphenol found in grapes and several plant extracts and (iii) rapamycin, isolated from Streptomyces hygroscopicus.

Decreased transfusion needs associated with hydroxyurea therapy in Algerian patients with thalassemia major or intermedia

BACKGROUND

Studies of evolution of transfusion requirements in thalassemic patients treated with hydroxyurea have produced somewhat conflicting results, especially in patients with thalassemia major. Our aims were to determine the proportion of good responders to hydroxyurea in a population of transfusion-dependent thalassemic patients and to identify the factors associated with a decrease of transfusion needs.

STUDY DESIGN AND METHODS

Hydroxyurea treatment was initiated in 9 patients with thalassemia intermedia (TI) and 45 with thalassemia major (TM). Patients received transfusions when their hemoglobin (Hb) levels dropped below 6 g per dL. A decrease in annual transfusion requirements greater than 70 percent defined a good response, between 40 and 70 percent a partial response, and smaller than 40 percent no response.

RESULTS

The response was good in 8 (90%) patients with TI and 20 (44.5%) with TM, partial in 9 (20%) patients with TM, and absent in 1 (10%) with TI and 16 (35.5%) with TM. In TM patients, transfusion needs decreased by 56 percent over the first year of hydroxyurea treatment. By univariate analysis, a better response to hydroxyurea was associated with older age at the first transfusion (p = 0.02), higher prehydroxyurea Hb (p = 0.0004), codon 6(-A) mutation (p = 0.002), TI (p = 0.03), and history of splenectomy (p = 0.05). Xmn1-/- was associated with a worse response (p = 0.0001). By multivariate analysis, a better response was associated with the Xmn1 polymorphism (p = 0.008).

CONCLUSION

Hydroxyurea may be an alternative to transfusions for TI patients as well as for TM patients in countries that have limited blood supplies.

Expression of the gamma-globin gene is sustained by the cAMP-dependent pathway in beta-thalassaemia

The present study found that the cyclic adenosine monophosphate (cAMP)-dependent pathway efficiently induced gamma-globin expression in adult erythroblasts, and this pathway plays a role in gamma-globin gene (HBG) expression in beta-thalassaemia. Expression of HBG mRNA increased to about 46% of non-HBA mRNA in adult erythroblasts treated with forskolin, while a cyclic guanosine monophosphate (cGMP) analogue induced HBG mRNA to levels <20% of non-HBA mRNA. In patients with beta-thalassaemia intermedia, cAMP levels were elevated in both red blood cells and nucleated erythroblasts but no consistent elevation was found with cGMP levels. The transcription factor cAMP response element binding protein (CREB) was phosphorylated in nucleated erythroblasts and its phosphorylation levels correlated with HBG mRNA levels of the patients. Other signalling molecules, such as mitogen-activated protein kinases and signal transducers and activators of transcription proteins, were phosphorylated at variable levels and showed no correlations with the HBG mRNA levels. Plasma levels of cytokines, such as erythropoietin, stem cell factor and transforming growth factor-beta were increased in patients, and these cytokines induced both HBG mRNA expression and CREB phosphorylation. These results demonstrate that the cAMP-dependent pathway, the activity of which is augmented by multiple cytokines, plays a role in regulating HBG expression in beta-thalassaemia.

Identification of Two New Synthetic Histone Deacetylase Inhibitors That Modulate Globin Gene Expression in Erythroid Cells from Healthy Donors and Patients with Thalassemia

We have identified two new histone deacetylase (HDAC) inhibitors (9 and 24) capable of inducing the expression of gamma-globin and/or beta-globin promoter-driven reporter genes in a synthetic model of Hb switch. Both compounds also increased, with different mechanisms, the gamma/(gamma+beta) ratio expressed in vitro by normal human erythroblasts. Compound 9 increased the levels of gamma-globin mRNA and the gamma/(gamma+beta) ratio (both by 2-fold). Compound 24 increased by 3-fold the level of gamma-globin and decreased by 2-fold that of beta-globin mRNA, increasing the gamma/(gamma+beta) ratio by 6-fold, and raising (by 50%) the cell HbF content. Both compounds raised the acetylation state of histone H4 in primary cells, an indication that their activity was mediated through HDAC inhibition. Compounds 9 and 24 were also tested as gamma/(gamma+beta) mRNA inducers in erythroblasts obtained from patients with beta(0) thalassemia. Progenitor cells from patients with beta(0) thalassemia generated in vitro morphologically normal proerythroblasts that, unlike normal cells, failed to mature in the presence of EPO and expressed low beta-globin levels but 10 times higher-than-normal levels of the alpha hemoglobin-stabilizing protein (AHSP) mRNA. Both compounds ameliorated the impaired in vitro maturation in beta(0) thalassemic erythroblasts, decreasing AHSP expression to normal levels. In the case of two patients (of five analyzed), the improved erythroblast maturation was associated with detectable increases in the gamma/(gamma+beta) mRNA ratio. The low toxicity exerted by compounds 9 and 24 in all of the assays investigated suggests that these new HDAC inhibitors should be considered for personalized therapy of selected patients with beta(0) thalassemia.

Modern treatment of thalassaemia intermedia

The term thalassaemia intermedia includes a large spectrum of conditions of varying severity. Blood transfusion and chelation are necessary in some patients, especially during childhood, in order to promote growth and prevent bone deformities. Alloimunisation, however, is frequent and can be difficult to control. Splenectomy is usually needed at some time because of hypersplenism and mechanical encumbrance. Reactivation of HbF is possible only in a small proportion of patients: hydroxycarbamide (also known as hydroxyurea) appears to be the most effective drug for this purpose. Antioxidant agents, although theoretically useful, do not improve haemoglobin levels. Stem cell transplantation is an option limited to the severe forms. Gene therapy and other molecular approaches are subjects of intense study. Numerous complications, including pulmonary hypertension, thrombotic events, pseudoxanthoma elasticum and osteoporosis, have been described and all contribute to complicate the treatment of a disease that represents a significant burden for the patients and their families.

Molecular therapies in beta-thalassaemia

The beta-thalassaemias have a major global impact on health and mortality. Allogeneic haemopoietic stem cell transplantation is the only approach that may lead to a cure but this approach is not available to most patients. The mainstay treatment for the majority remains life-long blood transfusion in combination with a rigorous regime of iron chelation. Improved understanding of the pathophysiology and molecular basis of the disease has provided clues for more effective strategies that aim to correct the defect in beta-globin chain synthesis at the primary level or redress the alpha/beta-globin chain imbalance at the secondary level. Improved understanding of the molecular basis of the disease complications, such as iron overloading, has also provided clues for potential molecular targets at the tertiary level.

The prevention and management of stroke in sickle cell anaemia

Perhaps the most important clinical complication of sickle cell anaemia is stroke, an event that occurs in approximately 5-10% of children who inherit this disorder. To prevent recurrent or progressive CNS damage, the institution of regular red blood cell (RBC) transfusions is the standard of care. In addition, children at high risk of developing stroke, as screened by transcranial Doppler, also benefit from regular RBC transfusions for stroke prevention. In this review, standard and novel techniques of RBC transfusion, and also alternative therapies to treat children with or at risk for stroke are considered. In addition, haematopoietic cell transplantation, the only curative option for sickle cell anaemia, is considered, and speculation about its present and future application in this clinical setting is discussed.

Single and combination drug therapy for fetal hemoglobin augmentation in hemoglobin E-beta 0-thalassemia: Considerations for treatment

Patients with hemoglobin E (Hb E)-beta 0-thalassemia, one of the most common hemoglobinopathies worldwide, could benefit from drugs that increase fetal and total hemoglobin levels and thereby decrease the need for transfusions. The long-term clinical outcome of such therapy, its hematologic effects, and which patients are likely to benefit from treatment are unknown. Consequently, the use of such drugs for Hb E-beta 0-thalassemia is limited, and countries where resources for safe and regular transfusion are scarce cannot benefit from them. In a multicenter trial of 42 patients treated with hydroxyurea for two years, almost half the patients demonstrated a significant increase in steady-state hemoglobin level. Drug toxicity was minimal. Combined treatment of hydroxyurea with erythropoietin benefited selected patients, but the addition of sodium phenyl butyrate was ineffective. After 5 years of follow-up, a subset of patients remained off transfusions. Hydroxyurea should be considered for a subset of Hb E-beta 0-thalassemia patients.

DNA hypomethylation therapy for hemoglobin disorders: Molecular mechanisms and clinical applications

Reactivation of fetal hemoglobin (HbF) expression is an important therapeutic option in patients with hemoglobin disorders. In sickle cell disease (SCD), an increase in HbF would interfere with the polymerization of sickle hemoglobin while in beta-thalassemia, an increase in gamma-globin chain synthesis would decrease non-alpha:alpha chain imbalance. Hydroxyurea, an inducer of HbF, is the only currently approved agent for the treatment of patients with moderate and/or severe SCD. However, about one third of patients with SCD do not respond to HU, and in beta-thalassemia, the clinical response is unimpressive. The last decade has seen a renewed interest in the use of inhibitors of DNA methylation in the treatment of patients with hemoglobin disorders. In this review, we discuss the role of DNA methylation in gamma-globin gene regulation, describe clinical trials with agents that hypomethylate DNA and speculate about the future role of DNA hypomethylation therapy in patients with SCD and beta-thalassemia.

Thalassemia intermedia: Revisited

Thalassemia intermedia encompasses a wide clinical spectrum of beta-thalassemia phenotypes. Some thalassemia intermedia patients are asymptomatic until adult life, whereas others are symptomatic from as young as 2 years of age. A number of clinical complications commonly associated with thalassemia intermedia are rarely seen in thalassemia major, including extramedullary hematopoiesis, leg ulcers, gallstones and thrombophilia. Prevention of these complications, possibly with blood transfusion therapy, is ideal since they may be difficult to manage. Currently, many patients with thalassemia intermedia receive only occasional or no transfusions, since they are able to maintain hemoglobin levels between 7-9 g/dl; the risk of iron overload, necessitating adequate chelation therapy, is also a contributing factor. At present, there are no clear guidelines for initiating and maintaining transfusions in thalassemia intermedia for the prevention or treatment of complications. Here, we review the major clinical complications in thalassemia intermedia and suggest some therapeutic strategies based on retrospective clinical observations.

In vivo and in vitro studies of fetal hemoglobin induction by hydroxyurea in β-thalassemia/hemoglobin E patients

OBJECTIVE

Some, but not all, beta-thalassemia/hemoglobin E (beta-thal/HbE) patients respond to hydroxyurea treatment. It would be helpful if patient responses to hydroxyurea could be screened in vitro to identify responders and nonresponders before beginning in vivo treatment.

MATERIALS AND METHODS

Thirteen beta-Thal/HbE patients were treated with hydroxyurea orally for 2 years at a starting dose of 5 mg/kg/day for 5 days/week with escalation to a maximum of 10 mg/kg/day. For comparison, erythroid cells obtained from peripheral blood of the same patients 1 year after they had stopped hydroxyurea treatment were treated with hydroxyurea in vitro. The gamma-globin mRNA was measured by real-time reverse-transcription polymerase chain reaction, fetal hemoglobin (HbF) by high-performance liquid chromatography, (G)gamma- and (A)gamma-globin chains by Triton X-100 acid urea polyacrylamide gel electrophoresis.

RESULTS

Treatment of cells in primary culture with 30 microM hydroxyurea for 96 hours significantly increased the fractional HbF content in beta-Thal/HbE patients. The (G)gamma:(A)gamma-globin mRNA was induced 0.30- to 8-fold in vitro and 0.30- to 6-fold in vivo (r(2) = 0.51, p = 0.16 by paired t-test); the fractional HbF content was induced 0.50- to 19-fold in vitro and 0.30- to 12-fold in vivo (r(2) = 0.61, p = 0.20) and the (G)gamma:(A)gamma-globin chain ratio was increased 0.80- to 1.40-fold in vitro and 1- to 1.20-fold in vivo (r(2) = 0.62, p = 0.13).

CONCLUSION

The correlation of in vivo and in vitro results of HbF synthesis and globin mRNA suggest that in vitro testing may predict the in vivo response.

Spontaneous switch from Agamma- to beta-globin promoter activity in a stable transfected dual reporter vector

Here it is analyzed the expression of a mini locus dual reporter construct composed by a micro-LCR and by the promoters for (A)gamma- and beta-globin gene, each one linked to a different Luciferase, in stably transfected GM979 cells for as long as 1-2 years from transfection. The transfected GM979 cells rapidly (within 1 month) evolved into a stable population which expresses constant levels of reporters for more than a year of continuous bulk culture. No silencing of the inserted construct was observed over time. In contrast, after 1 month, the reporter activity (both from (A)gamma- and beta-promoter) expressed per cell increased over time. The analysis of the Luciferase contained in single cell clones indicated that the higher reporter activity was due to increased gene expression per cell rather than to clonal selection of the most expressing clones. Since the activity driven by the beta-promoter increased 10-fold more than that driven by the (A)gamma one, the ratio between (A)gamma-driven/((A)gamma-driven + beta-driven) reporter activity in the cells decreased after 1 month and became similar to the gamma/(gamma + beta) globin mRNA ratio expressed by adult erythroid cells. Moreover, although both cells from early and late bulk culture responded to incubation with butyric acid, a known inducer of fetal globin gene expression, by increasing the reporter activity driven by the (A)gamma-promoter, only cells from late bulk culture decreased, as normal primary erythroblasts do, the activity of the reporter driven by the beta-promoter. These results suggest that the rapid changes in activity driven by the (A)gamma- and beta-globin promoters occurring during the first month after transfection may represent a novel in vitro model to study epigenetic regulation of the (A)gamma- and beta-promoter during the fetal to adult hemoglobin switch and confirm GM979 cells stably transfected with the dual reporter construct as a reliable assay for automated screening of chemical inducers of fetal globin gene activation.

Two beta-globin cluster-linked polymorphic loci in thalassemia patients of variable levels of fetal hemoglobin

OBJECTIVE

To correlate different polymorphisms of the beta-globin cluster with fetal hemoglobin (HbF) level in beta-thalassemia and E-beta thalassemia patients.

METHODS

Fifteen thalassemia patients, seven with high HbF and not requiring transfusion, eight with lower HbF and requiring transfusion were studied for beta-globin mutation, concurrent inheritance of alpha-thalassemia, RFLP haplotype, a C-->T polymorphism at -158 of Ggamma and configuration of an (AT)(x)T(y) motif at -540 of beta-globin gene.

RESULTS

Senegal 5'beta-haplotype and the polymorphism at -158 of G(gamma) was (P = 0.063) was linked to the high-HbF phenotype but the (AT)(9)T(5) configuration of the (AT)(x)T(y) motif was not (P = 0.6). Study of 30 chromosomes revealed 7 different configurations of the (AT)(x)T(y) motif. Association of these motifs with specific beta-globin mutations of this region has also been determined.

CONCLUSION

The senegal haplotype and the polymorphism at -158 of G(gamma) was linked to the high-HbF phenotype.

Hydroxyurea in thalassemia intermedia—a promising therapy

Pharmacological agents such as hydroxyurea (HU) have been known to cause induction of fetal hemoglobin and possibly may alleviate the symptoms in thalassemia intermedia patients. Thirty-seven patients with beta-thalassemia intermedia were enrolled to assess response to HU therapy. Major response was defined as transfusion independence or hemoglobin rise of more than 20 g/l and minor response as rise in hemoglobin of 10-20 g/l or reduction in transfusion frequency by 50%. The median age was 10 years (range: 4-50 years) and median follow-up was 12 months (range: 4-36 months). Twenty-six patients (70.2%) showed response to HU therapy. Seventeen patients (45.9%) were major responders, and nine patients (24.3%) showed minor response. There was no correlation of response with beta-thalassemia mutation or XmnI polymorphism; however, the presence of alpha(3.7) deletion was associated with major response in three patients. Mean fetal hemoglobin (HbF) levels rose on HU therapy. Older age, low baseline F cell percent, and low baseline HbF levels (below 10%) were predictors of poor response. Response was evident within 1 month of starting HU therapy in the majority of responders. Thus, a short trial of HU therapy can predict durable response.

New Strategies in the Treatment of the Thalassemias

In addition to the severe beta thalassemias, hematologists have begun to recognize the more severe forms of alpha thalassemia, namely hemoglobin (Hb) H disease and Hb H/Hb Constant Spring, as well as the beta compound heterozygote, beta thalassemia/HbE. Clinically, variably severe anemia becomes apparent in the first year accompanied by occasionally massive expansion of erythropoiesis. The most anemic patients require regular red blood cell transfusions to avoid death from cardiac failure. However, the inevitable iron accumulation leads to dysfunction, primarily involving the heart, liver, and endocrine system; thus, regularly transfused patients require iron chelation. A major discovery was that allogeneic bone marrow (stem cell) transplantation in severely affected subjects with both alpha and beta thalassemia could result in cure. Current work deals with specific complications, such as iron overload and endocrine, cardiopulmonary, thrombophilic, and osteopenic problems. The thalassemias are likely to benefit in the future from specific gene therapy. There are also important advances in genetic counseling based on results of early fetal diagnosis.

The role of fetal hemoglobin–enhancing agents in thalassemia

Augmentation of fetal hemoglobin (HbF) synthesis can reduce the severity of beta-thalassemia by improving the imbalance between alpha- and non-alpha-globin chains. However, previous clinical trials of pharmacologic induction of HbF in thalassemia produced inconsistent results. Striking responses in HbF and total hemoglobin synthesis were occasionally observed, but in most patients, the increase in gamma-globin synthesis was inadequate to influence the clinical course of thalassemia. A small number of patients treated with azacytidine demonstrated a consistent response, but the development of this drug was abandoned due to concerns over toxicity. Decitabine, an analog of azacytidine, is a more potent inhibitor of DNA methyltransferase, and may be less toxic in clinical use. Trials in sickle cell anemia have confirmed that decitabine is effective in patients refractory to hydroxyurea. The clinical trials of decitabine in thalassemia must carefully evaluate the dose and route of administration, and address concerns about long-term side effects.

Cell-based therapies for birth defects: a role for adult stem cell plasticity?

Cell therapy can offer a reasonable approach to the treatment of specific birth defects, particularly those for which hematopoietic stem cells (HSCs) can be used to restore (even partially) the number of cells, protein levels, or enzyme activity. Relatively few clinical experiences have been published on this subject, but when a natural selective advantage exists for the cell graft, a degree of "rescue" is possible. Strategies have been developed to confer a selective advantage through genetic engineering of donor cells, and this approach may prove valuable in the treatment of birth defects, as it is in hematological malignancy. Stem cell (SC) plasticity, or transdifferentiation, may offer another route for delivery of cells to established or developing organs. A wide variety of studies support the concept that adult tissue-specific SCs can, if displaced from their normal niche to another, be reprogrammed to produce cell types appropriate to their new environment. Clinical observations reveal that persistent tissue microchimerism develops not only in blood lineages after transfusion, but also in thyroid follicular epithelium via transplacental exchange. In addition, hepatic and renal parenchyma also become chimeric following allografts or bone marrow transplantation (BMT). Experimental models indicate that a renal glomerulosclerosis phenotype can be transferred by grafting whole BM, and that a severe liver disorder in fah-/- mice can be overcome by grafting HSCs and then exerting a selection pressure. It may be possible in the future to exploit the ability of adult SCs to contribute to diverse tissues; however, our understanding of the processes involved is at a very early stage.

Meeting the clinical challenge of care for Jehovah’s Witnesses1 1Editor’s Note: This article represents the current position of the Watch Tower Society on the use of blood components and fractions in the care of patients who are Jehovah’s Witnesses

Quality patient care entails more than simply biomedical interventions. Respect for the wishes, values, and preferences of patients are important elements of quality care. Unique aspects of the beliefs of Jehovah's Witnesses may present physicians with ethical and clinical conflicts. Witnesses believe that allogeneic blood transfusion (ie, whole blood, red blood cells, white cells, platelets, and plasma) and preoperative autologous blood deposit (PAD) are prohibited by several Biblical passages. This article reviews the Witness position on medical care, blood components, and fractions, placing these and related interventions into categories that may help physicians to individualize clinical management plans and meet the challenge of caring for patients who are Jehovah's Witnesses. It includes an overview of cost, safety, efficacy, and medicolegal issues related to patient care using transfusion-alternative strategies.