Outcome of patients with hemoglobinopathies given either cord blood or bone marrow transplantation from an HLA-identical sibling. Blood. 2013;122:1072-1078. [PMID: 23692854 DOI: 10.1182/blood-2013-03-489112]

Allogeneic stem cell transplantation for thalassemia major

Allogeneic stem cell transplant remains the only curative option for β-thalassemia major. In patients with good risk features it is reasonable to anticipate a greater than 90% chance of a successful transplant outcome. The conventional risk stratification system has limitations and alternative systems are being explored to better identify subsets that require innovative approaches. Several novel regimens have been evaluated to reduce treatment-related morbidity and mortality. There remain challenges in improving the clinical outcome of high-risk patients. There are limited data on the role of splenectomy before transplantation or optimal posttransplant chelation and care of these patients.

Combined umbilical cord blood and bone marrow from HLA-identical sibling donors for hematopoietic stem cell transplantation in children with hemoglobinopathies

BACKGROUND

It is well established that umbilical cord blood and bone marrow are biologically different stem cell sources.

PATIENTS AND METHODS

We analyzed the feasibility and outcome of hematopoietic stem cell transplantation (HSCT) in 13 children (median age 5.9 years) with hemoglobinopathies after the co- infusion of cord blood (CB) and bone marrow (BM) from the same human leucocyte antigen (HLA) identical sibling donor. We also compared outcomes of children with co-transplantation to outcomes in children with hemoglobinopathies who had received a BM (n = 21) or CB (n = 22) transplant alone.

RESULTS

Compared to CB transplant (CBT) recipients, the co-transplant group had more rapid neutrophil (17 vs. 25 days, P = 0.013) and platelet (29 vs. 48 days, P = 0.009) recovery and less transplant related mortality. Patients who received a co-transplant had a lower incidence of ≥ grade II acute (0% vs. 26.3%) and chronic (0% vs. 21%) graft versus host disease (GVHD) compared to BM transplant (BMT) recipients (P = 0.055 and 0.045, respectively). With a median follow-up of >60 months in each treatment group, the 5-year probability of event free survival (EFS) was 100% in the co-transplant group, 90% after BMT and 86% after CBT (P = 0.42).

CONCLUSION

Co-transplantation of CB and BM from HLA-identical sibling donors appears to be a feasible and effective strategy to further optimize outcomes of HSCT for hemoglobinopathies.

Blood and marrow transplantation for sickle cell disease: is less more?

Blood and marrow transplantation is a curative therapy for patients with sickle cell disease yet this option is seldom used. Clinical studies have shown however that children transplanted for this condition can achieve excellent results. In children with sickle cell disease transplanted following conditioning with busulfan, cyclophosphamide, and anti-thymocyte globulin, cure rates in excess of 80% can be obtained when an HLA-matched sibling is used as the donor. However, the large majority of patients with sickle cell disease will not have such a donor, or will not be able to tolerate high dose conditioning regimens. Therefore novel approaches such as non-myeloablative regimes, and alternative donors such as haploidentical, unrelated, or cord blood grafts are currently being explored in clinical trials. Recent reports on non-myeloablative conditioning (HLA-matched or haploidentical donors) highlight the safety and efficacy of these approaches with low mortality and high efficacy suggesting that in the near future non-myeloablation could be the preferred type of conditioning and donor availability will not be a barrier anymore to proceed to transplant. This review will focus on the results obtained when bone marrow transplants are used to treat sickle cell disease and will discuss the results obtained with these novel approaches.

Treatment of alpha(0)-thalassemia (--(SEA)/--(SEA)) via serial fetal and post-natal transfusions: Can early fetal intervention improve outcomes?

OBJECTIVE AND IMPORTANCE

Homozygous Southeast Asian alpha-thalassemia mutation (--(SEA)/--(SEA)) results in deletion of all alpha-globin genes (alpha(0)-thalassemia). Since all alpha-globin chains are absent, hemoglobin F cannot be synthesized, and hemoglobin Bart's becomes the dominant fetal hemoglobin. Hemoglobin Bart's is a γ tetramer with a very high oxygen affinity, thus oxygen delivery to the tissues is poor. Clinical manifestations include severe fetal anemia, hydrops fetalis, fetal demise, and high risk of neurodevelopmental impairment in the rare survivors.

CLINICAL PRESENTATION

A 39-year-old Vietnamese woman presented to our center at 28 0/7 weeks' gestation with fetal alpha(0)-thalassemia (--(SEA)/--(SEA) type deletion) and ultrasound markers suggestive of severe fetal anemia.

INTERVENTION

The fetus was treated with four intrauterine transfusions followed by post-natal chronic transfusions. Formal neurodevelopmental testing (Battelle Developmental Inventory, Second Edition) was performed at 18 months of age, and the developmental quotient was 93 (32nd percentile) with all subdomains noted within normal limits, indicating overall intact neurodevelopment.

CONCLUSION

We posit that earlier diagnosis and fetal treatment, prior to clinical findings suggestive of fetal anemia, may improve long-term outcomes by enhancing oxygen delivery to the tissues of the developing fetus.

The ethics of a proposed study of hematopoietic stem cell transplant for children with “less severe” sickle cell disease

Hematopoietic stem cell transplant (HSCT) is the only cure for sickle cell disease (SCD). HSCT using an HLA-identical sibling donor is currently an acceptable treatment option for children with severe SCD, with expected HSCT survival >95% and event-free survival >85%. HSCT for children with less severe SCD (children who have not yet suffered overt disease complications or only had mild problems) is controversial. It is important to consider the ethical issues of a proposed study comparing HLA-identical sibling HSCT to best supportive care for children with less severe SCD. In evaluating the principles of nonmaleficence, respect for individual autonomy, and justice, we conclude that a study of HLA-identical sibling HSCT for all children with SCD, particularly hemoglobin SS and Sβ0-thalassemia disease, is ethically sound. Future work should explore the implementation of a large trial to help determine whether HSCT is a beneficial treatment of children with less severe SCD.

Red blood cells of sickle cell disease patients exhibit abnormally high abundance of N-methyl D-aspartate receptors mediating excessive calcium uptake

Recently we showed that N-methyl D-aspartate receptors (NMDARs) are expressed in erythroid precursors (EPCs) and present in the circulating red blood cells (RBCs) of healthy humans, regulating intracellular Ca(2+) in these cells. This study focuses on investigating the possible role of NMDARs in abnormally high Ca(2+) permeability in the RBCs of patients with sickle cell disease (SCD). Protein levels of the NMDAR subunits in the EPCs of SCD patients did not differ from those in EPCs of healthy humans. However, the number and activity of the NMDARs in circulating SCD-RBCs was substantially up-regulated, being particularly high during haemolytic crises. The number of active NMDARs correlated negatively with haematocrit and haemoglobin levels in the blood of SCD patients. Calcium uptake via these non-selective cation channels was induced by RBC treatment with glycine, glutamate and homocysteine and was facilitated by de-oxygenation of SCD-RBCs. Oxidative stress and RBC dehydration followed receptor stimulation and Ca(2+) uptake. Inhibition of the NMDARs with an antagonist memantine caused re-hydration and largely prevented hypoxia-induced sickling. The EPCs of SCD patients showed higher tolerance to memantine than those of healthy subjects. Consequently, NMDARs in the RBCs of SCD patients appear to be an attractive target for pharmacological intervention.

Impact of β-globin mutations on outcome of matched related donor hematopoietic stem cell transplantation for patients with β-thalassemia major

The clinical outcome of hematopoietic stem cell transplantation (HSCT) for patients with β-thalassemia major (β-TM) can be affected by several factors. We investigated the influence of β-globin gene mutation in patients with β-TM on the clinical outcome of HSCT and conducted a prospective study of consecutive β-TM patients who underwent allogeneic HSCT at our center. Among 87 included patients, 62 (71%) had homozygous and 25 (29%) had compound heterozygous β-globin gene mutations. Intervening sequence II-1 appeared to be the most common mutation, with an occurrence rate of 33% in β-globin alleles. With a median follow-up of 12 months, the thalassemia-free survival and overall survival probabilities were 83% (standard error, 4%) and 90% (standard error, 3%), respectively. Overall survival was not found to be associated with the β-globin gene mutation status, but thalassemia-free survival was significantly improved in patients with homozygous mutations compared with patients with compound heterozygous mutations in univariate (91.2% versus 64.0%, P = .009) and multivariable (hazard ratio, 3.83; P = .014) analyses. This is the first report on the impact of β-globin mutation status on the outcome of β-TM after allogeneic HSCT and helps to better illustrate the course and prognosis of β-TM after transplantation.

Reduced toxicity, myeloablative conditioning with BU, fludarabine, alemtuzumab and SCT from sibling donors in children with sickle cell disease

BU and CY (BU/CY; 200 mg/kg) before HLA-matched sibling allo-SCT in children with sickle cell disease (SCD) is associated with ~85% EFS but is limited by the acute and late effects of BU/CY myeloablative conditioning. Alternatives include reduced toxicity but more immunosuppressive conditioning. We investigated in a prospective single institutional study, the safety and efficacy of a reduced-toxicity conditioning (RTC) regimen of BU 12.8-16 mg/kg, fludarabine 180 mg/m(2), alemtuzumab 54 mg/m(2) (BFA) before HLA-matched sibling donor transplantation in pediatric recipients with symptomatic SCD. Eighteen patients, median age 8.9 years (2.3-20.2), M/F 15/3, 15 sibling BM and 3 sibling cord blood (CB) were transplanted. Mean whole blood and erythroid donor chimerism was 91% and 88%, at days +100 and +365, respectively. Probability of grade II-IV acute GVHD was 17%. Two-year EFS and OS were both 100%. Neurological, pulmonary and cardiovascular function were stable or improved at 2 years. BFA RTC and HLA-matched sibling BM and CB allo-SCT in pediatric recipients result in excellent EFS, long-term donor chimerism, low incidence of GVHD and stable/improved organ function.

A call for policy action in sub-Saharan Africa to rethink diagnostics for pregnancy affected by sickle cell disease: differential views of medical doctors, parents and adult patients predict value conflicts in Cameroon

Sickle cell disease (SCD) is a debilitating illness that affects the life expectancy of patients. It is possible to test for SCD before birth, to allow for reproductive options to parents. However, under Cameroonian Law, voluntary abortion is a criminal offense and medical abortion is permitted only "…if it is done by an authorized professional and justified by the need to save the mother from grave health jeopardy." The objective of the present study was to compare the views of Cameroonian doctors, parents with at least one living SCD-affected child, and adult SCD patients, regarding prenatal genetic diagnosis and termination of SCD-affected pregnancy. We conducted a quantitative sociological survey of 110 doctors, 130 parents, and 89 adult patients. The majority accepted the prenatal genetic diagnosis for SCD (78.7%, 89.8%, and 89.2%, respectively). Parents (62.5%) were more in favor of termination of SCD-affected pregnancy, than doctors and adults patients (36.1% and 40.9% acceptance, respectively). Parents and patients who found medical abortion acceptable cited fear to have a SCD-affected child (98.1 and 88.9%) and the poor quality of the affected child's health (92.6% and 81.5%). The data underscore the urgency of policy action to place emphasis on: premarital screening, early detection and care of SCD, socio-economic measures to assist SCD-affected families, appropriateness to consider maternal distress due to fetal anomalies in medical abortion legislation. These novel findings signal potential value-based conflicts on the horizon, and can usefully inform the future policy actions in the African continent as OMICS biotechnologies are increasingly employed in global health. To the best of our knowledge, the present study is the first attempt in sub-Saharan Africa to attempt to triangulate the views of multiple stakeholders towards prenatal diagnosis of SCD and termination of an affected pregnancy.

Psychosocial stressors of sickle cell disease on adult patients in Cameroon

Sickle Cell Disease (SCD) is a debilitating illness that affects quality of life. Studies of the psychosocial burden of SCD on patients have been rarely reported in Africa. We used a quantitative method, with face-to-face administered questionnaires, to study indices of psychosocial stressors on adult SCD patients in Cameroon. The questionnaire included a 36-item stress factors scale evaluating general perceptions of stress and five main stressors' domain: disease factors, hospital factors, financial factors, family factors and quality of personal-life factors. Items pertaining to psychosocial stressors involved four response options with increasing severity: 0, 1, 2 or 3. Non-parametric tests were used for analysis. The majority of the 83 participants were urban dwellers, female, 20-30 years old, single, unemployed, with at least a secondary or tertiary education. Median age at diagnosis was 100 months; 47.8% had >3 painful vaso-oclusive crises annually. Only 4.8% had been treated with hydroxyurea. The majority reported moderate to severe difficulty coping with SCD. The "degree of clinical severity" category displayed the highest median score (2.0), while familial stressors showed the lowest (0.8). Being female, married, with low education level, an additional affected sibling and low direct income were significantly associated with specific stressors' categories. In Cameroon, there is an urgent need to implement policies that ensure affordable access to health-care and practices to reduce SCD morbidity and improve patients' quality of life.

Haematopoietic stem cell transplantation for severe sickle cell disease in childhood: a single centre experience of 50 patients

Despite improvements in medical management, sickle cell disease (SCD) remains associated with severe morbidity and decreased survival. Allogeneic haematopoietic stem cell transplantation (HSCT) remains the only curative approach. We report the outcome of 50 consecutive children with severe SCD that received HSCT in our unit between November 1988 and April 2013. The stem cell source was bone marrow (n = 39), cord blood (n = 3), bone marrow and cord blood (n = 7) and peripheral blood stem cells (n = 1). All patients had ≥1 severe manifestation: 37 presented with recurrent vaso-occlusive crises/acute chest syndrome, 27 cerebral vasculopathy and 1 nephropathy. The conditioning regimen consisted of busulfan + cyclophosphamide (BuCy) before November 1991 and BuCy + rabbit antithymocyte globulin after that date. Since 1995, all patients have been treated with hydroxycarbamide (HC) prior to transplantation for a median duration of 2·7 years. Median age at transplantation and median follow-up was 8·3 and 7·7 years, respectively. Acute graft-versus-host disease (GVHD) and chronic GVHD were observed in 11 and 10 patients, respectively. An excellent outcome was achieved, with 8-year overall survival and event-free survival (EFS) rates of 94·1% and 85·6%, respectively. Since HC introduction, no graft failure occurred and EFS reached 97·4%. Prior treatment with HC may have contributed to successful engraftment.

Hemoglobin disorders: a look to the future

In this issue of Blood, Locatelli et al compare the results of histocompatible family donor bone marrow and cord blood transplants (BMT and CBT) for severe β thalassemia (SBT) and sickle cell disease (SCD) as experienced by the Eurocord and European Blood and Marrow Transplantation group and collaborating centers in the United States, Hong Kong, and Israel between 1994 and 2005. Obviously, many changes in medical care and particularly MHC typing occurred over that decade, so this retrospective represents a moving target, but some firm points can be made for which we are indebted to this excellent group.

Allogeneic transplantation strategies including haploidentical transplantation in sickle cell disease

Sickle cell disease (SCD) is the most common inherited hemoglobinopathy. Despite antenatal counseling and neonatal screening programs implemented in higher income countries, SCD is still associated with multiple morbidities and early mortality. To date, the only curative approach to SCD is hematopoietic stem cell transplantation, but this therapy is not yet established worldwide. The registries of the European Blood and Marrow Transplant (EBMT) and the Centre for International Blood and Marrow Transplant Research (CIBMTR) account, respectively, for 611 and 627 patients receiving transplantations for SCD. Most of these patients were transplanted with grafts from an HLA-identical sibling donor. The main obstacles to increasing the number of transplantations are a lack of awareness on the part of physicians and families, the absence of reliable prognostic factors for severity, and the perceived risk that transplantation complications may outweigh the benefits of early transplantation. Results show that more than 90% of patients having undergone an HLA-identical sibling transplantation after myeloablative conditioning are cured, with very limited complications. Major improvement is expected from the use of new reduced-toxicity conditioning regimens and the use of alternative donors, including unrelated cord blood transplantations and related haploidentical bone marrow or peripheral blood stem cell transplantations.