Acquired aplastic anemia in children

Diagnosis and management of acquired aplastic anemia in childhood. Guidelines from the Marrow Failure Study Group of the Pediatric Haemato-Oncology Italian Association (AIEOP)

Acquired aplastic anemia (AA) is a rare heterogeneous disorder characterized by pancytopenia and hypoplastic bone marrow. The incidence is 2-3 per million population per year in the Western world, but 3 times higher in East Asia. Survival in severe aplastic anemia (SAA) has improved significantly due to advances in hematopoietic stem cell transplantation (HSCT), immunosuppressive therapy, biologic agents, and supportive care. In SAA, HSCT from a matched sibling donor (MSD) is the first-line treatment. If a MSD is not available, options include immunosuppressive therapy (IST), matched unrelated donor, or haploidentical HSCT. The purpose of this guideline is to provide health care professionals with clear guidance on the diagnosis and management of pediatric patients with AA. A preliminary evidence-based document prepared by a group of pediatric hematologists of the Bone Marrow Failure Study Group of the Italian Association of Pediatric Hemato-Oncology (AIEOP) was discussed, modified and approved during a series of consensus conferences that started online during COVID 19 and continued in the following years, according to procedures previously validated by the AIEOP Board of Directors.

Unrelated umbilical cord blood transplantation with low-dose anti-thymocyte globulin for children with severe aplastic anemia: A case series

OBJECTIVE

This study aimed to investigate the prognosis of unrelated umbilical cord blood transplantation (UCBT) using low-dose anti-thymocyte globulin (ATG) in children diagnosed with severe aplastic anemia (SAA).

METHODS

This retrospective case series study was conducted involving pediatric SAA patients treated at the Capital Institute of Pediatrics from January 2020 to February 2023. All patients underwent a reduced-intensity conditioning (RIC) regimen alongside low-dose ATG.

RESULTS

The study comprised nine patients (five males) with a median age of 5 years (range: 1.7 to 7 years). The median follow-up duration was 799 days (range: 367 to 1481 days), during which all patients survived. The median time interval from diagnosis to transplantation was 3 months (range: 1 to 9 months). The median dosage of ATG administered was 5 mg/kg (range: 2.5 to 7.5 mg/kg). The median durations for granulocyte and platelet engraftment were 15 days (range: 12 to 23 days) and 26 days (range: 12 to 41 days), respectively. Three patients experienced grade 2-4 acute graft-versus-host disease (aGVHD). Epstein-Barr virus (EBV) reactivation was observed in three patients, while cytomegalovirus (CMV) reactivation occurred in seven patients, with no cases of CMV disease or post-transplant lymphoproliferative disorder (PTLD). One patient experienced recurrence 15 months after transplantation due to influenza A infection.

CONCLUSION

These findings indicate that SAA patients may attain a favorable prognosis following UCBT with a RIC regimen combined with low-dose ATG.

Eltrombopag combined with immunosuppressive therapy for pediatric severe aplastic anemia

BACKGROUND

Severe aplastic anemia (SAA) is caused by immune-mediated destruction. Standard immunosuppressive therapy (IST) is effective but needs to be improved.

METHODS

The data of patients with SAA and received IST were analyzed retrospectively to conducted this historical control study.

RESULTS

A total of 115 SAA patients (60 males; median age of 5.77 years and median follow-up time of 45 months) were enrolled in this study. The complete response rates (CRR) of the eltrombopag group at 3 and 6 months were higher than the control group (30.3% vs.8.2% at 3 months; 50.0% vs. 10.2% at 6 months). The overall response rates (ORR) showed no differences. There were significant differences in the times from G-CSF, Red blood cell transfusion, and Platelet transfusion between the two groups. No difference in overall survival (OS), event-free survival (EFS), and relapse rate between two groups. There is no variable were associated with prognosis in both groups.

CONCLUSION

Addition of eltrombopag to IST confers faster hematological response and higher early hematological response in pediatric SAA patients.

IMPACT

Addition of eltrombopag to standard immunosuppressive therapy confers faster hematological response and higher early hematological response in pediatric severe aplastic anemia patients. Eltrombopag showed reliable safety but had no impact on long-term response and prognosis. This article is a historical controlled study consisting of 115 pediatric severe aplastic anemia patients and makes up for the lack of clinical data deficient on pediatric severe aplastic anemia with TPO-RA combined with IST.

Clinical Signs and Treatment of New-Onset Bone Marrow Failure Associated SARS-CoV-2 Infection in Children: A Single Institution Prospective Cohort Study

Background

Viral infections can cause direct and indirect damage to hematopoietic stem cells. The objectives of this study were to identify the frequency and severity of aplastic anemia in children infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) as well as recognize the response to treatment.

Methodology

13 children with newly diagnosed severe aplastic anemia were enrolled in this prospective clinical trial. Blood samples were obtained from all patients to detect SARS-CoV-2 antibodies, and nasopharyngeal swabs were collected for reverse-transcription Polymerase Chain Reaction to detect SARS-CoV-2 viruses. According to the laboratory results, patients were classified as having SARS-CoV-2 positive antibodies and SARS-CoV-2 negative antibodies. Both groups received combined cyclosporine (CsA) + Eltrombopag (E-PAG). The hematological response, either complete response (CR) or partial response (PR), no response (NR), and overall response (OR) rates of combined E-PAG + CsA treatment after 6 months were evaluated.

Results

Four children were recognized to have aplastic anemia and SARS-CoV-2 positive antibodies. Two patients fulfilled the hematological criteria for CR and no longer required transfusion of packed red blood cells (PRBCs) or platelets, and one had PR and was still PRBC transfusion-dependent but no longer required platelet transfusion. The remaining patient showed NR, and he had died before reaching the top of the HSCT waiting list. Moreover, six patients in the SARS-CoV-2 negative antibodies group had CR, while three patients had PR. The difference in ANC, Hg, and platelet counts between both groups was not significant.

Conclusion

The SARS-CoV-2 virus is added to several viral infections known to be implicated in the pathogenesis of aplastic anemia. Studies are needed to establish a definitive association and determine whether the response of bone marrow failure to standard therapy differs from that of idiopathic cases.

Acquired aplastic anaemia after SARS-CoV-2 infection in China: a case report

Since the coronavirus disease 2019 (COVID-19) pandemic began, several research groups in different countries have described cases of aplastic anaemia (AA) after COVID-19 or COVID-19 vaccination. Here, we present the case of a patient with new-onset AA in Changsha, China, that was presumably associated with preceding severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. We conducted an epidemiological assessment of the incidence rate of blood system diseases from July 1, 2022, to May 31, 2023, in the haematology department of the Second Xiangya Hospital of Central South University and Hunan Children's Hospital. The detection rates of AA and leukaemia in the first two months after the epidemic outbreak were higher than those before and during the outbreak. However, only the difference in the detection rate of leukaemia was statistically significant.

Alternative treatment modality for severe aplastic anemia in a resource-limited setting: a single-institution prospective cohort study from Upper Egypt

This study compared the efficacy and safety of CsA monotherapy with eltrombopag (E-PAG) + CsA combined treatment in children with severe aplastic anemia (SAA). The study including 30 children had SAA. Ten were a retrospective cohort treated with CsA monotherapy. The other 20 were prospective cohort received E-PAG + CsA. All patients were evaluated for partial (PR) and complete (CR) hematological response at 3, 6, and 12 months. overall response (OR), overall survival rates (OS), and treatment safety. OR for the E-PAG patients was 40% after 3 months of therapy. At 6 months, this had increased to 75% with significantly higher CR rate (40%) than in the CsA group (p = 0.0001). After a year of treatment, the CR for the E-PAG + CsA regimen had increased to 50% and the OR to 85%, compared to 20% in the CsA group (p = 0.0001). The OS at 12 months was 100% in the E-PAG+ CsA group compared to 80% in the CsA cohort. At 24 months, the OS in the E-PAG + CsA group was 90%. In conclusion, E-PAG+ CsA was found to be a safe and effective alternative treatment for children with SAA particularly in countries with limited resources.

Inherited bone marrow failure syndromes and germline predisposition to myeloid neoplasia: A practical approach for the pathologist

The diagnostic work up and surveillance of germline disorders of bone marrow failure and predisposition to myeloid malignancy is complex and involves correlation between clinical findings, laboratory and genetic studies, and bone marrow histopathology. The rarity of these disorders and the overlap of clinical and pathologic features between primary and secondary causes of bone marrow failure, acquired aplastic anemia, and myelodysplastic syndrome may result in diagnostic uncertainty. With an emphasis on the pathologist's perspective, we review diagnostically useful features of germline disorders including Fanconi anemia, Shwachman-Diamond syndrome, telomere biology disorders, severe congenital neutropenia, GATA2 deficiency, SAMD9/SAMD9L diseases, Diamond-Blackfan anemia, and acquired aplastic anemia. We discuss the distinction between baseline morphologic and genetic findings of these disorders and features that raise concern for the development of myelodysplastic syndrome.

Interplay Effect of Splenic Motion for Total Lymphoid Irradiation in Pediatric Proton Therapy

(1) Background: The most significant cause of an unacceptable deviation from the planned dose during respiratory motion is the interplay effect. We examined the correlation between the magnitude of splenic motion and its impact on plan quality for total lymphoid irradiation (TLI); (2) Methods: Static and 4D CT images from ten patients were used for interplay effect simulations. Patients' original plans were optimized based on the average CT extracted from the 4D CT and planned with two posterior beams using scenario-based optimization (±3 mm of setup and ±3% of range uncertainty) and gradient matching at the level of mid-spleen. Dynamically accumulated 4D doses (interplay effect dose) were calculated based on the time-dependent delivery sequence of radiation fluence across all phases of the 4D CT. Dose volume parameters for each simulated treatment delivery were evaluated for plan quality; (3) Results: Peak-to-peak splenic motion (≤12 mm) was measured from the 4D CT of ten patients. Interplay effect simulations revealed that the ITV coverage of the spleen remained within the protocol tolerance for splenic motion, ≤8 mm. The D100% coverage for ITV spleen decreased from 95.0% (nominal plan) to 89.3% with 10 mm and 87.2% with 12 mm of splenic motion; (4) Conclusions: 4D plan evaluation and robust optimization may overcome problems associated with respiratory motion in proton TLI treatments. Patient-specific respiratory motion evaluations are essential to confirming adequate dosimetric coverage when proton therapy is utilized.

Busulfan for Allogeneic Hematopoietic Stem Cell Transplantation in Children with Severe Aplastic Anemia: A Retrospective Study

INTRODUCTION

This retrospective study aimed to compare a range of conditioning regimens in children with severe aplastic anemia (SAA) undergoing allogeneic hematopoietic stem cell transplantation (allo-HSCT) at the Seventh Medical Center of PLA General Hospital between January 2008 and June 2017.

METHODS

Patients were categorized into the Bu (Bu + Flu + Cy + ATG-F regimen) and control (Flu + Cy + ATG-F) groups, with a median follow-up time after HSCT of 3.5 (range, 3.1-6.2) and 3.7 (3.2-5.9) years in the Bu and control groups, respectively.

RESULTS

No differences were observed between the two groups regarding the median time of peripheral blood neutrophil and platelet engraftment (p = 0.538 and p = 0.491); the 28-day engraftment rates of neutrophils were similar (p = 0.199), although higher for platelets with Bu (p = 0.044). Additionally, graft failure was 0% and 20.0% in the Bu and control groups, respectively (p = 0.004). In both groups, the incidence of grades III-IV (or grades II-IV) acute graft-versus-host disease (GVHD) and chronic GVHD was not significantly different (p > 0.05). Moreover, the 3-year overall survival and failure-free survival did not show significant differences (p = 0.670 and p = 0.908).

DISCUSSION

In children with SAA undergoing allo-HSCT, conditioning regimen with Bu + Flu + Cy + ATG-F is capable of enhancing the myeloablation effect, promoting donor hematopoietic stem cell engraftment, and reducing the graft failure rate. Furthermore, it does not increase the incidence of complications, including GVHD.

Outcomes and risk factors of hemorrhagic cystitis in pediatric allogeneic hematopoietic stem cell transplantation recipients using different graft source and condition with severe aplastic anemia

BACKGROUND

Hemorrhagic cystitis (HC) is a severe complication of allo-HSCT, characterized by irritative symptoms of the urinary tract and a higher morbidity rate. The risk factors and prognosis of HC are still unclear.

OBJECTIVE

The objective of this study is to identify risk factors and outcomes to improve treatment in pediatric SAA patients undergoing HSCTs in the Children's Hospital of Soochow University.

METHODS

A total of 97 SAA patients as a cohort were enrolled from 2010 to 2019 in the Children's Hospital of Soochow University and a number of factors related to HC and outcomes were analysed. In all transplants (except UCBT), patients received a combination of G-CSF stimulated bone marrow (BM) and peripheral blood stem cell (PBSC). The minimum number of CD34 + cells is 5 × 10⁶ cells/kg.

RESULTS

Mononuclear cells dose (MNC, cut off: 8.53 × 10⁸/kg) and grade II-IV acute graft versus host disease (aGVHD) were identified as independent risk factors for HC. Patients without HC had better overall survival (OS) than with HC (No HC: 98.6%±1.4% vs HC: 87.4% ± 6.8%, p = 0.03).

CONCLUSION

We concluded that aGVHD and MNC dose in graft might play an important role in the development of HC in pediatric SAA patients undergoing allo-HSCT. HC is also a key complication affecting the prognosis of children with SAA after allo-HSCT.

Association between haploidentical hematopoietic stem cell transplantation combined with an umbilical cord blood unit and graft-versus-host disease in pediatric patients with acquired severe aplastic anemia

Background:

Haploidentical hematopoietic stem cell transplantation (haplo-HSCT) based on granulocyte colony-stimulating factor plus anti-thymocyte regimens (‘Beijing Protocol’) provides a salvage treatment for patients of acquired severe aplastic anemia (SAA) in China. However, graft-versus-host disease (GVHD) is a major impediment of haplo-HSCT due to human leukocyte antigen disparity. Recently, haplo-HSCT combined with umbilical cord blood (UCB) (haplo-cord HSCT) is performed in clinical trials to potentially reduce the risk of severe GVHD. Nevertheless, studies comparing GVHD in pediatric patients receiving haplo and haplo-cord HSCT for SAA are limited.

Objective:

The objective of this study was to investigate the impact of UCB co-infusion on GVHD in pediatric patients receiving haplo-HSCT for SAA.

Design:

We conducted a retrospective study of 91 consecutive SAA children undergoing haploidentical transplantation based on the ‘Beijing Protocol’ with or without co-infusion of UCB in our center.

Methods:

All patients received uniform non-myeloablative conditioning and GVHD prophylaxis. We compared baseline characteristics and transplant outcomes between the haplo (n = 35) and haplo-cord (n = 56) recipients.

Results:

All 91 patients achieved hematopoietic recovery from haploidentical donors, with a higher incidence of peri-engraftment syndrome observed with the haplo-cord group as compared with the haplo group (75.0% versus 48.6%, p = 0.029). Notably, the haplo-cord group showed a lower incidence of II–IV acute GVHD (aGVHD) than the haplo group (16.1% versus 42.9%, p = 0.002). Observed incidences of chronic GVHD (cGVHD) and moderate to severe cGVHD in the haplo-cord group were also lower than that in the haplo group (25.6% versus 51.3%, p = 0.019; 16.2% versus 41.3%, p = 0.016, respectively). Haplo-cord HSCT was identified as the only factor associated with a lower incidence of II–IV aGVHD and cGVHD in multivariate analysis. However, no differences were observed between the two groups for infections and survival outcomes.

Conclusion:

Our data indicated that co-infusion of UCB in ‘Beijing Protocol’-based haplo-HSCT may be effective for reducing the risk of severe GVHD in SAA children.

Use of blood and its components in the treatment of anaemia in children

Blood transfusion is a well-established treatment for anaemia. Herein, blood and its components are transfused to replenish circulating blood volume, maintain the oxygen capacity of the blood and normalise the function of the coagulation system. Anaemia treatment by blood transfusions is a great challenge, especially with reference to paediatric patients. Blood is irreplaceable in a life-threatening situation, but it has its own side effects, just like all applied pharmacological products. Hence, it is extremely important to carefully select donors and utilise blood components according to the patient’s individual needs. Children represent a group that requires specific criteria to be met, mainly because of the fact that their physiological and haematological systems differ from those of adults. The most common types of anaemia seen in children are deficiency anaemias such as iron-deficiency anaemia, while less common are vitamin B12 deficiency anaemia or folate deficiency anaemia. Secondary anaemia is also relatively frequent in chronic diseases, among others, immunological or infectious, as well as renal, liver, endocrine and neoplastic diseases. Anaemia due to blood loss is also included in this group. Furthermore, some anaemias, such as aplastic anaemia (due to impaired erythrocyte production) and haemolytic anaemia (due to excessive destruction of red blood cells) may be congenital or acquired. Before deciding to implement blood therapy, the patient’s clinical condition or the different haematological, biochemical and immunological parameters at different stages of life should be considered. Since each transfusion may result in a variety of post-transfusion reactions, immunisation or transmission of infectious diseases, the decision to transfuse blood or blood components should be taken only when the patient cannot be treated effectively by any other means and the expected benefits of the transfusion outweigh the risks associated with possible complications. Considering the recipients’ low blood volume, low metabolic efficiency, higher haematocrit levels than in adults and immature immune system, products for these patients should be prepared in a special way. These components must ensure minimal risk of metabolic and haemostatic disorders. The collection of these products, as well as their preparation, storage and transfusion, should be carried out in accordance with current legislation.

Diagnostic Value of a Protocolized In-Depth Evaluation of Pediatric Bone Marrow Failure: A Multi-Center Prospective Cohort Study

Background

Severe multilineage cytopenia in childhood caused by bone marrow failure (BMF) often represents a serious condition requiring specific management. Patients are at risk for invasive infections and bleeding complications. Previous studies report low rates of identifiable causes of pediatric BMF, rendering most patients with a descriptive diagnosis such as aplastic anemia (AA).

Methods

We conducted a multi-center prospective cohort study in which an extensive diagnostic approach for pediatric patients with suspected BMF was implemented. After exclusion of malignant and transient causes of BMF, patients entered thorough diagnostic evaluation including bone marrow analysis, whole exome sequencing (WES) including copy number variation (CNV) analysis and/or single nucleotide polymorphisms (SNP) array analysis. In addition, functional and immunological evaluation were performed. Here we report the outcomes of the first 50 patients (2017-2021) evaluated by this approach.

Results

In 20 patients (40%) a causative diagnosis was made. In this group, 18 diagnoses were established by genetic analysis, including 14 mutations and 4 chromosomal deletions. The 2 remaining patients had short telomeres while no causative genetic defect was found. Of the remaining 30 patients (60%), 21 were diagnosed with severe aplastic anemia (SAA) based on peripheral multi-lineage cytopenia and hypoplastic bone marrow, and 9 were classified as unexplained cytopenia without bone marrow hypoplasia. In total 28 patients had undergone hematopoietic stem cell transplantation (HSCT) of which 22 patients with an unknown cause and 6 patients with an identified cause for BMF.

Conclusion

We conclude that a standardized in-depth diagnostic protocol as presented here, can increase the frequency of identifiable causes within the heterogeneous group of pediatric BMF. We underline the importance of full genetic analysis complemented by functional tests of all patients as genetic causes are not limited to patients with typical (syndromal) clinical characteristics beyond cytopenia. In addition, it is of importance to apply genome wide genetic analysis, since defects in novel genes are frequently discovered in this group. Identification of a causal abnormality consequently has implications for the choice of treatment and in some cases prevention of invasive therapies.

Cyclosporine Monotherapy in Pediatric Patients With Non-severe Aplastic Anemia: A Retrospective Analysis

Objective

The management of children with non-severe aplastic anemia (NSAA) is undefined and the efficacies and benefits of immunosuppressive therapy remain inconsistent. The study aimed to investigate the efficacy of Cyclosporine (CsA) monotherapy for pediatric NSAA.

Methods

Clinical data of children with NSAA who had been treated with CsA monotherapy at the outpatient department of Beijing Children's Hospital, Capital Medical University, National Children's Medical Center from January 2017 to March 2021 was collected retrospectively. Patients who had been treated <1 years until the end of follow-up were excluded. Transfusion-independent NSAA was further divided into moderate NSAA and mild NSAA according to the degree of cytopenia. Progression was defined as the development of transfusion-dependent AA or SAA and relapse was considered when treatment failed after initial response.

Results

A total of 95 pediatric patients with NSAA were enrolled in this study with 49 (51.6%) patients confirmed as mild NSAA, 38 (40%) as moderate NSAA and 8 (8.4%) as transfusion-dependent NSAA. The median treatment time of CsA was 22 (12–44) months. The overall response rate (ORR) was 57.9%, with 30.5% CR and 27.4% PR. Unexpectedly, patients with mild NSAA acquired lowest ORR (46.9%), then patients with moderate NSAA (63.2%), while 8 patients who were transfusion-dependent all had an active response to CsA. The granulocyte and megakaryocyte response was 46.9 and 55.8% respectively, while the erythrocyte response rate was as low as 22.5%. Univariate analyses revealed that patients with lower platelet count and higher interleukin 10 level predict an active response to CsA while higher level of fetal hemoglobin (HbF) tended to be a negative factor. Data of Treg cells before and after 1 year's treatment was available in a total number of 40 patients. Paired comparison found that the percentage of Treg cells in CD4+ T cells was decreased after 1 year's treatment of CsA (6.78 ± 2.72 vs. 5.23 ± 2.06, P = 0.001),both in responders and non-responders. The degree of decline in Treg cells between two distinctive response groups had no significant difference (P>0.05). With a median follow-up time of 22 months, 10.9% of responders relapsed and maintained NSAA while 27.5% of non-responders progressed to SAA or became transfusion-dependent. The overall progression rate was 11.6%.

Conclusion

CsA monotherapy had heterogeneous effects in the treatment of children NSAA Treatment approaches should be hierarchical and individual in clinical. Patients with lower platelet count and higher interleukin 10 level predicted an active response to CsA. While higher level of fetal hemoglobin (HbF) tended to be a negative factor. The percentage of Treg cells in CD4+ T cells was decreased broadly after treatment.

Effect of Wuzhi capsules on cyclosporine A concentration in children with aplastic anemia immunotherapy: a single-center observational study

OBJECTIVE

This research aimed to assess the effect of Wuzhi capsules (WZC) on the blood concentration of cyclosporine A (CsA) in renal aplastic anemia recipients.

METHODS

: This observational study was carried out at the Hematology Oncology Center, Beijing Children's Hospital between November 2019 and February 2020. A total of 102 Chinese AA recipients receiving CsA (6mg/kg/d) with or without WZC were included in this study. Baseline data, such as age, therapeutic drug monitoring data, and follow-up information were collected. The promotion concentration of CsA was calculated, and the pharmaceutical economics evaluation with combination of two drugs was also carried out.

RESULTS

: Dose- and body weight-adjusted trough concentrations (C₀/D/W) of CsA in the WZC group were found to be significantly higher than that in the non-WZC group (P<0.01). The average C₀ of CsA increased by (63.27±45.81) ng/mL. The incidence of adverse events was also not statistically significant between the two groups (P>0.05).

CONCLUSION

:WZC can increase CsA concentration without increasing adverse drug reactions. Efficient and convenient immunosuppressive effects on AA recipients can be achieved via immunosuppressant therapy in combination with WZC.

Hepatitis-Associated Aplastic Anemia: Etiology, Clinical Characteristics and Outcome

Hepatitis-associated aplastic anemia (HAA) is a form of acquired aplastic anemia (AA) in which bone marrow failure develops after an acute attack of hepatitis. Bone marrow failure leading to AA is generally severe in cases of HAA and fatal if left untreated. This retrospective multicenter study investigated clinical and laboratory characteristics, possible causes, treatment, and outcome of HAA in children. Twenty patients from 8 centers were included in the study. Aspartate aminotransferase and alanine aminotransferase were <3 to 5×upper limit of normal (ULN) in 2 patients, <5 to 10×ULN in 2 patients, and >10×ULN in 16 patients. Acute liver failure developed in 5 (29%) patients. Pancytopenia was simultaneously present in 6 of 20 (30%) patients. Eleven of the 20 patients (55%) were alive, in remission and transfusion free. Those who were alive either had undergone hematopoietic stem cell transplantation and/or immunosuppressive treatment, except 1 patient who had received no treatment. Patients with the diagnosis of acute hepatitis should be evaluated and followed up carefully for presence of cytopenia, so that definitive treatment of AA can be initiated in a timely and appropriate manner when needed.

First-line haploidentical stem cell transplantation in children and adolescents with severe aplastic anemia using mobilized peripheral blood as source of CD34+: Single-institutional experience in a transplant center from northeast Mexico

INTRODUCTION

The only curative treatment for severe aplastic anemia in children is an allogeneic stem cell transplant; however, few patients have a matched related or unrelated donor. Haploidentical stem cell transplantation (haplo-SCT) using bone marrow (BM) and peripheral blood stem cells (PBSC) has been recently described as effective and safe. In this study, we retrospectively report the outcome of twelve pediatric patients who underwent haplo-SCT using only PBSC.

METHODS

The conditioning regimen consisted on rabbit anti-thymocyte globulin (r-ATG) 2.5 mg/kg/d on days -7, -6,-5, and -4, and cyclophosphamide (Cy) 50 mg/kg/d on days -3 and -2. We used Cy 50 mg/kg/d on days +3 and +4, tacrolimus and mycophenolic acid as graft versus host disease (GVHD) prophylaxis.

RESULTS

The median follow-up was 1,099 days (45-1258 days). The overall survival rate up-to-date is 83.3%. In 10 of the 12 patients, a sustained graft was achieved. None of the patients had acute or chronic GVHD.

CONCLUSIONS

Haplo-SCT could be established as a first-line treatment when there is no matched related or unrelated donor. According to this short sample and previous reports, PBSC are a feasible option effectively used as the sole source of stem cells. Additionally, post-transplant cyclophosphamide remains a good strategy for GVHD prevention.

Diagnostic work-up for severe aplastic anemia in children: Consensus of the North American Pediatric Aplastic Anemia Consortium

The North American Pediatric Aplastic Anemia Consortium (NAPAAC) is a group of pediatric hematologist-oncologists, hematopathologists, and bone marrow transplant physicians from 46 institutions in North America with interest and expertise in aplastic anemia, inherited bone marrow failure syndromes, and myelodysplastic syndromes. The NAPAAC Bone Marrow Failure Diagnosis and Care Guidelines Working Group was established with the charge of harmonizing the approach to the diagnostic workup of aplastic anemia in an effort to standardize best practices in the field. This document outlines the rationale for initial evaluations in pediatric patients presenting with signs and symptoms concerning for severe aplastic anemia.

Efficacy and safety of eltrombopag in the first-line therapy of severe aplastic anemia in children

Eltrombopag is being investigated for the treatment of aplastic anemia (AA) by stimulating hematopoietic stem cell (HSC) proliferation. To evaluate the efficacy and safety of eltrombopag in the first-line therapy of pediatric AA. The present retrospective study assessed pediatric patients with newly diagnosed AA administered immunosuppressive therapy (IST) (rabbit ATG combined with CSA) with eltrombopag at a single center from March to September 2017. All patients were followed up for >2 years. A total of 14 patients (8 males), averagely aged 86 months, were enrolled in this study. Eltrombopag was administered with a median time to initiation of 19.5 days after IST; the median course of treatment was 253 days. Complete and overall response rates at 6 months were 64.3% (9/14 case) and 78.6% (11/14 cases), respectively. The survival rate was 100%, and no relapse occurred in responders. Eltrombopag was well-tolerated; however, the most common adverse events included indirect bilirubin elevation, jaundice, and transient liver-enzyme elevation. By the end of follow-up, bone marrow chromosomes were normal, and no abnormal myelodysplastic syndrome (MDS)-related clones appeared. Addition of eltrombopag to IST is associated with markedly increased complete response with respect to hematology in pediatric patients with SAA compared with a historical cohort, without intolerable side effects.

Allogeneic Hematopoietic Stem Cell Transplant Offer Good Outcomes in Pediatric Aplastic Anemia: Experience From Developing World

Between 2014 and 2020, 31 patients with severe aplastic anemia (SAA) underwent full match allogeneic hematopoietic stem cell transplantation at our center. Of the 31 patients with SAA, 19 had acquired aplastic anemia, 2 had Diamond Blackfan anemia and 10 had Fanconi anemia. Donors were either matched sibling (n=29), related donors (n=2), or unrelated donors (n=3). Peripheral blood stem cells were the graft source in all the cases except 1. Fludarabine-based reduced intensity conditioning was used in all except for patients with a diagnosis of Diamond Blackfan anemia. All patients except 1 achieved hematologic recovery in the form of neutrophil engraftment at 13 days (range, 9 to 17), whereas platelet engraftment occurred at 14 days (range, 10 to 18). Graft versus host disease (GvHD) prophylaxis consisted of cyclosporine and methotrexate ±antithymocyte globulin (horse/rabbit). Acute GvHD developed in 12.9% patients, whereas no patients developed chronic GvHD till the time of last follow-up. The 2-year overall survival for the entire cohort was 93.21±4.6%. In patients with SAA, allogeneic stem cell transplant using fludarabine-based conditioning regimens are very well tolerated and have excellent outcomes in a full match setting.

Atypical Outcomes for Hepatitis-associated Acquired Aplastic Anemia: 2 Case Studies and Review of the Literature

There is little data specifically dedicated to the long-term outcomes of the hepatitis-associated variant of aplastic anemia (HAAA). A majority of patients with nonsevere (moderate) aplastic anemia progress to severe aplastic anemia, and severe aplastic anemia typically results in death if left untreated. We present 2 unique cases of HAAA that contribute to our knowledge of the natural history of this disease variant. One patient had moderate HAAA that never progressed to severe disease. The second patient had severe HAAA that spontaneously resolved without treatment. The rare possibility of moderate HAAA failing to progress to fulfill severe criteria, or of severe HAAA spontaneously improving, may complicate early treatment decisions for some patients.

Postvaccination graft dysfunction/aplastic anemia relapse with massive clonal expansion of autologous CD8+ lymphocytes

Acquired aplastic anemia is a T-cell–mediated autoimmune bone marrow aplasia, without a known etiologic trigger. Clonal expansion of CD8+ effector T lymphocytes can occur following vaccination and accompany graft dysfunction or aplastic anemia relapse.

Efficacy of Rabbit Antithymocyte Globulin as a First-line Therapy in Children With Aplastic Anemia

BACKGROUND

The efficacy, safety, and outcome of rabbit antihuman thymocyte globulin (rATG) as initial therapy for children aplastic anemia (AA) were evaluated.

PATIENTS AND METHODS

Sixty-one children with AA were retrospectively analyzed, including 43 patients with severe AA and 18 patients with transfusion-dependent nonsevere AA. All patients received rATG in combination with cyclosporine A between September 2005 and January 2015.

RESULTS

The overall response rates were 55.7%, 68.9%, and 68.9% at 6, 12, and 18 months, respectively. Surprisingly, the overall complete response rate kept increasing from 9.8% at 12 months to 39.3% at 18 months, indicating a delayed response for rATG. Overall survival at 5 and 10 years was 72.1% and 67.2%, respectively. The overall survival of patients who responded between 3 and 12 months was significantly higher than that of nonresponders (71.4% vs. 47.4%).Antithymocyte globulin-related adverse reactions were significantly higher in severe AA (83.7%) than in nonsevere AA (55.6%) and these reactions were controllable and not life threatening with comprehensive measures.

CONCLUSIONS

This retrospective study shows an encouraging response and survival results in children with AA treated with rATG. Prolonged assessments were needed to evaluate the delayed responses to rATG. rATG could be used as an alternative in the first-line treatment of childhood AA.

Combination of haploidentical haematopoietic stem cell transplantation with an unrelated cord-blood unit in patients with severe aplastic anemia: a report of 146 cases

We analyzed the outcomes of 146 severe aplastic anemia (SAA) patients who received a combination of haploidentical haematopoietic stem cell transplantation (haplo-HSCT) and an unrelated cord-blood (UCB) unit between September 2011 and December 2017. One hundred and seventeen patients underwent transplantation as first-line therapy. Seven patients experienced early mortality, and among the evaluable 139 patients, one patient experienced primary graft failure (GF), while the other 138 patients achieved successful haploidentical donor engraftment; additionally, three patients experienced secondary GF. Six patients demonstrated delayed platelet recovery, and three patients demonstrated platelet GF. The median time for myeloid and platelet engraftment was 11 (range: 9-28) days and 15 (range: 9-330) days, respectively. With a median follow-up of 40 (range: 18-93) months, the cumulative incidences were 31.43% and 10.00% for grades II-IV and grades III-IV acute graft-versus-host disease (GVHD), respectively. The cumulative incidences of chronic GVHD (cGVHD) and moderate-severe cGVHD were 36.23% and 11.71%, respectively. There was no patient relapse. The probabilities of 4-year overall survival and GVHD-free, failure-free survival were 81.4 ± 3.3% and 69.2 ± 3.9%, respectively. These encouraging preliminary results indicated that haplo-HSCT combined with the infusion of UCB is a feasible choice for SAA patients without matched donors.

Idiopathic Aplastic Anemia in Children and Adults: Diagnosis, Treatments, and Management - A Review

Aplastic Anemia (AA) is also known as idiopathic aplastic anemia (IAA) and the production of new blood cells ceases in AA, which leads to an abnormal hematological syndrome such as pancytopenia and suppression of hypo-cellular bone marrow. The pathophysiology of AA in most cases is immune-mediated and is stimulated by type 1 cytotoxic T cells. Reliable early diagnostic tests of IAA are not yet available, therefore most of the cases are identified in advanced stages. Recently, abnormal immune response and hematopoietic cell deficiencies are defined genetically, such as in target cells of telomere repair gene mutations and by the dysregulation of T-cell activation pathways. Importantly, anti-thymocyte globulins and cyclosporine-associated immunosuppression are successful treatments for restoring blood cell production in most of the cases, however, clonal hematologic diseases remain challenging. In the current review, we have discussed the common practices in the treatment, pathophysiology, diagnosis, and management of AA.

Allogeneic Bone Marrow Transplants for Pediatric Severe Aplastic Anemia: Real-world Data comparing Matched Related and Unrelated Donors in a Developing Country. Retrospective study on behalf of the Pediatric Hematopoietic Stem Cell Transplant Working Group of the Brazilian Bone Marrow Transplantation Society (SBTMO) and the Brazil-Seattle Consortium (Gedeco)

In this study, we report on major MRD or URD BMT outcomes in pediatric patients with SAA in Brazil. This was a retrospective study, which included 106 patients ≤18 years old who received a first BMT for SAA. All patients received bone marrow as graft source from an MRD (n = 69) or a URD (n = 37). Conditioning regimen was non-myeloablative in 73.6% of cases, and GVHD prophylaxis comprised a calcineurin inhibitor plus methotrexate in 89.6% of patients. After a median follow-up of 4.5 years after BMT, 81 patients are alive, with a 4-year OS of 77% and no statistically significant difference between the MRD and URD groups (82% vs. 69%, respectively; P = .08). Grade III-IV aGVHD at 6 months and cGVHD at 2 years were observed in 8% and 14% of cases, respectively, and were not statistically different between the groups. Twenty-five (23%) patients died at a median of 2.9 months after BMT. Our study showed that 4-year OS after BMT was not statistically different between MRD and URD recipients. This study shows that the outcomes of pediatric patients transplanted for SAA with a URD in Brazil are approaching those of MRD transplants. In contrast, OS after MRD BMT was lower than we would expect based on previous reports. The wide range of preparatory regimens used by the study centers highlights the need for standardized protocols for these children. Our findings provide a benchmark for future studies focused on improving BMT outcomes in this setting in Brazil.

Patient features and survival of pediatric aplastic anemia in the USA: a large institution experience

BACKGROUND

We performed the first epidemiologic investigation to examine association of demographics and clinical characteristics at diagnosis, as well as health care expense coverage, with survival of US children with aplastic anemia (AA).

METHODS

We obtained electronic medical record data of 1140 children aged 0-19 years diagnosed with AA followed at a pediatric health system between 2004 and 2014. Kaplan-Meier curve and Cox proportional hazards regressions were used.

RESULTS

Self-pay patients had a mortality risk five times higher than that of those insured by publicly funded insurance (hazards ratio, 95% CI: 6.0, 3.7-9.8). Other features associated with higher mortality risk include pancytopenia (hazards ratio, referent: 4.2, constitutional AA); underweight (2.0, normal-weight); platelet count <50 × 109/l (1.3, ≥50 × 109/l); male sex (1.3, female); and ages at diagnosis 6-11, 11-16 and 16-19 years (1.6, 1.9, 2.3, 1-3 years), respectively.

CONCLUSIONS

Self-pay was the strongest prognostic factor for pediatric AA mortality. Older age, pancytopenia, underweight, male sex and lower platelet count were also associated with increased risk of mortality. These findings may be useful for providers, researchers and policymakers to ensure effective health care delivery to this population and to motivate future etiologic research and establishment of a surveillance registry.

Autologous cord blood transplantation in children with acquired severe aplastic anemia

OBJECTIVE

To investigate the efficacy of ACBT for acquired SAA in children.

METHODS

Four patients including three girls and one boy were diagnosed with acquired SAA. Their ages were 5, 3, 1, and 3 years, respectively. Patients received an immunoablative preparative regimen using low-dose antithymocyte globulin, cyclophosphamide, and fludarabine. The unrelated human umbilical cord MSC were infused before the autologous cord blood was transfused on day 0. The first and second patients were not treated with immunosuppressive agents after transplantation. The third and the fourth patients received cyclosporine A for half a year after transplantation followed by a 6-month taper.

RESULTS

Initial hematopoietic reconstitution was seen in all the four patients. There was no association between engraftment time and the number of total cells and CD34+ cells. Relapse was seen in the first case about half a year after the transplantation. The other three patients with durable hematopoietic reconstitution are with good quality of life. No GVHD was observed.

CONCLUSIONS

Three of four patients maintained prolonged hematopoiesis following an immunosuppressive-based preparative regimen and infusion of autologous cord blood cells. It is recommended that cyclosporine be maintained for 6 months after transplantation. ACBT could be considered for acquired SAA if available.

The histopathology of bone marrow failure in children

Bone marrow failure (BMF) is a rare but life-threatening disorder that usually manifests as (pan)cytopenia. BMF can be caused by a variety of diseases, but inherited BMF (IBMF) syndromes are a clinically important cause, especially in children. IBMF syndromes are a heterogeneous group of genetic disorders characterized by BMF, physical abnormalities, and predisposition to malignancy. An accurate diagnosis is critical, as disease-specific management, surveillance, and genetic counselling are required for each patient. The major differential diagnoses of IBMF syndromes are acquired aplastic anemia (AA) and refractory cytopenia of childhood (RCC). These diseases have overlapping features, such as BM hypocellularity and/or dysplastic changes, which make the differential diagnosis challenging. RCC has been defined as a histomorphologically distinct entity. Therefore, understanding the BM histopathology of these diseases is essential for the differential diagnosis. However, the BM histopathological features have not been characterized in detail, as descriptions of BM histopathology are very limited due to the rarity of the diseases. This review provides a detailed description of the BM histopathology in cases of RCC, AA, and the four most common IBMF syndromes: Fanconi anemia (FA), dysketatosis congenita (DC), Diamond-Blackfan anemia (DBA), and Shwachman-Diamond syndrome (SDS). An overview, including the clinical features and diagnosis, is also provided.

Updated Guidelines for the Treatment of Acquired Aplastic Anemia in Children

PURPOSE OF REVIEW

This review aimed to provide updated guidelines for the management of children with acquired aplastic anemia (AA), particularly focusing on hematopoietic stem cell transplantation (HSCT).

RECENT FINDINGS

Failure-free survival for children with aplastic anemia has been shown to be better after bone marrow transplantation (BMT) from matched or one-locus mismatched related donors (MRD/1MMRD) than after immunosuppressive therapy (IST). A combination of the absence of minor paroxysmal nocturnal hemoglobinuria clones and short telomere length was identified as a strong predictor of a poor response to IST. Upfront HSCT from matched unrelated donors (MUD) and MRD was recently demonstrated to have comparable outcomes. Moreover, unrelated cord blood transplantation (UCBT) and haploidentical HSCT have shown promising outcomes, and the fludarabine/melphalan-based regimen has resulted in excellent survival without poor graft function. BMT from MRD/1MMRD is the treatment of choice. When a MRD/1MMRD is not available, upfront BMT from a MUD should be considered for patients with only a slim chance of responding to IST. UCBT and haploidentical HSCT are promising options. This updated treatment algorithm should improve overall outcomes for children with AA.

Microbe-Induced Inflammatory Signals Triggering Acquired Bone Marrow Failure Syndromes

Acquired bone marrow failure syndromes encompass a unique set of disorders characterized by a reduction in the effective production of mature cells by the bone marrow (BM). In the majority of cases, these syndromes are the result of the immune-mediated destruction of hematopoietic stem cells or their progenitors at various stages of differentiation. Microbial infection has also been associated with hematopoietic stem cell injury and may lead to associated transient or persistent BM failure, and recent evidence has highlighted the potential impact of commensal microbes and their metabolites on hematopoiesis. We summarize the interactions between microorganisms and the host immune system and emphasize how they may impact the development of acquired BM failure.

Unmanipulated haploidentical haematopoietic stem cell transplantation for children with severe aplastic anaemia

Haploidentical haematopoietic stem cell transplantation (haplo-HSCT) used to be a third-line treatment option for childhood severe aplastic anaemia (SAA). We conducted this retrospective study of 36 children (38 transplants) who received haplo-HSCT from human leucocyte antigen (HLA)-mismatched related donors between July 2002 and November 2013 at five HSCT centres in China, including 17 cases that were 5/6 HLA matched (Group 1) and 21 that were 4/6 or 3/6 HLA matched (Group 2). Although patients in Group 2 had a higher incidence of grade II-IV acute graft-versus-host disease (57·9% vs. 5·9%, P = 0·001), they had similar rates of graft failure (5·3% vs. 5·9%, P = 0·742) and overall survival (80·8% vs. 93·8%, P = 0·234) as Group 1. Unmanipulated haplo-HSCT is an effective treatment for SAA children with satisfactory outcome of this cohort, especially in the 5/6 HLA-matched group. For patients in critical situations, such as unresponsive to immunosuppressive therapy, refractory infection and failing first HSCT, to bring forward the timing of haplo-HSCT is a feasible salvage strategy with better and faster donor accessibility.

Disrupted lymphocyte homeostasis in hepatitis-associated acquired aplastic anemia is associated with short telomeres

Hepatitis‐associated aplastic anemia (HAA) is a variant of acquired aplastic anemia (AA) in which immune‐mediated bone marrow failure (BMF) develops following an acute episode of seronegative hepatitis. Dyskeratosis congenita (DC) is an inherited BMF syndrome characterized by the presence of short telomeres, mucocutaneous abnormalities, and cancer predisposition. While both conditions may cause BMF and hepatic impairment, therapeutic approaches are distinct, making it imperative to establish the correct diagnosis. In clinical practice, lymphocyte telomere lengths (TL) are used as a first‐line screen to rule out inherited telomeropathies before initiating treatment for AA. To evaluate the reliability of TL in the HAA population, we performed a retrospective analysis of TL in 10 consecutively enrolled HAA patients compared to 19 patients with idiopathic AA (IAA). HAA patients had significantly shorter telomeres than IAA patients (P = 0.009), including four patients with TL at or below the 1st percentile for age‐matched controls. HAA patients had no clinical features of DC and did not carry disease‐causing mutations in known genes associated with inherited telomere disorders. Instead, short TLs were significantly correlated with severe lymphopenia and skewed lymphocyte subsets, features characteristic of HAA. Our results indicate the importance of caution in the interpretation of TL measurements in HAA, because, in this patient population, short telomeres have limited specificity. Am. J. Hematol. 91:243–247, 2016. © 2015 The Authors. American Journal of Hematology Published by Wiley Periodicals, Inc.

Successful bone marrow transplantation of an adolescent young adult female with pregnancy-associated aplastic anemia

Cases of pregnancy-associated severe aplastic anemia (SAA) have been reported in the literature with historically high rates of mortality. We report the case of a 17-year-old female diagnosed with SAA at 26 weeks of gestation. She experienced intrauterine fetal demise and did not achieve hematologic remission after delivery. She received a histocompatible sibling donor bone marrow transplant 7 weeks after her diagnosis and remains in remission, at 1-year posttransplant. We review available literature and suggest that when a histocompatible sibling donor is available, bone marrow transplantation should be considered as a first-line therapy for patients with pregnancy-associated SAA.

CXCR4 expression on pathogenic T cells facilitates their bone marrow infiltration in a mouse model of aplastic anemia

Aplastic anemia (AA) is a disease characterized by T-cell-mediated destruction of bone marrow (BM) hematopoietic stem and progenitor cells. Physiologically, T cells migrate to the BM in response to chemokines, such as SDF-1α, the ligand for CXCR4. However, how T cells traffic to the BM in AA is poorly understood. CXCR4 is aberrantly expressed in immune-mediated diseases and its regulation by nuclear factor-κB (NF-κB) in cancer models is well documented. In this study, we show that CXCR4 is highly expressed on BM-infiltrating CD4(+) and CD8(+) T cells in a mouse model of AA. Inhibiting CXCR4 in AA mice, using CXCR4(-/-) splenocytes or AMD3100, significantly reduced BM infiltration of T cells. We also report that NF-κB occupancy at the CXCR4 promoter is enhanced in BM-infiltrating CD8(+) T cells of AA mice. Moreover, inhibiting NF-κB signaling in AA mice using Bay11 or dehydroxymethylepoxyquinomicin, or transferring p50(-/-) splenocytes, decreased CXCR4 expression on CD8(+) T cells, significantly reduced BM infiltration of T cells, and strongly attenuated disease symptoms. Remarkably, therapeutic administration of Bay11 significantly extended survival of AA mice. Overall, we demonstrate that CXCR4 mediates migration of pathogenic T cells to the BM in AA mice, and inhibiting NF-κB signaling may represent a novel therapeutic approach to treating AA.

Umbilical cord blood transplantation supplemented with the infusion of mesenchymal stem cell for an adolescent patient with severe aplastic anemia: a case report and review of literature

Delayed hematopoietic recovery and increased rate of engraftment failure limit the use of umbilical cord blood transplantation (UCBT). We describe a case of severe aplastic anemia treated by UCBT combined with mesenchymal stem cells. Our case reveals that infusing mesenchymal stem cells early (about 40 days) after UCBT may promote hematopoietic recovery. This experience will guide clinical scientists, especially hematologists, to deal with similar situations and encourage them to widen this strategy.