Recent advances in the diagnosis and treatment of pediatric acquired aplastic anemia.

Acquired aplastic anemia (AA) in children is a rare bone marrow failure that requires several special considerations for its diagnosis and treatment compared with that in adults. The most common issue is the differential diagnosis with refractory cytopenia of childhood and inherited bone marrow failure syndromes, which is crucial for making decisions on the appropriate treatment for pediatric AA. In addition to detailed morphological evaluation, a comprehensive diagnostic work-up that includes genetic analysis using next-generation sequencing will play an increasingly important role in identifying the underlying etiology of pediatric AA. When discussing treatment strategies for children with acquired AA, the long-term sequelae and level of hematopoietic recovery that affect daily or school life should also be considered, although the overall survival rate has reached 90% after immunosuppressive therapy or hematopoietic cell transplantation (HCT). Recent advances in HCT for pediatric patients with acquired AA have been remarkable, with the successful use of upfront bone marrow transplantation from a matched unrelated donor, unrelated cord blood transplantation or haploidentical HCT as salvage treatment, and fludarabine/melphalan-based conditioning regimens. This review discusses current clinical practices in the diagnosis and treatment of acquired AA in children based on the latest data.

Childhood Myelodysplastic Syndrome.

Myelodysplastic syndrome (MDS) in children is rare, accounting for < 5% of all childhood hematologic malignancies. With the advent of next-generation sequencing, the etiology of many childhood MDS (cMDS) cases has been elucidated with the finding of predisposing germline mutations in one-quarter to one-third of cases; somatic mutations have also been identified, indicating that cMDS is different than adult MDS. Herein, cMDS classification schema, clinical presentation, laboratory values, bone marrow histology, differential diagnostic considerations, and the recent molecular findings of cMDS are described.

Haploidentical Hematopoietic Stem Cell Transplantation in Pediatric Patients with Acquired Hypocellular Bone Marrow Failure.

Children with acquired hypocellular bone marrow failure of unknown cause (AHBMF) are usually diagnosed either with severe aplastic anemia (SAA) or refractory cytopenia of childhood (RCC). Patients with AHBMF who lack a matched donor and who failed or relapsed after immunosuppressive therapy (IST) need alternative therapies. Haploidentical hematopoietic stem cell transplantation (haplo-HSCT) offers a curative treatment for these patients. We report a multicenter Spanish experience with haplo-HSCT in pediatric patients with AHBMF. Eleven pediatric patients (SAA, n = 9; RCC, n = 2) underwent haplo-HSCT with different lymphodepletion strategies. Most patients (10 of 11) had previously failed to respond or relapsed after IST. The conditioning regimen was reduced intensity in SAA and myeloablative in RCC. Patients with SAA received low-dose radiotherapy as part of their conditioning regimen. All patients engrafted. Viral reactivation was common (8 of 11). Acute GVHD grade ≥II was seen in 5 patients. Chronic GVHD was diagnosed in 4 of the long-term survivors. Transplantation-associated microangiopathy was a frequent complication in SAA patients and was related to worse outcome. Two patients died of transplantation-related complications. Overall survival was 81%, with a median follow-up of 36 months. Haplo-HSCT can be a successful salvage curative treatment for pediatric patients with AHBMF, but with significant toxicities that must be addressed. Transplantation-associated microangiopathy was the most critical complication.

[Morphological diagnosis of childhood bone marrow failure syndromes].

In 2008, the World Health Organization proposed a provisional entity of childhood myelodysplastic syndrome (MDS) without a blasts increase, which was referred to as the refractory cytopenia of childhood (RCC). We performed a central review of bone marrow morphology in 252 children with acquired bone marrow failure syndromes to clarify the clinical relevance of the RCC. The RCC was divided two categories, namely, RCC without multilineage dysplasia (MLD) and RCC with MLD, which is similar to MDS with MLD in adult MDS. Furthermore, the clinical outcomes were investigated for cases diagnosed with aplastic anemia, RCC without MLD, and RCC with MLD. The response rates to immunosuppressive therapy and the incidence of the development of the new chromosomal aberration did not significantly differ among the three groups. The RCC with MLD can be adopted in childhood MDS since children with this condition exhibited a frequent chromosomal aberration at the time of diagnosis and a high frequency of secondary graft failure after a hematopoietic cell transplantation.

Case Report: Refractory Cytopenia With a Switch From a Transient Monosomy 7 to a Disease-Ameliorating del(20q) in a NHEJ1-Deficient Long-term Survivor.

We report the case of a male Pakistani patient with a pathogenic homozygous loss of function variant in the non-homologous end-joining factor 1 (NHEJ1) gene. The growth retarded and microcephalic boy with clinodactyly of both hands and hyperpigmentation of the skin suffered from recurrent respiratory infections. He was five and a half years old when he came to our attention with refractory cytopenia and monosomy 7. Hematopoietic stem cell transplantation was considered but not feasible because there was no suitable donor available. Monosomy 7 was not detected anymore in subsequent bone marrow biopsies that were repeated in yearly intervals. Instead, seven and a half years later, a novel clone with a del(20q) appeared and steadily increased thereafter. In parallel, the patient's blood count, which had remained stable for over 20 years without necessitating any specific therapeutic interventions, improved gradually and the erythropoiesis-associated dysplasia resolved.

Prospective validation of the provisional entity of refractory cytopenia of childhood, proposed by the World Health Organization.

In 2008, the World Health Organization proposed a new entity of childhood myelodysplastic syndrome (MDS), which was referred to as refractory cytopenia of childhood (RCC). However, whether this morphological classification reflects clinical outcomes remains unclear. We performed a prospective evaluation of bone marrow morphology in 252 children with acquired bone marrow failure between 2009 and 2013. Of 252 patients, 63 were diagnosed with aplastic anaemia (AA), 131 with RCC without multilineage dysplasia (RCC-w/o-MLD) and 58 with RCC with MLD (RCC-MLD). One patient with AA, three with RCC-w/o-MLD and nine with RCC-MLD presented with chromosomal abnormalities at diagnosis (P = 0·001). The response rates to immunosuppressive therapy (IST) at 6 months and the cumulative incidence of clonal evolution at 5 years did not significantly differ among the three groups. A multivariate analysis revealed that the morphological classification of RCC-MLD was a significant risk factor for secondary graft failure after haematopoietic cell transplantation (HCT) (P = 0·003). In view of these findings, RCC could be divided into two categories, RCC-w/o-MLD and RCC-MLD, because children with this condition exhibited a distinct morphology, frequent chromosomal abnormalities at diagnosis and a high frequency of secondary graft failure after HCT.

[Diagnosis and treatment of childhood myelodysplastic syndrome].

Myelodysplastic syndrome (MDS) is a group of clonal hematopoietic disorders characterized by peripheral cytopenia and morphological abnormalities in hematopoietic cells, i.e., myelodysplasia. Aging-related somatic variants acquired in the hematopoietic cells are associated with MDS pathogenesis in adults. However, pediatric MDS often occurs because of germline predispositions. Myelodysplasia can be observed in not only MDS but also other hematopoietic and non-hematopoietic disorders, such as infections and primary immunodeficiencies. Therefore, careful differential diagnosis between MDS and other diseases is necessary. The bone marrow histopathology should be evaluated for accurate differentiation of MDS without excess blasts from aplastic anemia and MDS with excess blasts from acute myeloid leukemia. The treatment strategy for childhood MDS differs based on disease subtypes. The clinical courses of pediatric MDS without excess blasts are heterogeneous; therefore, it is crucial to assess the prognostic values of clinical and cytogenetic findings. In contrast, allogeneic hematopoietic cell transplantation should be considered as the only curative option for pediatric MDS with excess blasts.

Daratumumab therapy for post-HSCT immune-mediated cytopenia: experiences from two pediatric cases and review of literature.

BACKGROUND: Immune-mediated cytopenias (AIC) are challenging complications following allogeneic hematopoietic stem cell transplantation (HSCT). While broad-acting immunosuppressive agents like corticosteroids are often standard of care, several novel therapies which target specific immunological pathways have recently been developed and provide hope for patients with steroid-refractory courses and may limit long-term toxicity. The successful off-label use of the plasma cell depleting anti-CD38 antibody daratumumab was published in several case reports, suggesting efficacy, i.e., in patients with antibody-mediated AIC refractory to previous B cell depletion. We want to share our experience with two children, whom we treated with daratumumab, including one fatal course with uncontrolled disease. Given the absence of substantial data from HSCT registries or prospective trials, we furthermore provide a critical review of the literature on daratumumab treatment of AIC. CASE PRESENTATIONS: Patient 1 (P1), an 11-year-old girl with lipopolysaccharide-responsive and beige-like anchor protein (LRBA) deficiency who developed immune-mediated thrombocytopenia (AIT) from day +58 after HSCT, showed a complete response to daratumumab after the fourth of six total daratumumab doses. She remains transfusion independent for over a year of follow-up. Previously, her thrombocytopenia was refractory to corticosteroids, rituximab, intravenous immunoglobulins (IVIG), eltrombopag, cyclosporine A, and sirolimus. Patient 2 (P2), a 6-year-old boy with CD40 ligand (CD40L) deficiency, developed both AIT and hemolytic anemia (AIHA) after HSCT on days +58 and +83, respectively, and was also treated with daratumumab after being previously refractory to prednisolone, rituximab, and IVIG. Yet, he did neither respond to daratumumab nor the concomitantly administered methyprednisolone pulse, plasmapheresis, and eculizumab and succumbed due to refractory disease. CONCLUSION: Reviewing the literature on the use of daratumumab for refractory AIC post-HSCT, we consider daratumumab a promising agent for this life-threatening disorder: ten of the twelve patients reached transfusion independency in the literature. However, treatment failures are likely to be underreported. Thus, controlled trials are needed to explore the safety and efficacy of daratumumab in this rare post-HSCT complication.

SF3B1 Mutation but Not Ring Sideroblasts Identifies a Specific Group of Myelodysplastic Syndrome-Refractory Cytopenia With Multilineage Dysplasia.

BACKGROUND: Integrating the proportion of ring sideroblasts and SF3B1 mutation status is required for diagnosis of sideroblastic subgroups in myelodysplastic syndrome (MDS) as proposed by the World Health Organization 2016 classification. However, the clinical implications of SF3B1 mutation and ring sideroblasts in MDS-refractory cytopenia with multilineage dysplasia (MDS-RCMD) remain unclear. PATIENTS AND METHODS: Clinical and laboratory features in 238 MDS-RCMD patients were retrospectively analyzed, and the prognostic significance of SF3B1 mutation and ring sideroblasts on overall survival and leukemia-free survival in total MDS-RCMD patients and different subgroups stratified by the percentage of ring sideroblasts or SF3B1 mutation status were evaluated. RESULTS: MDS-RCMD patients with ring sideroblasts ≥ 15% showed a significantly higher prevalence of SF3B1 mutation compared to ring sideroblasts 5%-14% or ring sideroblasts < 5% (75.6% vs. 15.1% vs. 6.4%, P < .001). In multivariate analysis, SF3B1 mutation was associated with a significantly prolonged survival (hazard ratio [HR] = 0.430, P = .013) and reduced leukemic transformation (HR = 0.174, P = .021) in total MDS-RCMD patients, while ring sideroblasts showed no independent effect on either survival or leukemic transformation. There were no significant differences in clinical characteristics or survival between MDS-RCMD patients with ring sideroblasts ≥ 15% and ring sideroblasts 5%-14% in the presence of SF3B1 mutation. Furthermore, SF3B1 mutation showed an independent prognostic effect on overall survival in MDS-RCMD patients with ring sideroblasts 5%-14% (HR = 0.195, P = .046). CONCLUSION: SF3B1 mutation, not the presence of ring sideroblasts, identifies a distinct subtype and showed independent prognostic value on survival and leukemia transformation in MDS-RCMD patients.

Clinical impact of dysplastic changes in acquired aplastic anemia: A systematic study of bone marrow biopsies in children and adults.

Aplastic anemia (AA) is a rare disorder characterized by suppression of bone marrow function, which can progress to myelodysplastic syndrome (MDS) or to acute myeloid leukemia (AML). To determine if there are characteristics in bone marrow biopsies in children and adults previously diagnosed with acquired AA, which could predict progression to MDS, we evaluated 118 hypocellular bone marrow biopsies from adults (76 patients) and children (42) diagnosed initially with acquired AA previously to any treatment. Histology was reviewed according to a detailed protocol including Bennett and Orazi criteria for hypocellular myelodysplastic syndrome (h-MDS) and Bauman et al. criteria for refractory cytopenia of childhood (RCC). Twelve patients (10.2%; 6 children and 6 adults) progressed to MDS after a median time of 56 months. Criteria described by Bennett and Orazi suggestive of h-MDS in bone marrow biopsies were detected in 16 cases (13.5%; 8 adults and 8 children), and none in patients that progressed to MDS/AML. Twenty adults' biopsies (26.3%) had the histological criteria used for the diagnosis of pediatric RCC, and none showed MDS/AML evolution. Ten children (23.8%) were reclassified morphologically as RCC, and only one progressed to MDS. In this population with acquired aplastic anemia (AAA), no histological/immunohistochemical (H/IHC) bone marrow findings could discriminate patients with higher risk for myeloid clonal progression, which questions the diagnosis of h-MDS/RCC based only on the finding of dysplasia in the cases without increased blasts and/or the characteristic genetic abnormalities.

Evans Syndrome in Childhood: Long Term Follow-Up and the Evolution in Primary Immunodeficiency or Rheumatological Disease.

Evans syndrome (ES) is a rare but challenging condition, characterized by recurrent and refractory cytopenia episodes. Recent discoveries highlighted that an appropriate diagnostic workup is fundamental to identify an underlying immune dysregulation such as primary immunodeficiencies or a rheumatological disease. We hereby describe clinical features and laboratory results of 12 pediatric patients affected by ES referred to the Pediatric Onco-Hematology Unit of Bologna. Patients experienced a median of four acute episodes of cytopenia with 9 years as median age at the onset of symptoms. In 8/12 (67%) patients an underlying etiology, primary immunodeficiencies, or rheumatological disease was identified. In 4/12 children, other immune manifestations were associated (Thyroiditis, Celiac disease, Psoriasis, Vitiligo, Myositis, Membranoproliferative Glomerulonephritis). ES remained the primary diagnosis in four patients (33%). At a median follow-up time of 4 years, 5/12 (42%) patients revealed a chronic ITP, partially responsive to second line therapy. Immunoglobulin Replacement Therapy (IRT) was effective with a good hematological values control in three patients with a secondary ES (ALPS, CVID, and a patient with Rubinstein Taybi Syndrome and a progressive severe B cell deficiency with hypogammaglobulinemia). Our experience highlights that, in pediatric patients, ES is often only the first manifestation of an immunological or rheumatological disease, especially when cytopenias are persistent or resistant to therapy, with an early-onset or when are associated with lymphadenopathy.

Wilms' tumor 1 mRNA expression: a good tool for differentiating between myelodysplastic syndrome and aplastic anemia in children?

Objectives: To evaluate the value of Wilms' tumor 1 mRNA (WT1) expression in the differential diagnosis of childhood myelodysplastic syndrome (MDS) and aplastic anemia (AA). Methods: This study compared WT1 expression levels in children of MDS and AA to evaluate its value in differential diagnosis. Results: WT1 overexpression rate and mean WT1 expression level were significantly higher in MDS compared to AA (P = 0.000 and P = 0.013, respectively). Patients with RCC and normal cytogenetics exhibited significantly greater portion of patients exposing WT1 overexpression, compared to all AA subtypes (P = 0.001, P = 0.000 and P = 0.001, respectively). ROC curve analysis revealed that WT1 expression could differentiate between RCC with normal cytogenetics and non-severe AA. Based on a cut-off value of 1.45%, WT1 expression provided a sensitivity of 23.2% and a specificity of 100%. Discussion: In the present study, WT1 overexpression rate was gradually decreased in RAEB group, RCC group and AA subtypes, and the mean WT1 expression level of the MDS patients was significantly higher than that of the AA group. It is very difficult to differentiate between RCC with normal cytogenetics and NSAA in children. Our results showed significant differences in WT1 overexpression rate between these two groups. When we set the cut-off value as 1.45%, WT1 expression levels could be used to differentiate between cases of RCC with normal cytogenetics and NSAA in children. Conclusion: WT1 expression might be useful for distinguishing between myelodysplastic syndrome and aplastic anemia in children.

Differences in the bone marrow histology between childhood myelodysplastic syndrome with multilineage dysplasia and refractory cytopenia of childhood without multilineage dysplasia.

AIMS: Refractory cytopenia of childhood (RCC) is subdivided into myelodysplastic syndrome with multilineage dysplasia (MDS-MLD) and RCC without (w/o) multilineage dysplasia (RCC without MLD). Although RCC is a histomorphological distinct entity, the bone marrow (BM) histology of RCC is not yet characterised in relation to multilineage dysplasia. We investigated the BM histological features of RCC to clarify the characteristics of BM histology of MDS-MLD in childhood compared to RCC without MLD. METHODS AND RESULTS: The BM histology and cytology in 60 RCC patients from the nationwide registry of Japanese Childhood AA-MDS Study Group were reviewed retrospectively. Although a thorough genetic assessment, including GATA2 and/or SAMD9, was not performed, inherited BM failure disorders were excluded by a cytogenetic test, a chromosome fragility test and a telomere length measurement along with careful clinical assessments. Among the 60 patients, 20 (33%) of MDS-MLD and 40 (67%) of RCC w/o MLD were classified according to their BM cytology. We then investigated the BM histological features and compared them between the two groups. The BM cellularity, distribution pattern of haematopoiesis, frequency of left-shifted granulopoiesis, numbers of micromegakaryocytes and p53 immunostaining-positive cells were significantly different between the groups. The BM histology of MDS-MLD in childhood showed higher cellularity, the more common occurrence of diffuse distribution pattern, more frequently left-shifted granulopoiesis and more micromegakaryocytes and p53 immunostaining-positive cells than RCC without MLD. CONCLUSIONS: Our results showed that MDS-MLD in childhood had a characteristic BM histology compared to RCC without MLD. The clinical relevance of MDS-MLD in childhood needs to be evaluated.

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.

Current opinions on refractory cytopenia of childhood / 国际儿科学杂志

Myelodysplastic syndromes are a group of malignant myeloid clonal diseases that originate from hematopoietic stem/progenitor cells.They are characterized by decreased peripheral blood cells,dysplasia of one or multiple lineages of myeloid hematopoietic cells,and prone to transform into acute myeloid leukemia.Refractory cytopenia of childhood is the most common clinical type of MDS in children.Its clinical manifestations include the decrease in one or multiple lineages of peripheral blood cells,abnormal development of the myeloid lineage,and the absence of excess blasts.This type was first introduced in WHO children's MDS in 2008.Considering the low incidence and lack of specific diagnostic methods,difficulty in early diagnosis and poor prognosis of RCC,we summarize the definition,clinical manifestations,laboratory tests,diagnosis and differential diagnosis,and treatment strategies of RCC in this review.

A Case Report of Successful Treatment with Kamikihito and Kyukikyogaito for Refractory Cytopenia of Childhood / 日本東洋医学雑誌

An eight-year-old girl was referred and admitted to our hospital with the chief complaint of purpura on her lower legs. Blood tests revealed pancytopenia, and bone marrow findings showed marrow hypoplasia. Refractory cytopenia of childhood (RCC) was diagnosed based on the central diagnostic system of the Myelodysplastic Syndrome Committee of the Japanese Society of Pediatric Hematology. Immunosuppressive therapy was performed with the administration of rabbit antithymocyte globulin, methylprednisolone and cyclosporin A,but it was not effective. Eight months after admission to our hospital, Kampo treatment was started based on traditional Kampo diagnosis. After treatment with oral administration of kamikihito and kyukikyogaito, her pancytopenia gradually improved. Erythrocyte transfusion was discontinued after 2 months, and concentrated platelet transfusion also became unnecessary after 3 months. As a result of improvement in pancytopenia, her white blood cell count, hemoglobin value, and platelet count reached almost normal levels after 16 months. The scheduled bone marrow transplantation was canceled. The action mechanisms of kamikihito and kyukikyogaito for RCC are not clear, and their effective rates are also unknown. However, Kampo treatments are less invasive, inexpensive, and have few side effects. We believe that Kampo medicine is a therapeutic method that should be actively attempted in cases of RCC with poor response to standard treatment.

Bone marrow failure in childhood: central pathology review of a nationwide registry.

Refractory cytopenia of childhood (RCC) was proposed as a provisional entity in the 2008 WHO classification of myelodysplastic syndromes (MDS). It is defined as a childhood MDS featuring persistent cytopenia without increase blasts in bone marrow (BM) or peripheral blood (PB). Because the majority of RCC cases feature hypocellularity and pancytopenia, it is quite challenging to differentiate RCC from acquired aplastic anemia (AA) and many kinds of inherited bone marrow failure syndromes (IBMFS). Diagnosis of RCC requires BM histology of characteristic features such as isolated erythroid islet with left shift, abnormal localization and micromegakaryocytes. The Japanese Society of Pediatric Hematology/Oncology has opened the central registry review system since 2009 to evaluate childhood cases of bone marrow failure (BMF). It has reviewed cytology and BM pathology of all registered BMF cases, which number more than 1,700. In the evaluation of BMF, BM pathology is important to assess the mechanism of hematopoiesis. Pathological dysplasia should be differentiated from cytological dysplasia. A central review system is important for rare diseases, such as pediatric BMF. Standardization of pathological diagnosis should be established upon consensus findings, descriptions, and diagnostic approaches. In this review, the pathology of pediatric BMF syndromes is summarized.

Reversible Cerebral Vasoconstriction Syndrome Promptly Diagnosed with Magnetic Resonance Imaging Including Magnetic Resonance Angiography During Immunosuppressive Therapy in a 16-Year-Old Girl with Refractory Cytopenia of Childhood.

Reversible cerebral vasoconstriction syndrome (RCVS) is a syndrome characterized by severe headache with segmental vasoconstriction of the cerebral arteries that resolves within 12 weeks. A 16-year-old girl with refractory cytopenia of childhood, who was receiving the immunosuppressant cyclosporine, developed severe headache and was diagnosed with RCVS using magnetic resonance imaging, including magnetic resonance angiography (MRA). MRA is a non-invasive and very effective technique for diagnosing RCVS. MRA should be performed at the onset of severe headache during immunosuppressant administration for children with hematological disorders and may prevent sequelae such as posterior reversible encephalopathy syndrome or ischemic attack.