Response to upfront azacitidine in juvenile myelomonocytic leukemia in the AZA-JMML-001 trial.

Allogeneic hematopoietic stem cell transplantation (HSCT) is the only curative therapy for most children with juvenile myelomonocytic leukemia (JMML). Novel therapies controlling the disorder prior to HSCT are needed. We conducted a phase 2, multicenter, open-label study to evaluate the safety and antileukemic activity of azacitidine monotherapy prior to HSCT in newly diagnosed JMML patients.

Loss of the Fanconi anemia-associated protein NIPA causes bone marrow failure.

Inherited bone marrow failure syndromes (IBMFSs) are a heterogeneous group of disorders characterized by defective hematopoiesis, impaired stem cell function, and cancer susceptibility. Diagnosis of IBMFS presents a major challenge due to the large variety of associated phenotypes, and novel, clinically relevant biomarkers are urgently needed. Our study identified nuclear interaction partner of ALK (NIPA) as an IBMFS gene, as it is significantly downregulated in a distinct subset of myelodysplastic syndrome-type (MDS-type) refractory cytopenia in children.

Molecular profile of inflammatory and megakaryocytic factors in pediatric myelodysplastic syndrome with acute myelofibrosis.

Pediatric fibrotic myelodysplastic syndromes (ped-MDS-MF) and pediatric primary myelofibrosis (ped-PMF) are rare, and the molecular changes which mediate fibrosis have never been investigated. Histology and gene expression profile of 119 fibrosis/angiogenesis/inflammation/megakaryopoiesis-related factors in bone marrow biopsies were performed (two ped-MDS-MF and one ped-PMF). In one progressive ped-MDS, comparison of MF grade 0 (no myelofibrosis) and MF grade 2 (dense network of reticulin fibres) after 4 months showed that expression of fibrosis-related transcripts increased and dysplastic megakaryocytes formed a dense net of CD42b proplatelets.

Constitutional mutations cause familial myelodysplastic syndrome and transient monosomy 7.

Familial myelodysplastic syndromes arise from haploinsufficiency of genes involved in hematopoiesis and are primarily associated with early-onset disease. Here we describe a familial syndrome in seven patients from four unrelated pedigrees presenting with myelodysplastic syndrome and loss of chromosome 7/7q. Their median age at diagnosis was 2.

Prevalence, clinical characteristics, and prognosis of GATA2-related myelodysplastic syndromes in children and adolescents.

Germline GATA2 mutations cause cellular deficiencies with high propensity for myeloid disease. We investigated 426 children and adolescents with primary myelodysplastic syndrome (MDS) and 82 cases with secondary MDS enrolled in 2 consecutive prospective studies of the European Working Group of MDS in Childhood (EWOG-MDS) conducted in Germany over a period of 15 years. Germline GATA2 mutations accounted for 15% of advanced and 7% of all primary MDS cases, but were absent in children with MDS secondary to therapy or acquired aplastic anemia.

Bone marrow immunophenotyping by flow cytometry in refractory cytopenia of childhood.

Refractory cytopenia of childhood is the most common type of childhood myelodysplastic syndrome. Because the majority of children with refractory cytopenia have a normal karyotype and a hypocellular bone marrow, differentiating refractory cytopenia from the immune-mediated bone marrow failure syndrome (very) severe aplastic anemia can be challenging. Flow cytometric immunophenotyping of bone marrow has been shown to be a valuable diagnostic tool in differentiating myelodysplastic syndrome from non-clonal cytopenias in adults.

[Refractory cytopenia of children and acquired aplastic anemia: a clinical and pathological study of 130 cases].

Objective: To explore the clinical characteristics and histopathological morphology features of bone marrow biopsies between refractory cytopenia of children (RCC) and acquired aplastic anemia (AAA) to facilitate the diagnosis, differential diagnosis and treatment of RCC and AAA.

Methods: We retrospectively analyzed clinical data and histopathological morphology of bone marrow biopsies in RCC or AAA patients referred to our hospital from January 2011 to December 2012.

Results: There were totally 130 patients studied.

Hematopoietic stem cell transplantation in children and young adults with secondary myelodysplastic syndrome and acute myelogenous leukemia after aplastic anemia.

Secondary myelodysplastic syndrome and acute myelogenous leukemia (sMDS/sAML) are the most serious secondary events occurring after immunosuppressive therapy in patients with aplastic anemia. Here we evaluate the outcome of hematopoietic stem cell transplantation (HSCT) in 17 children and young adults with sMDS/sAML after childhood aplastic anemia. The median interval between the diagnosis of aplastic anemia and the development of sMDS/sAML was 2.

Juvenile-like (inflammatory/hyperplastic) mucosal polyps of the gastrointestinal tract in neurofibromatosis type 1.

Aims: Diffuse neurofibromatosis/ganglioneuromatosis, solitary/plexiform neurofibroma, periampullary carcinoids and gastrointestinal stromal tumour (GIST) are the main gastrointestinal manifestations of neurofibromatosis type 1 (NF-1, von Recklinghausen disease). Inflammatory (juvenile-like) polyps have not been recognised to date as specific gastrointestinal (GI) manifestations of NF-1.

Methods And Results: We describe four males aged 23-65 years with NF-1 and inflammatory (juvenile-like) gastrointestinal polyps, and review the literature for similar cases.

Comparison of horse and rabbit antithymocyte globulin in immunosuppressive therapy for refractory cytopenia of childhood.

Refractory cytopenia of childhood is the most common subtype of myelodysplastic syndrome in children. In this study, we compared the outcome of immunosuppressive therapy using horse antithymocyte globulin (n=46) with that using rabbit antithymocyte globulin (n=49) in 95 patients with refractory cytopenia of childhood and hypocellular bone marrow. The response rate at 6 months was 74% for horse antithymocyte globulin and 53% for rabbit antithymocyte globulin (P=0.

Apoptotic cells and clonally expanded cytotoxic T cells in bone marrow trephines of patients with myelodysplastic syndrome.

Aims: There is increasing evidence that autoimmunity is involved in the pathogenesis of myelodysplastic syndromes (MDS). We examined the number of apoptotic cells, and analysed the T cells and the T cell receptor gene rearrangements in bone marrow trephines of patients with low-grade MDS [refractory anaemia (RA), refractory anaemia with ringed sideroblasts (RAS) and refractory cytopenia with multilineage dysplasia (RCMD)] to investigate the correlation between T cells and apoptosis.

Methods And Results: Bone marrow trephines from 30 patients with RA, seven patients with RCMD, four patients with RAS and 11 normal bone marrow donors were stained for CD3 and for apoptotic cells using immunohistochemistry and terminal deoxynucleotidyl transferase 2'-deoxyuridine, 5'-triphosphate (dUTP) nick end labelling (TUNEL) technique, respectively.

Morphological differentiation of severe aplastic anaemia from hypocellular refractory cytopenia of childhood: reproducibility of histopathological diagnostic criteria.

Aims: To evaluate the reproducibility and reliability of the histomorphological criteria differentiating severe aplastic anaemia (SAA) and hypoplastic refractory cytopenia of childhood (RCC), the most frequently acquired hypocellular bone marrow conditions of childhood.

Methods And Results: We performed a double-blind interobserver study of 100 different cases of SAA and RCC among seven haematopathologists of the European Working Group of MDS in Childhood (EWOG-MDS) and the German SAA study. Cases with foci of typical myelodysplastic syndrome (MDS) morphology, such as patchy erythropoiesis with defective maturation, in an otherwise highly hypocellular or adipocytic bone marrow were classified as having RCC.

Spliceosomal gene aberrations are rare, coexist with oncogenic mutations, and are unlikely to exert a driver effect in childhood MDS and JMML.

Somatic mutations of the spliceosomal machinery occur frequently in adult patients with myelodysplastic syndrome (MDS). We resequenced SF3B1, U2AF35, and SRSF2 in 371 children with MDS or juvenile myelomonocytic leukemia. We found missense mutations in 2 juvenile myelomonocytic leukemia cases and in 1 child with systemic mastocytosis with MDS.

Classification of childhood aplastic anemia and myelodysplastic syndrome.

Hypoplastic BM disorders in children and adolescents comprise a broad spectrum of disorders. Acquired severe aplastic anemia (SAA), refractory cytopenia of childhood (RCC), a subtype of myelodysplastic syndrome (MDS), and inherited BM failure (IBMF) disorders are the main and most difficult hematological differential diagnoses. Whereas IBMF disorders can often be diagnosed by their clinical features and/or underlying genetic aberrations, the morphological distinction between SAA and hypocellular RCC has been controversial.

Diagnosis and classification of myelodysplastic syndrome: International Working Group on Morphology of myelodysplastic syndrome (IWGM-MDS) consensus proposals for the definition and enumeration of myeloblasts and ring sideroblasts.

The classification of myelodysplastic syndromes is based on the morphological criteria proposed by the French-American-British (FAB) and World Health Organization (WHO) groups. Accurate enumeration of blast cells, although essential for diagnosis of myelodysplastic syndrome and for assignment to prognostic groups, is often difficult, due to imprecise criteria for the morphological definition of blasts and promyelocytes. An International Working Group on Morphology of Myelodysplastic Syndrome (IWGM-MDS) of hematopathologists and hematologists expert in the field of myelodysplastic syndrome reviewed the morphological features of bone marrows from all subtypes of myelodysplastic syndrome and agreed on a set of recommendations, including recommendations for the definition and enumeration of blast cells and ring sideroblasts.

Myelodysplastic syndrome in children and adolescents.

Myelodysplastic syndromes (MDS) are clonal disorders characterized by ineffective hematopoiesis and subsequent frequent development of acute myeloid leukemia (AML). In children and adolescents, MDS are uncommon disorders, accounting for less than 5% of hematopoietic malignancy, with great heterogeneity in presentation and clinical course. The genetic changes predisposing children to MDS are largely obscure.

Immunosuppressive therapy with anti-thymocyte globulin and cyclosporine A in selected children with hypoplastic refractory cytopenia.

It is currently unknown whether immunosuppressive therapy or hematopoietic stem cell transplantation is the most appropriate treatment strategy for children with refractory cytopenia and normal karyotype or trisomy 8. We report on 31 children with hypoplastic refractory cytopenia treated with immunosuppressive therapy consisting of antithymocyte globulin and cyclosporine. At 6 months, 22 of 29 evaluable patients had a complete or partial response; a total of ten patients achieved a complete response at varying time points.

TERC mutations in children with refractory cytopenia.

Mutations in the human telomerase RNA gene (TERC) cause autosomal dominant dyskeratosis congenita and have been detected in individuals with bone marrow failure. Here, we screened for TERC mutations in a cohort of 80 children with hypocellular myelodysplastic syndrome and detected TERC alterations in two of them.