New KCNN4 Variants Associated With Anemia: Stomatocytosis Without Erythrocyte Dehydration.

The K+ channel activated by the Ca2+, KCNN4, has been shown to contribute to red blood cell dehydration in the rare hereditary hemolytic anemia, the dehydrated hereditary stomatocytosis. We report two de novo mutations on KCNN4, We reported two de novo mutations on KCNN4, V222L and H340N, characterized at the molecular, cellular and clinical levels. Whereas both mutations were shown to increase the calcium sensitivity of the K+ channel, leading to channel opening for lower calcium concentrations compared to WT KCNN4 channel, there was no obvious red blood cell dehydration in patients carrying one or the other mutation. The clinical phenotype was greatly different between carriers of the mutated gene ranging from severe anemia for one patient to a single episode of anemia for the other patient or no documented sign of anemia for the parents who also carried the mutation. These data compared to already published KCNN4 mutations question the role of KCNN4 gain-of-function mutations in hydration status and viability of red blood cells in bloodstream.

Germline mutations of the CBL gene define a new genetic syndrome with predisposition to juvenile myelomonocytic leukaemia.

BACKGROUND: CBL missense mutations have recently been associated with juvenile myelomonocytic leukaemia (JMML), an aggressive myeloproliferative and myelodysplastic neoplasm of early childhood characterised by excessive macrophage/monocyte proliferation. CBL, an E3 ubiquitin ligase and a multi-adaptor protein, controls proliferative signalling networks by downregulating the growth factor receptor signalling cascades in various cell types. METHODS AND RESULTS: CBL mutations were screened in 65 patients with JMML. A homozygous mutation of CBL was found in leukaemic cells of 4/65 (6%) patients. In all cases, copy neutral loss of heterozygosity of the 11q23 chromosomal region, encompassing the CBL locus, was demonstrated. Three of these four patients displayed additional features suggestive of an underlying developmental condition. A heterozygous germline CBL p.Y371H substitution was found in each of them and was inherited from the father in one patient. The germline mutation represents the first hit, with somatic loss of heterozygosity being the second hit positively selected in JMML cells. The three patients display a variable combination of dysmorphic features, hyperpigmented skin lesions and microcephaly that enable a 'CBL syndrome' to be tentatively delineated. Learning difficulties and postnatal growth retardation may be part of the phenotype. CONCLUSION: A report of germline mutations of CBL in three patients with JMML is presented here, confirming the existence of an unreported inheritable condition associated with a predisposition to JMML.

[Childhood acute lymphoblastic leukemia: 12 cases in Mali]. / Leucémie aiguë lymphoblastique de l'enfant: 12 observations au Mali.

INTRODUCTION: Data about childhood acute lymphoblastic leukemia, the most common childhood malignancy in industrialized countries, are scarce in African publications. The purpose of this prospective, unicentric study were to assess the socio-demographic, clinic and laboratory characteristics of the children treated for lymphoblastic leukemia in our pediatric oncology unit in Gabriel Touré Teaching Hospital in Bamako, Mali. PATIENTS AND METHODS: This study includes all children between 1 and 15 years old treated for cytologically documented acute lymphoblastic leukemia from January 1, 2007 to September 30, 2009. RESULTS: A total of 12 cases including 8 boys and 4 girls (sex ration, 2) were treated during the study period. Mean age was 92 months. Age was less than 4 years old in 2 cases. 5 (41,7%) were between 5 and 9 years in 5 (41.7%) and between 10 to 15 years in five. At the time of presentation, 9 patients (75%) were in a cachectic state; 10 had lymphadenopathies, splenomegaly and hepatomegaly; and 2 had neurological involvement. The delay for definitive diagnosis was 5 months in 4 cases (33,3 %) and less than 5 months in the remaining cases. Initial white blood cell count was more than 50 000/mm3 in 10 cases and less less than 50 000/mm3 in 2 cases. All patients were treated using the LAL GFAOP protocol including LAL1 in 6 cases, LAL2 in 5 and LAL3 in 1. Treatment complications were included 6 undocumented infections in 6 cases, hemorrhage in 2 and severe anemia in 4. Four patients died. At 5 years follow-up, overall survival rate was 66,7%. CONCLUSION: A multicentric study including a greater number of children is needed to increase understanding of the characteristics of childhood acute lymphoblastic leukemia in sub-Saharan Africa.

Is Acute Myeloblastic Leukemia in Children Under 2 Years of Age a Specific Entity? A Report from the FRENCH ELAM02 Study Group.

The clinical and biological characteristics of children under 2 years (infants) with acute myeloid leukemia (AML) are different from those of older children. We aimed to describe the specific characteristics of this population and the potential factors that influence the prognosis. We analyzed data concerning 438 children with newly-diagnosed AML treated in the ELAM02 protocol between March 2005 and December 2011, of which 103 were under 2 years old at diagnosis. The evaluation criteria were overall survival (OS) and event-free survival (EFS) of infants vs older children. The clinical and biological features were secondary criteria. Infants presented more frequent extra-medullary presentation than older children. They had a significantly higher proportion of skin lesions and central nervous system involvement (15% vs 3%, p < 0.0001 and 26% vs 12%, p = 0.0005, respectively). The global incidence of KMT2A rearrangements was nearly 55% for infants vs 11% for older children (p < 0.0001). Median 5-year OS was 70.4% for infants vs 71.4% for older children (p = 0.83). Five-year EFS was 67% for infants vs 58% for older children (p = 0.27). Infants with AML represent a cohort of patients with specific clinical and biological features. These remarkable differences had no significant impact on their outcome in the ELAM02 protocol.

[Tolerance and efficacy of atovaquone-proguanil for the treatment of paediatric imported Plasmodium falciparum malaria in France: clinical practice in a university hospital in Paris]. / Tolérance et efficacité de l'atovaquone-proguanil dans le traitement du paludisme d'importation àPlasmodium falciparum de l'enfant en France métropolitaine: expérience d'un centre hospitalier parisien.

UNLABELLED: Only few drugs for uncomplicated Plasmodium falciparum malaria are available in children. Atovaquone-proguanil is a recent antimalarial drug licensed in France for the uncomplicated P. falciparum malaria in adults. Few paediatric studies have evaluated atovaquone-proguanil in children for uncomplicated malaria in endemic area, but no study have evaluated this treatment for imported malaria. OBJECTIVE: To evaluate treatment by atovaquone-proguanil for uncomplicated and imported P. falciparum malaria in children. METHODS: We retrospectively evaluated the tolerance and the efficacy of atovaquone-proguanil in the children admitted in Robert-Debré Hospital (Paris) for a P. falciparum malaria. From January 2004 to December 2005, 48 children with a median age of 7,5 years (IQR 4-11) were treated with atovaquone-proguanil for a uncomplicated P. falciparum malaria, except for 5 children who had an isolated hyperparasitemia greater or equal to 5%. RESULTS: Atovaquone-proguanil was stopped for 3/48 children because of vomiting. Fever resolved in all the children between Day 3 and 7, following the beginning of the treatment. One child, with a favourable outcome, had a positive parasitemia at Day 4 equal to the initial parasitemia (0,1%). No late therapeutic failure was observed among the 24 children evaluated up to one month after starting treatment. CONCLUSION: Atovaquone-proguanil is an efficient and well-tolerated antimalarial treatment for uncomplicated P. falciparum malaria in children. The risk of vomiting should lead to a systematic initial hospitalisation of children treated with atovaquone-proguanil.

[Bone marrow examination of inherited diseases in children]. / Valeur diagnostique du myélogramme au cours des pathologies constitutionnelles de l'enfant.

Inherited diseases and metabolism inborn errors with hematologic abnormalities such as cytopenias are observed early in the infant or childhood. Most of them require an acute observation of the bone marrow to determine quantitative and qualitative morphological peculiarities of each cell line in order to charatherize cytological signs of these childhood hereditary diseases and differentiate them from acquired disorders, which are particularly frequent in pediatric. So, after a brief review of hematopoietic physiology in healthy neonates and infant, we'll consider the physiopathology and bone marrow aspect of the erythroid (Blackfan-Diamond anemia, congenital dyserythropoietic...), megacaryocytic (Wiskott-Aldrich syndrome, congenital amegakaryocytic thrombocytopenia...) and granulocytic cell line (Kostmann syndrome, WHIM syndrome...) in hereditary disorder. Considering the hematologic consequences of metabolism inborn errors and storage diseases, the last part of this review will be dedicated to the examination of the bone marrow encountered in those diseases such as mitochondrial cytopathy, orotic aciduria or lysinuric aciduria intolerance.

[Normal and abnormal cytological aspects of peripheral blood cells in neonates and young children]. / Aspect cytologique normal et pathologique du sang chez le nouveau-né et le jeune enfant.

Morphological alterations of blood cells are observed early in most hereditary disorders. Therefore, the cytological study of the blood cells is a must for the diagnosis of these disorders in neonates and children. Knowledge of the quantitative and qualitative physiological peculiarities of blood cells in neonates is mandatory for an accurate interpretation. In the present article, the main cytological characteristics of blood cells in healthy neonates and infants and their abnormalities associated with hereditary or acquired blood disorders are reviewed.

Performance evaluation of the Sysmex XN-1000 hematology analyzer in assessment of the white blood cell count differential in pediatric specimens.

INTRODUCTION: The automated XN-1000 hematology analyzer enables to perform a blood cell count and a leukocyte differential. When abnormal cells were detected, a flag was generated by the analyzer and a manual microscopic examination of the corresponding blood film was performed. METHODS: We compared the white blood cell differentials provided by the automated hematology analyzer XN-1000 in a pediatric population (n = 765) with those obtained through microscopic examination by cytologists and those obtained using a previous version of this analyzer, the XE-2100. Leukocytes count as well as flags sensitivity and specificity was analyzed. RESULTS: The leukocytes count provided by the analyzer is in good accordance with the differential obtained by manual count in children older than 3 months. The sensitivity for blast detection is 99% and the detection of reactive cells is 63%. The flag specificity remains low (<35%) for blood samples collected from infants between 8 days and 2 years of age, but increases up to 67% thereafter. The results obtained with the XN-1000 analyzer show an improvement in comparison with those obtained with the XE-2100 analyzer. CONCLUSION: The automated WBC differential provided by the XN-1000 analyzer in the pediatric setting is accurate, but a meticulous microscopic examination of blood smears remains necessary for infants up to 3 months of age to validate the analyzer flags.

Multicentric evaluation of the MDR phenotype in leukemia. French Network of the Drug Resistance Intergroup, and Drug Resistance Network of Assistance Publique-Hôpitaux de Paris.

The wide discrepancies in the frequency of 'positive' samples for multidrug resistance (MDR) phenotype within the same type of tumor observed in the literature justified the need for the definition of consensus recommendations. To define standard techniques of MDR phenotype measurement, we ran a large multicentric evaluation of the different methods available. Thirty-six French centers participated in the study, and 742 samples of 2-10 x 10(6) viable cells were sent by overnight express mail between December 1993 and February 1996. The same batches of MRK16, 4E3 and UIC2 were used. Nineteen samples of leukemia (12 AML, 1 ALL, 6 lymphoproliferative syndromes) and six leukemic cell lines with different levels of MDR expression were tested. Five meetings reached agreement concerning the guidelines for each technique, except immunocytochemistry. The 19 fresh samples were tested by each center using one to four techniques among cytofluorometry, immunocytochemistry, functional tests and RT-PCR. Five samples were diagnosed as 'negative' according to local criteria, with few discordant results (0 to 16% of 'positive' results). For all the 14 remaining samples, large discrepancies were observed from center to center, and from one technique to another. No correlations could be found between techniques. Flow cytometric analysis of cells already exposed to MRK16 or control IgG2A, fixed in paraformaldehyde and sent to centers did not reduce the discrepancies between centers in two of the four samples with moderate expression, emphasizing the role of histogram interpretation. The use of alternative monoclonal antibodies (4E3 and UIC2) did not reduce the discrepancies observed. In a second step, the K562 parental cell line, a low resistant subline (K562/HHT100, x7 resistance index to DNR) and a high resistant subline (K562/HHT300, x125 resistance index to DNR) were sent blindly three times, with an increasing level of recommendations for flow cytometry. Dramatic improvements were observed in cytometric results when the result was expressed as the ratio of arithmetic mean of fluorescence of antibody (10 microg of MRK16)/arithmetic mean of fluorescence of control (10 microg IgG2A): the proportion of expected results increased from 61 to 100% for K562, and from 37 to 85% for K562/HHT100. For uptake and drug efflux measurements, the use of 1 h uptake of 0.1 microM of rhodamine, followed by 1 h efflux +/-10 microM of verapamil, permitted an increased reproducibility of the technique from 71 to 100% for K562 and K562/HHT100. Whatever the technique used, concordant results were obtained for K562/HHT300. The immunocytochemistry, using several antibodies (MRK16, JSB1 and C219) gave many non-interpretable results (44%), due to a frequent high background and discordant results between antibodies in the same centers, and discordant conclusions between centers. The group does not recommend this technique for circulating tumoral cells.

[Reproductibility of the morphological identification of schisocytes and evaluation of non observer-dependent methods]. / Schizocytes : reproductibilité du diagnostic morphologique et intérêt de méthodes observateur-indépendantes.

Schistocytes are red blood cell fragments observed on a blood smear. They are a mark of mechanical haemolytic anaemias whose group of the thrombotic micro-angiopathies requires an urgent treatment. The detection of the schistocytes and sometimes their quantification are thus of primary importance. To evaluate this search for schistocytes, several surveys of practice were carried out (1999-2003) including pictures of blood fields (identification of schistocytes among abnormal red blood cells) near biologists of variable level of specialization. The aim was to try to lead to a consensus, in particular for the morphological criterias of identification. Our results indicated that: 1) the biologists are badly sensitized with the importance of this research and the consequences of their response for the diagnosis; 2) the morphological identification of the schistocytes is difficult with an important variability of the criteria according to the observers. An investigation overviewed by the French Group of Cellular Hematology (Delphi method) allowed the development of a morphological consensus (fragments of triangular/crescent/helmet forms with rectilinear zone testifying to the zone of break). In order to cancel the observer-dependent identification of the schistocytes, a software of morphometric analysis (Q-WIN, Leica) was developed for sorting, starting from digitalized microscopic fields, the fragmented - among the normal - red blood cells. The results appeared encouraging, but not yet optimized. An automated analyzer (Bayer ADVIA 120) was also evaluated for the measurement of the schizocytes ("fragmented red blood cells" parameter). The moderate over-estimation of the real schizocytes (+ 0,4%) encouraged to observe the clinical value of the fragmented red blood cells detection in a group of patients that undergone a bone-marrow transplantation. The predictive value of the test (98%) was satisfactory.

Translocation t(1;19) in acute lymphoblastic leukemia patients with cytological presentation simulating L3-ALL (Burkitt-like).

The t(1;19) in B-lineage ALL is classically associated with a FAB L1/L2 phenotype and the expression of cIg. Recent reports have demonstrated immuno-phenotypic and molecular heterogeneity among cases demonstrating apparently identical karyotypic abnormalities. We report 5 cases of t(1;19) with cytological features resembling an L3 (Burkitt-like) phenotype, suggesting that accurate assessment of these cases requires detailed correlation of cytological, immunological and molecular characteristics.

Myelodysplastic syndromes in childhood: is the FAB classification relevant? Report of 81 children from a French multicentre study. French Group of Cellular Hematology.

We reviewed the peripheral blood and bone marrow smears of 81 children with myelodysplastic syndrome (MDS). The morphological FAB classification was applicable in 59 children (72.8%): RAEB and RAEBt were the most frequent, 32 cases (39.5%). CMML was observed in 15 cases (18.5%) and in 25% of them, serological evidence for a recent EBV infection was demonstrated. In 22 cases (27.2%), the FAB classification was not convenient. In some of these children, dysmyelopoiesis was associated with constitutional disorders. Among these various inherited conditions, Down syndrome in which myelodysplasia is the expression of an abnormal clonal hematopoiesis, and mitochondrial cytopathies in which MDS is the hematological expression of a polyclonal multi-organ disease. The FAB classification does not appear to be satisfactory for all the disorders included in the group of childhood MDS and should be modified for specific use in children.

[Role of the biologist in the study of schistocytes]. / Rôle du biologiste confronté à la recherche de schizocytes.

The appearance of schistocytes in a peripheral blood film is considered to be an important diagnostic marker for thrombotic microangiopathy. However, the morphological analysis of schistocytes remains uneasy. To determine practice patterns in the biological management of schistocytosis, the French Group of Cellular Hematology from the French Society of Hematology conducted a survey on the approach of the diagnosis of microangiopathy. A guideline is proposed in order to cancel the substantial variation among biologists.

[Elective phagocytosis of polynuclear neutrophils caused by medullary macrophages and autoimmune neutropenia in children]. / Phagocytose èlective de polynucléaires neutrophiles par les macrophages médullaires et neutropénie auto-immune de l'enfant.

UNLABELLED: Autoimmune neutropenia (AIN) is a frequent cause of chronic neutropenia especially in youngest children. Its diagnosis is established by immunological proof of the autoimmune mechanism. The aim of this study is to better describe this autoimmune process and to show the contribution of bone marrow smears to this diagnosis. PATIENTS AND METHODS: Ten children, six girls and four boys, were examined between 1990 and 1995. Eight of them had typical AIN, confirmed by the presence of antibodies against neutrophils. Two other patients were included on the basis of bone marrow pictures. Five non-neutropenic children with normal bone marrow smears were chosen as controls. Bone marrow analysis was always performed by the same cytologist according to a reproducible technique. RESULTS: Six out of ten patients had important features of elective phagocytosis of neutrophils by marrow macrophages (unlike controls) without signs of dysgranulopoiesis or hemophagocytosis. Antibodies against neutrophils were detected in six patients with phagocytosis and in four patients without these cytological features. In two other children presenting the same bone marrow picture and clinical profile, an autoimmune process was probable, even in the absence of antibodies against neutrophils. Some patients had several infections and were given immunoglobulins and/or granulocyte colony-stimulating factor (G-CSF) therapy. The efficacy of Immunoglobulin was not constant, whereas G-CSF was effective at low doses and shortened the duration of infections. CONCLUSION: Prolonged neutropenia in childhood must lead to look for phagocytosis by marrow macrophages in bone marrow smears, as a possible sign of autoimmunity. Growth factors may temporarily be used associated with antibiotics therapy in severe and prolonged infections.

[Hematologic manifestations of inborn errors of metabolism]. / Manifestations hématologiques dans les erreurs innées du métabolisme.

Haematological symptoms can be helpful for the diagnosis of metabolic diseases. A megaloblastic anemia orientates to folate and cobalamine anomalies when associated with homocystinemia and decreased plasma methionine levels, or to congenital oroticuria (hypochromia), Pearson syndrome (sideroblasts and vacuolisation of precursors) and thiamine transporter abnormality (sideroblasts) in the absence of homocystinuria. An hemolytic anemia orientates to anomalies of anaerobic glycolysis, heme synthesis, or iron metabolism, and Wilson disease. A pancytopenia orientates to organic aciduria, lysinuric protein intolerance, mevalonic aciduria and lysosomal storage diseases (Gaucher, Niemann Pick, Wolman) when hepatosplenomegaly is present. Uremic hemolytic syndrome and hemophagocytic lymphohistiocytosis respectively orientate to B12 anomalies, lysinuric protein intolerance, lysosomal storage diseases and organic aciduria.

[Neonatal alloimmune neutropenias. Importance of treatment with granulocyte colony-stimulating factor (G-CSF). Report of 2 new cases]. / Neutropénies allo-immunes néonatales. Intérêt du traitement par facteur de croissance granuleux (G-CSF). Deux nouvelles observations.

UNLABELLED: Alloimmune neonatal neutropenia is a rare event. Usually asymptomatic, it may however in some cases result in a severe sepsis. Treatment with recombinant granulocyte colony-stimulating factor (G-CSF) has been recently proposed. CASE REPORT: We report two new cases in infected newborns of a successful treatment of alloimmune neonatal neutropenia with G-CSF, resulting in complete neutrophil recovery in less than 72 hours. Moreover, the treatment was well tolerated. CONCLUSION: The analysis of these two cases and of those previously reported indicates that G-CSF represents the first-choice treatment in this affection when infectious signs are present in the neonate.

[Lysinuric dibasic protein intolerance: characteristic aspects of bone marrow involvement]. / Intolérance aux protéines dibasiques avec lysinurie: aspect caractéristique de l'atteinte médullaire.

BACKGROUND: The marrows of patients with lysinuric protein intolerance (LPI) are generally considered as normal, even though autoerythrophagocytosis has been observed in some of them. CASE REPORTS: Lysinuric protein intolerance was recognized in two 12 and 15-year-old brothers who had been diagnosed following an immuno-hematological investigation. Clinical history had been characterized by a neonatal macrophage activation syndrome (hepatosplenomegaly, pancytopenia, hypofibrinogenemia and hypertriglyceridemia). A putative diagnosis of familial lymphohistiocytosis had been ruled out because of unusual clinical and immunological course. Both brothers had displayed chronic aversion to high-protein foods, failure to thrive, osteoporosis and developmental delay. Metabolic investigations had revealed chronic hyperammonemia while cationic aminoaciduria (lysine, arginine and ornithine) was only present during L-citrulline supplementation. Bone marrow examinations had been performed during the neonatal period and during later metabolic investigations. They both displayed a peculiar red cell and granulocytes phagocytosis by histiocytes and granulocytes precursors. CONCLUSIONS: This aspect of bone marrow could be considered as a specific sign of LPI. This report suggests that appropriate metabolic investigations should be performed in any unexplained macrophage activation syndrome.

[Epidemiology and prognosis of childhood cancers at Gabriel-Touré Teaching Hospital (Bamako, Mali)]. / Épidémiologie et pronostic des cancers pédiatriques au CHU Gabriel-Touré de Bamako (Mali).

UNLABELLED: Cancer today is being treated as a public health problem in Africa, as in developed countries. OBJECTIVE: The aim of this retrospective study was to evaluate the epidemiology and outcome of children treated in the Pediatric Oncology Unit of Gabriel Touré Teaching Hospital in Bamako (Mali), six years after it opened. METHODS: Retrospective study of the files of all children aged 15 and younger diagnosed with cancer and treated by chemotherapy between January 1, 2005, and December 31, 2010. RESULTS: The study included 690 children. Their mean age was 24 months. The time from observation of first symptoms to consultation was less than 3 months in 200 cases (29%), from 3 to 10 months in 256 (37.1%), and more than 10 months in 234 (33.9%). The five most common childhood cancers were malignant non-Hodgkin's lymphoma (NHL) (n=231, 33.5%), retinoblastoma (n=170, 24.6%), nephroblastoma (n=102, 14.8%), acute lymphoblastic leukemia (n=54, 7%), and Hodgkin's disease (n=34, 4%). Six years after the unit opened and after a mean follow-up of 3 years, we recorded 272 deaths (39.4%); at least 238 children are still alive (34.5%), with 180 cases (26.1%) lost to follow-up. CONCLUSION: Childhood cancer survival is still low in Mali, and the rate of loss to follow-up quite high.

An intragenic ERG deletion is a marker of an oncogenic subtype of B-cell precursor acute lymphoblastic leukemia with a favorable outcome despite frequent IKZF1 deletions.

Oncogenic subtypes in childhood B-cell precursor acute lymphoblastic leukemia (BCP-ALL) are used for risk stratification. However, a significant number of BCP-ALL patients are still genetically unassigned. Using array-comparative genomic hybridization in a selected BCP-ALL cohort, we characterized a recurrent V(D)J-mediated intragenic deletion of the ERG gene (ERG(del)). A breakpoint-specific PCR assay was designed and used to screen an independent non-selected cohort of 897 children aged 1-17 years treated for BCP-ALL in the EORTC-CLG 58951 trial. ERG(del) was found in 29/897 patients (3.2%) and was mutually exclusive of known classifying genetic lesions, suggesting that it characterized a distinct leukemia entity. ERG(del) was associated with higher age (median 7.0 vs. 4.0 years, P=0.004), aberrant CD2 expression (43.5% vs. 3.7%, P<0.001) and frequent IKZF1 Δ4-7 deletions (37.9% vs. 5.3%, P<0.001). However, ERG(del) patients had a very good outcome, with an 8-year event-free survival (8-y EFS) and an 8-year overall survival of 86.4% and 95.6%, respectively, suggesting that the IKZF1 deletion had no impact on prognosis in this genetic subtype. Accordingly, within patients with an IKZF1 Δ4-7 deletion, those with ERG(del) had a better outcome (8-y EFS: 85.7% vs. 51.3%; hazard ratio: 0.16; 95% confidence interval: 0.02-1.20; P=0.04). These findings have implications for further stratification including IKZF1 status.