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Coronavirus disease-2019 in children has been linked to various clinical presentation, from paucisymptomatic cutaneous eruptions, to multisystemic inflammatory syndrome. We report the case of an 8-year-old boy who presented with persistent fever and pancytopenia, associated to a skin rash. An extensive etiological workup showed a positive serology for severe acute respiratory syndrome coronavirus 2 and Epstein-Barr virus. A few weeks later, type B acute lymphocytic leukemia was diagnosed. This case underlines the polymorphic appearance of coronavirus disease-2019 and the need for critical appraisal.

International audience; The nucleoside analogue, 2-chlorodeoxyadenosine (2CDA), was reported to be an active treatment for childhood Langerhans cell histiocytosis (LCH) without risk organ (RO−) involvement. However, we lack data on long-term effects of 2CDA treatment, including the disease reactivation rate, permanent sequelae and long-term tolerance. This study included 44 children from the French LCH registry, treated for a RO− LCH with 2CDA monotherapy (median number of six courses). The median age at the beginning of 2CDA was 3·6 years (range, 0·3–19·7 years) and the median follow-up after was 5·4 years (range, 0·6–15·1 years). Objective response to 2CDA was observed in 25 patients (56·8%), while six patients (13·6%) had stable disease and 13 patients (29·5%) exhibited progressive disease. Among patients without progression, only two experienced disease reactivation after 2CDA discontinuation. The five-year cumulative incidence of disease progression or reactivation after 2CDA therapy initiation was 34·3%. The lymphopenia reported in all cases [72% below absolute lymphocyte count (ALC) of 0·5 G/l], was addressed with appropriate prophylactic measures. Other toxicities above grade 2 were uncommon, and no second malignant neoplasm or neuropathy was reported. The five-year overall survival was 97·7%. In conclusion, we could confirm that 2CDA monotherapy was a beneficial long-term therapy for treating patients with RO− LCH. Appropriate management of induced immune deficiency is mandatory.

International audience; We describe the clinical, hematologic and genetic characteristics of a retrospective series of 126 subjects from 64 families with hereditary xerocytosis. Twelve patients from six families carried a KCNN4 mutation, five had the recurrent p.Arg352His mutation and one had a new deletion at the exon 7-intron 7 junction. Forty-nine families carried a PIEZO1 mutation, which was a known recurrent mutation in only one-third of the cases and private sequence variation in others; 12 new probably pathogenic missense mutations were identified. The two dominant features leading to diagnosis were hemolysis that persisted after splenectomy and hyperferritinemia, with an inconstant correlation with liver iron content assessed by magnetic resonance imaging. PIEZO1-hereditary xerocytosis was characterized by compensated hemolysis in most cases, perinatal edema of heterogeneous severity in more than 20% of families and a major risk of post-splenectomy thrombotic events, including a high frequency of portal thrombosis. In KCNN4-related disease, the main symptoms were more severe anemia, hemolysis and iron overload, with no clear sign of red cell dehydration; therefore, this disorder would be better described as a ‘Gardos channelopathy’. These data on the largest series to date indicate that PIEZO1-hereditary xerocytosis and Gardos channelopathy are not the same disease although they share hemolysis, a high rate of iron overload and inefficient splenectomy. They demonstrate the high variability in clinical expression as well as genetic bases of PIEZO1-hereditary xerocytosis. These results will help to improve the diagnosis of hereditary xerocytosis and to provide recommendations on the clinical management in terms of splenectomy, iron overload and pregnancy follow-up.

Transporter associated with antigen processing (TAP) is essential for the stabilization and surface expression of major histocompatibility complex class I molecules of all nucleated cells. TAP deficiency syndrome, also known as bare lymphocyte syndrome type I, is a rare primary immunodeficiency disorder. We report a case of TAP1 deficiency revealed by skin lesions long before the occurrence of respiratory infectious manifestations.

The most frequent germline mutations responsible for non syndromic congenital sideroblastic anemia are identified in ALAS2 and SLC25A38 genes. Iron overload is a key issue and optimal chelation therapy should be used to limit its adverse effects on the development of children. Our multicentre retrospective descriptive study compared the strategies for diagnosis and management of congenital sideroblastic anemia during the follow-up of six patients with an ALAS2 mutation and seven patients with an SLC25A38 mutation. We described in depth the clinical, biological and radiological phenotype of these patients at diagnosis and during follow-up and highlighted our results with a review of available evidence and data on the management strategies for congenital sideroblastic anemia. This report confirms the considerable variability in manifestations among patients with ALAS2 or SLC25A38 mutations and draws attention to differences in the assessment and the monitoring of iron overload and its complications. The use of an international registry would certainly help defining recommendations for the management of these rare disorders to improve patient outcome.

Matriptase-2 is a transmembrane serine protease that negatively regulates hepcidin expression by cleaving membrane-bound hemojuvelin. Matriptase-2 has a complex ectodomain, including a C-terminal serine protease domain and its activation requires an autocatalytic cleavage. Matriptase-2 mutations have been reported in several patients with iron-refractory iron deficiency anemia. Here we describe a patient with 2 missense mutations in the second class A low-density lipoprotein receptor (LDLRA) domain. Functional studies of these 2 mutations and of a previously reported mutation in the second C1r/C1s, urchin embryonic growth factor and bone morphogenetic protein 1 (CUB) domain were performed. Transfection of mutant cDNAs showed that membrane targeting of the 2 LDLRA mutants was impaired, with Golgi retention of the variants. The activating cleavage was absent for the LDLRA mutants and reduced for the CUB mutant. All 3 mutated proteins were still able to physically interact with hemojuvelin but only partially repressed hepcidin expression compared with wild-type matriptase-2. Our results underline the importance of LDLRA and CUB domains of matriptase-2.

We report the case of a 2-month-old infant with a single apparently ecchymotic lesion on the shoulder that raised suspicions of abuse. The medicolegal examination concluded that the appearance of the lesion was only mildly suggestive of an ecchymosis. A second, temporally remote examination confirmed this doubt. The evolution of the lesion, notably an increase in its volume, allowed us to rule out a traumatic lesion and was suggestive of a vascular tumor. The histological type of the tumor was a tufted angioma. There was thrombocytopenia and consumptive coagulopathy. All these data confirmed the diagnosis of Kasabach–Merritt syndrome. In contrast to benign infantile hemangiomas, which are frequent and well-known in clinical practice, vascular tumors complicated by Kasabach–Merritt syndrome are rare. They deserve to be widely known because they mandate rapid medical management and because they are one of the only differential diagnoses of ecchymosis, especially in children. When there is doubt about the traumatic nature of a cutaneous lesion, a temporally remote examination is essential. The evolution of the lesion may then suggest a dermatologic origin.

Background: A high frequency of virus infections has been recently pointed out in the exacerbations of asthma in children. Objectives: To confirm this, using conventional and molecular detection methods, and expanding the study to younger children. Study design: One hundred and thirty-two nasal aspirates from 75 children hospitalized for a severe attack of asthma were studied (32 infants, mean age 9.1 months; and 43 children, mean age 5.6 years). According to the virus, a viral isolation technique, immunofluorescence assays (IFA) or both were used for the detection of rhinovirus, enterovirus, respiratory syncytial (RS) virus, adenovirus, coronavirus 229E, influenza and parainfluenza virus. Polymerase chain reaction (PCR) assays were used for the detection of rhinovirus, enterovirus, RS virus, adenovirus, coronavirus 229E and OC43, Chlamydia pneumoniae and Mycoplasma pneumoniae. Results: Using IFA and viral isolation techniques, viruses were detected in 33.3% of cases, and by PCR techniques, nucleic acid sequences of virus, Chlamydia pneumoniae and Mycoplasma pneumoniae were obtained in 71.9% of cases. The combination of conventional and molecular techniques detects 81.8% of positive samples. Two organisms were identified in the same nasal sample in 20.4% of the cases. The percentage of detections was higher (85.9%) in the younger group than in the other (77%). The most frequently detected agents were rhinovirus (46.9%) and RS virus (21.2%). Using PCR rather than conventional techniques, the detection rates were increased 5.8- and 1.6-fold in rhinovirus and RS virus infections, respectively. The detection levels of the other organisms are as follows: 9.8, 5.1, 4.5, 4.5, 4.5, 3.7, and 2.2% for enterovirus, influenza virus, Chlamydia pneumoniae, adenovirus, coronavirus, parainfluenza virus, and Mycoplasma pneumoniae, respectively. Conclusion: These results confirm the previously reported high frequency of rhinovirus detection in asthmatic exacerbations in children. They also point out the frequency of RS virus detection, and emphasize the fact that PCR assays may be necessary to diagnose respiratory infections in asthma.

Nature Communications 4: Article number: 1884 (2013); Published: 21 May 2013; Updated: 23 September 2013. In the first paragraph of the Methods section in this Article, case 8 (K8 in Table 1) was incorrectly referred to as case 4. The following is the correct sentence: ‘Case 8 (ref. 3) and family 3 (refs 32, 33) were case reports, these patients expressed a moderate form of anaemia and haemolysis without initial evidence of perinatal oedema or pseudohyperkalaemia.

International audience; Dehydrated hereditary stomatocytosis is a genetic condition with defective red blood cell membrane properties that causes an imbalance in intracellular cation concentrations. Recently, two missense mutations in the mechanically activated PIEZO1 (FAM38A) ion channel were associated with dehydrated hereditary stomatocytosis. However, it is not known how these mutations affect PIEZO1 function. Here, by combining linkage analysis and whole-exome sequencing in a large pedigree and Sanger sequencing in two additional kindreds and 11 unrelated dehydrated hereditary stomatocytosis cases, we identify three novel missense mutations and one recurrent duplication in PIEZO1, demonstrating that it is the major gene for dehydrated hereditary stomatocytosis. All the dehydrated hereditary stomatocytosis-associated mutations locate at C-terminal half of PIEZO1. Remarkably, we find that all PIEZO1 mutations give rise to mechanically activated currents that inactivate more slowly than wild-type currents. This gain-of-function PIEZO1 phenotype provides insight that helps to explain the increased permeability of cations in red blood cells of dehydrated hereditary stomatocytosis patients. Our findings also suggest a new role for mechanotransduction in red blood cell biology and pathophysiology.

Background: "Drepagreffe" is a French national prospective trial involving 67 sickle cell anemia (SCA)-children with a history of abnormal cerebral arterial velocities by TCD, and comparing for the first time the outcome of cerebral vasculopathy following transfusion program (TP) or transplantation (HSCT). Inclusion criteria at enrollment were children with SCA (SS/Sb0), younger than 15 years, with a history of abnormal cerebral arterial velocities (TAMMX ≥ 200 cm/sec) and placed on long-term TP, with at least one non-SCA sibling, and with parents accepting HLA-typing and HSCT if a genoidentical donor was available. The 2 arms (TP/HSCT) were defined by the random-availability of a genoidentical donor. Seven of the 67 patients had a history of stroke. Transplanted patients (n=32) received a conditioning regimen of Busilvex-CY 200 mg/kg and 20 mg/kg rabbit Thymoglobulin, with CSA and a short course of MTX or MMF for GvHD prophylaxis. In the TP arm (n=35), HbS% was maintained at < 30%, with an Hb at 9-11g/dL. At enrollment and 12 months post-enrollment, blood screening, Doppler, and cerebral MRI/MRA were performed along with cognitive performance testing, the latter being done in parallel in the non-SCA siblings. Preliminary findings on cerebral velocities as the primary endpoint were reported at the last ASH meeting (abstract 67237), and demonstrated that all patients were alive at one year and that the 32 transplanted patients had no chronic GVHD and the same hemoglobin profile as their donor. Velocities were significantly lower post-HSCT than under TP (p Patients and Methods: We report here the cerebral imaging (MRI/MRA) and cognitive performance data performed at enrollment and after 12 months. The scoring applied for MRI was: 3 = territorial, 2 = borderzone (cortical and subcortical), 1 = white matter or basal ganglia infarcts, 0 to 3 = atrophia, and for MRA: 1 = mild stenosis (25-49%), 2 = moderate stenosis (50-74%), 3 = severe stenosis (75-99%), 4 = occlusion for each artery and 0 to 2 for Moya presence. Cognitive testing using the WPPSI-3 (3-6 yr), WISC-4 (7-16 yr) or WAIS-3 (>16 yr) scales, depending on the age, was performed in patients and in siblings when possible. Results: MRI/MRA data were available in 66/67 patients. At enrollment (M0), ischemic lesions and stenoses were present in 25 and 35/66 patients, respectively. Cognitive testing was obtained in 64 patients and 56 siblings. Paired analysis with siblings (Table 1) showed significant differences in Verbal Comprehension Index (VCI) with a mean difference of 7.6±14.5(p =0.0004), Processing Speed Index (PSI) 6.3±20.5 (p =0.04), and Full Scale IQ (FSIQ) 7.3±15.0 (p =0.01). After exclusion of the 7 patients with stroke history, significant differences were still observed in VCI (p =0.013) and FSIQ (p =0.019). Patient cognitive performance indexes were correlated negatively and significantly with the MRI and MRA scores (Table 2). At post-enrollment (M12),ischemic lesions and stenoses were present in 26/66 patients. The mean variation in MRI and MRA scores between M12 and M0 was not significantly different between the 2 arms (Table 3). The cognitive tests were performed at M12 in 60 patients (Table 4) and the performance indexes were improved in the TP compared to the HSCT arm, but only significantly for FSIQ. Conclusion This first prospective trial initially showed that HSCT reduces more significantly the cerebral velocities at M12 and in a higher proportion of patients than TP. Here, we show that patients with a history of abnormal cerebral velocities had significantly lower cognitive performances than their siblings, even in the absence of stroke history; however, there was no significant difference between the 2 arms for the outcomes of ischemic lesions and stenosis at M0 and M12. The fact that cognitive performances were improved in the TP compared to the HSCT arm might be explained by the stress of the HSCT procedure and the lack of schooling during this period. Despite the higher ability of HSCT to decrease velocities at M12 compared to TP, a longer follow-up will be required to demonstrate its effect on stenosis and cognitive performances; therefore, patients will be reassessed at 3 years post-HSCT. Disclosures Bernaudin: Novartis: Research Funding.

Abstract 462 Alpha hemoglobin stabilizing protein (AHSP), a small 102-residue protein previously known as erythroid differentiation-related factor (EDRF), is present only in erythroid cells, where it acts as a chaperone of α-Hb by forming a stable complex which prevents the aggregation of excess α-Hb that by precipitation would damage membrane structure and trigger cell death. AHSP knock-out mice exhibit ineffective erythropoiesis with reticulocytosis, abnormal erythrocyte morphology, intracellular inclusion bodies, and increased production of reactive oxygen species (ROS) with subsequent cellular oxidative damage as observed in thalassemias. A similar disorder involving AHSP has not yet been found in humans as a cause of thalasssemia. We report here a first case presenting such a syndrome, for a family originating from SE Asia. Their second child was referred to the hospital one month after birth, because of palor and anemia. Biological tests demonstrated a hemolytic microcytic anemia (Hb 6.9 g/dl, MCV : 73.2 fL and MCH 25 pg) and 3% Hb Bart's detected by CE-HPLC. No abnormality was revealed for the molecular screening for α-thal, including detection of common and rare α locus deletions using Gap-PCR and MLPA analysis, the sequencing of α1 and α2 genes, and the sequencing of the HS-40 core sequence. We considered thus the possibility for an abnormality of a modulator gene; the AHSP gene and its promoter region were sequenced. The proband was found to be homozygous for a mutation in exon 3 (c.167 T>G), while the parents and the first son were heterozygous for it. This mutation changes Val 56 to a Gly: the modified residue is not in direct contact with α-Hb but located in the corner between the three helices of the AHSP molecule and could play some role in the stability of the protein. To demonstrate that this abnormal AHSP could be the cause of the thalassemic syndrome, this molecule was produced as a Glutathione-S-transferase (GST) fusion protein by protein engineering in E.coli using both the pGEX6P-AHSP and the pGEX6P-α-AHSP co-expression vectors after site-directed mutagenesis. The yield of the mutated AHSP was lower than that of the wild type when solubilized suggesting that it was less stable than the normal. The kinetics of protein interaction indicate a factor of 2-3 decrease in the affinity. In addition a 20%-30% decrease in capture within GST micro-column of normal α-globin by the mutated recombinant GST-AHSP was observed. Studying the intragenic polymorphisms of the AHSP gene in this family, we observe that the mutated allele belongs to more weakly expressed “clade B” group and the two normal alleles to the “clade A” group as defined by Lai et al (BJH, 2006, 133, 675-682). Up to now, only 3 mutants have been described in the AHSP gene but none was found to impair the association with normal α-Hb chain. This case is thus the first evidence of an isolated α-thal not linked with the α locus but rather with a mutated AHSP. Heterozygous carriers for this AHSP mutation are clinically normal, but the homozygous patient having only the low expressed unstable AHSP presents a more severe α-thal syndrome than that caused by simple α-gene deletion(s). Disclosures: No relevant conflicts of interest to declare.