Intravenous immunoglobulin vs observation in childhood immune thrombocytopenia: a randomized controlled trial.

Management of children with newly diagnosed immune thrombocytopenia (ITP) consists of careful observation or immunomodulatory treatment. Observational studies suggest a lower risk for chronic ITP in children after intravenous immunoglobulin (IVIg) treatment. In this multicenter randomized trial, children aged 3 months to 16 years with newly diagnosed ITP, platelet counts 20 × 109/L or less, and mild to moderate bleeding were randomly assigned to receive either a single infusion of 0.8 g/kg IVIg or careful observation. Primary outcome was development of chronic ITP, which at the time of study initiation was defined as a platelet count lower than 150 × 109/L after 6 months. Two hundred six children were allocated to receive IVIg (n = 102) or careful observation (n = 104). Chronic ITP occurred in 18.6% of the patients in the IVIg group and 28.9% in the observation group (relative risk [RR], 0.64; 95% confidence interval [CI], 0.38-1.08). Platelet counts lower than 100 × 109/L at 12 months (current definition of chronic ITP) were observed in 10% of children in the IVIg group and 12% in the observation group (RR, 0.83; 95% CI, 0.38-1.84). Complete response rates in the first 3 months were significantly higher in the IVIg group. Immunoglobulin G Fc receptor IIb genetic variations were associated with early complete response in both groups. Grade 4 to 5 bleeding occurred in 9% of the patients in the observation group vs 1% in the IVIg group. This trial was registered at www.trialregister.nl as NTR 1563.

Bleeding phenotype and diagnostic characterization of patients with congenital platelet defects.

Phenotypic characterization of congenital platelet defects (CPDs) could help physicians recognize CPD subtypes and can inform on prognostic implications. We report the analyses of the bleeding phenotype and diagnostic characteristics of a large cohort of adult patients with a confirmed CPD. A total of 96 patients were analyzed and they were classified as Glanzmann thrombasthenia, Bernard-Soulier syndrome, dense granule deficiency, defects in the ADP or thromboxane A2 (TxA2) pathway, isolated thrombocytopenia or complex abnormalities. The median ISTH-BAT bleeding score was nine (IQR 5-13). Heavy menstrual bleeding (HMB) (80%), post-partum hemorrhage (74%), post-operative bleeds (64%) and post-dental extraction bleeds (57%) occurred most frequently. Rare bleeding symptoms were bleeds from the urinary tract (4%) and central nervous system (CNS) bleeds (2%). Domains with a large proportion of severe bleeds were CNS bleeding, HMB and post-dental extraction bleeding. Glanzmann thrombasthenia and female sex were associated with a more severe bleeding phenotype.

The phenotypic spectrum of germline YARS2 variants: from isolated sideroblastic anemia to mitochondrial myopathy, lactic acidosis and sideroblastic anemia 2.

YARS2 variants have previously been described in patients with myopathy, lactic acidosis and sideroblastic anemia 2 (MLASA2). YARS2 encodes the mitochondrial tyrosyl-tRNA synthetase, which is responsible for conjugating tyrosine to its cognate mt-tRNA for mitochondrial protein synthesis. Here we describe 14 individuals from 11 families presenting with sideroblastic anemia and YARS2 variants that we identified using a sideroblastic anemia gene panel or exome sequencing. The phenotype of these patients ranged from MLASA to isolated congenital sideroblastic anemia. As in previous cases, inter- and intra-familial phenotypic variability was observed, however, this report includes the first cases with isolated sideroblastic anemia and patients with biallelic YARS2 variants that have no clinically ascertainable phenotype. We identified ten novel YARS2 variants and three previously reported variants. In vitro amino-acylation assays of five novel missense variants showed that three had less effect on the catalytic activity of YARS2 than the most commonly reported variant, p.(Phe52Leu), associated with MLASA2, which may explain the milder phenotypes in patients with these variants. However, the other two missense variants had a more severe effect on YARS2 catalytic efficiency. Several patients carried the common YARS2 c.572 G>T, p.(Gly191Val) variant (minor allele frequency =0.1259) in trans with a rare deleterious YARS2 variant. We have previously shown that the p.(Gly191Val) variant reduces YARS2 catalytic activity. Consequently, we suggest that biallelic YARS2 variants, including severe loss-of-function alleles in trans of the common p.(Gly191Val) variant, should be considered as a cause of isolated congenital sideroblastic anemia, as well as the MLASA syndromic phenotype.

Pediatric Diamond-Blackfan anemia in the Netherlands: An overview of clinical characteristics and underlying molecular defects.

INTRODUCTION: Diamond-Blackfan anemia (DBA) is characterized by hypoplastic anemia, congenital anomalies, and a predisposition for malignancies. Most of our understanding of this disorder stems from molecular studies combined with extensive data input from international patient registries. OBJECTIVES: To create an overview of the pediatric DBA population in the Netherlands. METHODS: Forty-three patients diagnosed with DBA from all Dutch university pediatric hospitals were included in this study, and their clinical and genetic characteristics were collected from patient records. RESULTS: Congenital malformations were present in 24 of 43 patients (55.8%). An underlying genetic defect was identified in 26 of 43 patients (60.5%), the majority of which were found in the RPS19 gene (12 of 43, 27.9%) with 1 patient carrying a mutation in a novel DBA candidate gene, RPL9. In 31 of 35 (88.6%) patients, an initial response to glucocorticoid treatment was observed. Six patients (14.0%) underwent hematopoietic stem cell transplantation, and eleven patients (11 of 43, 25.6%) became treatment-independent spontaneously. CONCLUSION: In agreement with previous reports, the Dutch pediatric DBA population is both clinically and genetically heterogeneous. National and international registries, together with more extensive genetic testing, are crucial to increase our understanding of genotype and phenotype correlations of this intriguing disorder.

Familial macrothrombocytopenia due to a double mutation in cis in the alpha-actinin 1 gene (ACTN1), previously considered to be chronic immune thrombocytopenic purpura.

Congenital thrombocytopenia can easily be misdiagnosed as immune thrombocytopenic purpura, as is illustrated by this case of a woman and her two children. Doubts arose when steroid/IVIG therapy failed in the mother and the thrombocytopenia in the children persisted. By means of next-generation sequencing, two missense variants in cis in the ACTN1 gene of the affected family members were identified, both of unknown significance. We conclude, after further analysis of these mutations with, among others, in silico prediction tools, that the thrombocytopenia has a genetic cause, in particular the ACTN1 mutations, and is not immune mediated.

Severe Ankyrin-R deficiency results in impaired surface retention and lysosomal degradation of RhAG in human erythroblasts.

Ankyrin-R provides a key link between band 3 and the spectrin cytoskeleton that helps to maintain the highly specialized erythrocyte biconcave shape. Ankyrin deficiency results in fragile spherocytic erythrocytes with reduced band 3 and protein 4.2 expression. We use in vitro differentiation of erythroblasts transduced with shRNAs targeting ANK1 to generate erythroblasts and reticulocytes with a novel ankyrin-R 'near null' human phenotype with less than 5% of normal ankyrin expression. Using this model, we demonstrate that absence of ankyrin negatively impacts the reticulocyte expression of a variety of proteins, including band 3, glycophorin A, spectrin, adducin and, more strikingly, protein 4.2, CD44, CD47 and Rh/RhAG. Loss of band 3, which fails to form tetrameric complexes in the absence of ankyrin, alongside GPA, occurs due to reduced retention within the reticulocyte membrane during erythroblast enucleation. However, loss of RhAG is temporally and mechanistically distinct, occurring predominantly as a result of instability at the plasma membrane and lysosomal degradation prior to enucleation. Loss of Rh/RhAG was identified as common to erythrocytes with naturally occurring ankyrin deficiency and demonstrated to occur prior to enucleation in cultures of erythroblasts from a hereditary spherocytosis patient with severe ankyrin deficiency but not in those exhibiting milder reductions in expression. The identification of prominently reduced surface expression of Rh/RhAG in combination with direct evaluation of ankyrin expression using flow cytometry provides an efficient and rapid approach for the categorization of hereditary spherocytosis arising from ankyrin deficiency.

Clinical Course of Two Children with Unstable Hemoglobins: The Effect of Hydroxyurea Therapy.

Case reports on the effect of hydroxyurea (HU) therapy for unstable hemoglobins (Hbs) are sparse; only three adult cases have been reported. We report for the first time on the effect of HU therapy in children carrying unstable Hbs. The first case concerns a female child with a familial history of chronic hemolytic anemia. She was diagnosed with Hb Volga (HBB: c.83C>A) at the age of 7 months. At age 6, treatment options were reconsidered due to increasing fatigue and decreasing Hb concentration. The second case also concerns a female child with chronic hemolytic anemia and icterus since the age of 5. She was diagnosed with Hb Köln (HBB: c.295G>A) at the age of 9. At age 10, treatment options were reconsidered due to decreased general condition and poor school performance. Both children were started on HU therapy. The child with Hb Volga showed reduced clinical symptoms and increased average Hb concentrations. She has been on HU therapy for over 7 years at preparation of this manuscript. The child with Hb Köln showed decreasing Hb concentrations upon start of therapy; clinical symptoms did not improve. Therapy was discontinued after 3½ months. The Hb Volga case report suggests that HU therapy could improve clinical symptoms in some patients with unstable Hbs. Based on these and previously published cases, it was speculated that response can be predicted by the percentage of Hb F and reticulocyte counts.

Bleeding spectrum in children with moderate or severe von Willebrand disease: Relevance of pediatric-specific bleeding.

The bleeding phenotype of children with von Willebrand disease (VWD) needs to be characterized in detail to facilitate diagnosis during childhood and aid in the planning and assessment of treatment strategies. The objective was to evaluate the occurrence, type, and severity of bleeding in a large cohort of children with moderate and severe VWD. We included 113 children (aged 0-16 years) with Type 1 (n = 60), 2 (n = 44), and 3 (n = 9) VWD with von Willebrand factor (VWF) antigen and/or VWF ristocetin cofactor levels ≤ 30 U/dL from a nation-wide cross-sectional study ("Willebrand in the Netherlands" study). Bleeding severity and frequency were determined using the International Society on Thrombosis and Hemostasis-Bleeding Assessment Tool (ISTH-BAT) with supplementary pediatric-specific bleeding symptoms (umbilical stump bleeding, cephalohematoma, cheek hematoma, conjunctival bleeding, postcircumcision and postvenipuncture bleeding). We found that all 26 postmenarche girls experienced menorrhagia. Other common bleedings were cutaneous (81%), oropharyngeal (64%), prolonged bleeding from minor wounds (58%), and epistaxis (56%). Pediatric-specific bleeding symptoms were present in 44% of patients. ISTH-BAT bleeding score was higher in index cases than in affected family members (median, 12.0 vs. 6.5, P < 0.001), higher in Type 3 VWD than in Type 2 or 1 (17.0 vs. 10.5 or 6.5, P < 0.001) and higher in children with severe (<10 U/dL) than moderate VWD (10-30 U/dL) (11.0 vs. 7.0, P < 0.001). Frequency of any bleeding, epistaxis, and oral cavity was higher in types 2 and 3 than in Type 1 VWD and was associated with VWF levels. We conclude that pediatric-specific bleeding symptoms occurred in a large proportion of children with moderate or severe VWD and should be included when evaluating children for VWD.

The prognostic significance of early treatment response in pediatric relapsed acute myeloid leukemia: results of the international study Relapsed AML 2001/01.

The prognostic significance of early response to treatment has not been reported in relapsed pediatric acute myeloid leukemia. In order to identify an early and easily applicable prognostic factor allowing subsequent treatment modifications, we assessed leukemic blast counts in the bone marrow by morphology on days 15 and 28 after first reinduction in 338 patients of the international Relapsed-AML2001/01 trial. Both day 15 and day 28 status was classified as good (≤20% leukemic blasts) in 77% of patients. The correlation between day 15 and 28 blast percentages was significant, but not strong (Spearman correlation coefficient = 0.49, P<0.001). Survival probability decreased in a stepwise fashion along with rising blast counts at day 28. Patients with bone marrow blast counts at this time-point of ≤5%, 6-10%, 11-20% and >20% had 4-year probabilities of survival of 52%±3% versus 36%±10% versus 21%±9% versus 14%±4%, respectively, P<0.0001; this trend was not seen for day 15 results. Multivariate analysis showed that early treatment response at day 28 had the strongest prognostic significance, superseding even time to relapse (< or ≥12 months). In conclusion, an early response to treatment, measured on day 28, is a strong and independent prognostic factor potentially useful for treatment stratification in pediatric relapsed acute myeloid leukemia. This study was registered with ISRCTN code: 94206677.

Occurrence of FVIII Inhibitors in Hemophilia A Patients Following an Institutional Switch to a Third Generation B-Domain-Deleted FVIII.

In 2018, Refacto AFR, a B-domain-deleted third-generation FVIII concentrate, became our preferential product. After the introduction, the development of inhibitors was prospectively monitored; retrospectively, we sought for risk factors in the patients who developed a de-novo inhibitor. Over a period of 15 months, 4/19 adult patients with non-severe haemophilia who were treated on demand for surgery, developed high titer antibodies to FVIII after administration of Refacto AFR; 5/52 mostly severe patients on prophylaxis, developed an inhibitor (3 ≥ 0.1 BU; 1 > 0.6 BU, 1 high titre) after they switched to Refacto AFR; all were children <14 years of age and with >100 exposure days, none related to surgery or intensive treatment; all received KovaltryR before. In conclusion: inhibitors were encountered in on demand patients and previously treated prophylaxis patients; this observation might be a coincidental finding, but also risk factors like genotype and surgery and/or that Refacto AFR is more immunogenic should be considered. For the patients on prophylaxis we hypothesize that loss of tolerance by preceding KovaltryR might have contributed to inhibitor development.

Erroneous exchange of asparaginase forms in the treatment of acute lymphoblastic leukemia.

For the treatment of children with acute lymphoblastic leukemia (ALL), Dutch pediatric oncologists use the Dutch Childhood Oncology Group ALL 10 protocol. This protocol is complex, as it comprises many different drug regimens. One of the drugs is asparaginase which is available in different forms with different pharmacokinetics: Escherichia coli asparaginase, Erwinia asparaginase, and pegylated E. coli asparaginase [polyethylene glycol (PEG) asparaginase]. Here, we report the case of a 3-year-old patient treated with ALL who was 8 times erroneously treated with E. coli asparaginase instead of PEG asparaginase. As E. coli asparaginase was administered to the patient in the lower dosage regimen of PEG asparaginase, she was undertreated, but at the end of the treatment the patient was in complete remission. This case report describes the actual course of treatment, the reasons why it went wrong, and possible preventive measures.

Free air intraperitoneally during chemotherapy for acute lymphoblastic leukemia: consider pneumatosis cystoides intestinalis.

Intraperitoneal free air in a child with acute lymphoblastic leukemia (ALL) treated with induction chemotherapy is an ominous sign suspective of gastrointestinal perforation. We report a case of pneumatosis cystoides intestinalis (PCI) with free intraperitoneal air without bowel perforation in a child with Down syndrome during ALL induction treatment. PCI is a physical sign characterized by gas-filled cysts of the submucosa or subserosa of the bowel that can lead to pneumoperitoneum. Clinical management of this case in respect to reported literature on PCI and specific characteristics of patients treated with ALL induction chemotherapy are discussed.

Congenital platelet disorders and health status-related quality of life.

BACKGROUND: Patients with congenital blood platelet disorders (CPDs) demonstrate a predominantly mucocutaneous bleeding tendency. Repeated bleeds throughout life can have a significant impact on health status-related quality of life (HR-QoL), but few studies have investigated HR-QoL in patients with CPDs. OBJECTIVES: To determine HR-QoL in patients with suspected or confirmed CPDs as compared with the general Dutch population and to assess the association between bleeding phenotype and HR-QoL. METHODS: Data were derived from the Thrombocytopathy in the Netherlands (TiN) study, a cross-sectional study of individuals suspected for a congenital platelet defect. TiN patients with an increased ISTH Bleeding Assessment Tool (ISTH-BAT) score (>3 in men and > 5 in women) were included for analysis. HR-QoL was assessed with the Short Form (SF)-36 survey. Bleeding symptoms were evaluated with the ISTH-BAT, resulting in a bleeding score. RESULTS: One hundred fifty-six patients were analyzed, of whom 126 (81%) were women. Sixty-two patients (40%) had a confirmed CPD. Compared to the general Dutch population, patients with a suspected or confirmed CPD reported decreased physical functioning, limitations in daily activities due to physical health problems, limitations in social activities, decreased energy levels and fatigue, pain, and lower general health status. HR-QoL was not correlated with the ISTH-BAT score and was similar in patients with a confirmed CPD and those in whom a CPD could not be diagnosed. CONCLUSION: A bleeding tendency in patients with a suspected or confirmed CPD significantly impacts HR-QoL, independent of a confirmed explanatory diagnosis.

Flow cytometric mepacrine fluorescence can be used for the exclusion of platelet dense granule deficiency.

BACKGROUND: δ-storage pool disease (δ-SPD) is a bleeding disorder characterized by a reduced number of platelet-dense granules. The diagnosis of δ-SPD depends on the measurement of platelet ADP content, but this test is time consuming and requires a relatively large blood volume. Flow cytometric analysis of platelet mepacrine uptake is a potential alternative, but this approach lacks validation, which precludes its use in a diagnostic setting. OBJECTIVES: To evaluate the performance of platelet mepacrine uptake as a diagnostic test for δ-SPD. PATIENTS/METHODS: Mepacrine fluorescence was determined with flow cytometry before and after platelet activation in 156 patients with a suspected platelet function disorder and compared with platelet ADP content as a reference test. Performance was analyzed with a receiver operating characteristic (ROC) curve. RESULTS: Eleven of 156 patients had δ-SPD based on platelet ADP content. Mepacrine fluorescence was inferior to platelet ADP content in identifying patients with δ-SPD, but both mepacrine uptake (area under the ROC curve [AUC] 0.87) and mepacrine release after platelet activation (AUC 0.80) had good discriminative ability. In our tertiary reference center, mepacrine uptake showed high negative predicitive value (97%) with low positive predictive value (35%). Combined with a negative likelihood ratio of 0.1, these data indicate that mepacrine uptake can be used to exclude δ-SPD in patients with a bleeding tendency. CONCLUSION: Mepacrine fluorescence can be used as a screening tool to exclude δ-SPD in a large number of patients with a suspected platelet function disorder.

Possible lower rate of chronic ITP after IVIG for acute childhood ITP an analysis from registry I of the Intercontinental Cooperative ITP Study Group (ICIS).

In children, one-third of immune thrombocytopenic purpura (ITP) patients follow a chronic course. The present study investigated whether treatment with intravenous immunoglobulin (IVIG) at the time of diagnosis of ITP is of prognostic significance, using data from 1984 children entered in Registry I of the Intercontinental Cooperative ITP Study Group. A matched pairs analysis compared children with thrombocytopenia (platelet count <150 x 10(9)/l) 6 months following diagnosis with children whose platelet count was normal 6 months after diagnosis. It was found that children initially treated with IVIG were more likely to have a normal platelet count 6 months after diagnosis than children not receiving IVIG (odds ratio 1.81; 95% confidence interval: 1.25-2.64). This result was independent of age, gender, country of origin, platelet count at diagnosis or infection preceding the diagnosis of ITP. In a similar analysis, comparing children with a platelet count <50 x 10(9)/l 6 months after diagnosis with children whose platelet count was > or =50 x 10(9)/l at that time point, the former group was less often treated with IVIG than with steroids (P = 0.02). Prospective studies are required to further explore this potential effect of IVIG.

Effects of age and genetic variations in VKORC1, CYP2C9 and CYP3A4 on the phenprocoumon dose in pediatric patients.

AIM: To study the effects of clinical and genetic factors on the phenprocoumon dose requirement in pediatric patients and to develop a dosing algorithm. METHODS: Pediatric patients who used phenprocoumon were invited to participate in a retrospective follow-up study. Clinical information and genotypes of genetic variations in CYP2C9, VKORC1, CYP4F2, CYP2C18 and CYP3A4 were collected and tested with linear regression for association with phenprocoumon dose requirement. RESULTS: Of the 41 patients included in the analysis, age, VKORC1, CYP2C9*2/*3 and CYP3A4*1B were statistically significantly associated with dose requirement, and together explained 80.4% of the variability in phenprocoumon dose requirement. CONCLUSION: Our study reveals that age and genetic variations explain a significant part of the variability in phenprocoumon dose requirement in pediatric patients.

H. pylori infection in childhood chronic immune thrombocytopenic purpura.

Several studies have reported remission of immune thrombocytopenic purpura ( ITP) after eradication of a coexistent Helicobacter pylori infection in adults. Data in children are limited. Here we report the results of a prospective study of Helicobacter pylori determination and eradication in children with chronic ITP in the Netherlands.

Lymphadenopathy driven by TCR-Vγ8Vδ1 T-cell expansion in FAS-related autoimmune lymphoproliferative syndrome.

FAS-dependent apoptosis in Vδ1 T cells makes the latter possible culprits for the lymphadenopathy observed in patients with FAS mutations.Rapamycin and methylprednisolone resistance should prompt clinicians to look for Vδ1 T cell proliferation in ALPS-FAS patients.