Highly impaired platelet ultrastructure in two families with novel IKZF5 variants.

Heterozygous variants in the IKZF5 gene, encoding transcription factor Pegasus, were recently discovered to be causal of inherited thrombocytopenia (IT). We screened 90 patients suspected of inherited thrombocytopenia for variants in 101 genes associated with inherited bleeding disorders and report the clinical presentation of two Danish families with novel variants in IKZF5. Platelet ultrastructure and cytoskeleton were evaluated by immunofluorescent microscopy (IF) and found to be highly abnormal, demonstrating severe disturbances of distribution and expression of non-muscular myosin, filamin, ß-tubulin and α tubulin. Number of alpha granules were reduced, and platelets elongated when evaluated by TEM. In both families a child carrying a rare IKZF5 variant was affected by developmental delay. The proband of family A presented with recurrent infections and was examined for an immunodeficiency. The concentration of naive B-cells was found moderately reduced by leucocyte subpopulation examination, indicating an impaired cellular immunity. T-cells were marginally low with reduced share and concentration of CD45RApos, CD31pos, CD4pos recent thymic immigrants as signs of reduced thymic output. The novel IKZF5 variants co-segregated with thrombocytopenia in both families and both probands had significant bleeding tendency. Through comprehensive characterizations of the platelet morphology and function linked to the specific phenotypes we add novel insight to IKZF5-associated thrombocytopenia, which may help to identify and classify more cases with IKZF5 associated IT.

Absolute immature platelet count may predict imminent platelet recovery in thrombocytopenic children following chemotherapy.

BACKGROUND: Immature platelets are the youngest circulating platelets and they reflect the rate of thrombopoiesis. The immature platelet fraction (IPF) or the absolute immature platelet count (AIPC) may predict platelet count recovery following chemotherapy-induced thrombocytopenia in pediatric patients and help guiding prophylactic platelet transfusion therapy. PROCEDURE: To test IPF and AIPC as predictors of platelet recovery, 19 children with platelet nadirs of less than 20 × 10(9)/L after chemotherapy were prospectively enrolled. IPF, platelet count, and C-reactive protein (CRP) were analyzed in 416 paired samples from 37 patients with malignancies to test if IPF-levels were CRP dependent. RESULTS: A significant increase of 0.6 × 10(9)/L in AIPC was seen between 1 and 2 days prior to platelet count recovery. No predictive day-to-day differences were found for IPF. Platelet count recovery did not occur significantly earlier for patients with a peak IPF > 10% than for those patients with a peak IPF < 10%. IPF and AIPC showed no correlation to CRP. AIPC was in contrast to IPF not influenced by platelet transfusions. CONCLUSION: AIPC increased significantly between 24 and 48 hours before platelet recovery whereas IPF showed no significant increase during the same time period. AIPC may be a better indicator than IPF for predicting platelet recovery after chemotherapy in pediatric patients.

Rare embryonal and sarcomatous central nervous system tumours: State-of-the art and future directions.

The introduction of molecular methods into the diagnostics of central nervous system (CNS) tumours and the subsequent deciphering of their molecular heterogeneity has resulted in a significant impact on paediatric neurooncology. Particularly in the field of rare embryonal and sarcomatous CNS tumours, novel tumour types have been delineated and introduced in the recent 5th edition of the WHO classification of CNS tumours. The rarity and novelty of these tumour types result in diagnostic and therapeutic challenges. Apart from distinct histopathological and molecular features, these tumour types exhibit characteristic clinical properties and require different therapeutic approaches for optimal patient management. However, based on the limited availability of clinical data, current therapeutic recommendations have to be based on data from small, predominantly retrospective patient cohorts. Within this article, we provide guidance for diagnostic work-up and clinical management of rare CNS embryonal tumours ('embryonal tumour with multi-layered rosettes', ETMR; 'CNS neuroblastoma, FOXR2-activated', CNS NB-FOXR2; 'CNS tumour with BCOR-ITD, CNS BCOR-ITD) and rare CNS sarcomatous tumours ('primary intracranial sarcoma, DICER1-mutant', CNS DICER1; 'CIC-rearranged sarcoma', CNS CIC). By emphasizing the significant consequences on patient management in paediatric CNS tumours, we want to encourage wide implementation of comprehensive molecular diagnostics and stress the importance for joint international efforts to further collect and study these rare tumour types.

Subcutaneous anti-D treatment of idiopathic thrombocytopenic purpura in children.

We investigated the effect of subcutaneous anti-D IgG as platelet enhancing therapy in children with idiopathic thrombocytopenic purpura (ITP). Twenty-three children were treated with subcutaneous anti-D 50 microg/kg. The median platelet count increased from 7 x 10(9) to 31 x 10(9)/L on day 3 (P < 0.01). The median decline in hemoglobin was 1.3 g/dl. Two children experienced minor fever and chills within 24 hr of treatment. Pain at the injection site was common but self-limiting with no effect on activity level. These results suggest subcutaneous anti-D IgG 50 microg/kg as an effective and well-tolerated treatment option in childhood ITP.

Danish clinical guidelines for examination and treatment of overweight and obese children and adolescents in a pediatric setting.

Overweight children are at an increased risk of becoming obese adults, which may lead to shorter life expectancies in the current generation of children as compared to their parents. Furthermore, being an overweight child has a negative psycho-social impact. We consider obesity in children and adolescents a chronic illness, which is in line with the American Medical Society. We summarize the evidence for the efficacy of a combination of diet, physical activity and behavior-focused interventions in a family-based setting. The present guidelines propose a multidisciplinary service implemented as a "chronic care model" based on "best clinical practice" inspired by an American expert committee and the daily practice of The Children's Obesity Clinic at Copenhagen University Hospital Holbaek. Children and adolescents should be referred for examination and treatment in a pediatric setting when BMI corresponds to an isoBMI of minimum 30 or BMI corresponds to an isoBMI of 25 and complex obesity is suspected. Obtaining a thorough medical history is pivotal. We propose a structured interview to ensure collection of all relevant information. We recommend physical examination focused on BMI, waist circumference, growth, pubertal stage, blood pressure, neurology and skin and provide comprehensive paraclinical investigations for obesity and obesity related conditions. Treatment of obesity in children and adolescents is fully dependent on the combined effort of the entire family. This cannot be overemphasized! The main principle of the treatment is developing an individual detailed plan for every patient to reduce caloric intake whilst increasing physical activity, leaving no ambiguity with the recommendations.

Case report: stimulation of puberty in a girl with chemo- and radiation therapy induced ovarian failure by transplantation of a small part of her frozen/thawed ovarian tissue.

AIM OF THE STUDY: To induce puberty by transplantation of frozen/thawed ovarian tissue collected prior to gonadotoxic treatment for a cancer. PATIENTS AND METHODS: A 9-year-old girl with Ewing sarcoma had one ovary excised and cryopreserved prior to chemo- and radiotherapy. Functional activity of the remaining ovary was destroyed during treatment. Four and a half years later the girl remained pre-pubertal with postmenopausal levels of FSH. Two of ten pieces of frozen/thawed cortex were transplanted to the remaining ovary in order to stimulate puberty. RESULTS: Four months after the transplantation FSH returned to low levels. During the following year puberty gradually progressed to Tanner stage B4 and P3 and regular menstrual cycles started. However, after 19 months the function of the graft ceased. CONCLUSIONS: We have shown for the first time in a girl treated for cancer that transplanted ovarian tissue can regain function and secrete estradiol in a sufficient amount to induce puberty. In addition, the majority of her ovarian tissue remains frozen with a possibility to support fertility in adult life.

[Differences in the treatment of idiopathic thrombocytopenic purpura in children]. / Forskelle i behandling af børn med idiopatisk trombocytopenisk purpura.

INTRODUCTION: Idiopathic thrombocytopenic purpura (ITP) is a rare immune-mediated bleeding disorder that usually takes a self-limiting and benign course. Due to the risk of intracranial haemorrhage, treatment regimens tend to be active. We present treatment data from 17 paediatric departments in Denmark (1998-2000), focusing on regional differences in treatment strategy. MATERIAL AND METHODS: As part of a prospective Nordic study, clinical findings and treatment were recorded for 109 children with newly diagnosed ITP. The course in the following six months was reported for 91 children. Results are compared for three geographical regions: East, North and South. RESULTS: Pharmacotherapy, almost exclusively intravenous immunoglobulin, was given within 14 days of diagnosis to 89%, 70%, and 48% in regions East, North, and South, respectively. A very low platelet count was the main indication. Platelet transfusion was given to 24%, 0% and 4%, respectively. There were no differences in remission rates or frequency of mucosal bleeding during follow-up, but treatment rates were 6.3, 4.7, and 3.0 per patient-year with severe thrombocytopenia. Chronic ITP lasting more than six months developed in 26%, 33%, and 18%, respectively. CONCLUSION: We found obvious regional differences in treatment strategy which reflect differences in international clinical guidelines. The initial treatment approach had no influence on morbidity, time of remission or risk of chronic course.

[Epidemiology, disease presentation and course of idiopathic thrombocytopenic purpura in Danish children from 1998-2000]. / Epidemiologi, sygdomspraesentation og forløb af idiopatisk trombocytopenisk purpura hos børn i Danmark 1998-2000.

INTRODUCTION: Idopathic Thrombocytopenic Purpura (ITP) is a condition with isolated thrombocytopenia and bleeding symptoms in skin and mucous membranes. It is easy to establish the diagnosis, but treatment is controversial, possibly due to different estimates of the risk for serious bleeding. We present the epidemiology and clinical course of ITP during the first 6 months after diagnosis in Danish children diagnosed from 1998-2000. MATERIALS AND METHODS: The Nordic Society of Paediatric Haematology and Oncology conducted a prospective registration study of children with newly diagnosed ITP from 1998-2000. The study included children < 15 years of age with newly diagnosed, untreated ITP and platelet count (TBC) < 30 x 10(9) /l. Information about bleeding symptoms, TBC, treatment and ITP related episodes was recorded at diagnosis and during the first six months. RESULTS: Of 109 included children 81% had a short symptom history, 46% a preceding viral infection. At diagnosis 62% had TBC < 10 x 10(9) /l, 41% mucosal bleeding, and 72% received medical treatment. Follow-up was available for 91 children. Sixty seven children with acute ITP had TBC < 150 x 10(9) /l for 11 days (median). Twenty four children suffered chronic ITP, 8 of them had persistent TBC < 20 x 10(9) /l. Insidious onset had a 64% predictive value for chronic ITP. Of the 57 registered ITP-related episodes, 45 occurred in chronic cases, 23 of them in six of the children with persistent TBC < 20 x 10(9) /l. CONCLUSION: It is likely that children with newly diagnosed ITP recover quickly, and the risk of serious bleeding is low. A small group of children with persistent severe thrombocytopenia experience significant morbidity.

Epitope specificity and isotype of monoclonal anti-D antibodies dictate their ability to inhibit phagocytosis of opsonized platelets.

Rh immune globulin (WinRho SDF; Cangene, Mississauga, ON, Canada) is an effective treatment for autoimmune thrombocytopenic purpura; however, maintaining a sustained supply for its use in autoimmune thrombocytopenic purpura and its primary indication, hemolytic disease of the newborn, makes the development of alternative reagents desirable. We compared Rh immune globulin and 6 human monoclonal anti-D antibodies (MoAnti-D) with differing isotypes and specificities for their ability to opsonize erythrocytes and inhibit platelet phagocytosis in an in vitro assay. Results demonstrated that opsonization of erythrocytes with Rh immune globulin significantly (P < .001) reduced phagocytosis of fluorescently labeled opsonized platelets in an Fc-dependent manner. Of the MoAnti-D that shared specificity but differed in isotype, only IgG3 antibodies could significantly (P < .001) inhibit platelet phagocytosis. In contrast, 2 MoAnti-D shared isotypes and differed in specificity; however, only one could significantly (P < .001) inhibit platelet phagocytosis. The results suggest that MoAnti-D epitope specificity and isotypes are critical requirements for optimal inhibition of opsonized platelet phagocytosis.

A review of anti-D treatment of childhood idiopathic thrombocytopenic purpura.

Treatment of childhood idiopathic thrombocytopenic purpura is still an area of controversy. We reviewed the literature on anti-D treatment. Most studies used intravenous anti-D. Single doses of 50 microg/kg increased the platelet count to >or=20x10(9)/L in 70% of the children within 3 days. Intravenous anti-D seems safe in classic childhood ITP although hemolysis and occasionally renal failure may be of concern. A few studies reported intramuscularly or subcutaneously administered anti-D. Further studies on the optimal dose and route of administration of anti-D are warranted.