Darintr Sosothikul

Activation of endothelial cells, coagulation and fibrinolysis in children with Dengue virus infection

Dengue virus causes a febrile illness: Dengue fever (DF), and less frequently a life-threatening illness: Dengue hemorrhagic fever (DHF). Although severe bleeding remains a major cause of death in DHF, the pathogenesis of bleeding is poorly understood. This prospective cohort study was designed to determine the extent of activation of endothelial cells and the hemostatic system in correlation with clinical severity, and also to detect the best prognostic factor(s) for DHF. Endothelial cell activation, coagulation, anticoagulant and fibrinolysis parameters were measured in 42 children with Dengue infections (20 with DF and 22 with DHF) during three phases of illness. In DHF patients, during the febrile phase, von Willebrand factor antigen (vWF:Ag), tissue factor (TF) and plasminogen activator inhibitor (PAI-1) were significantly elevated, while platelet counts and ADAMTS 13 (a disintegrin and metalloprotease with thrombospondin repeats) were significantly low compared to DF patients. During the toxic phase, soluble thrombomodulin (sTM), tissue plasminogen activator (t-PA) and PAI-1 were also significantly increased, while ADAMTS 13 and thrombin activatable fibrinolysis inhibitor (TAFIa) were significantly low compared to DF patients. Abnormal vWF multimers were seen only in DHF patients. For endothelial cell injury and release of procoagulant components, activation of the coagulation cascade with thrombin generation, increased antifibrinolytic factors and consumption of natural anticoagulants, each appeared to play an important role in the development of hemorrhage in Dengue patients. Using logistic regression analysis, we found plasma VWF:Ag to be the best indicator of progression to DHF.

Eltrombopag for children with chronic immune thrombocytopenia (PETIT2): a randomised, multicentre, placebo-controlled trial.

BACKGROUND The thrombopoietin receptor agonist eltrombopag has been shown to be safe, tolerable, and effective for adults with chronic immune thrombocytopenia. We aimed to investigate the safety and efficacy of eltrombopag for children with chronic immune thrombocytopenia. METHODS PETIT2 was a two part, randomised, multicentre, placebo-controlled study done at 38 centres in 12 countries (Argentina, Czech Republic, Germany, Hong Kong, Israel, Italy, Russia, Spain, Taiwan, Thailand, UK, and USA). Paediatric patients aged 1-17 years who had chronic immune thrombocytopenia and platelet counts less than 30 × 10(9) per L were randomly assigned (2:1) to receive eltrombopag or placebo. We stratified patients by age into three cohorts (patients aged 12-17 years, 6-11 years, and 1-5 years) before randomly entering them into a 13 week, double-blind period. Randomisation was done by the GlaxoSmithKline Registration and Medication Ordering System and both patients and study personnel were masked to treatment assignments. Patients who were allocated eltrombopag received tablets (except for those aged 1-5 years who received an oral suspension formulation) once per day for 13 weeks. Starting doses for patients aged 6-17 were based on bodyweight, and ethnic origin and ranged between 50 mg/day and 25 mg/day (starting dose for patients aged 1-5 years was 1·2 mg/kg/day or 0·8 mg/kg/day for east Asian patients). Patients who completed the double-blind period entered a 24 week open-label treatment period in which all patients received eltrombopag at either the starting dose (if they were formerly on placebo) or their established dose. The primary outcome was the proportion of patients achieving platelet counts of at least 50 × 10(9) per L in the absence of rescue therapy for 6 or more weeks from weeks 5 to 12 of the double-blind period. The intention-to-treat population included in the efficacy assessment consisted of all patients who were randomly assigned to one of the treatment groups, and the safety population included all patients who received at least one dose of study drug. This trial is registered with ClinicalTrials.gov, number NCT01520909. FINDINGS Beginning in March 15, 2012, 92 patients were enrolled, and the trial was completed on Jan 2, 2014. 63 patients were assigned to receive eltrombopag and 29 were assigned to receive placebo. In the double-blind period, three patients discontinued treatment because of adverse events: two patients in the eltrombopag group withdrew because of increased liver aminotransferases and one in the placebo group withdrew because of abdominal haemorrhage. 25 (40%) patients who received eltrombopag compared with one (3%) patient who received placebo achieved the primary outcome of platelet counts of at least 50 × 10(9) per L for 6 of the last 8 weeks of the double-blind period (odds ratio 18·0, 95% CI, 2·3-140·9; p=0·0004). Responses were similar in all cohorts (eltrombopag vs placebo: 39% vs 10% for patients aged 12-17 years, 42% vs 0% for patients aged 6-11 years, and 36% vs 0% for patients aged 1-5 years). Proportionately fewer patients who received eltrombopag (23 [37%] of 63 patients) had WHO grades 1-4 bleeding at the end of the double-blind period than did those who received placebo (16 [55%] of 29 patients); grades 2-4 bleeding were similar (three [5%] patients who received eltrombopag vs two [7%] patients who received placebo). During the 24-week open-label treatment period, 70 [80%] of 87 patients achieved platelet counts of 50 × 10(9) per L or more at least once. Adverse events that occurred more frequently with eltrombopag than with placebo included nasopharyngitis (11 [17%] patients), rhinitis (10 [16%] patients), upper respiratory tract infection (7 [11%] patients), and cough (7 [11%] patients). Serious adverse events occurred in five (8%) patients who received eltrombopag and four (14%) who received placebo. Safety was consistent between the open-label and double-blind periods. No deaths, malignancies, or thromboses occurred during the trial. INTERPRETATION Eltrombopag, which produced a sustained platelet response in 40% of patients with chronic immune thrombocytopenia, is a suitable therapeutic option for children with chronic symptomatic immune thrombocytopenia. We identified no new safety concerns and few patients discontinued treatment because of adverse events. FUNDING GlaxoSmithKline.

Pediatric reference values for molecular markers in hemostasis.

Background The hemostatic system is a developing and changing process relative to age. Objectives To distinguish the differences in hemostatic parameters between children and adults, and to establish the normal range of these parameters in children of different age groups. Design/Methods Blood was obtained from healthy children aged 1 to 18 years (n=70) and adults (n=26). Children were categorized into 3 age groups: 1 to 5 years, 6 to 10 years, and 11 to 18 years. Several coagulation and fibrinolysis parameters were determined. Results Children in all age groups showed no significant difference in mean levels of von Willebrand factor antigen and activity, activated partial thromboplastin time, fibrinogen, activated factor VII, tissue plasminogen activator, plasminogen activator inhibitor-1, and thrombin activatable fibrinolysis inhibitor compared with adults. However, children aged 1 to 5  years had significantly higher mean values of soluble thrombomodulin (P=0.001), prothrombin time (P=0.03), tissue factor (P<0.001), thrombin-antithrombin complex (P<0.001), and D-dimer (P=0.009) whereas they had significantly lower mean levels of protein C activity (P=0.02) than did adults. Conclusions These data indicate physiologic differences in the hemostatic system between children and adults and should serve as a useful reference guide in interpreting test results for children with suspected bleeding disorders.

NUDT15 c.415C>T increases risk of 6-mercaptopurine induced myelosuppression during maintenance therapy in children with acute lymphoblastic leukemia.

Acute lymphoblastic leukemia (ALL) is the most common hematologic malignancy in children[1][1]. Prolongation of therapy by incorporating a maintenance phase, containing 6-mercaptopurine (6-MP) as the backbone, has improved treatment outcomes in pediatric ALL[2][2]–[4][3]. However, 6-MP can cause

Fibrolamellar carcinoma presenting as a pancreatic mass: case report and review of the literature.

Fibrolamellar carcinoma is a subtype of hepatocellular carcinoma with distinct clinicopathologic features including presentation at a younger age. Although early studies suggested that fibrolamellar carcinoma had a better prognosis than conventional hepatocellular carcinoma, most later studies have found no difference. Patients often have lymph node metastases at presentation in addition to the hepatic primary. We describe an unusual case in a Thai boy who presented with a pancreatic mass that was clinically suspected to be a primary pancreatic tumor, but on biopsy was found to be metastatic fibrolamellar carcinoma. To our knowledge, this manner of presentation has not been previously reported for fibrolamellar carcinoma, nor has metastatic spread to the pancreas.

Reference values for thrombotic markers in children.

Thromboembolic events are an increasingly common problem encountered in children. The laboratory diagnosis of thrombotic disorders in children differs from that in adults. To establish the normal reference of natural anticoagulant parameters in children of different age groups, plasma from healthy children between the ages of 2 months and 16 years (n = 127) and adults (n = 30) were assayed for a disintegrin-like and metalloprotease with thrombospondin type 1 domain 13 (ADAMTS-13), von Willebrand factor collagen-binding activity (vWF:CB), tissue factor pathway inhibitor (TFPI), homocyteine and natural anticoagulants. Children were divided into four age groups: less than 1 year, 1–5 years, 6–10 years, and 11–16 years. The reference values for ADAMTS 13, homocysteine, and protein C activity were significantly lower in children of all age groups compared with those in the adults. Similarly, those for protein C antigen, total protein S, free protein S and antithrombin III (AT III) for children less than 1 year were significantly lower than in the adults. On the contrary, TFPI levels were significantly higher in the children for all age groups when compared with the adults. vWF:CB levels were comparable across all groups. There are age-related physiologic differences in ADAMTS-13, TFPI, homocysteine and natural anticoagulants between children and adults. Our data will provide physicians with a useful reference guide in interpreting test results of inhibitors of hemostatic parameters in children suspected of thrombotic disorders.

BRAF V600E mutation in pediatric intracranial and cranial juvenile xanthogranuloma

Juvenile xanthogranuloma (JXG) is a cutaneous form of non-Langerhans cell histiocytosis, primarily affecting children. The lesion is presumed to originate from either macrophages or dermal dendritic cells. JXG can rarely present as an isolated intracranial lesion and, in contrast to the dismal outcome of patients with systemic disease, cranial JXG has been shown to carry a more favorable prognosis. Here, we report for the first time 3 pediatric cases of JXG with a BRAF V600E mutation, 2 with intracranial lesions and 1 with cranial lesions. Although these intracranial/cranial lesions have been referred to as JXG, they likely differ from cutaneous JXG in both the clinical features and BRAF status. It may be more appropriate to classify intracranial/cranial JXG in the same group as Langerhans cell histiocytosis and Erdheim-Chester disease, which also have a BRAF V600E mutation. Further study of BRAF status in a larger series of JXG is warranted.

Adaptive immune defects in a patient with leukocyte adhesion deficiency type III with a novel mutation in FERMT3

To the Editor, Leukocyte adhesion deficiency (LAD) is a rare primary immunodeficiency disease characterized by impairment of phagocyte adhesion (1–3). Three subtypes have been classified by distinct phases of the adhesion cascade. LAD-III is caused by defects in signaling pathways used for integrin activation in all hematopoietic cell types leading to recurrent infections with poor platelet aggregation resembling Glanzmann’s thrombasthenia (4). Mutations in FERMT3 have been identified to underlie LAD-III (4, 5). FERMT3 encodes kindlin-3, one of the focal adhesion proteins which contain a FERM domain located at the carboxyl terminus binding to b-integrin cytoplasmic tails. This molecule cooperates with the cytoskeletal protein talin leading to integrin activation. It also stabilizes active conformations of the integrin subunits and the ligand binding (5, 6). Evidently, integrins are widely expressed in many cell types including T and B lymphocytes. Defects in integrin function therefore could lead to both innate and adaptive immune dysfunctions. However, almost all reported cases of LAD-III only had innate immune defects. Here, we describe a female Thai patient who was diagnosed with LAD-III, yet presenting with a mild atypical phenotype in which a humoral immune defect was detected. Our patient was the second child of consanguineous parents who were first cousins. The pedigree of the family is shown in Fig. 1a. She presented with early-onset severe gram-negative infections, thrombasthenia, hepatosplenomegaly, and defective wound healing. Between three and 8 months old, she experienced four episodes of bacterial pneumonia with sepsis. Firstly, she had severe pneumonia and subsequently developed acute respiratory distress syndrome. Cultures of tracheal suction specimens revealed Acinetobacter baumannii. Salmonella spp. was also reported from stool samples when she was found to have diarrhea. In the second episode of pneumonia, A. baumannii was reported again from specimens obtained by tracheal suctioning. Pseudomonas aeruginosa was isolated from ear discharge. Thirdly, the patient had pneumonia with septic shock. Tracheal suction cultures revealed Streptococcus mitis and Escherichia coli. Finally, necrotizing pneumonia was reported. The patient’s blood culture was positive for P. aeruginosa. She had the ability to form pus, although minimal, and umbilical cord separation occurred at the age of 9 days. After prolonged courses of antibiotics, the patient had developed mucocutaneous candidiasis. She did not suffer from invasive fungal infections, as described in other patients with LAD-III (3, 7). Her bleeding symptoms were mild and appeared only during episodes of infections, while spontaneous intracranial bleeding and/or massive pulmonary hemorrhage have been reported in patients with typical LAD-III (3, 7). Initial investigations and immunologic assessment at the age of 5 months revealed persistent leukocytosis with neutrophilia, anemia, and thrombocytopenia. A complete blood count showed a hematocrit of 28% (29–42), white blood cell count of 45,430 cells/mm (6000–17,500), neutrophils of 25,440 cells/ mm (4000–12,000), lymphocytes of 10,903 cells/mm (2000– 17,000), and platelets of 109,000 cells/mm (300,000–700,000). Flow cytometric analysis of lymphocyte populations demonstrated normal numbers of total T cells (CD3+), CD4+ T cells, CD8+ T cells, B cells (CD19+), and NK cells (CD16+56+).

Clinical and Molecular Characterization of Thai Patients with Wiskott–Aldrich Syndrome

Wiskott–Aldrich syndrome (WAS) is an X‐linked recessive primary immunodeficiency disorder caused by mutations in the gene encoding the WAS protein (WASP). Classic WAS is characterized by thrombocytopenia with small‐sized platelets, recurrent infections, eczema and increased susceptibility to autoimmune diseases and haematologic malignancies. Here, we reported on seven unrelated Thai individuals with classic WAS. In addition to clinical and immunologic characterization, mutation analysis by PCR‐sequencing the entire coding region of WASP was performed. Recurrent and novel mutations were successfully identified. A nonsense mutation, the c.55C>T (p.Q19X), has not been previously described, expanding the mutational spectrum of WASP. The patient with this newly described mutation developed cows milk allergy manifesting as angioedema and urticaria and had cytomegalovirus infection that was successfully treated with long‐term ganciclovir. This study reported long‐term follow‐up of seven patients with molecular confirmation of WAS and infrequent features in the patient with classic WAS carrying the novel nonsense mutation.

Adrenal insufficiency in non-transfusion-dependent α-thalassemia

Very few studies about adrenal insufficiency (AI) have been published with regard to non‐transfusion‐dependent (NTD) thalassemia, and none of those studies involved α‐thalassemia patients. The aim of this study was therefore to determine the prevalence of AI in patients with NTD α‐thalassemia, and to identify factors that predict the development of AI in this thalassemia subpopulation.