Nivolumab with or without ipilimumab in pediatric patients with high-grade CNS malignancies: Safety, efficacy, biomarker, and pharmacokinetics-CheckMate 908.

BACKGROUND: Therapeutic options are limited in pediatric CNS malignancies. CheckMate 908 (NCT03130959) is an open-label, sequential-arm, phase 1b/2 study investigating nivolumab (NIVO) and NIVO + ipilimumab (IPI) in pediatric patients with high-grade CNS malignancies. METHODS: Patients (N = 166) in 5 cohorts received NIVO 3 mg/kg every 2 weeks (Q2W) or NIVO 3 mg/kg + IPI 1 mg/kg every 3 weeks (4 doses) followed by NIVO 3 mg/kg Q2W. Primary endpoints included overall survival (OS; newly diagnosed diffuse intrinsic pontine glioma [DIPG]) and progression-free survival (PFS; other recurrent/progressive or relapsed/resistant CNS cohorts). Secondary endpoints included other efficacy metrics and safety. Exploratory endpoints included pharmacokinetics and biomarker analyses. RESULTS: As of January 13, 2021, median OS (80% CI) was 11.7 (10.3-16.5) and 10.8 (9.1-15.8) months with NIVO and NIVO + IPI, respectively, in newly diagnosed DIPG. Median PFS (80% CI) with NIVO and NIVO + IPI was 1.7 (1.4-2.7) and 1.3 (1.2-1.5) months, respectively, in recurrent/progressive high-grade glioma; 1.4 (1.2-1.4) and 2.8 (1.5-4.5) months in relapsed/resistant medulloblastoma; and 1.4 (1.4-2.6) and 4.6 (1.4-5.4) months in relapsed/resistant ependymoma. In patients with other recurrent/progressive CNS tumors, median PFS (95% CI) was 1.2 (1.1-1.3) and 1.6 (1.3-3.5) months, respectively. Grade 3/4 treatment-related adverse-event rates were 14.1% (NIVO) and 27.2% (NIVO + IPI). NIVO and IPI first-dose trough concentrations were lower in youngest and lowest-weight patients. Baseline tumor programmed death ligand 1 expression was not associated with survival. CONCLUSIONS: NIVO ± IPI did not demonstrate clinical benefit relative to historical data. The overall safety profiles were manageable with no new safety signals.

Nivolumab and Relatlimab in Patients With Advanced Melanoma That Had Progressed on Anti-Programmed Death-1/Programmed Death Ligand 1 Therapy: Results From the Phase I/IIa RELATIVITY-020 Trial.

PURPOSE: Nivolumab and relatlimab activity in advanced melanoma with prior progression on anti-programmed death-1/programmed death ligand 1 (PD-(L)1)-containing regimens is under investigation. RELATIVITY-047 demonstrated significantly improved progression-free survival (PFS) for nivolumab and relatlimab over nivolumab in previously untreated advanced melanoma. METHODS: The phase I/IIa, open-label RELATIVITY-020 trial part D assessed efficacy and safety of nivolumab and relatlimab in advanced melanoma with progression during, or within 3 months of, 1 (D1) or ≥ 1 (D2) anti-PD-(L)1-containing regimens. Safety was a primary end point. Objective response rate (coprimary end point) and PFS by blinded independent central review (BICR) were assessed. RESULTS: Five hundred eighteen patients (D1 = 354; D2 = 164) received nivolumab and relatlimab. Among evaluable patients, the objective response rate by BICR was 12.0% (95% CI, 8.8 to 15.8) in D1 (n = 351) and 9.2% (95% CI, 5.2 to 14.7) in D2 (n = 163). Responses appeared to be enriched among patients with tumors expressing programmed death ligand 1 or lymphocyte activation gene 3; however, responses were observed regardless of programmed death ligand 1 and lymphocyte activation gene 3 expression (1%). The median duration of response was not reached (95% CI, 12.9 to not reached) in D1 and 12.8 months (95% CI, 6.9 to 12.9) in D2. The median PFS by BICR was 2.1 months (95% CI, 1.9 to 3.5) in D1 and 3.2 months (95% CI, 1.9 to 3.6) in D2; the 6-month PFS rate was 29.1% (95% CI, 24.2 to 34.1) and 27.7% (95% CI, 20.5 to 35.4), respectively. The grade 3-4 treatment-related adverse event incidence was 15.0% in D1 and 12.8% in D2. One case of grade 3 myocarditis and no treatment-related deaths occurred across part D. CONCLUSION: Nivolumab and relatlimab had a manageable safety profile and demonstrated durable clinical activity in a proportion of patients with heavily pretreated advanced melanoma with prior progression on anti-PD-(L)1-containing regimens.[Media: see text].

Phase III trial of chemoradiotherapy with temozolomide plus nivolumab or placebo for newly diagnosed glioblastoma with methylated MGMT promoter.

BACKGROUND: Nearly all patients with newly diagnosed glioblastoma experience recurrence following standard-of-care radiotherapy (RT) + temozolomide (TMZ). The purpose of the phase III randomized CheckMate 548 study was to evaluate RT + TMZ combined with the immune checkpoint inhibitor nivolumab (NIVO) or placebo (PBO) in patients with newly diagnosed glioblastoma with methylated MGMT promoter (NCT02667587). METHODS: Patients (N = 716) were randomized 1:1 to NIVO [(240 mg every 2 weeks × 8, then 480 mg every 4 weeks) + RT (60 Gy over 6 weeks) + TMZ (75 mg/m2 once daily during RT, then 150-200 mg/m2 once daily on days 1-5 of every 28-day cycle × 6)] or PBO + RT + TMZ following the same regimen. The primary endpoints were progression-free survival (PFS) and overall survival (OS) in patients without baseline corticosteroids and in all randomized patients. RESULTS: As of December 22, 2020, median (m)PFS (blinded independent central review) was 10.6 months (95% CI, 8.9-11.8) with NIVO + RT + TMZ vs 10.3 months (95% CI, 9.7-12.5) with PBO + RT + TMZ (HR, 1.1; 95% CI, 0.9-1.3) and mOS was 28.9 months (95% CI, 24.4-31.6) vs 32.1 months (95% CI, 29.4-33.8), respectively (HR, 1.1; 95% CI, 0.9-1.3). In patients without baseline corticosteroids, mOS was 31.3 months (95% CI, 28.6-34.8) with NIVO + RT + TMZ vs 33.0 months (95% CI, 31.0-35.1) with PBO + RT + TMZ (HR, 1.1; 95% CI, 0.9-1.4). Grade 3/4 treatment-related adverse event rates were 52.4% vs 33.6%, respectively. CONCLUSIONS: NIVO added to RT + TMZ did not improve survival in patients with newly diagnosed glioblastoma with methylated or indeterminate MGMT promoter. No new safety signals were observed.

Management Practices for Asparaginase-associated Coagulopathy: A Survey of Pediatric Oncologists.

BACKGROUND: Coagulopathy and thrombosis are well-described complications of asparaginase therapy. However, treatment practices in pediatric hematology/oncology (PHO) patients vary widely as evidence-based guidelines for clinical management of these complications in this population are lacking. OBJECTIVE: The objective of this study was to assess management practices of asparaginase-related coagulopathy by pediatric hematologist/oncologist attending physicians. DESIGN/METHOD: Email survey sent to 2327 PHO physicians primarily practicing in the United States. RESULTS: Two hundred eighty-five (12.2%) attending physicians completed the survey. Only 4.6% (n=13/285) routinely prescribe prophylactic anticoagulation during induction chemotherapy for leukemia. Slightly more than half (n=145/250, 50.9%) of all providers perform baseline coagulation studies. Most providers that were surveyed (n=185/285, 64.9%) only replete coagulant factors if the patient experiences bleeding or bruising. One hundred thirty (n=130/285, 45.6%) physicians replace low fibrinogen. The median fibrinogen replacement was 100 mg/dL (range: 40 to 200 mg/dL) with the median target of at least 100 mg/dL (range: 50 to 200 mg/dL). A minority of physicians (n=39/250, 13.7%) replace low antithrombin. The median antithrombin cutoff activity level was 60% (range: 40% to 100%) with a median target of 75% (range: 40% to 125%). CONCLUSIONS: There is a significant variation in PHO physician practices for monitoring and management of asparaginase-associated hemostatic derangements. Evidence-based guidelines have the potential to standardize practices.

Acute thrombosis of a giant perimedullary arteriovenous fistula in a pediatric HHT patient.

Hereditary hemorrhagic telangiectasia (HHT) is an autosomal dominant hereditary disorder that results in arteriovenous malformations (AVMs) in the nose, mucocutaneous surfaces and visceral organs, including lung, brain, liver, bowel and rarely spinal cord. We describe a case of a young child with HHT who presented with acute paraparesis due to acute thrombosis of a spinal perimedullary arteriovenous fistula. Patient underwent coil embolization of spinal arteriovenous shunt with resolution of clinical symptoms. This case highlights the possibility of catastrophic complications in young children with HHT, the potential preventive role of screening for spinal AVMs in HHT and the importance of timely intervention.

A mutation in SLC37A4 causes a dominantly inherited congenital disorder of glycosylation characterized by liver dysfunction.

SLC37A4 encodes an endoplasmic reticulum (ER)-localized multitransmembrane protein required for transporting glucose-6-phosphate (Glc-6P) into the ER. Once transported into the ER, Glc-6P is subsequently hydrolyzed by tissue-specific phosphatases to glucose and inorganic phosphate during times of glucose depletion. Pathogenic variants in SLC37A4 cause an established recessive disorder known as glycogen storage disorder 1b characterized by liver and kidney dysfunction with neutropenia. We report seven individuals who presented with liver dysfunction multifactorial coagulation deficiency and cardiac issues and were heterozygous for the same variant, c.1267C>T (p.Arg423∗), in SLC37A4; the affected individuals were from four unrelated families. Serum samples from affected individuals showed profound accumulation of both high mannose and hybrid type N-glycans, while N-glycans in fibroblasts and undifferentiated iPSC were normal. Due to the liver-specific nature of this disorder, we generated a CRISPR base-edited hepatoma cell line harboring the c.1267C>T (p.Arg423∗) variant. These cells replicated the secreted abnormalities seen in serum N-glycosylation, and a portion of the mutant protein appears to relocate to a distinct, non-Golgi compartment, possibly ER exit sites. These cells also show a gene dosage-dependent alteration in the Golgi morphology and reduced intraluminal pH that may account for the altered glycosylation. In summary, we identify a recurrent mutation in SLC37A4 that causes a dominantly inherited congenital disorder of glycosylation characterized by coagulopathy and liver dysfunction with abnormal serum N-glycans.

Healthcare Utilization and Costs associated with Hereditary Hemorrhagic Telangiectasia Patients in a Large US Claims Database.

OBJECTIVE: To assess the health care costs and utilization in patients with hereditary hemorrhagic telangiectasia (HHT) in the United States. PATIENTS AND METHODS: Retrospective analysis of patients with HHT diagnosed between 2007 and 2017 was performed using deidentified administrative claims data from the OptumLabs Data Warehouse. Adult patients with new (incident) diagnosis of HHT between January 1, 2007, and December 31, 2017, were included. Comparisons were made using the Wilcoxon rank sum test. RESULTS: Three thousand nine hundred seventy-seven patients with a first diagnosis of HHT between 2007 and 2017 were identified, of which 3590 were matched 1:1 to non-HHT patients with similar baseline characteristics and comorbidities. These 3590 patients with HHT were 63.1% female and 83.9% white with a mean age of 51.1 ± 18.5 years, and a mean follow-up period of 3.2 ± 2.2 years (range, 1.0-11.7 years). Compared with the control group, the cumulative 5-year median total health care cost for patients with HHT was 41.4% higher ($21,118 vs $14,929; P < .001) in those with private commercial insurance and 31.7% higher ($35,462 vs $26,925; P < .001) in those with Medicare Advantage coverage. The median annual health care costs were significantly higher in patients with HHT with commercial insurance and Medicare Advantage in the first year after diagnosis ($4,333 vs $1,804; P < .001), and ($7,322 vs $5,245; P < .001), respectively, and remained higher throughout the duration of follow-up. Further analysis showed that outpatient clinic visits, hospital admission, imaging rates, invasive procedures, iron infusions, and blood transfusions were all significantly higher in the HHT group. CONCLUSION: Patients with HHT have significantly higher health care costs compared with a matched control group. A better understanding of the reasons underlying these cost differences will provide opportunities for patients, providers, and other stakeholders to better manage this rare condition.

Pediatric May-Thurner Syndrome-Systematic review and individual patient data meta-analysis.

BACKGROUND: The outcomes of deep vein thrombosis (DVT) in children with May-Thurner Syndrome (MTS) remain unclear. OBJECTIVES: This systematic review and patient-level meta-analysis aims to describe the outcomes of children with MTS presenting with DVT. METHODS: A systematic review of the published literature was performed. Data related to patients <18 years diagnosed with MTS and DVT was extracted. Risk of bias was assessed using the Murad criteria. Outcomes included vessel patency post-treatment, DVT recurrence, and post-thrombotic syndrome (PTS). Predictive and explanatory models were developed for these outcomes. RESULTS: In total, 109 cases were identified (age range 4-17 years; 77 females) in 28 studies; 75% of patients had ≥1 additional risk factor for DVT. PTS was seen in 61% of patients, DVT recurrence in 38%, and complete vessel patency post-treatment in 65%. The models developed to predict and explain PTS performed poorly overall. Recurrent thrombosis (adjusted for age and patency) predicted PTS (odds ratio [OR] 3.36, 95% confidence interval [CI] 1.28-8.82). DVT management strategies (adjusted for age and DVT characteristics) predicted vessel patency (OR 2.10, 95% CI 1.43-3.08). Lack of complete vessel patency (adjusted for age and thrombophilia) predicted recurrent DVT (OR 2.70, 95% CI 1.09-6.67). Sensitivity analyses showed the same direction of effects for all outcomes. CONCLUSIONS: PTS and DVT recurrence occur frequently in pediatric MTS. PTS prediction is complex and it was not possible to identify early predictors to guide clinical practice. Use of imaging-guided therapy and thrombus burden predicted venous patency, and lack of patency predicted DVT recurrence.

Oral Contraceptive Use in Obese Adolescents: A Cautionary Tale.

Venous thromboembolism (VTE) is a life-threatening complication rarely encountered with the use of combined oral contraceptives (COCs). Obesity is an additional thrombosis risk factor that has been shown to further increase the risk of VTE with the use of COCs. We present 5 cases of obese adolescents (body mass index >30 kg/m2) who encountered thrombosis complications while on COCs. Although the absolute risk of VTE events in the setting of COCs is rare, caution should be observed when choosing hormonal therapy and safer COCs alternatives discussed with adolescents who are obese.

Pediatric Myxopapillary Ependymomas: A Clinicopathologic Evaluation.

Myxopapillary ependymomas (MPEs) have an indolent clinical course, corresponding to World Health Organization Grade I. A total of 13 pediatric MPEs have been reported in the literature with "anaplastic features," including elevated proliferative activity (≥5 mitoses/10 high-power fields), necrosis, and microvascular proliferation. No consensus exists regarding the prognostic significance of such features. A retrospective clinicopathologic review of pediatric MPEs diagnosed between 1996 and 2018 at Mayo Clinic was performed. Totally, 8 pediatric MPEs (6 male; age: 7.52 to 16.88 y) were identified. Totally, 3 had disseminated disease at presentation. All patients underwent surgical resection (7 gross total; 1 subtotal). Totally, 5 cases harbored ≥5 mitoses/10 high-power fields (range: 5 to 9), 3 of which showed necrosis (2 with disseminated disease). Postsurgery, 2 patients received radiation; one with disseminated disease and another with increased mitotic activity/necrosis; neither has recurred (follow-up: 1.18 and 3.19 y). In all, 2 patients with disseminated disease, elevated mitotic activity, and necrosis had new metastatic disease/progression of nonresected metastatic foci (2.6 and 26.8 mo), received radiation therapy, and remain progression free (3.01 and 9.34 y). All patients are alive (median follow-up 1.31 y, range: 0.66 to 11.75). Among pediatric MPEs, the concurrent presence of elevated mitotic activity and necrosis may be associated with an aggressive clinical course, warranting closer surveillance and consideration of adjuvant therapies.

A prospective, blinded study of a PF4-dependent assay for HIT diagnosis.

Heparin-induced thrombocytopenia (HIT) is a life-threatening, prothrombotic, antibody-mediated disorder. To maximize the likelihood of recovery, early and accurate diagnosis is critical. Widely available HIT assays, such as the platelet factor 4 (PF4) heparin enzyme-linked immunosorbent assay (ELISA) lack specificity, and the gold-standard carbon 14-labeled serotonin release assay (SRA) is of limited value for early patient management because it is available only through reference laboratories. Recent studies have demonstrated that pathogenic HIT antibodies selectively activate PF4-treated platelets and that a technically simpler assay, the PF4-dependent P-selectin expression assay (PEA), may provide an option for rapid and conclusive results. Based upon predefined criteria that combined 4Ts scores and HIT ELISA results, 409 consecutive adults suspected of having HIT were classified as disease positive, negative, or indeterminate. Patients deemed HIT indeterminate were considered disease negative in the primary analysis and disease positive in a sensitivity analysis. The ability of PEA and SRA to identify patients judged to have HIT was compared using receiver operating characteristic curve statistics. Using these predefined criteria, the diagnostic accuracy of PEA was high (area under the curve [AUC], 0.94; 95% confidence interval [CI], 0.87-1.0) and similar to that of SRA (AUC, 0.91; 95% CI, 0.82-1.0). In sensitivity analysis, the AUCs of PEA and SRA were also similar at 0.88 (95% CI, 0.78-0.98) and 0.86 (95% CI, 0.77-0.96), respectively. The PEA, a technically simple nonradioactive assay that uses ∼20-fold fewer platelets compared with the SRA, had high accuracy for diagnosing HIT. Widespread use of the PEA may facilitate timely and more effective management of patients with suspected HIT.

Computer-based simulation to reduce EHR-related chemotherapy ordering errors.

BACKGROUND: The electronic health record (EHR) is a contributor to serious patient harm occurring within a sociotechnical system. Chemotherapy ordering is a high-risk task due to the complex nature of ordering workflows and potential detrimental effects if wrong chemotherapeutic doses are administered. Many chemotherapy ordering errors cannot be mitigated through systems-based changes due to the limited extent to which individual institutions are able to customize proprietary EHR software. We hypothesized that simulation-based training could improve providers' ability to identify and mitigate common chemotherapy ordering errors. METHODS: Pediatric hematology/oncology providers voluntarily participated in simulations using an EHR testing ("Playground") environment. The number of safety risks identified and mitigated by each provider at baseline was recorded. Risks were reviewed one-on-one after initial simulations and at a group "lunch-and-learn" session. At three-month follow-up, repeat simulations assessed for improvements in error identification and mitigation, and providers were surveyed about prevention of real-life safety events. RESULTS: The 8 participating providers identified and mitigated an average of 5.5 out of 10 safety risks during the initial simulation, compared 7.4 safety risks at the follow up simulation (p=0.030). Two of the providers (25%) reported preventing at least one real-world patient safety event in the clinical setting as a result of the initial training session. CONCLUSIONS: Simulation-based training may reduce providers' susceptibility to chemotherapy ordering safety vulnerabilities within the EHR. This approach may be used when systems-based EHR improvements are not feasible due to limited ability to customize local instances of proprietary EHR software.

Clinical Outcomes of May-Thurner Syndrome in Pediatric Patients: A Single Institutional Experience.

Introduction May-Thurner syndrome (MTS) is a vascular anatomic variant resulting in compression of the left common iliac vein by the right common iliac artery, affecting approximately 22% of the population. In adults, following acute deep vein thrombosis (DVT) of the iliofemoral veins, the incidence of postthrombotic syndrome (PTS) and recurrent DVT are high if treated with anticoagulation alone, warranting adjunctive treatment with thrombolysis and stent placement. However, there is paucity of literature documenting the course of treatment and associated outcomes in pediatric patients with MTS. Methods A retrospective chart review of pediatric patients (≤ 18 years of age) with radiologic confirmation of MTS with or without DVT evaluated and/or treated at our institution from January 1, 2005 through December 31, 2015 was conducted. Results Seventeen patients (4 male; 13 female) were identified. Median age was 15.4 years (range 8.8-17.1 years) with a median follow-up of 1.2 years (range 0.4-7.5 years). Thirteen (76.5%) patients presented with left lower extremity DVT. Management included catheter-directed thrombolysis ( n = 5), systemic thrombolysis ( n = 1), and mechanical thrombectomy ( n = 1). Fifteen patients were treated with anticoagulation including two patients with endovascular stents without DVT. Median duration of anticoagulation was 6.3 months (range 3.2-18.7 months). Ten patients (59%) underwent stent placements. Complete and partial thrombus resolution was noted in six patients each and no resolution in one patient. Four patients had recurrence/progression of thrombus ( n = 3 with stents) at a median time of 29 days (range 12-495 days). No bleeding complications were observed. Clinically documented or self-reported PTS was noted in 8 patients (62%). Conclusion There are no clear guidelines for MTS management in children and adolescents. In our cohort, thrombolysis, anticoagulation, or stent placements were not associated with bleeding risks, with recurrence/progression of DVT and signs and symptoms of PTS noted in 30 and 62%, respectively. Further studies are needed to determine a standardized treatment approach of the pediatric patient with MTS with or without thrombosis.

Cerebral sinovenous thrombosis in pediatric hemolytic uremic syndrome.

Hemolytic uremic syndrome (HUS) may result in thrombotic central nervous system complications. We present a child with diarrhea-associated HUS who developed new-onset focal seizures secondary to cerebral sinovenous thrombosis (CSVT). Her CSVT was treated with low-molecular-weight heparin. The patient's seizures were controlled with levetiracetam, and her HUS was managed supportively with hemodialysis. Repeat imaging nearly 6 months following presentation and initiation of anticoagulation demonstrated cerebral sinus enlargement and persistent intraluminal webbing. Anticoagulation was discontinued after 6 months, and she did not experience long-term gross neurologic sequelae. CSVT is a complication of HUS that has not been previously described. In this report, we summarize the thrombotic central nervous system complications of pediatric HUS.

Case Report: Development of Factor VIII Inhibitor in a Patient with an Uncommon de novo Mutation in the Factor VIII Gene.

The development of factor VIII inhibitors remains a significant clinical challenge in the management of hemophilia A. We present a patient of mixed ethnicity with severe hemophilia A who was found to have a F8 gene hemizygous c.5815G>T mutation resulting in an Ala1939Ser substitution (Ala1920Ser in legacy nomenclature) and possible splice site change that has been reported in only 1 patient previously. He developed an inhibitor shortly after starting replacement recombinant factor VIII (Advate®; Baxalta, Bannockburn, IL, USA) and was successfully treated with immune tolerance therapy. Our report describes the second patient reported to have severe hemophilia due to this mutation and the only case of a factor VIII inhibitor associated with this mutation.

Cross-Cultural Medical Care Training and Education: a National Survey of Pediatric Hematology/Oncology Fellows-in-Training and Fellowship Program Directors.

Pediatric hematologists/oncologists face complex situations such as breaking bad news, treatment/clinical trials discussions, and end-of-life/hospice care. With increasing diversity in patient and physician populations, cultural competency and sensitivity training covering different aspects of pediatric hematology/oncology (PDHO) care can help improve health care delivery and reduce disparities. Though it is considered a required component of fellowship training, there is no clearly defined curriculum meant specifically for PDHO fellows-in-training (PDHO-F). A national online survey of 356 PDHO-F and 67 PDHO program directors (PDHO-PD) was conducted to assess the educational experience, perceptions about identifying barriers including one's own biases and trainee comfort in delivering culturally sensitive care in various PDHO relevant clinical situations. One hundred and eleven (31.2%) PDHO-F and 27 (40.3%) PDHO-PD responded. 30.6% of PDHO-F "strongly agreed/agreed" they received comprehensive cross-cultural communication (CCC) training. The top two teaching methods were faculty role modeling and informal teaching. Majority of CCC training is in medical school or residency and only 10.8% of PDHO-F reported that most of their CCC training was in fellowship. In most clinical situations, there was a modest direct correlation between the fellow's level of agreement that they received comprehensive CCC training and their comfort level. Comfort level with some clinical situations was also significantly different based on year of training. Fellowship training programs should have CCC curricula which use experiential learning models and lay the foundation for promoting cultural awareness, self-reflection, and better patient-physician partnerships which can eventually adapt to and surmount the challenges unique to the physician's chosen field of practice.

Diagnostic laboratory standardization and validation of platelet transmission electron microscopy.

Platelet transmission electron microscopy (PTEM) is considered the gold standard test for assessing distinct ultrastructural abnormalities in inherited platelet disorders (IPDs). Nevertheless, PTEM remains mainly a research tool due to the lack of standardized procedures, a validated dense granule (DG) count reference range, and standardized image interpretation criteria. The aim of this study was to standardize and validate PTEM as a clinical laboratory test. Based on previously established methods, we optimized and standardized preanalytical, analytical, and postanalytical procedures for both whole mount (WM) and thin section (TS) PTEM. Mean number of DG/platelet (plt), percentage of plts without DG, platelet count (PC), mean platelet volume (MPV), immature platelet fraction (IPF), and plt light transmission aggregometry analyses were measured on blood samples from 113 healthy donors. Quantile regression was used to estimate the reference range for DG/plt, and linear regression was used to assess the association of DG/plt with other plt measurements. All PTEM procedures were standardized using commercially available materials and reagents. DG interpretation criteria were established based on previous publications and expert consensus, and resulted in improved operator agreement. Mean DG/plt was stable for 2 days after blood sample collection. The median within patient coefficient of variation for mean DG/plt was 22.2%; the mean DG/plt reference range (mid-95th %) was 1.2-4.0. Mean DG/plt was associated with IPF (p = .01, R2 = 0.06) but not age, sex, PC, MPV, or plt maximum aggregation or primary slope of aggregation (p > .17, R2 < 0.02). Baseline ultrastructural features were established for TS-PTEM. PTEM was validated using samples from patients with previously established diagnoses of IPDs. Standardization and validation of PTEM procedures and interpretation, and establishment of the normal mean DG/plt reference range and PTEM baseline ultrastructural features, will facilitate implementation of PTEM as a valid clinical laboratory test for evaluating ultrastructural abnormalities in IPDs.

EBV-PTLD, Adenovirus, and CMV in Pediatric Allogeneic Transplants With Alemtuzumab as Part of Pretransplant Conditioning: A Retrospective Single Center Study.

The risk of viral infections and reactivation occurring in the setting of pediatric allogeneic hematopoietic stem cell transplantation is a concern in the pediatric patient, especially with the use of Alemtuzumab (Campath) as a conditioning agent. The purpose of this study was to determine the incidence of Epstein-Barr virus posttransplant lymphoproliferative disorder (EBV-PTLD), cytomegalovirus (CMV), and adenovirus among pediatric recipients of alemtuzumab at our institution. We found that EBV-PTLD occurred in 2.1% of transplants (1 matched unrelated donor [MUD] recipient), CMV reactivation occurred in 12.5% of transplants (4 MUD and 2 matched related donor [MRD] recipients) with disseminated CMV in 2.1% of cases (1 MRD recipient), and adenovirus infection occurred in 8.3% of the total transplants (2 MUD and 2 MRD recipients). Alemtuzumab continues to be used as a method of graft-versus-host disease and graft failure prevention among pediatric recipients of hematopoietic stem cell transplantation and seems to be safer than previously reported. At our institution, alemtuzumab has not increased the risk for EBV-PTLD, CMV infection, or adenovirus.

Obesity, sedentary lifestyle, and video games: The new thrombophilia cocktail in adolescents.

Rates of venous thromboembolism have increased in the adolescent population over the last two decades, likely due to advanced diagnostics, increased use of central venous catheters, chronic medical conditions, obesity, and oral contraceptive use. Of these factors, a modifiable risk factor for adolescents is obesity. Sedentary lifestyle and prolonged immobilization are additional prothrombotic risk factors that are often associated with obesity. With ever-increasing screen time, sedentary behavior has risen accordingly, especially among gamers. We present four cases of adolescents who developed life-threatening venous thromboembolic events in the setting of obesity, sedentary lifestyle and/or immobilization, and prolonged video game use.