Neutropenia and intellectual disability are hallmarks of biallelic and de novo CLPB deficiency.

PURPOSE: To investigate monoallelic CLPB variants. Pathogenic variants in many genes cause congenital neutropenia. While most patients exhibit isolated hematological involvement, biallelic CLPB variants underlie a neurological phenotype ranging from nonprogressive intellectual disability to prenatal encephalopathy with progressive brain atrophy, movement disorder, cataracts, 3-methylglutaconic aciduria, and neutropenia. CLPB was recently shown to be a mitochondrial refoldase; however, the exact function remains elusive. METHODS: We investigated six unrelated probands from four countries in three continents, with neutropenia and a phenotype dominated by epilepsy, developmental issues, and 3-methylglutaconic aciduria with next-generation sequencing. RESULTS: In each individual, we identified one of four different de novo monoallelic missense variants in CLPB. We show that these variants disturb refoldase and to a lesser extent ATPase activity of CLPB in a dominant-negative manner. Complexome profiling in fibroblasts showed CLPB at very high molecular mass comigrating with the prohibitins. In control fibroblasts, HAX1 migrated predominantly as monomer while in patient samples multiple HAX1 peaks were observed at higher molecular masses comigrating with CLPB thus suggesting a longer-lasting interaction between CLPB and HAX1. CONCLUSION: Both biallelic as well as specific monoallelic CLPB variants result in a phenotypic spectrum centered around neurodevelopmental delay, seizures, and neutropenia presumably mediated via HAX1.

Forced deflation pulmonary function test: a novel method to evaluate lung function in infants and young children.

We describe the safety and feasibility of a forced deflation pulmonary function test (dPFT) in infants and young children. Fifty-two dPFT studies were performed in 26 patients (median age, 1.4 years). Forced vital capacity (FVC) and forced expiratory flow (FEF75 ) were normal in all except one case, but respiratory system compliance (Crs) was reduced in 24% patients. There were no significant differences in pre-blood and marrow transplantation FVC, FEF75 , and Crs between those patients who did and those who did not have posttransplant pulmonary complications. A larger study is needed to determine the prevalence and significance of PFT abnormalities in this age group.

A Pilot Study of Continuous Infusion of Mycophenolate Mofetil for Prophylaxis of Graft-versus-Host-Disease in Pediatric Patients.

Mycophenolate mofetil (MMF), an ester prodrug of mycophenolic acid (MPA), is used increasingly for graft-versus-host disease (GVHD) prophylaxis. Empiric fixed-dose-escalation strategies in pediatric hematopoietic cell transplantation (HCT) recipients have failed to achieve target MPA exposure. We evaluated the safety and feasibility of a pharmacokinetics-based dosing approach using a novel continuous infusion (CI) method of administration of MMF in pediatric HCT recipients. All patients received a myeloablative conditioning with cyclosporine A and MMF for GVHD prophylaxis. MMF was initiated on day 0 at a dose of 15 mg/kg every 8 hours. Based on steady-state pharmacokinetics, MMF was converted to CI to target a total MPA AUC(0-24) of 40 to 80 µg·hour/mL. The MMF dose was adjusted to maintain a total MPA steady-state concentration (Css) of 1.7 to 3.3 µg/mL. During the CI schedule, MPA AUC(0-24) was maintained at a mean of 40.1 µg·hour/mL (range, 20.6 to 63.8), and 17 of 19 patients (89%) achieved MPA Css within target of 1.7 to 3.3 µg/mL. Eighteen of 19 patients (95%) achieved neutrophil engraftment at a median of 13 days (range, 8 to 41) post-transplant and platelet engraftment at 39 days (range, 17 to 298) days post-transplant. Six of 18 assessable patients (33%) developed stages II to IV acute GVHD and 2 of 15 (13%) developed chronic GVHD. The MMF dose was reduced in 9 patients due to gastrointestinal symptoms (n = 6), low blood counts (n = 4), and viral infection (n = 3). Five patients with acute lymphoblastic leukemia relapsed, of whom 4 have died. Fifteen of 19 patients are alive with a median follow-up of 2.4 years (range, .4 to 4.9), with 3-year event-free and overall survival rates of 68% and 79%, respectively. In this pilot study of pharmacokinetically directed MMF dosing, we observed no toxic deaths, excellent engraftment, and low rates of grades III to IV acute and chronic GVHD. We found significantly lower half-life and higher drug clearance in pediatric HCT recipients compared with stable pediatric renal transplant patients or adult transplant patients. This regimen deserves further validation in a larger cohort of pediatric patients undergoing myeloablative transplantation.

Phototoxic dermatoses in pediatric BMT patients receiving voriconazole.

We investigated the incidence of phototoxic skin reactions in pediatric BMT recipients treated with voriconazole. Nine out of 40 patients (22.5%), all Caucasian, developed skin lesions in sun-exposed distributions. Dermatologic findings included sunburn-like erythema, pseudo-porphyria, linear papulovesicular lesions, severe erosive cheilitis, dermatoheliosis and lentigines. Patients were treated with sun avoidance, high-potency sunscreens, and topical steroids with significant improvement in all cases. Prolonged voriconazole use requires close monitoring for chronic skin toxicities. Long-term risks including the risk of skin cancer need to be investigated.

Reduced-intensity single-unit unrelated cord blood transplant with optional immune boost for nonmalignant disorders.

Children with many inherited nonmalignant disorders can be cured or their condition alleviated by hematopoietic stem cell transplantation (HSCT). Umbilical cord blood (UCB) units are a rapidly available stem cell source and offer great flexibility in HLA matching, allowing nearly uniform access to HSCT. Although reduced-intensity conditioning (RIC) regimens promise decreased treatment-related morbidity and mortality, graft failure and infections have limited their use in chemotherapy-naive patients. We prospectively evaluated a novel RIC regimen of alemtuzumab, hydroxyurea, fludarabine, melphalan, and thiotepa with a single-unit UCB graft in 44 consecutive patients with inborn errors of metabolism, immunity, or hematopoiesis. In addition, 5% of the UCB graft was re-cryopreserved and reserved for cord donor leukocyte infusion (cDLI) posttransplant. All patients engrafted at a median of 15 days posttransplant, and chimerism was >90% donor in the majority of patients at 1-year posttransplant with only 1 secondary graft failure. The incidence of grade II to IV graft-versus-host disease (GVHD) was 27% (95% confidence interval [CI], 17-43) with no extensive chronic GVHD. Overall survival was 95% (95% CI, 83-99) and 85% (95% CI, 64-93) at 1 and 5 years posttransplant, respectively. No significant end-organ toxicities were observed. The use of cDLI did not affect GVHD and showed signals of efficacy for infection control or donor chimerism. This RIC transplant regimen using single-unit UCB graft resulted in outstanding survival and remarkably low rates of graft failure. Implementation of the protocol not requiring pharmacokinetic monitoring would be feasible and applicable worldwide for children with inherited disorders of metabolism, immunity, or hematopoiesis. This trial was registered at www.clinicaltrials.gov as #NCT01962415.

Utilization and unexpected hospitalization rates of a pediatric emergency department 23-hour observation unit.

OBJECTIVES: The 23-hour observation units (OUs) may be used to avoid unnecessary hospital admissions. However, unexpected hospitalizations from the 23-hour OUs involve transfer of care and may decrease the efficiency and safety of care of the patient and the unit itself. The primary objective of this study was to determine the predictors of unexpected hospitalization for admissions to a pediatric 23-hour OU. METHODS: This is an observational prospective cohort study of patients admitted to a pediatric 23-hour OU. Bivariate and multivariate regression analyses identify factors associated with unexpected hospitalization. RESULTS: There were 4453 patients admitted to the 23-hour OU during the study. The overall rate of unexpected hospitalization was 20.3%; the mean 23-hour OU stay was 15 hours. Age, sex, race/ethnicity, and insurance status were not associated with increased unexpected hospitalization rates. Multivariate regression modeling revealed that unexpected hospitalization was associated with subgroups of resources used (intravenous medications and fluids, cardiorespiratory monitoring, respiratory therapist use, and supplemental oxygen), of subspecialty consultation, and of diagnosis categories (including asthma, adenitis, cellulitis, bronchiolitis, and esophageal foreign body ingestions). Experience of the health care provider involved in the care of the patient was not associated with increased unexpected hospitalization. CONCLUSIONS: Most of the patients (80%) were successfully discharged from the 23-hour OU. Demographics of the patient and practitioner characteristics did not influence the risk of unexpected hospitalizations; however, certain patient diagnoses, use of resources,and subspecialty consultation did increase the risk of unexpected hospitalization and, therefore, may guide future admission criteria for pediatric 23-hour OU.

Witnessed and unwitnessed esophageal foreign bodies in children.

OBJECTIVE: The purpose of this study was to describe the clinical presentation of children with either an unwitnessed or witnessed esophageal foreign body. METHODS: Retrospective chart review was performed. Patients were identified using ICD-9 code for esophageal foreign body. Clinical data and management techniques, along with complications were abstracted. RESULTS: For the 5-year period of review, 255 patients were identified with an esophageal foreign body. 214 children had a witnessed ingestion. The mean age of the unwitnessed ingestion group was 2.3 years, compared to 4.6 years for a witnessed ingestion. In both groups, males and females were distributed equally and the most common ingested object was a coin. Bivariate, unadjusted analysis revealed that history of wheeze (OR, 4.35) and fever (OR, 11.15) had the largest association with patients who had an unwitnessed ingestion. Multivariate analysis indicated that any physical findings of wheeze, rhonchi, stridor, or retractions were associated significantly with a diagnosis of an unwitnessed foreign body. Children less than 2 years of age and with a documented fever are also predictive of an unwitnessed ingestion. Eleven children (4.3%) with esophageal abnormalities were also noted to have foreign bodies. CONCLUSIONS: Children who present to the emergency department two years old and younger, who have a documented fever and with respiratory findings should be considered at risk for having a retained esophageal foreign body. Children with esophageal abnormalities may also be at risk for retained esophageal foreign bodies.