Optimization of Ganciclovir and Valganciclovir Starting Dose in Children by Machine Learning.

BACKGROUND AND OBJECTIVES: Ganciclovir (GCV) and valganciclovir (VGCV) show large interindividual pharmacokinetic variability, particularly in children. The objectives of this study were (1) to develop machine learning (ML) algorithms trained on simulated pharmacokinetics profiles obtained by Monte Carlo simulations to estimate the best ganciclovir or valganciclovir starting dose in children and (2) to compare its performances on real-world profiles to previously published equation derived from literature population pharmacokinetic (POPPK) models achieving about 20% of profiles within the target. MATERIALS AND METHODS: The pharmacokinetic parameters of four literature POPPK models in addition to the World Health Organization (WHO) growth curve for children were used in the mrgsolve R package to simulate 10,800 pharmacokinetic profiles. ML algorithms were developed and benchmarked to predict the probability to reach the steady-state, area-under-the-curve target (AUC0-24 within 40-60 mg × h/L) based on demographic characteristics only. The best ML algorithm was then used to calculate the starting dose maximizing the target attainment. Performances were evaluated for ML and literature formula in a test set and in an external set of 32 and 31 actual patients (GCV and VGCV, respectively). RESULTS: A combination of Xgboost, neural network, and random forest algorithms yielded the best performances and highest target attainment in the test set (36.8% for GCV and 35.3% for the VGCV). In actual patients, the best GCV ML starting dose yielded the highest target attainment rate (25.8%) and performed equally for VGCV with the Franck model formula (35.3% for both). CONCLUSION: The ML algorithms exhibit good performances in comparison with previously validated models and should be evaluated prospectively.

Urinary tract infections in very premature neonates: the definition dilemma.

BACKGROUND AND OBJECTIVES: Data on urinary tract infections (UTIs) in very preterm neonates (VPTNs) are scarce. We aimed to (i) describe the characteristics of UTIs in VPTNs and (ii) compare the diagnostic practices of neonatal clinicians to established pediatric guidelines. METHODS: All VPTNs (<29 weeks GA) with a suspected UTI at the CHU Sainte-Justine neonatal intensive care unit from January 1, 2014, and December 31, 2019, were included and divided into two definition categories: Possible UTI, and Definite UTI. RESULTS: Most episodes were Possible UTI (87%). Symptoms of UTIs and pathogens varied based on the definition category. A positive urinalysis was obtained in 25%. Possible UTI episodes grew 2 organisms in 62% of cases and <50,000 CFU/mL in 62% of cases. CONCLUSION: Characteristics of UTIs in VPTNs vary based on the definition category and case definitions used by clinicians differ from that of established pediatric guidelines.

Treatment of Congenital Cytomegalovirus and Ganciclovir Therapeutic Drug Monitoring in Twin Preterm Infants.

Congenitally acquired cytomegalovirus (CMV) infection is the most prevalent congenital infection worldwide and the most frequent cause of acquired sensorineural hearing loss. The burden of the disease is even more important in premature and very low birth weight infants. However, few data exist on the treatment with intravenous ganciclovir and oral valganciclovir in this vulnerable population. We report the case of twins congenitally infected with CMV and born prematurely at 27 weeks' gestation. Treatment regimens were initially individualized for their prematurity and renal function, and then adjusted with therapeutic drug monitoring (TDM) to adapt to their continuously evolving physiologic maturation. As infants were aging, the plasmatic half-life of ganciclovir slowly decreased to term infant values around 10 weeks of chronological age, or 37 weeks of postmenstrual age. Results for blood polymerase chain reaction tests became negative and long-term follow-ups were satisfactory in both twins. The limited data for infants born before 32 weeks of gestation or at less than 1200 g and evolution of ganciclovir pharmacokinetic parameters justify the use of TDM in these settings.

Epstein-Barr virus seroprevalence and viral load at disease onset in children with inflammatory bowel disease.

Background and Aim: Patients with inflammatory bowel disease (IBD) are at increased risk for life-threatening complications of Epstein-Barr virus (EBV), including lymphoproliferative diseases. These complications are likely related to inherent immune dysfunction and immunomodulating therapies often used. We aimed to determine the seroprevalence of EBV at diagnosis in our population, its impact on disease at onset, and the risk of active EBV infection. Methods: We included patients newly diagnosed with IBD for whom an EBV serology was performed over a 2-year period. Demographic information and data on disease characteristics were collected retrospectively. Stored serum from the time of diagnosis was retrieved when available for the patients with positive EBV serology, and quantitative polymerase chain reaction testing was performed to assess the pre-treatment viral load of EBV. Results: One hundred twenty patients were included in the study. Fifty-three patients (44.2%) had positive EBV serology at diagnosis. Stratified by age group, the prevalence of seropositive patients was for 0 to <10 years 35%, 10 to <17 years 46%, and ≥17 years 50%. Overall, therapies started within 6 months of diagnosis were similar in both the seropositive and seronegative groups. Within the seropositive group, 66% received systemic corticosteroids, 32.1% infliximab, 5.7% adalimumab, and 5.7% azathioprine. Conclusion: EBV seroprevalence is high in pediatric patients with IBD. EBV seropositivity did not seem to influence the severity of disease at onset or initial choice of therapy.

Exploration de l'association possible entre la consommation d'antibiotiques et l'émergence de résistance dans un centre hospitalier universitaire mère-enfant.

Background: The emergence of antibiotic resistance has contributed to the development of multidrug-resistant bacteria, which is a major concern. Objectives: The primary objective was to explore the possible association between antibiotic use and the emergence of resistance in a mother-child university hospital. Method: This retrospective study was conducted in a university hospital centre. Antibiotic-bacteria pairs were established, taking into account the number of isolates, actual antibiotic use, and clinical relevance. For each pair, a comparison of 2 variables (antibiotic utilization and rate of resistance) was quantified with the Pearson coefficient. Three analyses were conducted: no lag between utilization and resistance, 1-year lag, and 2-year lag. Results: Thirty antibiotic-bacteria pairs were selected from hematology-oncology and 18 from neonatology. In hematology-oncology, 6 pairs had a positive correlation (Pearson coefficient > 0.7): 2 pairs involving meropenem, 2 involving ceftazidime, and 2 involving piperacillin-tazobactam. In 3 of these cases, there was no lag between consumption of antibiotics and presence of resistance. In neonatology, 3 antibiotic-bacteria pairs had a positive correlation, 1 each involving vancomycin, cloxacillin, and meropenem. Conclusions: It is possible to explore the potential association between consumption of antibiotics and emergence of resistance in a particular centre. Our exploratory approach was based on manual data processing. It would be interesting to consider a continuous systematic approach, allowing automatic generation of correlations.

Pharmacokinetics, Pharmacodynamics, and Therapeutic Drug Monitoring of Valganciclovir and Ganciclovir in Transplantation.

Ganciclovir and valganciclovir are first choice drugs for the prevention and treatment of cytomegalovirus infection and disease in solid organ and stem cell transplant recipients. Only a few studies on the pharmacokinetics and exposure/efficacy or exposure/safety relationships of ganciclovir and valganciclovir in transplant recipients have been published so far, and there are still controversies about the exposure parameter to use for therapeutic drug monitoring (TDM). We performed an extensive literature review of the clinical pharmacokinetics data, the exposure/effect relationships in terms of efficacy and safety, and the available tools for valganciclovir and ganciclovir TDM in adults and pediatrics transplant recipients. The pharmacokinetics of ganciclovir and valganciclovir is well described in adults and children, and a high interindividual variability is commonly observed. In contrast, the drug pharmacodynamics has been poorly described in adults and barely in children. The average 24-hour area under the concentration-time curve (AUC0-24h ) seems to be the best predictor of efficacy and toxicity. The benefit of TDM remains controversial in adult patients but should be considered in children due to higher interindividual variability and lower probability of target attainment. Several bayesian estimators based on limited sampling strategies have been developed with this aim and may be used in clinical practice for the AUC-based individual dose adjustment of ganciclovir and valganciclovir.

Thoroughly Validated Bayesian Estimator and Limited Sampling Strategy for Dose Individualization of Ganciclovir and Valganciclovir in Pediatric Transplant Recipients.

BACKGROUND AND OBJECTIVE: Given a high pharmacokinetic inter-individual variability and a low exposure target achievement, ganciclovir (GCV) therapeutic drug monitoring is sometimes used in children. We aimed to develop and validate Bayesian estimators based on limited sampling strategies for the estimation of GCV area under the concentration-time curve from 0 to 24 h in pediatric transplant recipients treated with valganciclovir (VGCV) or GCV. METHODS: Solid organ transplant or stem-cell transplant recipients who received GCV or VGCV and had available GCV concentrations per standard of care were retrospectively included in this study for pharmacokinetic modeling and development of Bayesian estimators using the iterative two-stage Bayesian method. Validation datasets included additional child recipients of a solid organ transplant or stem-cell transplant, and child recipients of a kidney or liver transplant enrolled in a previous study. Various combinations of three or two sampling times, applicable in clinical practice, were assessed based on the relative mean bias, standard deviation, and the root mean square error in a development dataset and three independent validation datasets. RESULTS: In the development dataset, the mean bias/standard deviation/root mean square error for the 1 h/2 h/3 h and 1 h/3 h limited sampling strategies were - 1.4%/9.3%/9.1% and - 3.5%/12.2%/12.3%, respectively for GCV, while for VGCV, the mean bias/standard deviation/root mean square error for the 1 h/2 h/6 h and 1 h/6 h limited sampling strategies were 0.7%/13.5%/13.3% and - 0.1%/12.1%/11.8%, respectively. In the independent validation datasets, seven (13%) and five (14%) children would have had misclassifications of their exposure using these Bayesian estimators and limited sampling strategies for VGCV and GCV, respectively. CONCLUSIONS: Three plasma samples collected at 1 h/2 h/3 h and 1 h/2 h/6 h post-dose for GCV and VGCV respectively, are sufficient to accurately determine GCV area under the concentration-time curve from 0 to 24 h for pharmacokinetic-enhanced therapeutic drug monitoring.

Pneumococcal vaccination during chemotherapy in children treated for acute lymphoblastic leukemia.

BACKGROUND: Children treated for acute lymphoblastic leukemia (ALL) are at high risk of invasive pneumococcal disease (IPD). We assessed immunity to S. pneumoniae among children after ALL treatment, and the impact of pneumococcal immunization during and after chemotherapy. METHODS: We performed an observational retrospective study of children treated for ALL at a single center. All children were fully immunized with three routine doses of pneumococcal conjugate vaccine (PCV) prior to ALL diagnosis. Children from Group 1 received a 13-valent PCV (PCV13) dose during the maintenance phase as well as a PCV13 booster after completing chemotherapy, while Group 2 only received the postchemotherapy dose. Serologic testing was performed after chemotherapy and again after the postchemotherapy dose. A serotype-specific antibody level ≥0.35 µg/ml was considered protective, and patients with protective levels for ≥70% of serotypes in the PCV7 vaccine were defined as seroprotected. RESULTS: A total of 71 children (median age 46 months, range 12-160) were included. At the end of chemotherapy, 53.1% of children in Group 1 (17/32) and 25.6% in Group 2 (10/39) were seroprotected (p = .018). After the postchemotherapy booster, seroprotection rates increased to 96.9% in Group 1 (31/32) and 100% in Group 2. CONCLUSIONS: Rates of pneumococcal seroprotection among children with ALL are low following chemotherapy, despite prior routine immunization. A PCV booster during chemotherapy may shorten the period of susceptibility to IPD in some children. However, irrespective of a booster during chemotherapy, a PCV dose postchemotherapy appears sufficient to confer high rates of seroprotection against IPD.

Profile of Antimicrobial Use in the Pediatric Population of a University Hospital Centre, 2015/16 to 2018/19.

BACKGROUND: Antimicrobial stewardship is a standard practice in health facilities to reduce both the misuse of antimicrobials and the risk of resistance. OBJECTIVE: To determine the profile of antimicrobial use in the pediatric population of a university hospital centre from 2015/16 to 2018/19. METHODS: In this retrospective, descriptive, cross-sectional study, the pharmacy information system was used to determine the number of days of therapy (DOTs) and the defined daily dose (DDD) per 1000 patient-days (PDs) for each antimicrobial and for specified care units in each year of the study period. For each measure, the ratio of 2018/19 to 2015/16 values was also calculated (and expressed as a proportion); where the value of this proportion was ≤ 0.8 or ≥ 1.2 (indicating a substantial change over the study period), an explanatory rating was assigned by consensus. RESULTS: Over the study period, 94 antimicrobial agents were available at the study hospital: 70 antibiotics (including antiparasitics and antituberculosis drugs), 14 antivirals, and 10 antifungals. The total number of DOTs per 1000 PDs declined from 904 in 2015/16 to 867 in 2018/19. The 5 most commonly used antimicrobials over the years, expressed as minimum/maximum DOTs per 1000 PDs, were piperacillin-tazobactam (78/105), trimethoprim-sulfamethoxazole (74/84), ampicillin (51/69), vancomycin (53/68), and cefotaxime (55/58). In the same period, the care units with the most antimicrobial use (expressed as minimum/maximum DOTs per 1000 PDs) were hematology-oncology (2529/2723), pediatrics (1006/1408), and pediatric intensive care (1328/1717). CONCLUSIONS: This study showed generally stable consumption of antimicrobials from 2015/16 to 2018/19 in a Canadian mother-and-child university hospital centre. Although consumption was also stable within drug groups (antibiotics, antivirals, and antifungals), there were important changes over time for some individual drugs. Several factors may explain these variations, including disruptions in supply, changes in practice, and changes in the prevalence of infections. Surveillance of antimicrobial use is an essential component of an antimicrobial stewardship program.

CONTEXTE: La gestion des antimicrobiens est une pratique courante dans les centres hospitaliers afin de réduire l'utilisation inappropriée des antimicrobiens et le risque de résistance. OBJECTIF: Décrire l'évolution de l'utilisation des antimicrobiens dans un centre hospitalier universitaire de 2015­16 à 2018­19. MÉTHODES: Dans cette étude rétrospective, descriptive et transversale, les dossiers pharmacologiques ont servi à déterminer le nombre de jours de traitement (NJT) et la dose définie journalière (DDD) par 1000 jours-présence (JP) pour chaque antimicrobien et pour chaque unité de soins par année de l'étude. Pour chaque mesure, on a également comparé le ratio de 2018­19 à celui de 2015­16, qui est exprimé en proportion; lorsque la valeur de cette proportion était ≤ 0,8 ou ≥ 1,2, ce qui indiquait un changement important durant la période de l'étude, une note explicative a été attribuée par consensus. RÉSULTATS: Durant la période à l'étude, 94 antimicrobiens ont été disponibles dans notre centre : 70 antibiotiques (dont les antiparasitaires et les antituberculeux), 14 antiviraux et 10 antifongiques. Le nombre total de NJT par 1000 JP a diminué de 904 en 2015­16 à 867 en 2018­19. Les cinq antimicrobiens utilisés le plus fréquemment et présentés en minimum / maximum de NJT par 1000 JP étaient les suivants : piperacilline-tazobactam (78/105), trimethoprim-sulfamethoxazole (74/84), ampicilline (51/69), vancomycine (53/68) et cefotaxime (55/58). Pendant la même période, les unités de soins qui faisaient la plus grande utilisation d'antimirobiens (exprimée en minimum / maximum de NJT par 1000 JP) étaient hématologie-oncologie (2529/2723), pédiatrie (1006/1408) et soins intensifs pédiatriques (1328/1717). CONCLUSIONS: Cette étude démontre une consommation stable d'antimicrobiens entre 2015­16 et 2018­19 dans un centre hospitalier universitaire mère-enfant canadien. Malgré le fait que la consommation entre les groupes d'antimicrobiens (antibiotiques, antiviraux, antifongiques) était stable, on a constaté d'importantes variations concernant certains médicaments individuels. Plusieurs facteurs peuvent expliquer cette variation, notamment des ruptures d'approvisionnement, des changements de pratique et des changements dans la prévalence d'infections. La surveillance de la consommation des antimicrobiens est une partie essentielle de tout programme d'antibiogouvernance.

Population pharmacokinetics of ganciclovir and valganciclovir in paediatric solid organ and stem cell transplant recipients.

AIMS: Ganciclovir (GCV) and its prodrug valganciclovir (VGCV) are first-line agents to prevent and treat cytomegalovirus in transplant recipients. There is high pharmacokinetic (PK) interindividual variability and PK data are scarce, especially in paediatric stem cell transplant (SCT) recipients. We sought to determine the optimal GCV and VGCV dosing in transplanted children. METHODS: We conducted a single-centre retrospective population PK (POPPK) study of IV GCV and enteral VGCV in paediatric solid organ transplant (SOT) and SCT recipients. We included children who were transplanted and had available plasma GCV concentrations, done per standard of care. POPPK analysis was performed using a nonlinear mixed effects modelling approach with NONMEM. Optimal dosing was determined based on the achievement of the surrogate efficacy target: GCV 24 h area under the concentration-time curve (AUC0-24h ) of 40-60 mg.h.L-1 . RESULTS: Fifty children with a median [range] age of 7.5 years [0.5-17.4] contributed 580 PK samples. A two-compartment model with first-order absorption with a lag time and first-order elimination fit the data well. Creatinine clearance and body weight (WT) were significant covariates for GCV clearance (CL); and WT for the volumes of distribution. IV GCV 15-20 mg.kg-1 .day-1 divided every 12 hours achieved the highest probability of target achievement (PTA) (33.0-33.8%). Enteral VGCV 30 and 40 mg.kg-1 .day-1 divided every 12 hours in children 0-<6 years, and 6-18 years, respectively, achieved the highest PTA (29.1-33.0%). CONCLUSION: This is the first POPPK model developed in children with either SOT or SCT. Concentration target achievement was low, suggesting a potential benefit for therapeutic drug monitoring to ensure optimal exposure.

Fusobacterium nucleatum Multiple Liver Abscesses in an Adolescent With Hemoglobin SC Disease.

Liver abscesses are poorly known in sickle cell disease. We report here multiple liver abscesses occurring in a 17-year-old patient with hemoglobin SC disease. A Fusobacterium nucleatum was identified on cyst puncture. Such complications have been described in only 11 children and young adults with hemoglobin SS/Sß-thalassemia diseases. Fusobacterium species are the most frequent pathogens reported and require anaerobic culture to be identified.

Association between child sexual abuse and infectious disease diagnoses.

BACKGROUND: Though many studies have linked child sexual abuse (CSA) to psychological health problems, little is known regarding the relationship between CSA and children and adolescents' physical health. OBJECTIVE: The objective of this study was to assess the relationship between CSA and infectious disease diagnoses. PARTICIPANTS: Of the 955 eligible children and adolescents who had a substantiated report of sexual abuse between 2001 and 2010, medical data was retrieved for 882 individuals, who formed the sexually abused group. These 882 participants were matched to 882 participants on age, gender, and administrative healthcare region to form the general population group. SETTING AND METHODS: This matched-cohort study, conducted in a large Canadian city, compared the number of infectious disease diagnoses between the date of the substantiated sexual abuse report and August 1, 2013, between the two groups. RESULTS: Results indicate that sexually abused participants had 1.27 times more (95% CI - 1.13 to 1.42) infectious diseases diagnoses than those from the general population. They received 1.83 times more genitourinary infection diagnoses (95% CI - 1.43 to 2.33), 1.31 times more diagnoses for other types of infections (95% CI - 1.11 to 1.55) and 1.21 times more respiratory and ear infection diagnoses (95% CI - 1.05 to 1.40). There was no statistically significant difference regarding skin infection diagnoses. These results indicate an association between CSA and more frequent infectious diseases diagnoses.

Population Pharmacokinetics of Intravenous Linezolid in Premature Infants.

BACKGROUND: The emergence of coagulase-negative staphylococci with reduced vancomycin susceptibility in some neonatal intensive care units has resulted in an increase of linezolid use. Linezolid pharmacokinetics (PK) and safety in premature infants still need to be better established. METHODS: This was a retrospective PK study. All infants who received intravenous linezolid and had linezolid plasma concentrations per standard of care were included. Linezolid concentrations were measured by high performance liquid chromatography. A population PK model was developed using nonlinear mixed effects modeling. Optimal dosing was determined based on achievement of the surrogate pharmacodynamics target for efficacy: a ratio of the area under the concentration-time curve to minimum inhibitory concentration >80. We assessed the occurrence of thrombocytopenia and lactic acidosis in relation with drug exposure. RESULTS: A total of 78 plasma concentrations were collected from 26 infants, with a median postnatal age (PNA) of 24 days (8-88) and weight of 1423 g (810-3256). A 1-compartment model described linezolid data well. The final model included PNA and weight on clearance and weight on volume of distribution. Considering an MIC90 of 1 mg/L, all infants reached an area under the concentration-time curve/minimum inhibitory concentration > 80. Although thrombocytopenia and hyperlactatemia occurred frequently, they were not sustained and were not considered related to linezolid. CONCLUSION: and was well tolerated in critically ill premature infants. PNA was the main determinant of clearance.

Program to Manage New and Expensive Drugs in Pediatrics: Profile of a New Drug Policy and a 12-Month Descriptive Study.

BACKGROUND: With growing financial pressure and the range of new and expensive drugs, hospital administrators, clinicians, and pharmacy directors are facing tough decisions on how to manage drug budgets. At a Canadian mother-child hospital, a policy for new and expensive drugs was developed, with the goal of managing their use and costs. OBJECTIVES: To describe the development and implementation of a policy for new and expensive drugs in a mother-child teaching hospital and to describe the profile of requests for these therapies over a 12-month period. METHODS: A brainstorming session was conducted with members of the pharmacy and therapeutics committee to define the criteria for new and expensive drugs at the study hospital and a new process to evaluate requests for these drugs. Over the 12-month period following implementation of the policy, all requests for new and expensive drugs were evaluated through collection and analysis of relevant data. RESULTS: The new drug policy was launched on October 1, 2014. Over the following 12-month period, a total of 58 requests for new and expensive drugs were discussed, but only 47 request forms were completed and signed by a physician and a clinical pharmacist. CONCLUSIONS: New and expensive drugs represent a challenge for clinicians and hospital stakeholders. This study illustrates the implementation of a new policy for these drugs in a mother-child teaching hospital over a 12-month period.

CONTEXTE: Les budgets de plus en plus serrés et la gamme de médicaments nouveaux ou coûteux placent les administrateurs, les cliniciens et les directeurs de pharmacie des hôpitaux devant des décisions difficiles en ce qui touche la gestion des dépenses en médicaments. On a mis au point, dans un hôpital canadien mère-enfant, une politique concernant les médicaments nouveaux ou coûteux avec pour objectif de gérer leur utilisation et leurs coûts. OBJECTIFS: Décrire l'élaboration et la mise en place d'une politique sur les médicaments nouveaux ou coûteux dans un hôpital universitaire mère-enfant et décrire le profil des demandes pour ces pharmacothérapies sur une période de 12 mois. MÉTHODES: Les membres du comité de pharmacologie ont procédé à une séance de remue-méninges dans le but de définir les critères pour les médicaments nouveaux ou coûteux dans l'hôpital à l'étude et un nouveau processus servant à évaluer les demandes pour ces médicaments. Au cours des 12 mois suivant la mise en place de la politique, toutes les demandes pour des médicaments nouveaux ou coûteux ont été évaluées à l'aide d'une cueillette et d'une analyse de données pertinentes. RÉSULTATS: La nouvelle politique sur les médicaments a été lancée le 1er octobre 2014. Au cours des 12 mois suivants, un total de 58 demandes pour des médicaments nouveaux ou coûteux ont été analysées, mais seulement 47 formulaires de demande ont été remplis et signés par un médecin et un pharmacien clinicien. CONCLUSIONS: Les médicaments nouveaux ou coûteux représentent un défi pour les cliniciens et les parties prenantes des hôpitaux. La présente étude décrit la mise en place d'une nouvelle politique pour ces médicaments dans un hôpital universitaire mère-enfant sur une période de 12 mois.

Very Early-Onset Inflammatory Manifestations of X-Linked Chronic Granulomatous Disease.

Chronic granulomatous disease (CGD) is a rare primary immune deficiency caused by mutations in genes coding for components of the nicotinamide adenine dinucleotide phosphate oxidase, characterized by severe and recurrent bacterial and fungal infections, together with inflammatory complications. Dysregulation of inflammatory responses are often present in this disease and may lead to granulomatous lesions, most often affecting the gastrointestinal (GI) and urinary tracts. Treatment of inflammatory complications usually includes corticosteroids, whereas antimicrobial prophylaxis is used for infection prevention. Curative treatment of both infectious susceptibility and inflammatory disease can be achieved by hematopoietic stem cell transplantation. We report herein three patients with the same mutation of the CYBB gene who presented with very early-onset and severe GI manifestations of X-linked CGD. The most severely affected patient had evidence of antenatal inflammatory involvement of the GI and urinary tracts. Extreme hyperleukocytosis with eosinophilia and high inflammatory markers were observed in all three patients. A Mycobacterium avium lung infection and an unidentified fungal lung infection occurred in two patients both during their first year of life, which is indicative of the severity of the disease. All three patients underwent bone marrow transplantation and recovered fully from their initial symptoms. To our knowledge, these are the first reports of patients with such an early-onset and severe inflammatory manifestations of CGD.

Posaconazole Plasma Monitoring in Immunocompromised Children.

Plasma posaconazole exposure was assessed in 13 children who underwent a hematopoietic stem cell transplant. The median dosage was 12.5 mg/kg per day, divided into 3 doses. Of these 13 patients, 46.2% (6) and 30.8% (4) achieved concentrations higher than 0.7 and 1.25 mg/L, respectively. In children at high risk, a higher dosage might be needed to achieve target concentrations.

Protection against vaccine preventable diseases in children treated for acute lymphoblastic leukemia.

BACKGROUND: The objective of this retrospective study was to assess protection against vaccine preventable diseases (VPDs) in children treated for acute lymphoblastic leukemia (ALL). PROCEDURE: Clinical characteristics and vaccination records were collected. Antibodies against VPDs were measured after completion of chemotherapy and after a booster dose of vaccine. Immunization status of household members was evaluated. RESULTS: Sixty children were included. Median interval between the end of chemotherapy and enrolment in the study was 13 months (range 1-145). At ALL diagnosis, 81.3% of the children were up to date with their vaccination schedule. This proportion decreased to 52.9% at enrolment. Among the parents, 21% were up to date with their immunization schedule and 42% had received seasonal influenza vaccination. After chemotherapy, less than 50% of the patients were seroprotected against tetanus, diphtheria, polio 3, Haemophilus influenzae type b (Hib), and mumps and no more than 80% were seroprotected against polio 1 and 2, measles, rubella, and varicella. After a booster dose of vaccine, the rate of protection increased to over 90% for each of the following antigens: TT, DT, polio 1, Hib, measles, and rubella. Nevertheless, polio 3, mumps, and varicella-zoster virus antibodies titers/concentrations remained below seroprotective thresholds in over 20% of the patients. CONCLUSIONS: After chemotherapy for ALL, most of the children were not protected against VPDs. As the majority mounted a robust response to booster vaccines, efforts need to be done to improve protection against VPDs by implementing a systematic vaccine booster schedule. This could also be helped by reinforcing household members' immunization.