Clinical and functional spectrum of RAC2-related immunodeficiency.

ABSTRACT: Mutations in the small Rho-family guanosine triphosphate hydrolase RAC2, critical for actin cytoskeleton remodeling and intracellular signal transduction, are associated with neonatal severe combined immunodeficiency (SCID), infantile neutrophilic disorder resembling leukocyte adhesion deficiency (LAD), and later-onset combined immune deficiency (CID). We investigated 54 patients (23 previously reported) from 37 families yielding 15 novel RAC2 missense mutations, including one present only in homozygosity. Data were collected from referring physicians and literature reports with updated clinical information. Patients were grouped by presentation: neonatal SCID (n = 5), infantile LAD-like disease (n = 5), or CID (n = 44). Disease correlated to RAC2 activity: constitutively active RAS-like mutations caused neonatal SCID, dominant-negative mutations caused LAD-like disease, whereas dominant-activating mutations caused CID. Significant T- and B-lymphopenia with low immunoglobulins were seen in most patients; myeloid abnormalities included neutropenia, altered oxidative burst, impaired neutrophil migration, and visible neutrophil macropinosomes. Among 42 patients with CID with clinical data, upper and lower respiratory infections and viral infections were common. Twenty-three distinct RAC2 mutations, including 15 novel variants, were identified. Using heterologous expression systems, we assessed downstream effector functions including superoxide production, p21-activated kinase 1 binding, AKT activation, and protein stability. Confocal microscopy showed altered actin assembly evidenced by membrane ruffling and macropinosomes. Altered protein localization and aggregation were observed. All tested RAC2 mutant proteins exhibited aberrant function; no single assay was sufficient to determine functional consequence. Most mutants produced elevated superoxide; mutations unable to support superoxide formation were associated with bacterial infections. RAC2 mutations cause a spectrum of immune dysfunction, ranging from early onset SCID to later-onset combined immunodeficiencies depending on RAC2 activity. This trial was registered at www.clinicaltrials.gov as #NCT00001355 and #NCT00001467.

Talin variant P229S compromises integrin activation and associates with multifaceted clinical symptoms.

Adhesion of cells to the extracellular matrix (ECM) must be exquisitely coordinated to enable development and tissue homeostasis. Cell-ECM interactions are regulated by multiple signalling pathways that coordinate the activation state of the integrin family of ECM receptors. The protein talin is pivotal in this process, and talin's simultaneous interactions with the cytoplasmic tails of the integrins and the plasma membrane are essential to enable robust, dynamic control of integrin activation and cell-ECM adhesion. Here, we report the identification of a de novo heterozygous c.685C>T (p.Pro229Ser) variant in the TLN1 gene from a patient with a complex phenotype. The mutation is located in the talin head region at the interface between the F2 and F3 domains. The characterization of this novel p.P229S talin variant reveals the disruption of adhesion dynamics that result from disturbance of the F2-F3 domain interface in the talin head. Using biophysical, computational and cell biological techniques, we find that the variant perturbs the synergy between the integrin-binding F3 and the membrane-binding F2 domains, compromising integrin activation, adhesion and cell migration. Whilst this remains a variant of uncertain significance, it is probable that the dysregulation of adhesion dynamics we observe in cells contributes to the multifaceted clinical symptoms of the patient and may provide insight into the multitude of cellular processes dependent on talin-mediated adhesion dynamics.

Patterns and Outcomes of Epoprostenol Use in Infants with Congenital Diaphragmatic Hernia Requiring Extracorporeal Life Support.

OBJECTIVE: To describe our experience utilizing epoprostenol for pulmonary hypertension (PH) in infants with congenital diaphragmatic hernia (CDH) requiring extracorporeal life support (ECLS). STUDY DESIGN: We retrospectively reviewed infants diagnosed with CDH who required ECLS at our institution from 2013 to 2023. Data collected included demographics, disease characteristics, medication administration patterns, and hospital outcomes. We first compared infants who received intravenous epoprostenol and those who did not. Among infants who received epoprostenol, we compared survivors and nonsurvivors. χ² test/Fisher's exact and Mann-Whitney tests were used, with significance defined at P < .05. RESULTS: Fifty-seven infants were included; 40 (70.2%) received epoprostenol. Infants receiving epoprostenol had lower observed/expected total fetal lung volume (O/E TFLV) on magnetic resonance imaging (20 vs 26.2%, P = .042) as well as higher prenatal frequency of liver-up (90 vs 64.7%, P = .023) and "severe" classification (67.5 vs 35.3%, P = .007). Survival with and without epoprostenol was comparable (60% vs 64%, P = .23). Of those receiving epoprostenol, both survivors and nonsurvivors had similar prenatal indicators of disease severity. Most (80%) of hernia defects were classified as type C/D and 68% were repaired <72 hours after ECLS cannulation. The median age at initiation of epoprostenol was day of life 6 (IQR: 4, 7) in survivors and 8 (IQR: 7, 16) in nonsurvivors (P = .012). Survivors had shorter ECLS duration (11 vs 20 days, P = .049). Of nonsurvivors, refractory PH was the cause of death for 13 infants (81%). CONCLUSIONS: In infants with CDH requiring ECLS, addition of epoprostenol appears promising and earlier initiation may affect survival.

Multiplexed Functional Assessment of Genetic Variants in CARD11.

Genetic testing has increased the number of variants identified in disease genes, but the diagnostic utility is limited by lack of understanding variant function. CARD11 encodes an adaptor protein that expresses dominant-negative and gain-of-function variants associated with distinct immunodeficiencies. Here, we used a "cloning-free" saturation genome editing approach in a diploid cell line to simultaneously score 2,542 variants for decreased or increased function in the region of CARD11 associated with immunodeficiency. We also described an exon-skipping mechanism for CARD11 dominant-negative activity. The classification of reported clinical variants was sensitive (94.6%) and specific (88.9%), which rendered the data immediately useful for interpretation of seven coding and splicing variants implicated in immunodeficiency found in our clinic. This approach is generalizable for variant interpretation in many other clinically actionable genes, in any relevant cell type.

BT595, a 10% Human Normal Immunoglobulin, for Replacement Therapy of Primary Immunodeficiency Disease: Results of a Subcohort Analysis in Children.

PURPOSE: To assess the efficacy, pharmacokinetics, and safety of a new, highly purified 10% IVIg (BT595, Yimmugo®) administered in children with PID. METHODS: This was an open-label, prospective, uncontrolled, multicenter Phase III pivotal trial. Among the 67 subjects in the trial were 18 pediatric patients aged 2 to 17 years with diagnosis of PID included in this analysis. They received doses between 0.2 and 0.8 g/kg body weight for approximately 12 months at intervals of either 3 or 4 weeks. Dosage and dosing interval were based on each patient's pre-trial infusion schedule. The rates of acute serious bacterial infections (SBI), secondary efficacy, safety, and pharmacokinetic outcomes were evaluated. RESULTS: No SBI occurred in the pediatric population. Two hundred sixty infusions were administered to the 18 pediatric patients. The mean (SD) IgG trough level was 8.55 (1.67) g/L at baseline and 8.84 (2.17) g/L at the follow-up visit after the last BT595 infusion. At the single infusions respectively, the average mean IgG trough levels ranged between 8.52 and 10.58 g/L. More than 85% of all infusions administered were not associated with any infusional AE (start during or within 72 h post-infusion). None of the severe or serious AEs were related to the investigational medicinal product (IMP). No premedication was used. Thirteen children reached a maximum infusion rate between > 2.0 and 8 mL/kg/h; no AE with an onset during the infusion occurred at these infusion rates. CONCLUSION: BT595 is effective, convenient, well tolerated, and safe for the treatment of children with PID. TRIAL REGISTRATION: EudraCT: 2015-003652-52; NCT02810444, registered June 23, 2016.

Lentiviral Gene Therapy Combined with Low-Dose Busulfan in Infants with SCID-X1.

BACKGROUND: Allogeneic hematopoietic stem-cell transplantation for X-linked severe combined immunodeficiency (SCID-X1) often fails to reconstitute immunity associated with T cells, B cells, and natural killer (NK) cells when matched sibling donors are unavailable unless high-dose chemotherapy is given. In previous studies, autologous gene therapy with γ-retroviral vectors failed to reconstitute B-cell and NK-cell immunity and was complicated by vector-related leukemia. METHODS: We performed a dual-center, phase 1-2 safety and efficacy study of a lentiviral vector to transfer IL2RG complementary DNA to bone marrow stem cells after low-exposure, targeted busulfan conditioning in eight infants with newly diagnosed SCID-X1. RESULTS: Eight infants with SCID-X1 were followed for a median of 16.4 months. Bone marrow harvest, busulfan conditioning, and cell infusion had no unexpected side effects. In seven infants, the numbers of CD3+, CD4+, and naive CD4+ T cells and NK cells normalized by 3 to 4 months after infusion and were accompanied by vector marking in T cells, B cells, NK cells, myeloid cells, and bone marrow progenitors. The eighth infant had an insufficient T-cell count initially, but T cells developed in this infant after a boost of gene-corrected cells without busulfan conditioning. Previous infections cleared in all infants, and all continued to grow normally. IgM levels normalized in seven of the eight infants, of whom four discontinued intravenous immune globulin supplementation; three of these four infants had a response to vaccines. Vector insertion-site analysis was performed in seven infants and showed polyclonal patterns without clonal dominance in all seven. CONCLUSIONS: Lentiviral vector gene therapy combined with low-exposure, targeted busulfan conditioning in infants with newly diagnosed SCID-X1 had low-grade acute toxic effects and resulted in multilineage engraftment of transduced cells, reconstitution of functional T cells and B cells, and normalization of NK-cell counts during a median follow-up of 16 months. (Funded by the American Lebanese Syrian Associated Charities and others; LVXSCID-ND ClinicalTrials.gov number, NCT01512888.).

NBAS Variants Are Associated with Quantitative and Qualitative NK and B Cell Deficiency.

PURPOSE: Biallelic pathogenic NBAS variants manifest as a multisystem disorder with heterogeneous clinical phenotypes such as recurrent acute liver failure, growth retardation, and susceptibility to infections. This study explores how NBAS-associated disease affects cells of the innate and adaptive immune system. METHODS: Clinical and laboratory parameters were combined with functional multi-parametric immunophenotyping methods in fifteen NBAS-deficient patients to discover possible alterations in their immune system. RESULTS: Our study revealed reduced absolute numbers of mature CD56dim natural killer (NK) cells. Notably, the residual NK cell population in NBAS-deficient patients exerted a lower potential for activation and degranulation in response to K562 target cells, suggesting an NK cell-intrinsic role for NBAS in the release of cytotoxic granules. NBAS-deficient NK cell activation and degranulation was normalized upon pre-activation by IL-2 in vitro, suggesting that functional impairment was reversible. In addition, we observed a reduced number of naïve B cells in the peripheral blood associated with hypogammaglobulinemia. CONCLUSION: In summary, we demonstrate that pathogenic biallelic variants in NBAS are associated with dysfunctional NK cells as well as impaired adaptive humoral immunity.

Dominant activating RAC2 mutation with lymphopenia, immunodeficiency, and cytoskeletal defects.

Ras-related C3 botulinum toxin substrate 2 (RAC2), through interactions with reduced NAD phosphate oxidase component p67 phox , activates neutrophil superoxide production, whereas interactions with p21-activated kinase are necessary for fMLF-induced actin remodeling. We identified 3 patients with de novo RAC2[E62K] mutations resulting in severe T- and B-cell lymphopenia, myeloid dysfunction, and recurrent respiratory infections. Neutrophils from RAC2[E62K] patients exhibited excessive superoxide production, impaired fMLF-directed chemotaxis, and abnormal macropinocytosis. Cell lines transfected with RAC2[E62K] displayed characteristics of active guanosine triphosphate (GTP)-bound RAC2 including enhanced superoxide production and increased membrane ruffling. Biochemical studies demonstrated that RAC2[E62K] retains intrinsic GTP hydrolysis; however, GTPase-activating protein failed to accelerate hydrolysis resulting in prolonged active GTP-bound RAC2. Rac2+/E62K mice phenocopy the T- and B-cell lymphopenia, increased neutrophil F-actin, and excessive superoxide production seen in patients. This gain-of-function mutation highlights a specific, nonredundant role for RAC2 in hematopoietic cells that discriminates RAC2 from the related, ubiquitous RAC1.

Bubble bilevel ventilation facilitates gas exchange in anesthetized rabbits.

BACKGROUND: Bubble continuous positive airway pressure is an established therapy for infants in respiratory distress. In resource-limited settings, few treatment options exist for infants requiring further respiratory support. A bubble bilevel device has been developed to provide nonelectric, time-cycled, pressure-limited respiratory support. We compared the efficacy of bubble bilevel ventilation with conventional mechanical ventilation in sedated rabbits. METHODS: Six adult rabbits under inhaled isoflurane general anesthesia were ventilated by alternating intervals of conventional and bubble bilevel ventilation for three 10-15-min periods. During each period, interval arterial blood gas (ABG) measurements were obtained after at least 10 min on the respective mode of ventilation. RESULTS: The bubble bilevel system was able to deliver the following pressures: 20/7, 15/5, 12/5, 8/5 cm H2O. The estimated differences in arterial blood gas values on bubble bilevel vs. ventilator were as follows (normalized values): pH 7.41 vs. 7.40, pCO2 37.7 vs. 40, pO2 97.6 vs. 80. In addition, the bubble bilevel ventilation delivered consistent pressure waveforms without interruption for over 60 min on two rabbits. CONCLUSION: This study demonstrates promising in vivo results on the efficacy of a novel bubble bilevel device, which may prove useful for infants in respiratory distress. IMPACT: Given the lack of personnel, funds or infrastructure to provide neonatal mechanical ventilation in resource-limited settings, additional low-cost, low-tech treatments are necessary to save infant lives. Bubble bilevel ventilation reliably delivers two levels of airway pressure to anesthetized rabbits resulting in normalization of blood gases comparable to those achieved on a traditional ventilator. If proven effective, simple technologies like this device have the potential to significantly impact neonatal mortality due to respiratory distress globally.

Bronchiectasis and Bronchiolectasis With Severe Herniating Pattern Associated With STAT1 Gain-of-Function Mutation: Detailed Clinicopathological Findings.

STAT1 gain-of-function (GOF) mutations are associated with a rare autosomal dominant immunodeficiency disorder with main clinical manifestations including chronic mucocutaneous candidiasis (CMC) and bronchiectasis. In addition, these patients show higher incidences of cerebral and extracerebral aneurysm, malignancies and various autoimmune conditions compared to the general population. Although previous publications have reported clinical findings in patients with STAT1 GOF mutation, they did not include histopathologic features. Herein, we describe the first case with detailed histologic findings in the lung of a 5-year-old patient with a de novo STAT1 GOF mutation, who presented with CMC and bronchiectasis. The biopsy showed severe bronchiolectasis with extensive airway dilatation and occasional disruptions. Peribronchiolar inflammation was not always present and evident mainly in areas of airway disruption; inflammation may have not been a main driver of the airway damage in this case. The airway dilatation often showed an interesting herniating pattern, possibly implying a connective tissue etiology. This case also demonstrates the diagnostic utility of whole exome sequencing as STAT1 GOF mutations are not detected by routine workup. The definitive diagnosis will lead to more specific treatments and increased surveillance for serious conditions, such as cerebral aneurysms and malignancies.

Defining clinical subgroups and genotype-phenotype correlations in NBAS-associated disease across 110 patients.

PURPOSE: Pathogenic variants in neuroblastoma-amplified sequence (NBAS) cause an autosomal recessive disorder with a wide range of symptoms affecting liver, skeletal system, and brain, among others. There is a continuously growing number of patients but a lack of systematic and quantitative analysis. METHODS: Individuals with biallelic variants in NBAS were recruited within an international, multicenter study, including novel and previously published patients. Clinical variables were analyzed with log-linear models and visualized by mosaic plots; facial profiles were investigated via DeepGestalt. The structure of the NBAS protein was predicted using computational methods. RESULTS: One hundred ten individuals from 97 families with biallelic pathogenic NBAS variants were identified, including 26 novel patients with 19 previously unreported variants, giving a total number of 86 variants. Protein modeling redefined the ß-propeller domain of NBAS. Based on the localization of missense variants and in-frame deletions, three clinical subgroups arise that differ significantly regarding main clinical features and are directly related to the affected region of the NBAS protein: ß-propeller (combined phenotype), Sec39 (infantile liver failure syndrome type 2/ILFS2), and C-terminal (short stature, optic atrophy, and Pelger-Huët anomaly/SOPH). CONCLUSION: We define clinical subgroups of NBAS-associated disease that can guide patient management and point to domain-specific functions of NBAS.

Efficacy of Early Pleurectomy for Severe Congenital Chylothorax.

BACKGROUND: Severe congenital chylothorax (SCC) may result in respiratory failure, malnutrition, immunodeficiency, and sepsis. Although typically managed with bowel rest, parenteral nutrition, and octreotide, persistent chylothoraces require surgical management. At our institution, a pleurectomy, unilateral or bilateral, in combination with mechanical pleurodesis and thoracic duct ligation is performed for SCC, and we describe our approach and outcomes. MATERIALS AND METHODS: We reviewed over 15-year period neonatal patients with SCC managed surgically with pleurectomy after medical therapy was unsuccessful. Patients were divided into two groups: those who underwent pleurectomy within 28 d of diagnosis (early group) and those who underwent pleurectomy after 28 d (late group). Resolution of chylothorax was defined by the absence of clinical symptoms as well as absent or minimal pleural effusion on chest X-ray. RESULTS: Of 40 patients diagnosed with SCC over the study period, 15 underwent pleurectomy, eight early [mean time to operation = 20 (IQR 17, 23) d] and 7 late [59 (42, 75) d, P = 0.001]. Overall survival was 67% (10 of 15). Seven of 8 (88%) neonates who underwent early pleurectomy survived versus 3 of 7 (43%) who underwent late pleurectomy (P = 0.07). Length of stay was lower in the early group than the late group [73 (57, 79) versus 102 (109, 213) d, P = 0.05]. All patients who survived to discharge had resolution of their chylothorax. CONCLUSIONS: Pleurectomy with mechanical pleurodesis and thoracic duct ligation is effective in the management of severe congenital chylothorax. When performed earlier, pleurectomy for severe congenital chylothorax may be associated with improved survival and shorter hospital length of stay.

Reference intervals for lymphocyte subsets in preterm and term neonates without immune defects.

BACKGROUND: In 6.5 years of newborn screening for severe combined immunodeficiency in California, 3,252,156 infants had DNA from dried blood spots (DBSs) assayed for T-cell receptor excision circles. Infants with T-cell receptor excision circle values of less than a designated cutoff on a single DBS, 2 DBS samples with insufficient PCR amplification, or known genetic risk of immunodeficiency had peripheral blood complete blood counts and lymphocyte subsets assayed in a single flow cytometry laboratory. Cases in which immune defects were ruled out were available for analysis. OBJECTIVE: We sought to determine reference intervals for lymphocyte subsets in racially/ethnically diverse preterm and term newborns who proved to be unaffected by any T-lymphopenic immune disorder. METHODS: Effective gestational age (GA) was defined as GA at birth plus postnatal age at the time of sample collection. After determining exclusion criteria, we analyzed demographic and clinical information, complete and differential white blood cell counts, and lymphocyte subsets for 301 infants, with serial measurements for 33 infants. Lymphocyte subset measurements included total T cells, helper and cytotoxic T-cell subsets, naive and memory phenotype of each T-cell subset, B cells, and natural killer cells. RESULTS: Reference intervals were generated for absolute numbers and lymphocyte subsets from infants with effective GAs of 22 to 52 weeks. Sex and ethnicity were not significant determinants of lymphocyte subset counts in this population. Lymphocyte counts increased postnatally. CONCLUSION: This study provides a baseline for interpreting comprehensive lymphocyte data in preterm and term infants, aiding clinicians to determine which newborns require further evaluations for immunodeficiency.

White matter microstructure among perinatally HIV-infected youth: a diffusion tensor imaging study.

We evaluated white matter microstructure integrity in perinatally HIV-infected (PHIV) youths receiving cART compared to age- and gender-matched healthy youths through DTI metrics using voxel-based morphometry (VBM). We investigated 14 perinatally HIV-infected patients (age 17.9 ± 2.5 years) on cART and 17 healthy youths (HC) (age 18.0 ± 3.0 years) using a 3T MRI scanner. Four DTI-derived metrics were fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD), and radial diffusivity (RD). Statistical analysis was done with voxel-based analysis of covariance (ANCOVA), with age and gender as covariates. Region-of-interest secondary analyses in statistically significant regions were also performed. Regional increases in FA in the PHIV youths were found in left middle frontal gyrus, right precuneus, right lingual gyrus, and left supramarginal gyrus. Increased MD was found in the right precentral gyrus while decreased MD was found in the white matter of the right superior parietal lobule and right inferior temporal gyrus/fusiform gyrus. Regions of increased/decreased RD overlapped with regions of increased/decreased MD. Both increased and decreased AD were found in three to four regions respectively. The regional FA, MD, RD, and AD values were consistent with the voxel-based analysis findings. The findings are mostly consistent with previous literature, but increased FA has not been previously reported for perinatally HIV-infected youths. Potentially early and prolonged therapy in our population may have contributed to this new finding. Both toxicity of antiretroviral therapy and indolent infection must be considered as causative factors in the DTI metric changes that we have observed.

An Early Investigation into Possible Alternatives to Stapled Hysterotomy in Open Fetal Surgery.

PURPOSE: We hypothesized that surgical energy could be used to create hysterotomies in open fetal surgery. STUDY DESIGN: Initial studies compared the LigaSure Impact and Harmonic ACE + 7 Shears in the efficiency of hysterotomy and thermal damage. Pregnant ewes at an estimated gestational age (EGA) of 116 to 120 days (term = 145; n = 7) underwent hysterotomy using either device. Hysterotomy edges were resected, and thermal injury extent was determined by histopathological assessment. Upon determining a superior device, subsequent studies compared this to the AutoSuture Premium Poly CS*-57 Stapler in uterine healing. Pregnant ewes (n = 6) at an EGA of 87 to 93 days underwent 6-cm hysterotomy in each gravid horn with either the stapler (n = 5) or Harmonic (n = 5) followed by closure and animal recovery. After 37 to 42 days, uterine healing was assessed by evaluating tensile strength and histopathology. RESULTS: Thermal damage was more extensive with the LigaSure (n = 11 hysterotomies) than with the Harmonic (n = 11; 5.6 ± 1 vs. 3.1 ± 0.6 mm; p < 0.0001);therefore, the Harmonic was selected for healing studies. Gross scar appearance and tensile strength were the same between the Harmonic and stapler. The stapler caused more fibrosis (4/7 samples with "moderate" fibrosis vs. 0/8 with the Harmonic; p = 0.02). CONCLUSION: The Harmonic ACE + 7 caused less thermal injury than the LigaSure Impact and performed similar to the CS*-57 Stapler in uterine healing with continued gestation.

Fetal intervention for congenital chylothorax is associated with improved outcomes in early life.

BACKGROUND: Congenital chylothorax (CC) can have devastating consequences for neonates. We sought to determine the outcomes of cases treated at our institution and evaluate the role of fetal intervention. MATERIALS AND METHODS: With Institutional Review Board approval, patients treated at our institution 09/2006-04/2016 with CC were reviewed. History and outcomes were compared between patients undergoing fetal intervention (fetal group) and patients who did not (control group). RESULTS: Twenty-three patients were identified. Mean gestational age at birth was 35 wk. Overall mortality was 30% (7 patients). Nineteen patients (83%) were prenatally diagnosed, and 10 patients (43%) underwent fetal intervention. Birth weight was significantly lower in the fetal group compared to the control group (median interquartile range [IQR]; 2.5 [2.3-3.0] versus 3.3 [2.6-3.7] kg, P = 0.02). Apgar scores were significantly higher in the fetal group than the control group at 1 and 5 min (median [IQR]; 6 [4-8] versus 1 [1-2], P = 0.005 and 8 [7-9] versus 2 [2-6], P = 0.008, respectively). For those patients with prenatal diagnosis of CC and hydrops fetalis, thrombosis and lymphopenia were both improved in the fetal group (thrombosis 0% versus 40%, P = 0.03; lymphocyte nadir [median {IQR}] 1.5 [0.6-2.9] versus 0.1 [0.05-0.2], P = 0.02). Duration of support with mechanical ventilation was significantly shorter in the fetal group (median [IQR]; 1 [0-40] versus 41 [29-75] d, P = 0.04). CONCLUSIONS: Fetal intervention for CC is associated with improved Apgar scores and decreased ventilator days and complications in patients with hydrops fetalis. Fetuses with chylothorax, especially those with hydrops, should be referred to a fetal center for evaluation.

Early appendectomy reduces costs in children with perforated appendicitis.

BACKGROUND: Perforated appendicitis can be managed with early appendectomy, or nonoperative management followed by interval appendectomy. We aimed to identify the strategy with the lowest health care utilization and cost. METHODS: We retrospectively reviewed the medical records of all children ≤18 years old with perforated appendicitis admitted to a single institution between January 2009 and March 2016. After excluding immunosuppressed patients and transfers from outside hospitals, we grouped the remaining patients by early or interval appendectomy. Cost accounting data were obtained from our institutional database. The primary outcome was total hospital cost over 2 y from initial admission for appendicitis. Other outcomes analyzed included initial admission costs, number of admissions, emergency room and clinic visits, percutaneous procedures, cross-sectional and overall imaging studies, and length of stay. RESULTS: A total of 203 children with perforated appendicitis were identified. After exclusion of immunosuppressed patients and outside hospital transfers, 94 patients were included in the study. Thirty-nine underwent early appendectomy and 55 initial nonoperative management; of these, 54 underwent elective interval appendectomy. Five of 55 patients (9%) failed initial nonoperative management and required earlier-than-planned appendectomy. Total cost over 2 y was significantly lower with early appendectomy than initial nonoperative management ($19,300 ± 14,300 versus $26,000 ± 17,500; P = 0.05). Early appendectomy resulted in fewer hospital admissions, clinic visits, invasive procedures, and imaging studies. CONCLUSIONS: Early appendectomy results in lower hospital costs and less health care utilization compared with initial nonoperative management with elective interval appendectomy. A prospective study will shed more light on this question and can assess the role of nonoperative management without interval appendectomy in children with perforated appendicitis.

Creating diagnostic criteria for perforated appendicitis using cross-sectional imaging.

INTRODUCTION: Preoperative determination of perforated versus acute appendicitis can be difficult. We compared CT and MRI performance in diagnosing perforated appendicitis, and created diagnostic criteria. METHODS: We retrospectively reviewed all pediatric patients who underwent appendectomy within one day of CT or MRI between 1/1/2013 and 1/16/2016. True diagnosis was determined by pathology report. Findings on CT/MRI were grouped into "hard" findings (abscess, pneumoperitoneum, extruded fecalith, appendiceal wall with visible hole) and "soft" findings (extensive/diffuse inflammation/free fluid, phlegmon). Correlation of white blood cell count (WBC), temperature, peritoneal signs, and symptom duration >72 h with perforation was assessed using logistic regression. Significant correlates were incorporated in clinical criteria. RESULTS: 135 patients underwent appendectomy after CT/MRI. Fifty patients underwent MRI and 85 CT. Using hard and/or soft findings, MRI was 86.7% sensitive and 74.3% specific, compared to 68.4% (p = 0.19) and 92.4% (p = 0.025) for CT. WBC > 15, temperature >38.0 °C, and peritoneal signs predicted perforation. Diagnostic accuracy of MRI was highest using imaging findings alone. Accuracy of CT was improved by mandating at least one of the previous three clinical correlates, resulting in 68.4% sensitivity and 93.9% specificity. CONCLUSIONS: MRI trended toward more sensitive and CT was more specific for complicated appendicitis. CT specificity is improved by our algorithm.

Pharmacokinetics, Safety, and Tolerability of Subcutaneous Immune Globulin Injection (Human), 10 % Caprylate/Chromatography Purified (GAMUNEX®-C) in Pediatric Patients with Primary Immunodeficiency Disease.

PURPOSE: This phase 4, multicenter, open-labeled, single-sequence, crossover study in pediatric patients (ages 2 to 16) with primary immunodeficiency disease (PID) evaluated the pharmacokinetics, safety, and tolerability for subcutaneously (SC) administered 10 % caprylate/chromatography purified human immune globulin injection (IGIV-C, GAMUNEX®) compared with intravenously (IV) administered IGIV-C. METHODS: This study included a screening phase, run-in phase (where required), IV treatment phase, SC treatment phase, and end of study/early termination visit. Eligible patients receiving a stable dose of IGIV-C entered into the IV phase to receive two IV infusions of IGIV-C (200-600 mg/kg per infusion) every 3-4 weeks. The weekly SC dose of IGIV-C was calculated using a conversion factor of 1.37 times the prior IV dose. RESULTS: Twelve subjects between the ages of 2 and 16 years participated in the clinical study with the median age being 11 years old. The adjusted weekly mean AUC0-τ,IV was 216,873.7 h*mg/dL for the IV phase versus a mean AUC0-τ,SC of 230,830.0 h*mg/dL for the SC phase. The mean (range) C trough was 997.2 (784-1320) mg/dL in the IV phase and 1325.0 (1077-1690) mg/dL in the SC phase. During the SC phase, 100.0 % of the patients (n = 11) experienced treatment-emergent adverse events (TEAEs) that were local infusion reactions and 9 patients (81.8 %) had TEAEs that were non-infusion site reactions. The majority of TEAEs were mild or moderate in severity. CONCLUSION: In pediatric patients with PID, SC-administered IGIV-C provides comparable overall serum exposure to total IgG to that produced by IV-administered IGIV-C. We have concluded that weekly SC administration of 10 % IGIV-C based on a dose conversion factor of 1.37 is safe and well-tolerated in pediatric patients with PID. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT01465958. https://clinicaltrials.gov/ct2/show/NCT01465958?term=NCT01465958.&rank=1.