The Relationship Between Eosinophilic Esophagitis and Immunotherapy.

Immunotherapy is a treatment approach based on the principle of incremental allergen exposure to achieve desensitization. Recently, oral immunotherapy has been introduced as a treatment of IgE-mediated food allergy. Some patients receiving oral immunotherapy for food allergy may develop eosinophilic esophagitis. Here, we summarize the literature examining this association, its treatment, and outcomes and discuss possible explanations for this clinical phenomenon. We further identify potential associations with aeroallergen sensitivity and other forms of immunotherapy including subcutaneous immunotherapy and sublingual immunotherapy. Finally, we discuss management of immunotherapy-induced eosinophilic esophagitis. Epicutaneous immunotherapy is highlighted as an area of therapeutic investigation.

In Vitro Osteogenesis Study of Shell Nacre Cement with Older and Young Donor Bone Marrow Mesenchymal Stem/Stromal Cells.

Bone void-filling cements are one of the preferred materials for managing irregular bone voids, particularly in the geriatric population who undergo many orthopedic surgeries. However, bone marrow mesenchymal stem/stromal cells (BM-MSCs) of older-age donors often exhibit reduced osteogenic capacity. Hence, it is crucial to evaluate candidate bone substitute materials with BM-MSCs from the geriatric population to determine the true osteogenic potential, thus simulating the clinical situation. With this concept, we investigated the osteogenic potential of shell nacre cement (SNC), a bone void-filling cement based on shell nacre powder and ladder-structured siloxane methacrylate, using older donor BM-MSCs (age > 55 years) and young donor BM-MSCs (age < 30 years). Direct and indirect cytotoxicity studies conducted with human BM-MSCs confirmed the non-cytotoxic nature of SNC. The standard colony-forming unit-fibroblast (CFU-F) assay and population doubling (PD) time assays revealed a significant reduction in the proliferation potential (p < 0.0001, p < 0.05) in older donor BM-MSCs compared to young donor BM-MSCs. Correspondingly, older donor BM-MSCs contained higher proportions of senescent, ß-galactosidase (SA-ß gal)-positive cells (nearly 2-fold, p < 0.001). In contrast, the proliferation capacity of older donor BM-MSCs, measured as the area density of CellTrackerTM green positive cells, was similar to that of young donor BM-MSCs following a 7-day culture on SNC. Furthermore, after 14 days of osteoinduction on SNC, scanning electron microscopy with energy-dispersive spectroscopy (SEM-EDS) showed that the amount of calcium and phosphorus deposited by young and older donor BM-MSCs on SNC was comparable. A similar trend was observed in the expression of the osteogenesis-related genes BMP2, RUNX2, ALP, COL1A1, OMD and SPARC. Overall, the results of this study indicated that SNC would be a promising candidate for managing bone voids in all age groups.

Antigen Geometry Tunes Mast Cell Signaling Through Distinct FcεRI Aggregation and Structural Changes.

Immunoreceptor tyrosine-based activation motif (ITAM)-containing Fc receptors are critical components of the innate and adaptive immune systems. FcεRI mediates the allergic response via crosslinking of IgE-bound receptors by multivalent antigens. Yet, the underlying molecular mechanisms that govern the response of FcεRI to specific antigens remain poorly understood. We compared responses induced by two antigens with distinct geometries, high valency DNP-BSA and trivalent DF3, and found unique secretion and receptor phosphorylation profiles that are due to differential recruitment of Lyn and SHIP1. To understand how these two antigens can cause such markedly different outcomes, we used direct stochastic optical reconstruction microscopy (dSTORM) super-resolution imaging combined with Bayesian Grouping of Localizations (BaGoL) analysis to compare the nanoscale characteristics of FcεRI aggregates. DF3 aggregates were found to be smaller and more densely packed than DNP-BSA aggregates. Using lifetime-based Förster resonance energy transfer (FRET) measurements, we discovered that FcεRI subunits undergo structural rearrangements upon crosslinking with either antigen, and in response to interaction with monovalent antigen presented on a supported lipid bilayer. The extent of conformational change is positively correlated with signaling efficiency. Finally, we provide evidence for forces in optimizing FcεRI signaling, such that immobilizing DF3 on a rigid surface promoted degranulation while increasing DNP-BSA flexibility lowered degranulation. These results provide a link between the physical attributes of allergens, including size, shape, valency, and flexibility, and FcεRI signaling strength. Thus, the antigen modulates mast cell outcomes by creating unique aggregate geometries that tune FcεRI conformation, phosphorylation and signaling partner recruitment.

Ethical Implications of Continuing Oral Immunotherapy After the Development of Eosinophilic Esophagitis.

Eosinophilic esophagitis (EoE) is a chronic allergic inflammatory disease requiring maintenance therapy. Traditionally, EoE has been a contraindication to oral immunotherapy (OIT) and a rationale for discontinuing treatment because OIT may induce EoE. Most, but not all patients with OIT-induced EoE experience symptom resolution and histologic remission after discontinuing OIT. Recent studies report OIT continuation even after EoE onset, despite the previously accepted standard of care. This creates clinical as well as ethical challenges for allergists treating these patients. Considering the published literature on EoE and OIT and the primary medical ethics principles of beneficence, nonmaleficence, autonomy, and justice, we discuss the ethical implications of pursuing desensitization despite the potential complications associated with EoE. When ethical principles are in opposition, shared decision-making should be employed to determine whether OIT should be continued after an EoE diagnosis. This article highlights the ethical dilemmas allergists face when determining whether patients with a diagnosis of EoE should continue OIT.

Novel Bone Void Filling Cement Compositions Based on Shell Nacre and Siloxane Methacrylate Resin: Development and Characterization.

Shell nacre from Pinctada species has been extensively researched for managing bone defects. However, there is a gap in the research regarding using shell nacre powder as a cement with improved biological and physicochemical properties. To address this, bone void filling cement was formulated by incorporating shell nacre powder and an organically modified ceramic resin (ormocer). The shell nacre powder was specifically processed from the shells of Pinctada fucata and analysed using thermogravimetric analysis (TGA), X-ray diffraction spectroscopy, Fourier transform infrared (FTIR), and Raman spectroscopy, confirming the presence of organic constituents and inorganic aragonite. Trace element analysis confirmed the eligibility of shell nacre powder for biomedical applications. Next, the ormocer SNLSM2 was synthesized through a modified sol-gel method. FTIR, Raman, TGA, and transmission electron microscopy studies revealed the presence of a ladder-structured siloxane backbone and methacrylate side chain. To develop chemical curable composite shell nacre cement (SNC), different amounts of shell nacre (24%, 48%, and 72%) were added to the SNLSM2 resin, and the impact on the physicochemical properties of the cement was studied. Among the compositions, SNC 72 exhibited significantly lower linear polymerization shrinkage (0.4%) and higher compressive (>100 MPa) and flexural strength (>35 MPa). SNC 72 was radiopaque, and the exotherm generated during the cement curing was minimal. Cytotoxicity studies with L929 cells revealed the non-cytotoxic nature of the cement. Overall, the findings of this study prove that the shell nacre cement is a promising candidate for managing bone voids.

Invasive group A streptococcal disease in Hawke's Bay, New Zealand: epidemiology, manifestations and impact.

AIMS: To describe the epidemiology, clinical features and healthcare impact of invasive group A streptococcal (iGAS) disease in Hawke's Bay from 2016 to 2021, to inform public health efforts. METHODS: The case definition of iGAS for this study was isolation of group A streptococcus (GAS) from blood culture. "Severe iGAS" included cases that required intensive care admission or died within 60 days. Cases were identified retrospectively from the Te Whatu Ora Te Matau a Maui Hawke's Bay laboratory database. Clinical data were obtained from inpatient electronic health records. RESULTS: A total of 93 cases of iGAS were identified in Hawke's Bay during the 6-year study period. The overall age-standardised incidence of iGAS was 5.6 per 100,000 (95%CI 4.1-7.4). The incidence was significantly higher among people of Pacific, Maori and Asian ethnicities than European/Other ethnicities, and higher in areas of socio-economic disadvantage. Skin infections were the most common source (70% of cases). Thirty-seven cases (41%) were classified as severe, including 11 deaths (12% case fatality rate). CONCLUSIONS: Further action is required to address inequities in social determinants of skin health in Hawke's Bay. Mandatory national notification of iGAS would provide opportunity for improved surveillance of GAS-related disease, and consideration of a public health response to iGAS disease in New Zealand.

Usefulness of the lupus low disease activity state as a treatment target in childhood-onset SLE.

OBJECTIVE: Treat-to-target (T2T) strategies are advocated to improve prognosis in childhood-onset SLE (cSLE). Proposed T2T states include SLEDAI score of <4 (SLEDAI-LD), limited corticosteroid use (low-CS), and lupus low disease activity state (LLDAS). We sought to compare T2T states for their association with cSLE prognosis under consideration of relevant disease characteristics such as pre-existing damage, race and lupus nephritis (LN). METHODS: Longitudinal data from 165 patients enrolled in the Cincinnati Lupus Registry were included. LN presence was based on renal biopsy, and patients were followed up until 18 years of age. RESULTS: The 165 patients (LN: 45, white: 95) entered the registry within a median of 0 (IQR: 0-1) year post diagnosis and were followed up for a median of 4 (IQR: 2-5) years during which 80%, 92% and 94% achieved LLDAS, low-CS and SLEDAI-LD. Patients with LN were significantly less likely to achieve any T2T state (all p<0.03) and required a significantly longer time to reach them (all p<0.0001). Over the study period, patients maintained low-CS, SLEDAI-LD or LLDAS for a median of 76% (IQR: 48%-100%), 86% (IQR: 55%-100%) or 39% (IQR: 13%-64%) of their follow-up. Significant predictors of failure to maintain LLDAS included LN (p≤0.0062), pre-existing damage (p≤0.0271) and non-white race (p≤0.0013). There were 22%, 20% and 13% of patients who reached SLEDAI-LD, CS-low and LLDAS and nonetheless acquired new damage. Patients with LN had a higher risk of new damage than patients without LN even if achieving low-CS (p=0.009) or LLDAS (p=0.04). CONCLUSIONS: Patients with LN and pre-existing damage are at higher risk of increased future damage acquisition, even if achieving a T2T state such as LLDAS. Among proposed common T2T states, the LLDAS is the hardest to achieve and maintain. The LLDAS may be considered the preferred T2T measure as it conveys the highest protection from acquiring additional disease damage.

Spatial Stochastic Model of the Pre-B Cell Receptor.

Survival and proliferation of immature B lymphocytes requires expression and tonic signaling of the pre-B cell receptor (pre-BCR). This low level, ligand-independent signaling is likely achieved through frequent, but short-lived, homo interactions. Tonic signaling is also central in the pathology of precursor B acute lymphoblastic leukemia (B-ALL). In order to understand how repeated, transient events can lead to sustained signaling and to assess the impact of receptor accumulation induced by the membrane landscape, we developed a spatial stochastic model of receptor aggregation and downstream signaling events. Our rule- and agent-based model builds on previous mature BCR signaling models and incorporates novel parameters derived from single particle tracking of pre-BCR on surfaces of two different B-ALL cell lines, 697 and Nalm6. Live cell tracking of receptors on the two cell lines revealed characteristic differences in their dimer dissociation rates and diffusion coefficients. We report here that these differences affect pre-BCR aggregation and consequent signal initiation events. Receptors on Nalm6 cells, which have a lower off-rate and lower diffusion coefficient, more frequently form higher order oligomers than pre-BCR on 697 cells, resulting in higher levels of downstream phosphorylation in the Nalm6 cell line.

Docking of Syk to FcεRI is enhanced by Lyn but limited in duration by SHIP1.

The high-affinity immunoglobulin E (IgE) receptor, FcεRI, is the primary immune receptor found on mast cells and basophils. Signal initiation is classically attributed to phosphorylation of FcεRI ß- and γ-subunits by the Src family kinase (SFK) Lyn, followed by the recruitment and activation of the tyrosine kinase Syk. FcεRI signaling is tuned by the balance between Syk-driven positive signaling and the engagement of inhibitory molecules, including SHIP1. Here, we investigate the mechanistic contributions of Lyn, Syk, and SHIP1 to the formation of the FcεRI signalosome. Using Lyn-deficient RBL-2H3 mast cells, we found that another SFK can weakly monophosphorylate the γ-subunit, yet Syk still binds the incompletely phosphorylated immunoreceptor tyrosine-based activation motifs (ITAMs). Once recruited, Syk further enhances γ-phosphorylation to propagate signaling. In contrast, the loss of SHIP1 recruitment indicates that Lyn is required for phosphorylation of the ß-subunit. We demonstrate two noncanonical Syk binding modes, trans γ-bridging and direct ß-binding, that can support signaling when SHIP1 is absent. Using single particle tracking, we reveal a novel role of SHIP1 in regulating Syk activity, where the presence of SHIP1 in the signaling complex acts to increase the Syk:receptor off-rate. These data suggest that the composition and dynamics of the signalosome modulate immunoreceptor signaling activities.

Chemical, Biological, Radiological, or Nuclear Response in Queensland Emergency Services: A Multisite Study.

A disaster overwhelms the normal operating capacity of a health service. Minimal research exists regarding Australian hospitals' capacity to respond to chemical, biological, radiological, or nuclear (CBRN) disasters. This article, and the research supporting it, begins to fill that research gap. We conducted a descriptive quantitative study with 5 tertiary hospitals and 1 rural hospital in Queensland, Australia. The study population was the hospitals' clinical leaders for disaster preparedness. The 25-item survey consisted of questions relating to each hospital's current response capacity, physical surge capacity, and human surge capacity in response to a CBRN disaster. Data were analyzed using descriptive statistics. The survey data indicated that over the previous 12 months, each site reached operational capacity on average 66 times and that capacity to respond and create additional emergency, intensive care, or surgical beds varied greatly across the sites. In the previous 12 months, only 2 sites reported undertaking specific hospital-wide training to manage a CBRN disaster, and 3 sites reported having suitable personal protective equipment required for hazardous materials. There was a noted shortfall in all the hospitals' capacity to respond to a radiological disaster in particular. Queensland hospitals are crucial to CBRN disaster response, and they have areas for improvement in their response and capacity to surge when compared with international preparedness benchmarks. CBRN-focused education and training must be prioritized using evidence-based training approaches to better prepare hospitals to respond following a disaster event.

VpreB surrogate light chain expression in B-lineage ALL: a report from the Children's Oncology Group.

Immunotherapies directed against B-cell surface markers have been a common developmental strategy to treat B-cell malignancies. The immunoglobulin heavy chain surrogate light chain (SLC), comprising the VpreB1 (CD179a) and Lamda5 (CD179b) subunits, is expressed on pro- and pre-B cells, where it governs pre-B-cell receptor (BCR)-mediated autonomous survival signaling. We hypothesized that the pre-BCR might merit the development of targeted immunotherapies to decouple "autonomous" signaling in B-lineage acute lymphoblastic leukemia (B-ALL). We used the Children's Oncology Group (COG) minimal residual disease (MRD) flow panel to assess pre-BCR expression in 36 primary patient samples accrued to COG standard- and high-risk B-ALL studies through AALL03B1. We also assessed CD179a expression in 16 cases with day 29 end-induction samples, preselected to have ≥1% MRD. All analyses were performed on a 6-color Becton-Dickinson flow cytometer in a Clinical Laboratory Improvement Amendment/College of American Pathologist-certified laboratory. Among 36 cases tested, 32 cases were at the pre-B and 4 cases were at the pro-B stages of developmental arrest. One or both monoclonal antibodies (mAbs) showed that CD179a was present in ≥20% of the B-lymphoblast population. All cases expressed CD179a in the end-induction B-lymphoblast population. The CD179a component of the SLC is commonly expressed in B-ALL, regardless of genotype, stage of developmental arrest, or National Cancer Institute risk status.

EGFR transactivates RON to drive oncogenic crosstalk.

Crosstalk between different receptor tyrosine kinases (RTKs) is thought to drive oncogenic signaling and allow therapeutic escape. EGFR and RON are two such RTKs from different subfamilies, which engage in crosstalk through unknown mechanisms. We combined high-resolution imaging with biochemical and mutational studies to ask how EGFR and RON communicate. EGF stimulation promotes EGFR-dependent phosphorylation of RON, but ligand stimulation of RON does not trigger EGFR phosphorylation - arguing that crosstalk is unidirectional. Nanoscale imaging reveals association of EGFR and RON in common plasma membrane microdomains. Two-color single particle tracking captured formation of complexes between RON and EGF-bound EGFR. Our results further show that RON is a substrate for EGFR kinase, and that transactivation of RON requires formation of a signaling competent EGFR dimer. These results support a role for direct EGFR/RON interactions in propagating crosstalk, such that EGF-stimulated EGFR phosphorylates RON to activate RON-directed signaling.

Clinical outcomes of campylobacteriosis: a case series analysis of hospitalisations associated with the Havelock North Campylobacter outbreak.

AIM: In August 2016, a large waterborne campylobacteriosis outbreak occurred in Havelock North, New Zealand. This analysis describes the clinical complications of cases admitted to hospital as a result of acute infection, identifies risk factors for hospitalisation and compares deaths between hospitalised and non-hospitalised cases. Hospital admissions with post-infectious sequelae were excluded as they are the subject of a separate analysis. METHODS: A case series analysis was undertaken by reviewing the electronic medical records of 933 residents of Hawke's Bay District Health Board with probable and confirmed campylobacteriosis linked to the Havelock North Campylobacter outbreak. RESULTS: A total of 67 hospital admissions, among 58 individuals, are described. Pre-existing comorbidity and advanced age were significant risk factors for hospital admission in univariate analysis. Dehydration (74.1%), electrolyte imbalance (35.8%) and acute kidney injury (27.6%) were common among hospitalised cases. The proportion of hospitalised cases that died within one year was significantly higher when compared to deaths among non-hospitalised cases (OR 5.0, 95% CI: 2.3-10.7), although this trend was not statistically significant after adjusting for age and comorbidity (OR 2.3, 95% CI: 0.96-5.3). CONCLUSIONS: This study highlights the serious health impacts that occurred from a campylobacteriosis outbreak of this magnitude.

Not just little adults: preparing a children's emergency department for COVID-19.

COVID-19 presented unique challenges in preparing our stand-alone children's emergency department for the pandemic and has demonstrated well the paediatric adage, 'children aren't little adults'.

UC Care Check-A Postoperative Neurosurgery Operating Room Checklist: An Interrupted Time Series Study.

BACKGROUND: The effectiveness of neurosurgical operating room (OR) checklists to improve communication, safety attitudes, and clinical outcomes is uncertain. PURPOSE: To develop, implement, and evaluate a post-operative neurosurgery operating room checklist. METHODS: Four large academic medical centers participated in this study. We developed an evidence-based checklist to be performed at the end of every adult-planned or emergent surgery in which all team members pause to discuss key elements of the case. We used a prospective interrupted time series study design to assess trends in clinical and cost outcomes. Safety attitudes and communication among OR providers were also assessed. RESULTS: There were 11,447 neurosurgical patients in the preintervention and 10,973 in the postintervention periods. After implementation, survey respondents perceived that postoperative checklists were regularly performed, important issues were communicated at the end of each case, and patient safety was consistently reinforced. Observed to expected (O/E) overall mortality rates remained less than one, and 30-day readmission rate, length of stay index, direct cost index, and perioperative venous thromboembolism and hematoma rates remained unchanged as a result of checklist implementation. CONCLUSION: A neurosurgical checklist can improve OR team communication; however, improvements in safety attitudes, clinical outcomes, and health system costs were not observed.

Multisite EGFR phosphorylation is regulated by adaptor protein abundances and dimer lifetimes.

Differential epidermal growth factor receptor (EGFR) phosphorylation is thought to couple receptor activation to distinct signaling pathways. However, the molecular mechanisms responsible for biased signaling are unresolved due to a lack of insight into the phosphorylation patterns of full-length EGFR. We extended a single-molecule pull-down technique previously used to study protein-protein interactions to allow for robust measurement of receptor phosphorylation. We found that EGFR is predominantly phosphorylated at multiple sites, yet phosphorylation at specific tyrosines is variable and only a subset of receptors share phosphorylation at the same site, even with saturating ligand concentrations. We found distinct populations of receptors as soon as 1 min after ligand stimulation, indicating early diversification of function. To understand this heterogeneity, we developed a mathematical model. The model predicted that variations in phosphorylation are dependent on the abundances of signaling partners, while phosphorylation levels are dependent on dimer lifetimes. The predictions were confirmed in studies of cell lines with different expression levels of signaling partners, and in experiments comparing low- and high-affinity ligands and oncogenic EGFR mutants. These results reveal how ligand-regulated receptor dimerization dynamics and adaptor protein concentrations play critical roles in EGFR signaling.