Preclinical efficacy of peanut-specific IgG4 antibody therapeutic IGNX001.

BACKGROUND: Existing therapeutic strategies are challenged by long times to achieve effect and often require frequent administration. Peanut-allergic individuals would benefit from a therapeutic that provides rapid protection against accidental exposure within days of administration while carrying little risk of adverse reactions. OBJECTIVE: Guided by the repertoire of human IgE mAbs from allergic individuals, we sought to develop a treatment approach leveraging the known protective effects of allergen-specific IgG4 antibodies. METHODS: We applied our single-cell RNA-sequencing SEQ SIFTER platform (IgGenix, Inc, South San Francisco, Calif) to whole blood samples from peanut-allergic individuals to discover IgE mAbs. These were then class-switched by replacing the IgE constant region with IgG4 while retaining the allergen-specific variable regions. In vitro mast cell activation tests, basophil activation tests, ELISAs, and an in vivo peanut allergy mouse model were used to evaluate the specificity, affinity, and activity of these recombinant IgG4 mAbs. RESULTS: We determined that human peanut-specific IgE mAbs predominantly target immunodominant epitopes on Ara h 2 and Ara h 6 and that recombinant IgG4 mAbs effectively block these epitopes. IGNX001, a mixture of 2 such high-affinity IgG4 mAbs, provided robust protection against peanut-mediated mast cell activation in vitro as well as against anaphylaxis upon intragastric peanut challenge in a peanut allergy mouse model. CONCLUSIONS: We developed a peanut-specific IgG4 antibody therapeutic with convincing preclinical efficacy starting from a large repertoire of human IgE mAbs from demographically and geographically diverse individuals. These results warrant further clinical investigation of IGNX001 and underscore the opportunity for the application of this therapeutic development strategy in other food and environmental allergies.

Biomarkers of peanut allergy in children over time.

BACKGROUND: Various biomarkers are used to define peanut allergy (PA). We aimed to observe changes in PA resolution and persistence over time comparing biomarkers in PA and peanut sensitised but tolerant (PS) children in a population-based cohort. METHODS: Participants were recruited from the EAT and EAT-On studies, conducted across England and Wales, and were exclusively breastfeed babies recruited at 3 months old and followed up until 7-12 years old. Clinical characteristics, skin prick test (SPT), sIgE to peanut and peanut components and mast cell activation tests (MAT) were assessed at 12 months, 36 months and 7-12 years. PA status was determined at the 7-12 year time point. RESULTS: The prevalence of PA was 2.1% at 7-12 years. Between 3 and 7-12 year, two children developed PA and one outgrew PA. PA children had larger SPT, higher peanut-sIgE, Ara h 2-sIgE and MAT (all p < .001) compared to PS children from 12 months onwards. SPT, peanut-sIgE, Ara h 2-sIgE and MAT between children with persistent PA, new PA, outgrown PA and PS were statistically significant from 12 months onwards (p < .001). Those with persistent PA had SPT, peanut-sIgE and Ara h 2-sIgE that increased over time and MAT which was highest at 36 months. New PA children had increased SPT and peanut-sIgE from 36 months to 7-12 years, but MAT remained low. PS children had low biomarkers across time. CONCLUSIONS: In this cohort, few children outgrow or develop new PA between 36 months and 7-12 years. Children with persistent PA have raised SPT, peanut-sIgE, Ara h 2-sIgE and MAT evident from infancy that consistently increase over time.

Basophil activation test as predictor of severity and threshold of allergic reactions to egg.

BACKGROUND: Identifying patients at risk of severe allergic reactions and/or low threshold of reactivity is very important, particularly for staple foods like egg. METHODS: One hundred and fifty children underwent double-blind placebo-controlled food challenge (DBPCFC) to baked egg (BE), skin prick testing and blood collection for serology and basophil activation test (BAT). Patients who passed BE DBPCFC underwent loosely cooked egg (LCE) DBPCFC. Severity of allergic reactions was classified following Practall guidelines and threshold dose was determined during DBPCFC. RESULTS: Sixty out of 150 (40%) children reacted to BE and 16 out of 77 (21%) to LCE on DBPCFC. Considering DBPCFC to BE, 23 children (38%) had severe reactions and 33 (55%) reacted to 0.13 g or less of egg protein (low threshold group). Two children (2 out of 16 = 12%) had severe reactions to LCE. Demographic, clinical and most immunological features were not significantly different between severe/non-severe BE reactors or low/high threshold groups. Severe BE reactors had higher ovomucoid-sIgE (p = .009) and higher BAT to BE (p = .001). Patients with lower threshold to BE had higher IgE-specific activity (p = .027) and BAT to egg (p = .007) but lower severity score (p = .008). Optimal cut-offs for ovomucoid-sIgE had 100% sensitivity, 35% specificity and 60% accuracy and for BAT 76% sensitivity, 74% specificity and 75% accuracy to identify BE severe reactors. Optimal cut-offs for specific activity had 70% sensitivity, 68% specificity and 69% accuracy and for BAT 70% sensitivity, 72% specificity and 71% accuracy to identify low threshold patients. CONCLUSIONS: BAT was the best biomarker to predict severity and threshold of allergic reactions to BE and can be useful when making decisions about management of egg allergy.

Partial Egg Consumption Modifies the Diagnostic Performance of Allergy Tests to Predict Outcome of Double-Blind Placebo-Controlled Food Challenges to Egg.

BACKGROUND: Many children are consuming some egg when they are diagnosed with egg allergy. We hypothesized that egg consumption could modify the diagnostic performance of allergy tests. OBJECTIVE: To stratify diagnostic performance of tests according to egg consumption status. METHODS: The BAT2 study (NCT03309488) participants underwent oral food challenge (OFC), food-frequency questionnaires, skin prick test (SPT), specific immunoglobulin E (sIgE) and specific immunoglobulin G4 (sIgG4) and basophil activation test (BAT). RESULTS: At study entry, 45% of participants reported partial egg consumption ("consumers") and 55% were avoiding egg strictly ("avoiders"). Avoiders had larger SPT (P < .001), higher BAT to egg (P < .001), sIgE to egg white (EW; P = .001) and to ovalbumin (OVA; P = .001), but not to ovomucoid (P = .231). Consumers had higher levels of sIgG4 to all egg allergens (P < .001) than avoiders. In consumers, the test with the best diagnostic performance was BAT (area under the curve [AUC] = .912) followed by SPT to raw egg (AUC = 0.805), EW-sIgE (AUC = 0.738), and OVA-sIgE (AUC = 0.732). In avoiders, the best tests were BAT (AUC = 0.834) and EW-sIgE (AUC = 0.833) followed by OVA-sIgE (AUC = 0.793) and SPT to EW (AUC=0.789). Using 100% sensitivity and 100% specificity cut-offs, the proportion of patients requiring OFC were 33% for BAT, 53% for SPT to raw egg, 61% for OVA-sIgE, and 73% for EW-sIgE for consumers; and 73% for BAT, 79% for EW-sIgE, and 93% for SPT to EW for avoiders. CONCLUSIONS: The diagnostic performance of tests is influenced by the immunomodulatory effect of egg consumption. BAT is the most reliable test and reduced the need for OFC, particularly in partial egg consumers.

Diagnostic utility of allergy tests to predict baked egg and lightly cooked egg allergies compared to double-blind placebo-controlled food challenges.

BACKGROUND: Double-blind placebo-controlled food challenges (DBPCFC) are the gold-standard to diagnose food allergy. However, they can cause allergic reactions of unpredictable severity. We assessed accuracy of current and new diagnostic tests compared to DBPCFC to baked egg (BE) and to lightly cooked egg (LCE). METHODS: Children aged 6 months to 15 years were assessed for possible egg allergy as part of the BAT2 study (NCT03309488). They underwent clinical assessment, skin prick test (SPT), specific IgE (sIgE) and basophil activation test (BAT). The results of the tests were compared with DBPCFC outcomes to both BE and LCE. RESULTS: A total of 150 children underwent DBPCFC to BE, 60 (40%) reacted to and 85 (57%) tolerated BE and 5 (3%) had inconclusive oral food challenges (OFC). Seventy-seven children tolerant to BE had DBPCFC to LCE and 16 reacted. The test within each modality with the best diagnostic performance for BE allergy was as follows: SPT to egg white (EW) (AUC = 0.726), sIgE to EW (AUC = 0.776) and BAT to egg (AUC = 0.783). BAT (AUC = 0.867) was the best test in the younger than 2 years age group. Applying 100% sensitivity and 100% specificity cut-offs, followed by OFC, resulted in 100% diagnostic accuracy. BAT enabled the greatest reduction in OFC (41%). Using sIgE followed by BAT allowed to reduce the number of BATs performed by about 30% without significantly increasing the number of OFC. CONCLUSIONS: The best diagnostic test was BAT to egg in terms of diagnostic accuracy and reduction in number of OFC. Using sIgE to EW followed by BAT required fewer BATs with sustained OFC reduction and diagnostic accuracy.

Ara h 2 Peptide Mix Improves the Diagnosis of Peanut Allergy and Is Relevant for Ara h 2-Induced Mast Cell Activation.

BACKGROUND: A precise diagnosis of peanut allergy is extremely important. We identified 4 Ara h 2 peptides that improved Ara h 2-specific IgE (sIgE) diagnostic accuracy. OBJECTIVE: To assess the diagnostic utility of sIgE to the mixture of these peptides and their role in mast cell response to peanut allergens. METHODS: sIgE to the peptide mix was determined using ImmunoCAP. Its diagnostic utility was compared with Ara h 2-sIgE and sIgE to the individual peptides. The functional relevance of the peptides was tested on the mast cell activation test using laboratory of allergic diseases 2 cell line and flow cytometry. RESULTS: A total of 52 peanut-allergic (PA), 36 peanut-sensitized but tolerant, and 9 nonsensitized nonallergic children were studied. Peptide mix-sIgE improved the diagnostic performance of Ara h 2-sIgE compared with Ara h 2-sIgE alone (area under the receiver operating characteristic curve .92 vs .89, respectively; P = .056). The sensitivity and specificity of Ara h 2-sIgE combined with the peptide mix were 85% and 96%, respectively. sIgE to individual peptides had the highest specificity (91%-96%) but the lowest sensitivity (10%-52%) compared with Ara h 2-sIgE (69% specificity and 87% sensitivity) or with peptide mix-sIgE (82% specificity and 63% sensitivity). Peptide 3 directly induced mast cell activation, and the peptide mix inhibited Ara h 2-induced activation of mast cells sensitized with plasma from Ara h 2-positive PA patients. CONCLUSIONS: sIgE to the peptide mix improved the diagnostic performance of Ara h 2-sIgE similarly to sIgE to individual peptides. The peptides interfered with Ara h 2-induced mast cell activation, confirming its relevance in peanut allergy.

Factors affecting timeliness in management of head and neck cancer.

BACKGROUND: Timeliness in the management of patients with head and neck cancer (HNC) can be affected by both patient and non-patient related factors. This study aims to investigate the factors associated with the timeliness of managing HNC. METHODS: A retrospective review was conducted on Western Health medical records including all new patients presenting to the Western Health HNC surgical outpatient clinic in the five-year period from first January 2017 to 31st December 2021 with the diagnosis of a HNC. Both patient and non-patient related factors were compared with the duration between a patient's referral to a HNC service and the commencement of their treatment. RESULTS: Two hundred and twenty-eight patients were included in this study. The median duration from referral to the commencement of treatment was 48 days. Lack of radiological or pathological investigations prior to referral to a HNC service as well as early staging were found to significantly impact timeliness in management. Socioeconomic factors such as non-English speaking backgrounds, distance from the hospital and lack of social supports were not found to negatively impact timeliness of management. CONCLUSION: The management of patients with HNC require careful consideration of all patient and non-patient related factors which may affect timeliness in management, particularly investigations performed prior to their referral to a HNC service.

Observational study on resource utilisation of patients with limited English proficiency (LEP) at a high-LEP serving community hospital emergency department.

Communication barriers often result in healthcare disparities. Language barriers in patients with limited English proficiency (LEP) frequently results in higher healthcare expenditures and potentially poorer patient-centred outcomes. Therefore, we decided to assess resource utilisation of patients with LEP at our high-LEP serving community hospital emergency department (ED) in Canada. Specifically, we examined whether LEP patients have a higher rate of CT utilisation and/or a higher rate of hospital admission from the ED.We enrolled 100 patients who presented to the ED in our study. Each patient's English proficiency was rated. We classified 31 patients as LEP patients and 69 patients as non-LEP patients. Within the LEP patients' group, 13 out of 31 patients (42%) received a CT scan, while in the non-LEP patients' group, 30 out of 69 patients (43%) received a CT scan. In addition, 28 out of 31 patients (90%) from the LEP patients' group were admitted to the hospital after the initial ED consultation, while in the non-LEP patients' group, 51 out of 69 patients (74%) were admitted.We did not find a difference in CT scan utilisation between LEP and non-LEP patients (p=0.89). Although there is a trend towards a higher hospital admission rate in LEP patients, our finding was not statistically significant (p=0.062).

Ara h 2-Specific IgE Presence Rather Than Its Function Is the Best Predictor of Mast Cell Activation in Children.

BACKGROUND: Ara h 2-specific IgE (Arah2-sIgE) is an excellent serologic marker for peanut allergy. However, not all subjects with detectable Arah2-sIgE react clinically. OBJECTIVE: To assess the importance of functional characteristics of Arah2-sIgE for Ara h 2-induced mast cell activation. METHODS: We studied a cohort of children assessed for peanut allergy. We determined Arah2-sIgE levels, Ara h 2/total IgE ratios and IgE avidity for Ara h 2 using ImmunoCAP (Thermo Fisher) and mast cell activation to Ara h 2 using flow cytometry. RESULTS: Samples from 61 of 100 children (46 peanut-allergic [PA] and 15 peanut-sensitized tolerant) who had Arah2-sIgE levels 0.10 kU/L or greater were studied. Arah2-sIgE and Ara h 6-specific IgE levels, Ara h 2/total IgE ratios, and the diversity of IgE for Ara h 2 epitopes were higher in PA compared with peanut-sensitized tolerant samples. The levels of IgE to peanut, Ara h 1, and Ara h 3 were not significantly different between groups. Results from the mast cell activation test to Ara h 2 strongly correlated with Arah2-sIgE levels (r = 0.722; P < .001) and Ara h 2/total IgE ratios (r = 0.697; P < .001) and moderately with Arah2-sIgE diversity (r = 0.540; P < .001). On a linear regression model, Arah2-sIgE levels (standardized ß-coefficient = 0.396; P = .008) and Ara h 2/total IgE ratios (standardized ß-coefficient = 0.0.669; P = .002) were the main determinants of mast cell response to Ara h 2. CONCLUSIONS: Most children sensitized to Ara h 2 are PA. Ara h 2-specific IgE titers and specific activity are the major determinants of mast cell response to Ara h 2.

Basophil activation test has high reproducibility and is feasible in the clinical setting.

BACKGROUND: The basophil activation test (BAT) has high accuracy to diagnose peanut allergy and can reduce the need for oral food challenges (OFC); however, so far it has not been incorporated in clinical practice. METHODS: We assessed the reproducibility of BAT within the same laboratory and between two different laboratories and the feasibility of using BAT in the clinical setting. RESULTS: One hundred and two children being assessed for peanut allergy were tested on BAT (72 allergic, 30 sensitized tolerant). There was little internal variation (coefficient of variation <15%) in the BAT and a very strong correlation (Rs > .95) between BAT performed across laboratories. The 2 BAT methods were strongly correlated but not interchangeable. In the cases of discrepancy, our in house BAT method was 100% accurate. BAT was feasible and well-accepted by clinicians: no patient with positive BAT was referred for OFC, leading to reduction in the number of OFC required. Twenty one percent of patients who underwent OFC reacted to peanut. A negative BAT also encouraged the performance of OFC in sensitized children who would otherwise be considered allergic, 50% of whom did not react and incorporated peanut in the diet. CONCLUSIONS: The BAT is a robust test that can reliably be transferred between laboratories; however, different BAT methods are not interchangeable. BAT was well integrated in the clinical decision-making process in a specialized center.

Materials used for mastoid obliteration and its complications: a systematic review.

OBJECTIVE: The objectives of this review are to identify the types of materials with their associated complications and respective considerations when used to obliterate the mastoid cavity. METHODS: A systematic search was performed across PubMed, Embase, Medline and Cochrane databases from January 2009 to January 2020 for randomized controlled trials and observational studies of patients that underwent mastoid obliteration. Studies that fulfilled the inclusion criteria were screened and scored according to the MINORS and relevance scores to determine final inclusion. Types of complications were grouped into minor and major complications based on the Clavien-Dindo classification. RESULTS: Two thousand five hundred and seventy-eight ears were evaluated. There were a total of 165 (7.9%) minor and 142 (6.8%) major complications in the autologous group. Overall complication rate is 14.8%. The major complications were largely recurrent and residual disease requiring revision surgery. There were 10 (18.5%) minor complications and three (5.6%) major complications in the allogenic group. The cumulative complications risk is 24%. For the synthetic group, there were 39 (8.0%) minor and 34 (7.6%) major complications. The cumulative complication rate is 16.6%. CONCLUSION: Current evidence on materials for mastoid obliteration has been evolving. Each material has its strengths and limitations. The trend over the last decade favours the use of autologous materials. The principle of using a material remains being cautious of not reimplanting skin that can lead to the development of a cholesteatoma. The choice of materials is dependent on patient factors as well as the surgeons' preference and experience.

Combining Allergen Components Improves the Accuracy of Peanut Allergy Diagnosis.

BACKGROUND: IgE to peanut often occurs in the absence of peanut allergy. Detection of allergen component specific IgE (sIgE) has improved diagnosis and birthed molecular allergen component arrays, in which sensitization to multiple allergen components can be measured simultaneously. OBJECTIVE: To improve the diagnostic utility of serology for peanut allergy, by mapping interactions of sIgE to multiple components and IgE functional characteristics. METHODS: A cohort of 100 children was studied, with a 60-children cohort employed for external validation. Levels of total IgE, sIgE to peanut, and peanut components were measured using singleplex ImmunoCAP and multiplex immuno solid-phase allergen chip (ISAC). Peanut IgE specific activity, avidity, and diversity were determined. Diagnostic modeling was performed using a Bayesian hierarchical model. RESULTS: Sensitization to the 112 allergens on ISAC (model 1) demonstrated the highest accuracy to diagnose peanut allergy (area under the curve [AUC] = 0.92). Sensitization to peanut components on ISAC (model 2) reported an AUC of 0.86 and on singleplex (model 3) an AUC of 0.92, which was greater than that of Ara h 2 sIgE alone (AUC = 0.90). Functional characteristics of peanut sIgE (model 4) reported an AUC of 0.89, which was greater than that of peanut sIgE (AUC = 0.75). Model 3 offered the highest predictive value and the second highest overall diagnostic accuracy. CONCLUSIONS: sIgE to a combination of allergen components (Ara h 1, 2, 3, and 6) is highly predictive of peanut allergy and superior to individual markers. Combining the functional characteristics of IgE was superior to peanut sIgE levels alone. These models can be applied in real time during clinical consultations using online calculators.

Cervical Nodal Metastatic Pituitary Carcinoma: A Case Report.

Pituitary carcinomas are rare tumors with only 170 cases reported in the literature.1 They form a very small proportion of pituitary tumors, which are commonly benign adenomas. Metastatic disease diagnosed by fine needle aspiration cytology is extremely rare and has only been reported in 6 patients,2-5 3 of whom had cervical nodal metastases, with other sites of metastases being the liver and cervical vertebra. We report a case of cervical metastatic pituitary carcinoma diagnosed by core needle biopsy.

COVID-19 did not delay time from referral to definitive management for head and neck cancer patients in a regional Victorian centre.

BACKGROUND: The COVID-19 pandemic has had widespread impacts on health services, particularly regarding the provision of urgent elective surgical services. It has influenced the evaluation of surgical patients, patient willingness to consult with medical services, and the ability to provide timely care to these patients. The aim of this study is to assess the impact of the COVID-19 pandemic on the time to definitive management for head and neck cancer in a regional setting. METHODS: A retrospective review was performed through the University Hospital Geelong Head and Neck Unit records and electronic medical records. Ethics approval for quality assurance was attained. The primary outcome was time from the first clinic appointment to commencement of definitive management. Statistical analysis was performed using Prism (version 8.0, GraphPad). RESULTS: A total of 127 patients were identified, 64 in the pre-COVID and 63 in the post-COVID period. In the post-COVID period, more patients (14.3%) had their first clinic appointment with telehealth compared to the pre-COVID period (1.6%). There was also no significant difference in time from referral to first clinic appointment or time from first clinic appointment to date of definitive treatment decision or multidisciplinary meeting. There was no significant difference in definitive treatment modality between groups. CONCLUSION: Despite increased adoption of telemedicine and increased public health considerations, there was no increase in time to definitive treatment from the time of referral to a regional head and neck cancer service.

Qualitative Interdisciplinary Learning Reviews of Non-COVID-19 Patients' Journeys During the COVID-19 Pandemic.

In the early months of 2020, hospital processes were changed in response to the coronavirus disease 2019 (COVID-19) pandemic. We present one community hospital's experience in conducting a series of interdisciplinary learning reviews (ILRs) on non-COVID-19 patient's journeys during the early months of the pandemic. An ILR is a method of reviewing medical records using a system lens to identify system-level opportunities for improvement. Using the ILR method, we identified several opportunities for improvement in caring for our patients.

Allergen-specific IgG show distinct patterns in persistent and transient food allergy.

BACKGROUND: Immediate food-allergic reactions are IgE-mediated, but many individuals with detectable allergen-specific IgE do not react to the food. Allergen-specific IgG may interfere with allergen-IgE interaction and/or through intracellular inhibitory signalling to suppress mast cell and basophil response to food allergens. We aimed to understand the role of allergen-specific IgG in food allergy and natural tolerance. METHODS: IgG and IgG isotypes specific to peanut, cow's milk and egg were measured using ImmunoCAP and ELISA respectively in samples of children with suspected food allergies. Expression of IgE and IgG and their receptors and expression of activation markers following allergen stimulation were measured on basophils and mast cells by flow cytometry, with and without blockade of FcγRIIα or FcγRIIß receptors. RESULTS: The levels of peanut-specific IgG, IgG1, IgG2, IgG3 and IgG4 in ELISA were higher in peanut-allergic than in non-peanut-allergic children. No difference in allergen-specific IgG isotypes was observed between allergic and non-allergic children to milk or egg, except for milk-specific IgG4 that was higher in non-cow's milk-allergic than in cow's milk-allergic children. Basophils and LAD2 cells expressed IgG receptors, but IgG and IgA were not detected on the surface of either cell type and blocking FcγRIIα or FcγRIIß did not modify basophil or mast cell activation in response to allergen in allergic or tolerant children. CONCLUSION: Allergen-specific IgG patterns were distinct in persistent (peanut) versus transient (milk and egg) food allergies. We found no evidence that FcγRIIα or FcγRIIß receptors affect allergen-induced activation of mast cells and basophils in food allergy or natural tolerance.

Diagnostic concordance of telemedicine for otolaryngology, head and neck surgery in regional Australia.

BACKGROUND: The use of telehealth during the COVID-19 pandemic has emerged as both a necessary and significant tool in the provision of safe and timely healthcare in the field of otolaryngology. Increased access to specialist care in a regional setting is an additional benefit. Variation in diagnostic accuracy of telehealth consultations may affect diagnosis and management. Therefore, our aim is to determine the diagnostic concordance of telemedicine for otolaryngology in an Australian regional setting with physical consultations. METHODS: Retrospective review was conducted for all patients who received an initial telemedicine appointment over a 7-month period during the COVID-19 pandemic in regional Victoria, Australia. Data were collected regarding initial diagnosis and management from telemedicine consultations, subsequent physical appointment findings and management and intraoperative findings. Statistical analysis was performed using Prism (version 8.0, GraphPad). RESULTS: Two hundred and fifty-nine patients were included. The most common conditions referred were for consideration of tonsillectomy with or without adenoidectomy (44.0%). Overall diagnostic concordance of the initial referrer was 63.3% and for telephone appointments, it was 81.9%. Concordance of recommended treatment plans between telephone and physical appointments was 96.9%. CONCLUSION: Although physical appointments are an essential aspect of practice in OHNS, there are significant benefits of phone only telemedicine within the context of a global pandemic which were compounded by a regional setting. Paediatric patients were found to have the highest concordance of diagnosis and treatment plans.