Poster Abstracts

Joseph Abbo, Benjamin Woerner, Allison Wang, Melanie K. Donahue, Judy Hines, James R. Baker Jr., Charles F. Schuler IV

Background: Transepidermal water loss (TEWL) is a measure of water loss through the epithelial barrier of the skin. Changes in baseline TEWL over time in food allergy models may provide insights as to the effects of allergic inflammation on the skin.

Objective: The goal of this work is to determine the optimal means to measure baseline TEWL in BALB/c mice in different experimental settings and to determine if repeated oral ovalbumin (OVA) challenges affect the epithelial barrier.

Methods: In BALB/c mice, baseline TEWL was measured at different body locations, under isoflurane anesthesia, with and without a heat lamp, and for both sexes. Mice underwent seven oral OVA challenges following a sensitization period of two weeks. Baseline TEWL was measured before each challenge.

Results: Although there was no significant difference between the sexes and with or without heat lamp use, baseline TEWL varied significantly between body location, and with isoflurane exposure (p < 0.05). Even though baseline TEWL increased significantly before the seventh OVA trial (p < 0.05), TEWL did not change significantly during the early trials. This implies that repeated exposure to oral allergen-induced anaphylaxis might cause systemic effects that increase epithelial barrier permeability over time.

Conclusion: This study sought to identify important factors that can affect the measurements of baseline TEWL data for mice in typical laboratory settings. The rise in TEWL prior to the seventh OVA trial indicates that systemic allergic reactions may impair the epithelial barrier integrity and/or point toward persistent type 2 allergic inflammation in the skin in the food allergy state.

Chun Chen, Olivia E. Benson, Chris L. Dorsett, Katarzyna W. Janczak, Matthew J. Wiest, Pamela T. Wong, and Jessica J. O’Konek

Rationale: While vaccines are commonly administered to infants, a major gap in knowledge exists in understanding their immune effects specific to early life. The immature infant immune system develops dependent upon environmental stimuli. Vaccine adjuvants may play important roles in shaping immune development.

Methods: Mice were immunized as neonates or adults with a hepatitis B vaccine (HB) with different choices of adjuvants (alum, alum+CpG, or CpG) that promote Th2 or Th1 immunity. Mice subsequently received a 2-dose vaccine series of ovalbumin (OVA) and the adjuvant MPLA or alum to determine alterations of heterologous immune responses.

Results: Immune responses to HB-alum vaccine were more strongly Th2 polarized when given earlier in life while HB-CpG induced Th1 polarized immune responses. The effects on immune skewing were not limited to HB, as early-life immunization with HB-alum also led to the development of more strongly Th2 polarized immune responses to subsequent immunization with OVA-MPLA. However, this Th2 predisposition was not observed in neonatal mice that were immunized with HB-alum+CpG. Mice that received early-life immunization with HB-CpG developed stronger Th1 polarized immune responses to subsequent OVA-alum immunization. Interestingly, mice that were immunized with either HB vaccine in adulthood generated OVA-specific responses consistent with the responses of naive mice. Early-life immunization with HB-alum also changed the phenotype of dendritic cells in the bone marrow, suggesting a role for trained immunity in the heterologous effects.

Conclusions: Immunization with adjuvants in early life influences the T cell polarization of immune responses to subsequent heterologous antigen exposure. Because vaccines are crucial elements of health in infancy, furthering our understanding of early-life immunization may allow for the development of vaccines that induce beneficial effects on immune development through rational choice of adjuvant.

Donahue M 1,2, Hines J 1, Wang A 2,3, Woerner B 1, Cannon J 1, Tsoi LC 2,4, O’Shea KM 1,2, Farazuddin M 2, Gudjonsson JE 2,4, Baker JR 1,2, Schuler CF 1,2,3

Rationale: While crosslinking of the high-affinity IgE receptor is well-characterized in mast cell degranulation, the role of adjunctive processes remains understudied. The LAD2 mast cell (MC) model is known to become adherent upon stimulation, while RNA sequencing of human samples collected during anaphylaxis revealed significant up-regulation of the focal adhesion kinase (FAK) pathway. Thus we sought to investigate the role of FAK and related MC adhesion molecules in allergen-mediated MC activation.

Methods: RBL-2H3 (rat) and LAD2 (human) MC models were sensitized with monoclonal immunoglobulin E (IgE), and degranulation induced by anti-IgE antibody or ionomycin was quantified by beta-hexosaminidase colorimetric assay and detection of CD63/CD107a staining by flow cytometry. Adhesion was assessed by measuring fluorescence from calcein-stained cells adhered to fibronectin-coated plates after washing off non-adherent cells. Murine anaphylaxis was induced using DNP-IgE/DNP-HSA (passive) or OVA-alum/oral ovalbumin (active) models in BALB/c mice. FAK activity was modulated by small molecule inhibition, degradation, and activation.

Results: Cell adhesion positively correlated with the degree of degranulation following stimulation with anti-IgE or ionomycin, with visible morphologic change by immunofluorescence. FAK antagonism in RBL-2H3 and LAD2 models reduced anti-IgE-induced beta-hexosaminidase release and adhesion preferentially over ionomycin-induced beta-hexosaminidase release and adhesion in a dose-dependent manner without cytotoxicity, as well as reduced LAD2 CD63/107a surface expression. Meanwhile FAK activation in RBL-2H3 model increased beta-hexosaminidase release. FAK small molecule inhibitor introduced during the effector phase of passive and active anaphylaxis models reversed temperature decrease and anaphylaxis scores. scRNAseq of LAD2 MCs revealed correlation between degranulation signature and FAK pathway genes with significant variation between anti-IgE- and ionomycin-induced activation.

Conclusion: MCs demonstrate a positive functional and gene expression association between degranulation and adhesion which is preferentially disrupted by FAK antagonism during IgE-induced activation as well as augmented with FAK agonism, suggesting a role for adhesion mediated by FAK in MC activation during allergic reactions.

Grace K. Lombardo, Evan Velarde, Yao Gu, Nicholas W. Lukacs and Wendy Fonseca*

Stem cell factor (SCF) binds to the c-Kit receptor, which is expressed in multiple myeloid cell populations and innate lymphoid cells (ILCs). We previously detected the proinflammatory SCF248 isoform highly upregulated in the lungs of chronic allergic mice, and elevated soluble SCF levels have been reported in the serum of asthmatic patients. While ILC progenitors (ILCp) express c-Kit, the role of SCF-c-Kit signaling in ILCp-to-ILC2 differentiation during type 2 inflammation remains unclear.Here, we investigated SCF/c-Kit activation in ILCp→ILC2 differentiation in type 2 pulmonary diseases. SCF knockout (Kitl^fl/fl-UBCCreERT) mice exhibited reduced airway allergy, characterized by decreased IL-13 expression and significantly lower lung ILC2 numbers compared to Cre^- (control) mice. Additionally, allergic control mice displayed increased SCF248 expression in bone marrow fibroblasts, along with elevated ILCp and ILC2 populations in both bone marrow and peripheral blood. In contrast, allergic SCF KO mice showed reduced ILCp and ILC2 numbers systemically. Mechanistically, IL-13 stimulation of naive bone marrow fibroblasts and OP9-DL1 cells induced SCF248 expression. Furthermore, ILCp cultured on OP9-DL1 cells expressing SCF248 upregulated ILC2 markers, suggesting a role for SCF248 in ILCp differentiation. These findings indicate that chronic airway allergy induces a systemic allergic microenvironment through IL-13-driven SCF248 overexpression in the lung and bone marrow, promoting persistent ILCp-to-ILC2 differentiation and sustaining a type 2 inflammatory environment in the lungs. This mechanism may extend to other Th2-driven diseases.

Evann Oleshansky, Charles Schuler, MD, Judy Hines, PhD, Melanie Donahue, MD

BACKGROUND. Focal adhesion kinase (FAK) is a protein that regulates cell adhesion and cytoskeletal organization in mast cells. When FAK is activated, conformational changes allow for autophosphorylation at Tyrosine 397, subsequent phosphorylation at additional sites, and downstream signaling cascades. Tyrosine 397 is a major site of phosphorylation in phospho-FAK (pFAK).

OBJECTIVE. This study aimed to define the effect of a FAK inhibitor (FAKi) and its vehicle on FAK, pFAK, and mast cell degranulation in RBL-2H3 cells, a well-defined mast cell model system.

METHODS. Western blotting was used to detect and quantify FAK and pFAK in the RBL cells. ImageJ software was used to normalize and quantify protein bands of interest versus a housekeeping gene, GAPDH. Various concentrations of the FAKi (PF-431396) and its vehicle, DMSO, were utilized. Mast cell degranulation was quantified by beta-hexosaminidase release from cells after activation with either IgE/anti-IgE or ionomycin.

RESULTS. FAK inhibition altered the western blot gel location of FAK but not pFAK (Tyr397). This change was driven by the vehicle used rather than the FAKi itself. The FAKi’s effect occurred across a range of concentrations, starting at 0.1 uM then 0.01uM, 0.001 uM, and 0 uM. pFAK was reduced in all conditions to which FAKi was applied. FAKi application reduced mast cell degranulation in the IgE-based conditions and in the ionomycin-based conditions.

CONCLUSIONS. FAK appears to play a prominent role in mast cell activation during food anaphylaxis. To understand related models and human data on FAK, relevant molecular data are needed to define the precise effect of this FAKi on anaphylaxis. Future work will focus on the interaction between various pFAK phosphorylation sites and the outcomes of mast cell degranulation.

Keerthikka Ravi, Nicole R. Falkowski and Gary B. Huffnagle

Lactobacillus johnsonii, a Gram - positive bacterium, when orally introduced into airway allergen mouse model can affect both mucosal and systemic immunity, by attenuating proinflammatory responses. It confers protection to neonatal offspring of L. johnsonii-supplemented mothers against severe respiratory syncytial virus immunopathology. The growing medical relevance of L. johnsonii highlights the need to understand its adaptation to diverse hosts. We conducted a comparative genomic analysis of L. johnsonii strains isolated from the gastrointestinal (GI) tract of diverse vertebrate hosts to determine the genetic basis of host specificity. Phylogenetic analysis revealed significant heterogeneity in genome sequence and content, with strains clustering into rodent- or avian-associated clades. Human isolates did not form a distinct clade. Functional analysis identified several genes to be significantly enriched in rodent isolates compared to avian isolates. These include genes associated with cell surface, accessory secretory (aSec) pathway, transcription, metabolism, and defense. Global transcriptomic analysis of L. johnsonii MR1, a rodent isolate, confirmed the active expression of 40 rodent-associated genes during both anaerobic in vitro growth and in vivo growth in mono-colonized germ-free mice. qPCR analysis further revealed unique regulation of these genes when mono-colonizing the stomach, ileum and colon of germ-free mice. These included genes linked to cell surface, carbon metabolism, and aSec pathways. These findings highlight the role of host-specific genes in nutrient adaptation and host-microbe interactions, offering insights into the ecological and evolutionary dynamics of L. johnsonii in the GI tract.

Kristy A. Srodawa, Nicole R. Falkowski, Gary B. Huffnagle

Anaphylaxis is a severe hypersensitivity reaction traditionally attributed to IgE-mediated mast cell degranulation [1-3]. However, alternative pathways, including IgG-and-neutrophil-mediated responses, suggest a broader mechanism of immune activation [2-4]. Additionally, non-immunological triggers to anaphylaxis such as cold and exercise indicate potential involvement of the nervous system [5, 6]. This study explores the role of metabotropic glutamate receptor 7 (mGluR7) in neuroimmune interactions using a murine knockout (KO) model.

mGluR7, a Group III inhibitory-G-protein-coupled receptor, is highly expressed in the central nervous system (CNS) but is also found in peripheral tissues, including mast cells [7, 8]. We observed that while wild-type (WT) mice exhibit minimal responses to subcutaneous histamine injection, mGluR7 KO mice undergo full anaphylaxis, marked by a significant temperature drop (~4°C vs. ~1°C in WT) and severe physiological distress. Pharmacological studies identified histamine receptor 1 (HR1) as the key mediator, with HR1 blockade abolishing anaphylaxis.

Flow cytometry analysis of bone marrow showed no hematopoietic defects, but KO spleens exhibited an unexpected, significant increase in neutrophils. This suggests a potential neuroimmune mechanism linking mGluR7 to immune regulation beyond anaphylaxis. Our findings highlight a novel role for the nervous system in modulating anaphylaxis and provide insight into non-traditional anaphylaxis triggers. Understanding mGluR7's function may offer new therapeutic strategies for preventing anaphylaxis and related immune disorders.

1. Rossi, C.M., M.V. Lenti, and A. Di Sabatino, Adult anaphylaxis: A state-of-the-art review. Eur J Intern Med, 2022. 100: p. 5-12.

2. Vitte, J., et al., Allergy, Anaphylaxis, and Nonallergic Hypersensitivity: IgE, Mast Cells, and Beyond. Med Princ Pract, 2022. 31(6): p. 501-515.

3. Nguyen, S.M.T., et al., Mechanisms Governing Anaphylaxis: Inflammatory Cells, Mediators, Endothelial Gap Junctions and Beyond. Int J Mol Sci, 2021. 22(15).

4. Reber, L.L., J.D. Hernandez, and S.J. Galli, The pathophysiology of anaphylaxis. J Allergy Clin Immunol, 2017. 140(2): p. 335-348.

5. Brevik, C. and M. Zuckerman, Cold Anaphylaxis: A Case Report. J Emerg Med, 2021. 60(2): p. 226-228.

6. Faihs, V., et al., Wheat-dependent exercise-induced anaphylaxis: subtypes, diagnosis, and management. J Dtsch Dermatol Ges, 2023. 21(10): p. 1131-1135.

7. Enza Palazzo1, *, Ida Marabese2, et al., Metabotropic Glutamate Receptor 7: From Synaptic Function to Therapeutic Implications. Current Neuropharmacology, 2016. 14: p. 504-513.

8. Alim, M.A., et al., Glutamate triggers the expression of functional ionotropic and metabotropic glutamate receptors in mast cells. Cell Mol Immunol, 2021. 18(10): p. 2383-2392.

Qingyang Liu, Shams Tabrez, Patrick Niekamp, Chang H Kim

Innate lymphoid cells (ILCs), strategically positioned throughout the body, undergo population declines over time. A solution to counteract this problem is timely mobilization of multipotential progenitors from the bone marrow. It remains unknown what triggers the mobilization of bone marrow ILC progenitors (ILCPs). We report that ILCPs are regulated by the circadian clock to emigrate and generate mature ILCs in the periphery. We found that circadian-clock-defective ILCPs fail to normally emigrate and generate ILCs. We identified circadian-clock-controlled endocrine and cytokine cues that, respectively, regulate the retention and emigration of ILCPs at distinct times of each day. Activation of the stress-hormone-sensing glucocorticoid receptor upregulates CXCR4 on ILCPs for their retention in the bone marrow, while the interleukin-18 (IL-18) and RORα signals upregulate S1PR1 on ILCPs for their mobilization to the periphery. Our findings establish important roles of circadian signals for the homeostatic efflux of bone marrow ILCPs.

Brandon Tepper 1 , Fatemeh Fattahi 1 , Laura Vallance 1 , Julia Holden 1 , Kareem Hussein 1 , Joshua Meier 1 , Ulus Atasoy 1,2

Background/Aim: The RNA-binding protein HuR (Elavl1) is a key post-transcriptional regulator that stabilizes mRNA transcripts involved in immune responses. This study evaluates the effects of HuR inhibition using the small molecule KH-3 and a novel transgenic knock-in mouse model on GATA3, a master regulator of Th2 cell differentiation.

Methods: CD4 + T cells were isolated from the spleens of C57BL/6 mice using a magnetic separation kit and pre-incubated with a proliferation dye. Cells were treated with KH-3 or its inactive analogue, KH-3B, for 2 hours, then stimulated with anti-CD3/CD28 for 3 days. GATA3 and Th2 cytokine expressions were assessed by flow cytometry. In additional experiments, splenic CD4 + T cells pre-incubated with KH-3 or KH-3B were activated for 4 days and then assessed for intracellular Th2 cytokines and GATA3 expression following 4 hours of treatment with PMA, ionomycin, and BFA. To further investigate HuR’s role, a GATA3 knock-in (KI) mouse model with disrupted HuR-binding sites in Gata3 mRNA was developed using CD4-Cre or Vav-Cre mice. CD4 + T cells from KI and control (GATA3 d/d ) mice were activated with anti-CD3/CD28 for 4 days and Th2 cytokines expression levels were evaluated by flow cytometry.

Results: Cells treated with KH-3 showed significantly reduced proliferation, and lower levels of Th2 cytokines and GATA3 expression. Similarly, CD4 + T cells from CD4-Cre and Vav-Cre GATA3 KI mice demonstrated a notable reduction in Th2 cytokine production compared to the control mice.

Conclusion: These findings underscore the critical role of HuR in regulating GATA3 expression and subsequent Th2 cytokine production. The results from our pharmacological intervention and transgenic mouse model provide compelling evidence of HuR’s involvement in GATA3 expression driven Th2-mediated immune responses.

Laura Vallance, Fatemeh Fattahi, Julia Holden, Kareem Hussein, Brandon Tepper, Joshua Meier, Steven Huang, Ulus Atasoy

Allergic asthma is a chronic inflammatory lung disease characterized by dysregulated Th2 immune responses, leading to persistent airway inflammation and remodeling. Despite advancements in biologic therapies targeting cytokines such as IL-4, IL-5, and IL-13, which provide relief for some patients, they remain costly, inaccessible to many, and fail to address upstream regulatory mechanisms. Our research focuses on the post-transcriptional control of Th2 inflammation through the RNA-binding protein HuR (Elavl1), a key regulator of GATA3 mRNA stability and translation.

Our earlier studies have confirmed HuR’s critical role in Th2 inflammation, supported by findings from asthmatic CD4+ T cells and innovative mouse models, including those where HuR is deleted in CD4+ T cells at various developmental stages, and a unique CD4-Cre GATA3 knock-in model with disrupted HuR-binding sites, providing essential mechanistic insights into HuR’s function.

In this study, we investigated KH-3, a novel small-molecule HuR inhibitor, in a preclinical allergic asthma model and in human CD4+ T cells isolated from lung tissue. In a house dust mite (HDM)-induced allergic airway inflammation model, KH-3 was administered intraperitoneally every other day for two weeks post-sensitization, significantly reducing airway inflammation compared to controls. Histological analysis showed substantially decreased inflammatory cell infiltration in lung tissues. In line, bronchoalveolar lavage fluid analysis revealed significantly reduced inflammatory cells and Th2 cytokines (IL-4, IL-5, IL-13) levels. QPCR and flow cytometry confirmed significant reductions in GATA3 expression and Th2 cytokine production in lung CD4+ T cells.

Additionally, our translational studies utilizing human CD4+ T cells isolated from lung tissue, provided by the University of Michigan Lung Biorepository, confirmed KH-3’s effectiveness in modulating GATA3 stability and Th2 cytokine responses.

These findings highlight KH-3’s potential as a novel strategy to disrupt GATA3-driven Th2 responses and mitigate airway inflammation in allergic asthma.

Abigail von Recklinghausen, Amanda Atanasio, YoonSeung Lee, Andre Limnander, Donna Farber, Matthew A. Sleeman, Jamie M. Orengo

Food allergy affects 8% of children and 11% of adults withing the US population. Type 2 inflammation is a key driver of the pathogenesis of food allergy as well as other allergic conditions such as atopic dermatitis, allergic rhinitis and asthma. Asthma is a chronic airway disorder, driven by various allergic and immune mechanisms which is largely controlled with therapeutic interventions, but can be fatal in rare cases. Allergen exposure is a known trigger of asthma exacerbations and systemic anaphylaxis that can lead to significant morbidity and mortality. While blocking IgE with anti-IgE therapy has clinical benefit, the relationship of total and allergen specific IgE in individuals with controlled asthma compared to those with fatal asthma (died from an asthma attack) is unknown. In the current study we sought to interrogate total IgE levels and IgE sensitization profiles for common food, perennial and seasonal allergens within cohorts of organ donors with fatal asthma, a history of asthma or no asthma.

Tissue and plasma samples from a cohort of 208 organ donors were made available to the Donna Farber Lab through a collaboration with Live on NY, a nonprofit organization committed to helping New York live on through organ and tissue donation. A subset of plasma samples from organ donors with fatal asthma (n=29), a history of asthma (n=38) and non-asthmatic controls (n=40) were analyzed for total IgE and a panel of allergen specific IgE using the ImmunoCAP platform. The panel for specific IgE included: cat dander (e1), dog dander (e5), cockroach (i6), D. farinae (d2), D. pteronyssinus (d1), birch (t3), oak (t7), mugwort (w6), common ragweed (w1), and timothy grass (g6), Alternaria alternata (m6) and Aspergillus fumigatus (m3), almond (f20), cashew (f202), cod fish (f3), egg white (f1), hazelnut (f17), milk (f2), peanut (f13), salmon (f41), scallop (f338), sesame (f10), shrimp (f24), soybean (f14), tuna (f40), walnut (f256) and wheat (f4).

Combined analysis of asthmatic samples (asthma history and fatal asthma) as compared to non-asthmatic controls revealed a general trend for increased IgE to food allergens in asthmatic samples with significantly increased IgE observed for shrimp, milk and egg allergens. Additionally, the levels of total IgE were significantly higher in sera from fatal asthma donors compared to non-asthmatic controls (median= 526 KU/L and 93.9 KU/L, respectively p<0.001). Perennial aeroallergen specific IgE, including IgE to cat, dog, cockroach and house dust mite allergens was also significantly increased in fatal asthma as compared to non-asthmatic controls. Similar trends were not observed for IgE-sensitization to seasonal or mold allergens.

Benjamin N. Woerner, Joseph Abbo, Allison Wang, Melanie K Donahue, Judy Hines, James R. Baker, Charles F. Schuler

Background: An increase in transepidermal water loss (TEWL) has been shown to precede food anaphylaxis during clinical oral food challenges. We sought to determine whether TEWL changes during mouse anaphylaxis to model the observed TEWL change in human food anaphylaxis.

Methods: Two IgE-based models were utilized: 1) Active systemic anaphylaxis (ASA) with an ovalbumin-alum sensitization followed 2 weeks later by ovalbumin challenges; and 2) Passive systemic anaphylaxis (PSA) with dinitrophenyl (DNP)-IgE given on day 1 followed on day 2 with a DNP-human serum albumin (HSA) challenge. Additionally, histamine IV injections were given in a non-IgE-mediated chemical anaphylaxis model. Diarrhea, reaction score, rectal temperature, and TEWL measurements were recorded pre-challenge and at 15-minute intervals post-challenge. TEWL was obtained by holding the tewameter against the mouse ear.

Results: TEWL increased during ASA (3.82 g/m2/h) and PSA (1.54 g/m2/h), whereas histamine challenges (-0.14 g/m2/h) and control mice (-0.36 g/m2/h) had no change in TEWL. Internal temperature drops (ASA: -1.03°C; PSA: -0.96°C; histamine: -4.90°C) and reaction scores (ASA: 3.19; PSA: 1.36; histamine: 3.80) recorded during the trials confirmed that an anaphylactic event occurred. MCPT-1 ELISA results  show an increased presence of MCPT-1 in the blood of challenged mice (14.22 ng/mL) as opposed to control mice (5.76 ng/mL), which also supports the transpiration of anaphylaxis.

Conclusion: For IgE-mediated anaphylaxis, an increase in TEWL preceded symptoms of allergic reactions, whereas TEWL did not change in control or histamine-treated mice. This aligns with observed TEWL changes in human food anaphylaxis, supporting future mechanistic investigations into this phenomenon.

Sarah Mathew, MPH1, Libby Brooks, MS1, Nancy Polmear-Swendris, MEd, RN1, Danica M. Aquino4, Ian F. Slack, MD1,2, Charles F. Schuler, IV, MD1,2, Yuhong Zhang, BA1, James R.  Baker, Jr., MD1,2,3, Kelly M. O’Shea, MD1,2

Rationale: M-SIBS is a prospective birth cohort study with intent to study the role and relationships between genetic, epigenetic, transcriptomic, microbiome, and environmental factors that contribute to food allergy pathogenesis.

Methods: Over the first three years of the proband's life, comprehensive phenotyping is conducted through surveys, which are stored in REDCap. A variety of biological samples-including blood, stool, breast milk, vaginal swab, foreskin, placental cores, water, and dust-are collected, processed, and stored at the University of Michigan Central Biorepository. Samples are obtained from the proband at the following time points: 2 weeks, 2 months, 5 months, 12 months, 24 months, and 36 months.

Testing for IgE-mediated food allergies is performed at 5 months, 12 months, 24 months, and 36 months. This includes both skin prick testing (SPT) and serum food-specific immunoglobulin E (IgE) testing. SPT is conducted by a trained food allergy nurse at the University of Michigan Clinical Research Unit, and IgE testing is performed on participant serum using the Phadia 250 machine in the M-SIBS laboratory. A skin prick test is considered positive if the wheal is at least 3 mm greater than the negative control. IgE testing is considered positive if the level exceeds 0.35 kU/L. If either test returns a positive result for a protocol-specified food, an oral food challenge (OFC) is scheduled, provided the child has not consumed a full serving of the food within the two weeks preceding the visit.

To recruit families for the study, we utilize social media, distribute flyers, and actively promote the study during various pregnancy classes hosted by Michigan Medicine. Eligibility requires that the proband have a first-degree relative with a history of atopic diseases, such as food allergies, eczema, allergic rhinitis, or asthma.

Results: Currently, we have thirty-eight active participating families.  Twenty women are pregnant, and twenty infants have been born, comprising of nine male (45.0%) and eleven female (55.0%) infants. Eighteen fathers and twelve siblings have provided consent for inclusion in the study. The current racial distribution of enrolled parents is as follows: forty White (81.6%), one Black (2.0%), three Asian (6.1%), five multi-racial (10.2%). The current ethnic breakdown is five Hispanic parents (10.2%) and forty-four non-Hispanic parents (89.8%). Regarding family history of atopy, the prevalence of asthma is n=8 (17.0%), allergic rhinitis is n=14 (29.8%), eczema is n=5 (10.6%), and food allergies is n=11 (23.4%).

Four infants have completed their 5-month visit, during which they underwent initial food allergy testing. Of these, three infants tested positive on either the skin prick test or food-specific serum IgE test—two for egg and one for peanut. Two of three food challenges have been completed: two egg oral food challenges (OFCs) passed, while the peanut OFC has not yet been performed.

As of March 2025, we have received 105 completed online screening questionnaires with 17 lost to follow up. 60 of those individuals successfully complete the second part of the screening process: a coordinator phone screen. Of those, 40 have consented (67%). 

George E. Freigeh, Kelly M. O’Shea, Jonathan Troost, Bridgette Kaul, Christopher Launius, Lea Franco, Charles Schuler IV

Rationale: The oral food challenge (OFC) remains the gold standard for diagnosis of food allergy, though utilization is partly limited by perceived risks. Transepidermal water loss (TEWL) has been shown to increase during food anaphylaxis. We present a randomized control trial utilizing real-time TEWL monitoring as a stopping criterion for adjudicating OFC as compared to standard OFC procedure.

Methods: Participants were aged 6 months through 5 years and had an allergist-confirmed diagnosis of peanut food allergy with a prior history of reaction and peanut sensitization (wheal ≥3 mm, total peanut IgE ≥5.0 kUa/L, and/or ARA H2 of > 0.35 kUa/L). Participants were randomized into two arms in a double-blind fashion. The control group used challenge stopping criteria determined by dose-limiting symptoms per CoFAR criteria. The intervention group used challenge stopping criteria based on rise in TEWL of 1 g/m2/h plus the presence of one objective allergic symptom or the presence of dose-limiting symptoms per CoFAR criteria, whichever came first.

Results: A total of 40 participants underwent OFCs, 18 in the intervention arm and 22 in the control arm. There was no significant difference in reaction rate or percentage of participants meeting stopping criteria between arms. There was a significantly lower rate of anaphylaxis among reactors in the intervention group (63% vs. 100%, p = 0.01) as well as a significantly lower mean CoFAR score in the intervention group, indicating less severe reactions (1.78 vs 2.50, p = 0.006). There was a significantly lower rate of epinephrine use among reactors in the intervention group (50% vs. 86%, p=0.04).

Conclusion: Real-time monitoring of TEWL during OFC can lead to reduced anaphylaxis rates and epinephrine use, which may ultimately increase accessibility and safety of OFCs.