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 monoclonal antibodies (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 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 (MATs), basophil activation tests (BATs), enzyme-linked immunosorbent assays (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 blocked these epitopes. IGNX001, a mixture of two 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. CONCLUSION: We developed a peanut-specific IgG4 antibody therapeutic with convincing preclinical efficacy starting from a large repertoire of human monoclonal IgE antibodies 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.

Vitellin/Vitellogenin Is an Important Allergen in German Cockroach.

INTRODUCTION: German cockroach (GCr) aeroallergens are associated with allergic rhinitis and asthma. Vitellogenin (Vg) and vitellin (Vn) are abundant proteins in GCr blood and eggs (including egg cases), respectively, and are possible high molecular mass allergens. Prior efforts to purify Vg/Vn yielded amounts too small for subsequent studies. In this study, we report the affinity purification of Vg/Vn from whole-body defatted GCr powder and determination of the binding of Vg/Vn to anti-GCr IgE. METHOD: New Zealand white rabbits were immunized with pure Vg/Vn in Freund's adjuvant, and IgG was purified from the rabbit sera and conjugated to cyanogen bromide (CNBr)-activated Sepharose. Aqueous extracts from GCr powder were passed over the column. After extensive washing, putative Vg/Vn was eluted in low-pH buffer, neutralized, and analyzed by SDS-PAGE and liquid chromatography high-resolution mass spectrometry (LC-HRMS). IgE binding of Vg/Vn was evaluated by inhibition of IgE binding to GCr-ImmunoCAP(I6) in sera from 10 GCr-allergic individuals. In addition, Vg/Vn was biotinylated and bound to ImmunoCAP-streptavidin, and direct IgE antibody binding to the immobilized Vg/Vn was determined in sera from 26 GCr-allergic individuals. RESULTS: Vg/Vn isolated by affinity chromatography was 91% pure by LC-HRMS; contaminants included Bla g 3 (0.9%), human keratin (6%), and rabbit IgG. Vg/Vn inhibited IgE binding to GCr-ImmunoCAP(I6) in 8 of 10 sera. In direct-binding experiments, 21/26 (80%) sera had anti-Vg/Vn IgE at >0.10 kUA/L, while 11/26 (42%) sera were >0.35 kUA/L. CONCLUSIONS: We affinity-purified Vg/Vn and demonstrated that Vg/Vn-specific IgE antibody is a major component of GCr-specific IgE.

Screening asthmatics for atopic status using the ALergy EXplorer (ALEX2) macroarray.

BACKGROUND: Screening asthma patients for atopy facilitates management. Since 2010, the core biomarker for screening asthma subjects for atopic status has been the qualitative Phadiatop. multi-aeroallergen screen. A more quantitative macroarray, the Allergy Explorer (ALEX2), shows promise as an alternative. OBJECTIVE: The study's goal was to examine the pros and cons of the use of ALEX2 in the screening of asthma patients for atopic status. METHODS: We evaluated the atopic (IgE-sensitization) status in asthmatic Amish and Hutterite farm children using the ImmunoCAP and ALEX2 assays in Phadiatop equivocal and positive subjects. RESULTS: All 42 asthmatic children were analyzed by Phadiatop and total serum IgE. Of these, 22 had a negative Phadiatop (<0.1 kUa/L) and total IgE <100 kU/L which defined them as non-atopic and they were excluded from ALEX2 testing. Of six children with equivocal Phadiatops (0.1-0.2 kUa/L-Group 1) and three children with a negative Phadiatop but total IgE >100 kUa/L (group 3), 44% (n = 4) had detectable IgE antibody by ALEX2 to mite, tree pollen, and other allergens not detected by Phadiatop, but confirmed by allergen-specific ImmunoCAP testing. In 11 Phadiatop positive subjects (>0.2 kUa/L-group 2), all but one were positive by ALEX2. IgE antibody specific for mold and rabbit aeroallergens matched their agricultural and pet exposure history. Three children were positive for IgE antibody to allergens in the profilin, nsLTP, or PR-10 cross-reactive protein families. CONCLUSION: Judicious use of ALEX2's enhanced specificity data not provided by the Phadiatop can aid in the interpretation of sensitization patterns and planning management of atopic asthmatics, but sensitization relevance must be confirmed by the patient's clinical history.

EAACI Molecular Allergology User's Guide 2.0.

Since the discovery of immunoglobulin E (IgE) as a mediator of allergic diseases in 1967, our knowledge about the immunological mechanisms of IgE-mediated allergies has remarkably increased. In addition to understanding the immune response and clinical symptoms, allergy diagnosis and management depend strongly on the precise identification of the elicitors of the IgE-mediated allergic reaction. In the past four decades, innovations in bioscience and technology have facilitated the identification and production of well-defined, highly pure molecules for component-resolved diagnosis (CRD), allowing a personalized diagnosis and management of the allergic disease for individual patients. The first edition of the "EAACI Molecular Allergology User's Guide" (MAUG) in 2016 rapidly became a key reference for clinicians, scientists, and interested readers with a background in allergology, immunology, biology, and medicine. Nevertheless, the field of molecular allergology is moving fast, and after 6 years, a new EAACI Taskforce was established to provide an updated document. The Molecular Allergology User's Guide 2.0 summarizes state-of-the-art information on allergen molecules, their clinical relevance, and their application in diagnostic algorithms for clinical practice. It is designed for both, clinicians and scientists, guiding health care professionals through the overwhelming list of different allergen molecules available for testing. Further, it provides diagnostic algorithms on the clinical relevance of allergenic molecules and gives an overview of their biology, the basic mechanisms of test formats, and the application of tests to measure allergen exposure.

Human IgE mAbs identify major antigens of parasitic worm infection.

BACKGROUND: Much of our understanding of the targets of IgE comes from studies of allergy, though little is known about the natural immunogenic targets seen after parasitic worm infections. OBJECTIVE: We used human monoclonal antibodies (mAbs) for an unbiased and comprehensive characterization of the immunodominant antigens targeted by IgE in conditions like allergy or helminth infection that are associated with elevated levels of IgE. METHODS: Using human hybridoma technology to immortalize IgE encoding B-cells from peripheral blood of subjects with filarial infections and elevated IgE, we generated naturally occurring human IgE mAbs. B-cell cultures were screened in an unbiased manner for IgE production without regard to specificity. Isolated IgE mAbs were then tested for binding to Brugia malayi somatic extracts using ImmunoCAP, immunoblot, and ELISA. Immunoprecipitation followed by mass spectrometry proteomics was used to identify helminth antigens that were then expressed in Escherichia coli for IgE binding characterization. RESULTS: We isolated 56 discrete IgE mAbs from 7 individuals with filarial infections. From these mAbs, we were able to definitively identify 19 filarial antigens. All IgE mAbs targeted filarial excreted/secretory proteins, including a family of previously uncharacterized proteins. Interestingly, the transthyretin-related antigens acted as the dominant inducer of the filaria-specific IgE antibody response. These filaria-specific IgE mAbs were potent inducers of anaphylaxis when passively administered to human FcεRI-expressing mice. CONCLUSIONS: We generated human hybridomas secreting naturally occurring helminth-specific IgE mAbs from filarial-infected subjects. This work provides much-needed insight into the ontogeny of helminth-induced immune response and IgE antibody response.

Longevity of Post-Explantation Systemic Symptom Improvement and Potential Etiologies: Findings From the ASERF Systemic Symptoms in Women-Biospecimen Analysis Study: Part 4.

BACKGROUND: Breast Implant Illness (BII) describes a variety of symptoms reported by patients with breast implants. Biospecimens data revealed minimal statistical differences between BII and non-BII cohorts. Baseline analysis of PROMIS data demonstrated significant differences between the BII cohort and the 2 control cohorts. OBJECTIVES: This study was designed to determine if patients in the BII cohort obtained any symptom improvement after explantation, whether symptom improvement was related to the type of capsulectomy, and which symptoms improved. METHODS: A prospective blinded study enrolled 150 consecutive patients divided equally into 3 cohorts. Baseline demographic data and a systemic symptoms survey, including PROMIS validated questionnaires, were obtained at baseline, 3 to 6 weeks, 6 months, and 1 year. RESULTS: A total of 150 patients were enrolled between 2019 and 2021. Follow-up at 1 year included 94% of the BII cohort and 77% of non-BII and mastopexy cohorts. At 1 year, 88% of patients showed at least partial symptom improvement, with a reduction of 2 to 20 symptoms. The PROMIS score in the BII cohort decreased at 1 year for anxiety, sleep disturbances, and fatigue. Systemic symptom improvement was noted out to 1 year in the BII cohort regardless of the type of capsulectomy performed. CONCLUSIONS: Parts 1-3 in this series concluded that there were no consistent differences in biospecimen results between the cohorts. Unlike the data observed in the biospecimen analysis, BII patients had heightened symptoms and poorer PROMIS scores at baseline compared to the control cohorts. The reduction of negative expectations and a potential nocebo effect could contribute to this improvement.

Ara h 2-specific IgE is superior to whole peanut extract-based serology or skin prick test for diagnosis of peanut allergy in infancy.

BACKGROUND: Screening of high-risk infants for peanut allergy (PA) before introduction is now recommended in the United States, but the optimal approach is not clear. OBJECTIVE: We sought to compare the diagnostic test characteristics of peanut skin prick test (SPT), peanut-specific IgE (sIgE), and sIgE to peanut components in a screening population of infants before known peanut exposure. METHODS: Infants aged 4 to 11 months with (1) no history of peanut ingestion, testing, or reaction and (2) (a) moderate-severe eczema, (b) history of food allergy, and/or (c) first-degree relative with a history of PA received peanut SPT, peanut-sIgE and component-IgE testing, and, depending on SPT wheal size, oral food challenge or observed feeding. Receiver-operator characteristic areas under the curve (AUCs) were compared, and diagnostic sensitivity and specificity were calculated. RESULTS: A total of 321 subjects completed the enrollment visit (median age, 7.2 months; 58% males), and 37 (11%) were found to have PA. Overall, Ara h 2-sIgE at a cutoff point of 0.1 kUa/L discriminated between allergic and nonallergic best (AUC, 0.96; sensitivity, 94%; specificity, 98%), compared with peanut-sIgE at 0.1 kUa/L (AUC, 0.89; sensitivity, 100%; specificity, 78%) or 0.35 kUa/L (AUC, 0.91; sensitivity, 97%; specificity, 86%), or SPT at wheal size 3 mm (AUC, 0.90; sensitivity, 92%; specificity, 88%) or 8 mm (AUC, 0.87; sensitivity, 73%; specificity, 99%). Ara h 1-sIgE and Ara h 3-sIgE did not add to prediction of PA when included in a model with Ara h 2-sIgE, and Ara h 8-sIgE discriminated poorly (AUC, 0.51). CONCLUSIONS: Measurement of only Ara h 2-sIgE should be considered if screening of high-risk infants is performed before peanut introduction.

Serological evidence for historical and present-day exposure of North American bison to Mycoplasma bovis.

BACKGROUND: Mycoplasma bovis causes mastitis, otitis, pneumonia and arthritis in cattle and is a major contributor to bovine respiratory disease complex. Around the year 2000, it emerged as a significant threat to the health of North American bison. Whether healthy bison are carriers of M. bovis and when they were first exposed is not known. To investigate these questions we used a commercially available ELISA that detects antibodies to M. bovis to test 3295 sera collected from 1984 through 2019 from bison in the United States and Canada. RESULTS: We identified moderately to strongly seropositive bison from as long ago as the late 1980s. Average seroprevalence over the past 36 years is similar in the United States and Canada, but country-specific differences are evident when data are sorted by the era of collection. Seroprevalence in the United States during the pre-disease era (1999 and prior) was significantly higher than in Canada, but was significantly lower than in Canada during the years 2000-2019. Considering individual countries, seroprevalence in the United States since the year 2000 dropped significantly as compared to the years 1985-1999. In Canada the trend is reversed, with seroprevalence increasing significantly since the year 2000. ELISA scores for sera collected from free-ranging bison do not differ significantly from scores for sera from more intensively managed animals, regardless of the era in which they were collected. However, seroprevalence among intensively raised Canadian bison has nearly doubled since the year 2000 and average ELISA scores rose significantly. CONCLUSIONS: Our data provide the first evidence that North American bison were exposed to M. bovis many years prior to the emergence of M. bovis-related disease. Patterns of exposure inferred from these results differ in the United States and Canada, depending on the era under consideration. Our data further suggest that M. bovis may colonize healthy bison at a level sufficient to trigger antibody responses but without causing overt disease. These findings provide novel insights as to the history of M. bovis in bison and will be of value in formulating strategies to minimize the impact of mycoplasmosis on bison health and production.

Accuracy of component-resolved diagnostics in peanut allergy: Systematic literature review and meta-analysis.

BACKGROUND: Peanut allergy diagnosis relies on clinical reactivity to peanut supported by detection of specific IgE (sIgE) antibodies. Extract-based sIgE tests have low specificity, so component-resolved diagnostics may complement whole-extract testing. METHODS: We systematically collected peanut allergen component data in seven databases and studied the diagnostic accuracy of peanut storage proteins (Arah1, 2, 3) and cross-reactive peanut proteins (Arah8 PR-10 and Arah9 lipid transfer protein) through meta-analyses. The systematic literature review included studies employing peanut components and oral food challenge (OFC) as reference standard in patients suspected of peanut allergy. Data for component sIgE at pre-defined detection thresholds were extracted and combined in random-effects bivariate meta-analyses. Risk of bias was assessed as recommended by Cochrane, with two additional quality items of importance for this review. RESULTS: Nineteen eligible studies presented data suitable for meta-analysis. In cross-sectional pediatric studies, the pooled sensitivity of Arah2-sIgE at 0.35 kUA /L cutoff was 83.3% [95% CI 75.6, 88.9] and specificity in diagnosing objective peanut allergy was 83.6% [95% CI 77.4, 88.4]. Compared with 0.1 and 1.0 kUA /L, this threshold provided the best diagnostic accuracy. At 0.35 kUA /L, Arah1 and Arah3 had comparable specificity (86.0% and 88.0%, respectively) but significantly lower sensitivity compared with Arah2 (37.0% and 39.1%, respectively; P < .05). CONCLUSION: sIgE to Arah2 can enhance the certainty of diagnosis and reduce the number of OFC necessary to rule out clinical peanut allergy in unclear cases.

Sensitization profiles to hazelnut allergens across the United States.

BACKGROUND: Measurement of IgE antibody to hazelnut components can aid in the prediction of allergic responses to the food. OBJECTIVE: To investigate the association between patient demographics (age, location) and patterns of allergic sensitization to hazelnut components across the United States and to investigate the degree of correlation between hazelnut sensitization with sensitization to other tree nuts, peanuts, and their components. METHODS: Serum samples from 10,503 individuals with hazelnut extract specific IgE (sIgE) levels of 0.35 kUA/L or higher were analyzed for IgE antibodies to Cor a 1, 8, 9, and 14 by ImmunoCAP. A subset of these patients were analyzed for IgE antibodies to peanut, walnut, and cashew nut IgE along with associated components. RESULTS: Among hazelnut sensitized individuals, children (<3 years old) were predominantly sensitized to Cor a 9 and Cor a 14. Conversely, Cor a 1 sIgE sensitization was much higher in adults than children, especially in the Northeastern United States. Cor a 8 sensitization was relatively constant (near 10%) across all ages. Cosensitization of hazelnut with other tree nuts and peanuts was related to correlation of IgE concentrations of individual component families. CONCLUSION: We conclude that sensitization to individual hazelnut components is highly dependent on age and/or geographic location. Component correlations suggest that cosensitization to hazelnut and walnut may be caused by their pathogenesis-related protein 10 allergens, nonspecific lipid transfer proteins, or seed storage proteins, whereas hazelnut and peanut cosensitization is more often caused by cross-reactivity of pathogenesis-related protein 10 (Cor a 1 and Ara h 8) and nonspecific lipid transfer proteins (Cor a 8 and Ara h 9).

Discovery and Validation of Agonistic Angiotensin Receptor Autoantibodies as Biomarkers of Adverse Outcomes.

BACKGROUND: Agonistic angiotensin II type 1 receptor autoantibodies (AT1RaAbs) have not been associated with functional measures or risk for adverse health outcomes. AT1RaAbs could be used to stratify patient risk and to identify patients who can benefit from angiotensin receptor blocker treatment. METHODS: Demographic and physiological covariates were measured in a discovery set of community-dwelling adults from Baltimore (N=255) and AT1RaAb associations with physical function tests and outcomes assessed. A group from Chicago (N=60) was used for validation of associations and to explore the impact of angiotensin receptor blocker treatment. RESULTS: The Baltimore group had 28 subjects with falls, 32 frail subjects, and 5 deaths. Higher AT1RaAbs correlated significantly with interleukin-6 (Spearman r=0.33, P<0.0001), systolic blood pressure (Spearman r=0.28, P<0.0001), body mass index (Spearman r=0.28, P<0.0001), weaker grip strength (Spearman r=-0.34, P<0.01), and slower walking speed (Spearman r=-0.30, P<0.05). Individuals with high AT1RaAbs were 3.9 (95% confidence interval, 1.38-11.0) times more likely to be at high risk after adjusting for age (P<0.05). Every 1 µg/mL increase in AT1RaAbs increased the odds of falling 30% after adjusting for age, sex, body mass index, and blood pressure. The Chicago group had 46 subjects with falls and 60 deaths. Serum AT1RaAb levels were significantly correlated with grip strength (Spearman r=-0.57, P<0.005), walking speed (Spearman r=-0.47, P<0.005), and falls (Spearman r=0.30, P<0.05). Every 1 µg/mL increase in AT1RaAbs, decreased time to death by 9% after adjusting for age, sex, body mass index, and blood pressure. Chronic treatment with angiotensin receptor blockers was associated with better control of systolic blood pressure and attenuation of decline in both grip strength and time to death. CONCLUSIONS: In older individuals, higher AT1RaAb levels were associated with inflammation, hypertension, and adverse outcomes. Angiotensin receptor blocker treatment may blunt the harm associated with high levels of AT1RaAb.

Epitope-Resolved Detection of Peanut-Specific IgE Antibodies by Surface Plasmon Resonance Imaging.

Peanut allergy can be life-threatening and is mediated by allergen-specific immunoglobulin E (IgE) antibodies. Investigation of IgE antibody binding to allergenic epitopes can identify specific interactions underlying the allergic response. Here, we report a surface plasmon resonance imaging (SPRi) immunoassay for differentiating IgE antibodies by epitope-resolved detection. IgE antibodies were first captured by magnetic beads bearing IgE ϵ-chain-specific antibodies and then introduced into an SPRi array immobilized with epitopes from the major peanut allergen glycoprotein Arachis hypogaea h2 (Ara h2). Differential epitope responses were achieved by establishing a binding environment that minimized cross-reactivity while maximizing analytical sensitivity. IgE antibody binding to each Ara h2 epitope was distinguished and quantified from patient serum samples (10 µL each) in a 45 min assay. Excellent correlation of Ara h2-specific IgE values was found between ImmunoCAP assays and the new SPRi method.

Sensitization profiles to peanut allergens across the United States.

BACKGROUND: Measurement of IgE antibody to peanut components can aid in the prediction of allergic responses the food. OBJECTIVE: To investigate the association between patient demographics (age, location) and allergic sensitization to peanut components across the United States. METHODS: Serum samples from 12,155 individuals with peanut extract specific IgE levels of 0.35 kUA/L or higher were analyzed for IgE antibodies to Ara h 1, 2, 3, 8, and 9 by ImmunoCAP. RESULTS: Among this population of peanut sensitized individuals, 79.1% of children (<3 years old) were sensitized to one or more peanut storage proteins (Ara h 1, 2, and/or 3), in contrast to 64.2% of adolescents (12-15 years old) and 22.1% of adults (>20 years old). Although sensitization was more prevalent to Ara h 2 than to the other storage proteins, a sizable fraction of patients were sensitized to Ara h 1 and/or 3 but not to Ara h 2 (eg, 13% of children <3 years old). Moreover, 9.6% of children, 10.2% of adolescents, and 10.5% of adults were sensitized to Ara h 9, whereas 2.4% of children, 49.4% of adolescents, and 42.9% of adults produced IgE to Ara h 8 (pathogenesis-related protein 10). Sensitization to Ara h 8 alone was markedly higher in the Northeastern United States relative to other regions of the country. CONCLUSION: We conclude that sensitization to individual peanut components is highly dependent on age and geographic location. Given that a severe allergic reaction to peanut is unlikely in individuals with isolated sensitization to Ara h 8, a sizable fraction of patients, in particular adolescents and adults, may be at lower risk than anticipated based only on demonstration of sensitization to whole peanut extract.

Single B-cell deconvolution of peanut-specific antibody responses in allergic patients.

BACKGROUND: The frequencies, cellular phenotypes, epitope specificity, and clonal diversity of allergen-specific B cells in patients with food allergy are not fully understood but are of major pathogenic and therapeutic significance. OBJECTIVE: We sought to characterize peanut allergen-specific B-cell populations and the sequences and binding activities of their antibodies before and during immunotherapy. METHODS: B cells binding fluorescently labeled Ara h 1 or Ara h 2 were phenotyped and isolated by means of flow cytometric sorting from 18 patients at baseline and 13 patients during therapy. Fifty-seven mAbs derived from allergen-binding single B cells were evaluated by using ELISA, Western blotting, and peptide epitope mapping. Deep sequencing of the B-cell repertoires identified additional members of the allergen-specific B-cell clones. RESULTS: Median allergen-binding B-cell frequencies were 0.0097% (Ara h 1) or 0.029% (Ara h 2) of B cells in baseline blood from allergic patients and approximately 3-fold higher during immunotherapy. Five of 57 allergen-specific cells belonged to clones containing IgE-expressing members. Almost all allergen-specific antibodies were mutated, and binding to both conformational and linear allergen epitopes was detected. Increasing somatic mutation of IgG4 members of a clone was seen in immunotherapy, whereas IgE mutation levels in the clone did not increase. CONCLUSION: Most peanut allergen-binding B cells isolated by means of antigen-specific flow sorting express mutated and isotype-switched antibodies. Immunotherapy increases their frequency in the blood, and even narrowly defined allergen epitopes are recognized by numerous distinct B-cell clones in a patient. The results also suggest that oral immunotherapy can stimulate somatic mutation of allergen-specific IgG4.

A randomized, double-blind, placebo-controlled pilot study of sublingual versus oral immunotherapy for the treatment of peanut allergy.

BACKGROUND: Although promising results have emerged regarding oral immunotherapy (OIT) and sublingual immunotherapy (SLIT) for the treatment of peanut allergy (PA), direct comparisons of these approaches are limited. OBJECTIVE: This study was conducted to compare the safety, efficacy, and mechanistic correlates of peanut OIT and SLIT. METHODS: In this double-blind study children with PA were randomized to receive active SLIT/placebo OIT or active OIT/placebo SLIT. Doses were escalated to 3.7 mg/d (SLIT) or 2000 mg/d (OIT), and subjects were rechallenged after 6 and 12 months of maintenance. After unblinding, therapy was modified per protocol to offer an additional 6 months of therapy. Subjects who passed challenges at 12 or 18 months were taken off treatment for 4 weeks and rechallenged. RESULTS: Twenty-one subjects aged 7 to 13 years were randomized. Five discontinued therapy during the blinded phase. Of the remaining 16, all had a greater than 10-fold increase in challenge threshold after 12 months. The increased threshold was significantly greater in the active OIT group (141- vs 22-fold, P = .01). Significant within-group changes in skin test results and peanut-specific IgE and IgG4 levels were found, with overall greater effects with OIT. Adverse reactions were generally mild but more common with OIT (P < .001), including moderate reactions and doses requiring medication. Four subjects had sustained unresponsiveness at study completion. CONCLUSION: OIT appeared far more effective than SLIT for the treatment of PA but was also associated with significantly more adverse reactions and early study withdrawal. Sustained unresponsiveness after 4 weeks of avoidance was seen in only a small minority of subjects.

Estrogen and progesterone decrease let-7f microRNA expression and increase IL-23/IL-23 receptor signaling and IL-17A production in patients with severe asthma.

BACKGROUND: Women have an increased prevalence of severe asthma compared with men. IL-17A is associated with severe asthma and requires IL-23 receptor (IL-23R) signaling, which is negatively regulated by let-7f microRNA. OBJECTIVE: We sought to Determine the mechanism by which 17ß-estradiol (E2) and progesterone (P4) increase IL-17A production. METHODS: IL-17A production was determined by using flow cytometry in TH17 cells from women (n = 14) and men (n = 15) with severe asthma. Cytokine levels were measured by using ELISA, and IL-23R and let-7f expression was measured by using quantitative PCR in TH17-differentiated cells from healthy women (n = 13) and men (n = 14). In sham-operated or ovariectomized female mice, 17ß-E2, P4, 17ß-E2+P4, or vehicle pellets were administered for 3 weeks before ex vivo TH17 cell differentiation. Airway neutrophil infiltration and CXCL1 (KC) expression were also determined in ovalbumin (OVA)-challenged wild-type female recipient mice with an adoptive transfer of OVA-specific TH17 cells from female and male mice. RESULTS: In patients with severe asthma and healthy control subjects, IL-17A production was increased in TH17 cells from women compared with men. IL-23R expression was increased and let-7f expression was decreased in TH17-differentiated cells from women compared with men. In ovariectomized mice IL-17A and IL-23R expression was increased and Let-7f expression was decreased in TH17 cells from mice administered 17ß-E2+P4 compared with those administered vehicle. Furthermore, transfer of female OVA-specific TH17 cells increased acute neutrophil infiltration in the lungs of OVA-challenged recipient mice compared with transfer of male OVA-specific TH17 cells. CONCLUSIONS: 17ß-E2+P4 increased IL-17A production from TH17 cells, providing a potential mechanism for the increased prevalence of severe asthma in women compared with men.

Suppression of the immunologic response to peanut during immunotherapy is often transient.

BACKGROUND: Studies suggest that oral immunotherapy (OIT) and sublingual immunotherapy (SLIT) for food allergy hold promise; however, the immunologic mechanisms underlying these therapies are not well understood. OBJECTIVE: We sought to generate insights into the mechanisms and duration of suppression of immune responses to peanut during immunotherapy. METHODS: Blood was obtained from subjects at baseline and at multiple time points during a placebo-controlled trial of peanut OIT and SLIT. Immunologic outcomes included measurement of spontaneous and stimulated basophil activity by using automated fluorometry (histamine) and flow cytometry (activation markers and IL-4), measurement of allergen-induced cytokine expression in dendritic cell (DC)-T-cell cocultures by using multiplexing technology, and measurement of MHC II and costimulatory molecule expression on DCs by using flow cytometry. RESULTS: Spontaneous and allergen-induced basophil reactivity (histamine release, CD63 expression, and IL-4 production) were suppressed during dose escalation and after 6 months of maintenance dosing. Peanut- and dust mite-induced expression of TH2 cytokines was reduced in DC-T-cell cocultures during immunotherapy. This was associated with decreased levels of CD40, HLA-DR, and CD86 expression on DCs and increased expression of CD80. These effects were most striking in myeloid DC-T-cell cocultures from subjects receiving OIT. Many markers of immunologic suppression reversed after withdrawal from immunotherapy and in some cases during ongoing maintenance therapy. CONCLUSION: OIT and SLIT for peanut allergy induce rapid suppression of basophil effector functions, DC activation, and TH2 cytokine responses during the initial phases of immunotherapy in an antigen-nonspecific manner. Although there was some interindividual variation, in many patients suppression appeared to be temporary.

Transfusion and component characteristics are not associated with allergic transfusion reactions to apheresis platelets.

BACKGROUND: Transfusion-related characteristics have been hypothesized to cause allergic transfusion reactions (ATRs) but they have not been thoroughly studied. The primary objective of this study is to evaluate the associations of infusion rate, infusion volume, ABO mismatching, component age, and pretransfusion medication with the incidence and severity of ATRs. A secondary objective is to compare the risk of these attributes relative to the previously reported risk factor for aeroallergen sensitization in transfusion recipients, as measured by an aeroallergen-specific immunoglobulin (Ig)E antibody screen. STUDY DESIGN AND METHODS: Clinical and transfusion-related data were collected on subjects with reported ATRs and uneventful (control) apheresis platelet (PLT) transfusions over a combined 21-month period at two academic medical centers. Control transfusions were selected as the next uneventful transfusion after an ATR was reported. Logistic regression, Mann-Whitney, and t tests were used to assess associations with ATRs. Previously reported aeroallergen-specific IgE screening data were incorporated into a multivariable logistic regression. RESULTS: A total of 143 ATRs and 61 control transfusions were evaluated among 168 subjects, ages 2 to 86 years. Infusion rate, infusion volume, ABO mismatching, component age, and pretransfusion medication showed no significant association with ATRs (p > 0.05). Neither infusion rate nor infusion volume increased the risk of anaphylaxis versus mucocutaneous-only ATRs. Aeroallergen sensitization has previously been associated with ATRs. After transfusion-related covariates were controlled for, aeroallergen sensitization remained significantly associated with ATRs (odds ratio, 2.68; 95% confidence interval, 1.26-5.69). CONCLUSIONS: Transfusion- and component-specific attributes are not associated with ATRs. An allergic predisposition in transfusion recipients is associated most strongly with ATR risk.