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.

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.

Evolution Toward Chip-Based Arrays in the Laboratory Diagnosis of Human Allergic Disease

Multiplex-based specific IgE antibody assays have emerged into the clinical immunology laboratory through the combined use of pure, recombinant allergenic molecules and new methods to simultaneously and accurately analyze specific IgE antibodies to hundreds of allergens. This review traces the historical development and examines outstanding questions related to the strengths and limitations of these new molecular allergen multipex technologies for the assessment of human allergic sensitization. Multiplexed technologies are poised to provide the most cost-effective and comprehensive evaluation of patients with suspected allergy as compared with the commonly used singleplex autoanalyzers. How analytically sensitive and quantitative are the multiplex technologies, down to 0.1 kUA/L? Because each allergen is viewed as a unique assay, how will analytical and clinical performance be documented at the manufacturing and clinical laboratory levels to guarantee reproducibility and obtain government regulatory clearance? Will interference by naturally occurring allergen-specific IgG compromise analytical performance? Successful resolution of these and other questions covered in this review will position multiplex technologies to become the single most-effective means of screening patients for allergic sensitization, assessing IgE antibody cross-reactivity, and planning therapy directed at the patient with allergy.

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.

LEVEL OF EVIDENCE: 4

A Cell-Free Protein Synthesis Platform to Produce a Clinically Relevant Allergen Panel

Allergens are used in the clinical diagnosis (e.g., skin tests) and treatment (e.g., immunotherapy) of allergic diseases. With growing interest in molecular allergy diagnostics and precision therapies, new tools are needed for producing allergen-based reagents. As a step to address this need, we demonstrate a cell-free protein synthesis approach for allergen production of a clinically relevant allergen panel composed of common allergens spanning a wide range of phylogenetic kingdoms. We show that allergens produced with this approach can be recognized by allergen-specific immunoglobulin E (IgE), either monoclonals or in patient sera. We also show that a cell-free expressed allergen can activate human cells such as peripheral blood basophils and CD34+ progenitor-derived mast cells in an IgE-dependent manner. We anticipate that this cell-free platform for allergen production will enable diagnostic and therapeutic technologies, providing useful tools and treatments for both the allergist and allergic patient.

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.

Bison movements change with weather: Implications for their continued conservation in the Anthropocene

Animal movement patterns are affected by complex interactions between biotic and abiotic landscape conditions, and these patterns are being altered by weather variability associated with a changing climate. Some animals, like the American plains bison (Bison bison L.; hereafter, plains bison), are considered keystone species, thus their response to weather variability may alter ecosystem structure and biodiversity patterns. Many movement studies of plains bison and other ungulates have focused on point-pattern analyses (e.g., resource-selection) that have provided information about where these animals move, but information about when or why these animals move is limited. For example, information surrounding the influence of weather on plains bison movement in response to weather is limited but has important implications for their conservation in a changing climate. To explore how movement distance is affected by weather patterns and drought, we utilized 12-min GPS data from two of the largest plains bison herds in North America to model their response to weather and drought parameters using generalized additive mixed models. Distance moved was best predicted by air temperature, wind speed, and rainfall. However, air temperature best explained the variation in distance moved compared to any other single parameter we measured, predicting a 48% decrease in movement rates above 28°C. Moreover, severe drought (as indicated by 25-cm depth soil moisture) better predicted movement distance than moderate drought. The strong influence of weather and drought on plains bison movements observed in our study suggest that shifting climate and weather will likely affect plains bison movement patterns, further complicating conservation efforts for this wide-ranging keystone species. Moreover, changes in plains bison movement patterns may have cascading effects for grassland ecosystem structure, function, and biodiversity. Plains bison and grassland conservation efforts need to be proactive and adaptive when considering the implications of a changing climate on bison movement patterns.

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.

Profiling serum antibodies with a pan allergen phage library identifies key wheat allergy epitopes

Allergic reactions occur when IgE molecules become crosslinked by antigens such as food proteins. Here we create the 'AllerScan' programmable phage display system to characterize the binding specificities of anti-allergen IgG and IgE antibodies in serum against thousands of allergenic proteins from hundreds of organisms at peptide resolution. Using AllerScan, we identify robust anti-wheat IgE reactivities in wheat allergic individuals but not in wheat-sensitized individuals. Meanwhile, a key wheat epitope in alpha purothionin elicits dominant IgE responses among allergic patients, and frequent IgG responses among sensitized and non-allergic patients. A double-blind, placebo-controlled trial shows that alpha purothionin reactivity, among others, is strongly modulated by oral immunotherapy in tolerized individuals. AllerScan may thus serve as a high-throughput platform for unbiased analysis of anti-allergen antibody specificities.

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.

Origins and clonal convergence of gastrointestinal IgE+ B cells in human peanut allergy

B cells in human food allergy have been studied predominantly in the blood. Little is known about IgE⁺ B cells or plasma cells in tissues exposed to dietary antigens. We characterized IgE⁺ clones in blood, stomach, duodenum, and esophagus of 19 peanut-allergic patients, using high-throughput DNA sequencing. IgE⁺ cells in allergic patients are enriched in stomach and duodenum, and have a plasma cell phenotype. Clonally related IgE⁺ and non-IgE-expressing cell frequencies in tissues suggest local isotype switching, including transitions between IgA and IgE isotypes. Highly similar antibody sequences specific for peanut allergen Ara h 2 are shared between patients, indicating that common immunoglobulin genetic rearrangements may contribute to pathogenesis. These data define the gastrointestinal tract as a reservoir of IgE⁺ B lineage cells in food allergy.

Mycosis Fungoides and Its Relationship to Atopy, Serum Total IgE, and Eosinophil Counts

INTRODUCTION

A recent serologic study and reports of increased serum total IgE (IgE-t) and eosinophil counts have suggested that the prevalence of atopy is more common in patients with mycosis fungoides (MF) than previously recognized.

PATIENTS AND METHODS

Patients with clinicopathologic features that were diagnostic and/or consistent with MF and/or the presence or absence of an atopic disorder (eg, allergic rhinitis, asthma, eczematous dermatitis), which was determined by patient history, eosinophil counts, and serum IgE-t obtained at evaluation, were selected from a patient registry. The MF population was divided into those with atypical and typical clinical presentations. We performed matching of controls using age, sex, and race from the 2005 to 2006 National Health Education Survey.

RESULTS

A history of allergic rhinitis was recorded for 186 of 728 patients (25.5%) with typical MF and 71 of 229 patients (31%) with atypical MF. However, the prevalence of asthma and eczema was low. The IgE-t and eosinophil counts were higher for patients with typical MF than for controls and for patients with atopic diathesis than for patients without atopy. The IgE-t and eosinophil counts were higher for the patients with advanced-stage MF compared with those for the patients with less-advanced disease for both atopic and nonatopic cohorts. In the Cox model with age and clinical stage as covariates, a history of atopy, increased IgE-t, and blood eosinophilia (> 500 cells/mm3) did not correlate with overall survival.

CONCLUSION

The findings from the present study did not reveal a significant association of atopy in patients with MF. However, atopy is a factor in the increased IgE-t and eosinophil counts observed in MF. Another factor is related to the disease stage, including possibly the influence of cytokines secreted by T-helper type 2-polarized neoplastic cells.

Advances in IgE Testing for Diagnosis of Allergic Disease

Since its discovery in 1967, IgE antibody detection in skin and blood has identified a state of allergic sensitization and served as a necessary but not sufficient risk factor that requires objective symptoms to make the definitive diagnosis of human allergic disease. More recently, quantitative IgE antibody levels in serum against allergenic extracts, molecules, and epitopes have pushed its application into more accurately identifying the specificity of the allergic response for targeting immunotherapy, predicting allergic symptom severity after allergen exposure, and attempting to distinguish tolerance from food allergy. This review examines new in vivo and in vitro developments in the design, performance, interference, and application of the methods used to identify allergic sensitization. The increasing accepted applications of molecular allergen and allergen epitope-based IgE antibody measurements, especially as applied to food allergy diagnosis and management, are highlighted as state-of-the-art advances. Despite these major advances in allergic sensitization documentation, their ultimate value requires integration by the clinician with the patient's history and pretest probability of disease.

Cross-reactive carbohydrate determinant interference in cellulose-based IgE allergy tests utilizing recombinant allergen components

Background

Cross-reactive carbohydrate determinant (CCD) structures found in plant and insect glycoproteins are commonly recognized by IgE antibodies as epitopes that can lead to extensive cross-reactivity and obscure in vitro diagnostic (IVD) serology results. With the introduction of component resolved diagnosis (CRD), recombinant non-glycosylated components have been utilized to mitigate the risk of CCD-specific IgE (sIgE) detection. However, a recent study has shown that CCD-sIgE may bind directly to the cellulose solid phase matrix used in certain in vitro diagnostic assays, eliminating the advantage of CRD over traditional extract-based testing. The aim of this study is to further investigate the prevalence of CCD-sIgE interference on a commonly-used in vitro sIgE automated platform which employs a cellulose-based matrix to immobilize CCD-free recombinant components.

Methods

Sera from patients sensitized to peanut, silver birch, and/or timothy grass were analyzed for CCD-sIgE reactivity on ImmunoCAP/Phadia and NOVEOS autoanalyzers against the MUXF3 carbohydrate component. Positive CCD-sIgE sera were further analyzed against non-glycosylated recombinant components bound to the ImmunoCAP solid phase in the absence and presence of a soluble CCD inhibitor. For comparison, sera were then analyzed on NOVEOS, a non-cellulose based automated sIgE assay.

Results

Sera from 35% of the sensitized population tested in this study were positive (≥0.35 kU/L) for CCD-sIgE. Of those positives, 17% resulted in CCD-sIgE-positive (false positive) results on ImmunoCAP using non-glycosylated allergosorbents that were negative on NOVEOS. Sera producing false-positive results on ImmunoCAP had varying levels of CCD-sIgE from 0.67 kU/L to 36.52 kU/L. The incidence of CCD interference was predominantly delimited to low-positive IgE results (0.35 kU_A/L– 3.00 kU_A/L).

Conclusion

Falsely elevated diagnostic allergen-sIgE results can commonly occur due to the presence of CCD-sIgE using assays that employ a carbohydrate matrix-based allergosorbent. Even the use of non-glycosylated recombinant allergenic components coupled to cellulose matrices do not reduce their risk of detection. The risk of CCD interference that compromises quantitative IgE results can be mitigated by the addition of a soluble CCD inhibitor to positive CCD-sIgE containing sera or by alternatively using a non-cellulose based sIgE assay, such as the NOVEOS assay.

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 kU_A /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 kU_A /L, this threshold provided the best diagnostic accuracy. At 0.35 kU_A /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.

Evidence linking atopy and staphylococcal superantigens to the pathogenesis of lymphomatoid papulosis, a recurrent CD30+ cutaneous lymphoproliferative disorder

Background

Primary cutaneous CD30+ lymphoproliferative disorders (CD30CLPD) are the second most common type of cutaneous T cell lymphoma (CTCL) and include lymphomatoid papulosis (LyP) and primary cutaneous anaplastic large cell lymphoma (pcALCL). Case reports and small patient series suggest an association of CD30CLPD with atopic disorders. However, the prevalence of atopy in patients with CD30CLPD in retrospective studies depends on patients’ recall which is not always reliable. More objective criteria of atopy include evidence of skin reactivity to allergens (positive prick test) and evidence of allergen-specific IgE in serum. This study was undertaken to test the hypothesis that atopy is prevalent in patients with CD30CLPD using serologic criteria of allergen-specific IgE antibodies to aeroallergens and Staphylococcal aureus enterotoxin superantigens (SSAgs).

Methods

We tested serum samples of CD30CLPD for common IgE-specific airborne allergens with the Phadiatop test, which if positive, is regarded as serologic evidence of atopy in adults. Sera were also tested for IgE antibodies reactive to three Staphylococcal enterotoxins with superantigenic properties (SSAg-IgE). Control sera were obtained from adult subjects evaluated for rhino-sinusitis and a negative Phadiatop test. Patients’ history of an atopic disorder was obtained by retrospective chart review.

Findings

Nearly 50% of patients with the most common LyP types (A and C) had a positive Phadiatop test for allergic sensitization to common airborne allergens, and total serum IgE (IgE-t) was increased compared to non-atopic controls. At the IgE antibody concentration generally used to define serologic atopy (≥ 0.35 kU_A/L), 8/31 (26%) samples of CD30CLPD and 7/28 (25%) samples of LyP were reactive to at least one SSAg-IgE compared to 3/52 (6%) control specimens (P = 0.016 and P = 0.028, respectively). TSST1-IgE was detected in 7 (23%) specimens of CD30CLPD, often together with SEB-IgE; SEA-IgE ≥ 0.35 kU_A/L was not detected. For control specimens, TSST1-IgE exceeded the 0.35 kU_A/L threshold in 3 (6%) specimens.

Conclusions

Patients with LyP types A and C have serologic evidence of atopy against common airborne antigens and SSAgs when compared to control adult subjects who had rhino-sinusitis and a negative Phadiatop test for aero-IgEs. Serologic evidence of atopy exceeded that determined by LyP patients’ personal history. The findings support our hypothesis that an atopic diathesis may contribute to the pathogenesis of the most common types of LyP (A and C).

Prevalence of atopy and staphylococcal superantigen-specific immunoglobulin E (IgE) antibodies and total serum IgE in primary cutaneous T- and B-cell lymphoma

The prevalence of atopy was investigated in 20 patients with Sézary syndrome (SS), 20 patients with plaque phase mycosis fungoides (MF), 9 patients with primary cutaneous marginal zone lymphoma (pcMZL) and 8 patients with primary cutaneous follicle center lymphoma (pcFCL) with the Phadiatop multi-allergen test. The relationship among serologic atopy, IgE reactivity against Staphyloccocal enterotoxin superantigens, and serum total IgE (IgE-t) levels and their prognostic implications in SS was investigated. Phadiatop test was positive in 45%, 15%, 33% and 0% of samples of SS, MF, pcMZL and pcFCL, respectively. IgE-t levels were also increased in SS, pcMZL and marginally MF. No correlation was found with patients' history of atopic disorders. Staphylococcal superantigen-specific IgE ≥ 0.35 kUa/L, most often against toxic shock syndrome toxin-1, was detected in 40% of Sézary samples followed by MF (20%). In the absence of serologic atopy (negative Phadiatop test), IgE-t levels for patients with SS and MF were not significantly higher than controls whereas the levels for pcMZL remained high. Furthermore, even with a negative Phadiatop test, IgE-t values were higher in sera of patients with SSAg-IgE ≥ 0.35 kUa/L vis-à-vis < 0.35 kUa/L across all diagnostic categories including controls albeit the difference was statistically significant only for SS. The presence of specific IgE antibodies ≥ 0.35 kUa/L, IgE-t > 122 kU/L or eosinophils > 500/µL had no impact on survival of patients with SS. These results indicate that a pathogenic link may exist between an atopic diathesis and development of SS and possibly pcMZL.

Comparison of multilocus sequence types found among North American isolates of Mycoplasma bovis from cattle, bison, and deer, 2007-2017

A prior multilocus sequence typing (MLST) study reported that Mycoplasma bovis isolates from North American bison possess sequence types (STs) different from those found among cattle. The 42 bison isolates evaluated were obtained in 2007 or later, whereas only 19 of 94 (~20%) of the available cattle isolates, with only 1 from North America, were from that same time. We compared STs of additional, contemporary, North American cattle isolates with those from bison, as well as isolates from 2 North American deer, all originating during the same timeframe, to more definitively assess potential strain-related host specificity and expand our understanding of the genetic diversity of M. bovis. From 307 isolates obtained between 2007 and 2017 (209 from cattle, 96 from bison, 2 from deer), we identified 49 STs, with 39 found exclusively in cattle and 5 exclusively in bison. Four STs were shared between bison and cattle isolates; one ST was found in cattle and in a deer. There was no clear association between ST and the health status of the animal of origin. An MLST-based phylogeny including 41 novel STs identified in our study reveals that STs found in bison fall within several divergent lineages that include STs found exclusively in cattle.

The soluble worm antigens-specific antibodies used as biomarkers of Schistosoma japonicum in a low prevalence and intensity endemic area of Hubei, China

The precise diagnosis of Schistosoma japonicum (S. japonicum) infection plays a critical role in achieving the ultimate goal of eliminating schistosomiasis in endemic regions. We evaluated the S. japonicum soluble worm antigen protein (SWAP) specific-IgG, IgG4 and IgE levels, and evaluated the association between S. japonicum infection and these antibodies in a sample of 837 residents from a S. japonicum-endemic area in Hubei province, China. The anticipants were divided into the Training Set (TS) and Validation Set (VS) based on the chronological order. Enzyme-linked immunosorbent assays were performed to detect the SWAP-specific antibodies. Three algorithms for identifying S. japonicum infection were generated in the TS and subsequently validated in the VS. The findings were further replicated in an independent cohort from an endemic area for Schistosoma mansoni (S. mansoni) in Brazil. Our results indicated for the first time that S. japonicum-infected individuals had higher levels of SWAP-specific IgG, IgG4 and IgE, and lower value of the IgE/IgG4 ratio than uninfected individuals in both the two sets (p <  0.01). Both the infected and uninfected individuals had a high prevalence of seropositivity for IgG. We further showed that the predictive model EGR (IgE/IgG4 ratio) score performed best in Chinese population (area under the receiver operating characteristic (AUROC) 0.905, sensitivity 82.7%, specificity 84.0% in the TS; AUROC 0.933, sensitivity 87.7%, specificity 89.1% in the VS). Nevertheless, the predictive model IgG4 score performed best in Brazilian cohort (AUROC 0.788, sensitivity 73.2%, specificity 73.3%). In summary, SWAP-specific IgG could be used as a biomarker for identifying individuals who have been previously exposed to S. japonicum, and furthermore the SWAP-specific IgE/IgG4 could be used as an immune biomarker for S. japonicum infection in particular in the endemic areas with low prevalence and intensity.

Perspectives on grassland conservation efforts: should we rewild to the past or conserve for the future?

Grasslands are among the most imperilled biomes of the world. Identifying the most appropriate framework for restoring grasslands is dependent on the objectives of restoration, which is inherently determined by human priorities. Debates over the appropriate conservation model for grasslands have often focused on which species of herbivores should be the focus of restoration efforts. Here we discuss three perspectives of herbivore-based conservation in North American grasslands. First, the Pleistocene rewilding perspective is based upon the idea that early humans contributed to the demise of megafauna that were important to the evolution and development of many of North America's grasslands; therefore, their aim of restoration is rewilding of landscapes to pre-human times. Second, the bison rewilding perspective considers American bison a keystone herbivore that is culturally and ecologically important to North American grasslands. A third perspective focuses on restoring the pattern and processes of herbivory on grasslands and is less concerned about which herbivore is introduced to the landscape. We evaluate each of these three conservation perspectives in terms of a framework that includes a human domain, an herbivore domain and a biophysical domain. While all conservation perspectives partly address the three domains, they all fall short in key areas. Specifically, they fail to recognize that past, current and future humans are intimately linked to grassland patterns and processes and will continue to play a role in structuring grasslands. Furthermore, these perspectives seem to only superficially consider the role of fragmentation and climate change in influencing grassland patterns and processes. As such, we argue that future grassland conservation efforts must depend on the development of a model that better integrates societal, economic and policy objectives and recognizes climate change, fragmentation and humans as an integral part of these ecosystems.This article is part of the theme issue 'Trophic rewilding: consequences for ecosystems under global change'.

Human IgE mAbs define variability in commercial Aspergillus extract allergen composition

Sensitization to Aspergillus species is associated with allergic respiratory diseases. Allergen immunotherapy with nonstandardized Aspergillus extracts is commonly used as therapy in these patients. Unfortunately, no method exists to measure the relevant allergen protein content in diagnostic and therapeutic extracts. Thus, there is a critical need for Aspergillus extract standardization. We hypothesized that development of Aspergillus-specific human IgE mAbs would allow for the characterization of the relevant human allergenic epitopes among currently available commercial Aspergillus fumigatus extracts. Patients with allergic bronchopulmonary mycosis were recruited from Vanderbilt University Medical Center. IgE antibody-secreting B cells were grown and immortalized using human hybridoma techniques first described here. Twenty-six human Aspergillus-reactive IgE mAbs were used as capture and detection reagents to characterize the Aspergillus allergen content of commercial extracts. We found extreme variability in the specificity and quantity of their protein targets. Just 4 mAbs reacted with all available extracts, and only 1 of 4 extracts contained the major allergen Asp f 1. This degree of variability will almost certainly affect the efficacy of these reagents when used in diagnosis and treatment. Human IgE mAbs represent an innovative tool for the evaluation of relevant human allergenic epitopes, which may assist in future development and long-term standardization of mold extracts.

Testosterone Attenuates Group 2 Innate Lymphoid Cell-Mediated Airway Inflammation

Sex hormones regulate many autoimmune and inflammatory diseases, including asthma. As adults, asthma prevalence is 2-fold greater in women compared to men. The number of group 2 innate lymphoid cells (ILC2) is increased in patients with asthma, and we investigate how testosterone attenuates ILC2 function. In patients with moderate to severe asthma, we determine that women have an increased number of circulating ILC2 compared to men. ILC2 from adult female mice have increased IL-2-mediated ILC2 proliferation versus ILC2 from adult male mice, as well as pre-pubescent females and males. Further, 5α-dihydrotestosterone, a hormone downstream of testosterone, decreases lung ILC2 numbers and IL-5 and IL-13 expression from ILC2. In vivo, testosterone attenuated Alternaria-extract-induced IL-5+ and IL-13+ ILC2 numbers and lung eosinophils by intrinsically decreasing lung ILC2 numbers, as well as by decreasing expression of IL-33 and thymic stromal lymphopoietin (TSLP), ILC2-stimulating cytokines. Collectively, these findings provide a foundational understanding of sexual dimorphism in ILC2 function.

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.

International Consensus Statement on Allergy and Rhinology: Allergic Rhinitis

BACKGROUND

Critical examination of the quality and validity of available allergic rhinitis (AR) literature is necessary to improve understanding and to appropriately translate this knowledge to clinical care of the AR patient. To evaluate the existing AR literature, international multidisciplinary experts with an interest in AR have produced the International Consensus statement on Allergy and Rhinology: Allergic Rhinitis (ICAR:AR).

METHODS

Using previously described methodology, specific topics were developed relating to AR. Each topic was assigned a literature review, evidence-based review (EBR), or evidence-based review with recommendations (EBRR) format as dictated by available evidence and purpose within the ICAR:AR document. Following iterative reviews of each topic, the ICAR:AR document was synthesized and reviewed by all authors for consensus.

RESULTS

The ICAR:AR document addresses over 100 individual topics related to AR, including diagnosis, pathophysiology, epidemiology, disease burden, risk factors for the development of AR, allergy testing modalities, treatment, and other conditions/comorbidities associated with AR.

CONCLUSION

This critical review of the AR literature has identified several strengths; providers can be confident that treatment decisions are supported by rigorous studies. However, there are also substantial gaps in the AR literature. These knowledge gaps should be viewed as opportunities for improvement, as often the things that we teach and the medicine that we practice are not based on the best quality evidence. This document aims to highlight the strengths and weaknesses of the AR literature to identify areas for future AR research and improved understanding.

N-glycan in cockroach allergen regulates human basophil function

INTRODUCTION

Cockroach allergen exposure elicits cockroach sensitization and poses an increased risk for asthma. However, the major components in cockroach allergen and the mechanisms underlying the induction of cockroach allergen-induced allergy and asthma remain largely elusive. We sought to examine the role of cockroach-associated glycan in regulating human basophil function.

METHODS

N-linked glycans from naturally purified cockroach allergen Bla g 2 were characterized by MALDI-TOF mass spectrometry. Binding of cockroach allergen to serum IgE from cockroach allergic subjects was determined by solid-phase binding immunoassays. Role of cockroach associated glycan in histamine release and IL-4 production from human basophils was examined. Expression of C-type lectin receptors (CLRs) and their role in mediating glycan-uptake in the basophils was also investigated.

RESULTS

MALDI-TOF mass spectrometric analysis of N-glycan from Bla g 2 showed complex hybrid-types of glycans that terminated with mannose, galactose, and/or N-acetyl glucosamine (GlcNAc). Deglycosylated Bla g 2 showed reduced binding to IgE and was less capable of inducing histamine release from human basophils. In contrast, N-glycan derived from Bla g 2 significantly inhibited histamine release and IL-4 production from basophils passively sensitized with serum from cockroach allergic subjects. An analysis of CLRs revealed the expression of DC-SIGN and DCIR, but not MRC1 and dectin-1, in human basophils. Neutralizing antibody to DCIR, but not DC-SIGN, significantly inhibited Bla g 2 uptake by human basophils. A dose-dependent bindings of cockroach allergen to DCIR was also observed.

CONCLUSIONS

These observations indicate a previously unrecognized role for cockroach allergen-associated glycans in allergen-induced immune reactions, and DCIR may play a role in mediating the regulation of glycan on basophil function.

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.

Microarray Technology Applied to Human Allergic Disease

IgE antibodies serve as the gatekeeper for the release of mediators from sensitized (IgE positive) mast cells and basophils following a relevant allergen exposure which can lead to an immediate-type hypersensitivity (allergic) reaction. Purified recombinant and native allergens were combined in the 1990s with state of the art chip technology to establish the first microarray-based IgE antibody assay. Triplicate spots to over 100 allergenic molecules are immobilized on an amine-activated glass slide to form a single panel multi-allergosorbent assay. Human antibodies, typically of the IgE and IgG isotypes, specific for one or many allergens bind to their respective allergen(s) on the chip. Following removal of unbound serum proteins, bound IgE antibody is detected with a fluorophore-labeled anti-human IgE reagent. The fluorescent profile from the completed slide provides a sensitization profile of an allergic patient which can identify IgE antibodies that bind to structurally similar (cross-reactive) allergen families versus molecules that are unique to a single allergen specificity. Despite its ability to rapidly analyze many IgE antibody specificities in a single simple assay format, the chip-based microarray remains less analytically sensitive and quantitative than its singleplex assay counterpart (ImmunoCAP, Immulite). Microgram per mL quantities of allergen-specific IgG antibody can also complete with nanogram per mL quantities of specific IgE for limited allergen binding sites on the chip. Microarray assays, while not used in clinical immunology laboratories for routine patient IgE antibody testing, will remain an excellent research tool for defining sensitization profiles of populations in epidemiological studies.

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.

Allergy Work-Up Including Component-Resolved Diagnosis: How to Make Allergen-Specific Immunotherapy More Specific

Symptoms are recorded by obtaining a clinical history. Allergen sensitization is demonstrated by skin prick test or allergen-specific IgE serology. IgE sensitizations to allergen sources can be identified knowing the relationship between major aeroallergens and homologous allergen families. Some develop allergic sensitization to pan-allergens. Allergen extracts do not allow definitive separation of the sources. IgE antibody analysis of the major allergenic molecules facilitates differentiation of sensitizing allergen sources. IgE sensitizations to inhalant allergens are only relevant in the case of corresponding symptoms. In questionable cases, conjunctival or nasal provocation tests help induce confirmatory symptoms and identify relevant allergens for immunotherapy.

Clinical History-Driven Diagnosis of Allergic Diseases: Utilizing in vitro IgE Testing

This case illustrates the importance of a thorough clinical history in providing an interpretation of previously collected IgE antibody serology as part of a workup for allergic disease. Although a yellow-jacket sting was the allergenic insult that led the patient to the emergency department, nonindicated IgE antibody serology tests were ordered that subsequently required interpretation. This report systematically evaluates the relative significance of previously measured IgE antibody serology responses to 4 major allergen groups (inhalants [aeroallergens], foods, venoms, and drugs) within the context of the patient's history. An algorithm that takes into account the pretest likelihood of disease and diagnostic sensitivity and specificity of the available IgE antibody tests is proposed for decisions about further IgE testing. This case study concludes that selection of testing methods, extract and molecular allergen specificities, and the final interpretation of the results from tests of sensitization such as serological (in vitro) IgE antibody assays requires knowledge of test parameters and clinical judgments based largely on a carefully collected clinical history and physical examination.

EAACI Molecular Allergology User's Guide

The availability of allergen molecules ('components') from several protein families has advanced our understanding of immunoglobulin E (IgE)-mediated responses and enabled 'component-resolved diagnosis' (CRD). The European Academy of Allergy and Clinical Immunology (EAACI) Molecular Allergology User's Guide (MAUG) provides comprehensive information on important allergens and describes the diagnostic options using CRD. Part A of the EAACI MAUG introduces allergen molecules, families, composition of extracts, databases, and diagnostic IgE, skin, and basophil tests. Singleplex and multiplex IgE assays with components improve both sensitivity for low-abundance allergens and analytical specificity; IgE to individual allergens can yield information on clinical risks and distinguish cross-reactivity from true primary sensitization. Part B discusses the clinical and molecular aspects of IgE-mediated allergies to foods (including nuts, seeds, legumes, fruits, vegetables, cereal grains, milk, egg, meat, fish, and shellfish), inhalants (pollen, mold spores, mites, and animal dander), and Hymenoptera venom. Diagnostic algorithms and short case histories provide useful information for the clinical workup of allergic individuals targeted for CRD. Part C covers protein families containing ubiquitous, highly cross-reactive panallergens from plant (lipid transfer proteins, polcalcins, PR-10, profilins) and animal sources (lipocalins, parvalbumins, serum albumins, tropomyosins) and explains their diagnostic and clinical utility. Part D lists 100 important allergen molecules. In conclusion, IgE-mediated reactions and allergic diseases, including allergic rhinoconjunctivitis, asthma, food reactions, and insect sting reactions, are discussed from a novel molecular perspective. The EAACI MAUG documents the rapid progression of molecular allergology from basic research to its integration into clinical practice, a quantum leap in the management of allergic patients.