Web-based survey investigating cardiovascular complications in hypermobile Ehlers-Danlos syndrome after COVID-19 infection and vaccination

BACKGROUND

Hypermobile Ehlers-Danlos syndrome is a heritable connective tissue disorder associated with generalized joint hypermobility but also other multisystem comorbidities, many of which may be exacerbated during a viral illness or after a vaccination. We sought to determine whether individuals with hypermobile Ehlers Danlos syndrome report an increase in adverse events, including cardiovascular events, after COVID-19 illness or vaccination.

METHODS

A cross-sectional web-based survey was made available from November 22, 2021, through March 15, 2022. 368 respondents primarily from the United States self-reported data including diagnosis. We used a Cox proportional hazards model with time varying indicators for COVID-19 illness or vaccination in the previous 30 days.

RESULTS

We found a significantly increased rate of new abnormal heart rhythms reported in the 30 days following COVID-19 illness. No additional cardiovascular events were reported after COVID-19 illness. 2.5% of respondents with COVID-19 illness were hospitalized. We did not find a statistically significant increased rate of cardiovascular events in the 30 days following any COVID-19 vaccination dose. Post COVID-19 vaccination, 87.2% of hypermobile Ehlers-Danlos syndrome respondents endorsed an expected adverse event (EAE), and 3.1% reported an emergency department visit/hospitalization, of those who received at least one vaccine dose. Events possibly reflecting exacerbation of orthostasis/dysautonomia were common.

CONCLUSION

Respondents did not report an increased rate of any cardiovascular events in the 30 days following COVID-19 vaccination; however, those with hypermobile Ehlers-Danlos syndrome experienced a high rate of expected adverse events after vaccination consistent with a high baseline prevalence of similar symptoms. No cardiovascular events other than new abnormal heart rhythms were reported at any point after a COVID-19 illness.

A randomized double-blinded trial to assess recurrence of systemic allergic reactions following COVID-19 mRNA vaccination

BACKGROUND

Systemic allergic reactions (sARs) following coronavirus disease 2019 (COVID-19) mRNA vaccines were initially reported at a higher rate than after traditional vaccines.

OBJECTIVE

We aimed to evaluate the safety of revaccination in these individuals and to interrogate mechanisms underlying these reactions.

METHODS

In this randomized, double-blinded, phase 2 trial, participants aged 16 to 69 years who previously reported a convincing sAR to their first dose of COVID-19 mRNA vaccine were randomly assigned to receive a second dose of BNT162b2 (Comirnaty) vaccine and placebo on consecutive days in a blinded, 1:1 crossover fashion at the National Institutes of Health. An open-label BNT162b2 booster was offered 5 months later if the second dose did not result in severe sAR. None of the participants received the mRNA-1273 (Spikevax) vaccine during the study. The primary end point was recurrence of sAR following second dose and booster vaccination; exploratory end points included biomarker measurements.

RESULTS

Of 111 screened participants, 18 were randomly assigned to receive study interventions. Eight received BNT162b2 second dose followed by placebo; 8 received placebo followed by BNT162b2 second dose; 2 withdrew before receiving any study intervention. All 16 participants received the booster dose. Following second dose and booster vaccination, sARs recurred in 2 participants (12.5%; 95% CI, 1.6 to 38.3). No sAR occurred after placebo. An anaphylaxis mimic, immunization stress-related response (ISRR), occurred more commonly than sARs following both vaccine and placebo and was associated with higher predose anxiety scores, paresthesias, and distinct vital sign and biomarker changes.

CONCLUSIONS

Our findings support revaccination of individuals who report sARs to COVID-19 mRNA vaccines. Distinct clinical and laboratory features may distinguish sARs from ISRRs.

TGFβ prevents IgE-mediated allergic disease by restraining T follicular helper 2 differentiation

Allergic diseases are common, affecting more than 20% of the population. Genetic variants in the TGFβ pathway are strongly associated with atopy. To interrogate the mechanisms underlying this association, we examined patients and mice with Loeys-Dietz syndrome (LDS) who harbor missense mutations in the kinase domain of TGFΒR1/2. We demonstrate that LDS mutations lead to reduced TGFβ signaling and elevated total and allergen-specific IgE, despite the presence of wild-type T regulatory cells in a chimera model. Germinal center activity was enhanced in LDS and characterized by a selective increase in type 2 follicular helper T cells (TFH2). Expression of Pik3cg was increased in LDS TFH cells and associated with reduced levels of the transcriptional repressor SnoN. PI3Kγ/mTOR signaling in LDS naïve CD4+ T cells was elevated after T cell receptor cross-linking, and pharmacologic inhibition of PI3Kγ or mTOR prevented exaggerated TFH2 and antigen-specific IgE responses after oral antigen exposure in an adoptive transfer model. Naïve CD4+ T cells from nonsyndromic allergic individuals also displayed decreased TGFβ signaling, suggesting that our mechanistic discoveries may be broadly relevant to allergic patients in general. Thus, TGFβ plays a conserved, T cell-intrinsic, and nonredundant role in restraining TFH2 development via the PI3Kγ/mTOR pathway and thereby protects against allergic disease.

Natural history study of patients with familial platelet disorder with associated myeloid malignancy

ABSTRACT

Deleterious germ line RUNX1 variants cause the autosomal dominant familial platelet disorder with associated myeloid malignancy (FPDMM), characterized by thrombocytopenia, platelet dysfunction, and a predisposition to hematologic malignancies (HMs). We launched a FPDMM natural history study and, from January 2019 to December 2021, enrolled 214 participants, including 111 patients with 39 different RUNX1 variants from 45 unrelated families. Seventy of 77 patients had thrombocytopenia, 18 of 18 had abnormal platelet aggregometry, 16 of 35 had decreased platelet dense granules, and 28 of 55 had abnormal bleeding scores. Nonmalignant bone marrows showed increased numbers of megakaryocytes in 12 of 55 patients, dysmegakaryopoiesis in 42 of 55, and reduced cellularity for age in 30 of 55 adult and 17 of 21 pediatric cases. Of 111 patients, 19 were diagnosed with HMs, including myelodysplastic syndrome, acute myeloid leukemia, chronic myelomonocytic leukemia, acute lymphoblastic leukemia, and smoldering myeloma. Of those 19, 18 were relapsed or refractory to upfront therapy and referred for stem cell transplantation. In addition, 28 of 45 families had at least 1 member with HM. Moreover, 42 of 45 patients had allergic symptoms, and 24 of 30 had gastrointestinal (GI) symptoms. Our results highlight the importance of a multidisciplinary approach, early malignancy detection, and wider awareness of inherited disorders. This actively accruing, longitudinal study will genotype and phenotype more patients with FPDMM, which may lead to a better understanding of the disease pathogenesis and clinical course, which may then inform preventive and therapeutic interventions. This trial was registered at www.clinicaltrials.gov as #NCT03854318.

A genome catalog of the early-life human skin microbiome

BACKGROUND

Metagenome-assembled genomes have greatly expanded the reference genomes for skin microbiome. However, the current reference genomes are largely based on samples from adults in North America and lack representation from infants and individuals from other continents.

RESULTS

Here we use deep shotgun metagenomic sequencing to profile the skin microbiota of 215 infants at age 2-3 months and 12 months who are part of the VITALITY trial in Australia as well as 67 maternally matched samples. Based on the infant samples, we present the Early-Life Skin Genomes (ELSG) catalog, comprising 9483 prokaryotic genomes from 1056 species, 206 fungal genomes from 13 species, and 39 eukaryotic viral sequences. This genome catalog substantially expands the diversity of species previously known to comprise human skin microbiome and improves the classification rate of sequenced data by 21%. The protein catalog derived from these genomes provides insights into the functional elements such as defense mechanisms that distinguish early-life skin microbiome. We also find evidence for microbial sharing at the community, bacterial species, and strain levels between mothers and infants.

CONCLUSIONS

Overall, the ELSG catalog uncovers the skin microbiome of a previously underrepresented age group and population and provides a comprehensive view of human skin microbiome diversity, function, and development in early life.

Severe food allergy reactions are associated with α-tryptase

BACKGROUND

Increased TPSAB1 copy numbers encoding ⍺-tryptase are associated with severe reactions in adults with Hymenoptera venom allergy, systemic mastocytosis, and idiopathic anaphylaxis.

OBJECTIVE

The primary objective was to assess the association between ⍺-tryptase and severity of food allergy.

METHODS

A total of 119 subjects underwent tryptase genotyping; 82 of them were from an observational food allergy cohort at the National Institute of Allergy and Infectious Disease (NIAID), and 37 were from a cohort of children who reacted to peanut oral food challenge (OFC) at Lurie Children's Hospital of Chicago. The primary predictor was presence or absence of ⍺-tryptase. The primary outcomes for both cohorts were measures of severity of food allergy reaction. Secondary outcomes included OFC symptom scores (Bock/Practical Allergy [PRACTALL] and Severity Grading Score for Acute Reactions [SGSAR]). Correlation between total α-tryptase isoforms and OFC scores was also assessed to account for gene dosage effects.

RESULTS

Among the subjects in the NIAID cohort, the presence of ⍺-tryptase was associated with a higher prevalence of food-triggered anaphylaxis than in those with only β-tryptase (P = .026). Similarly, only 1 of 6 subjects in the OFC cohort with only β-tryptase (17%) had a severe reaction, whereas 20 of 31 of subjects with α-tryptase (65%) had a severe reaction (P = .066). Subjects with ⍺-tryptase also had higher total SGSAR scores than did the subjects with no ⍺-tryptase (P = .003). In addition, there were also significant positive correlations between ⍺-tryptase isoform copy numbers and both higher total SGSAR and Bock/PRACTALL OFC scores (P = .008 and P = .003, respectively).

CONCLUSION

The presence of α-tryptase in subjects is correlated with a higher prevalence of anaphylaxis or severe reaction to food than in subjects without any α-tryptase.

Distinct CRTH2+CD161+ (peTh2) memory CD4+ T-cell cytokine profiles in food allergy and eosinophilic gastrointestinal disorders

INTRODUCTION

Although IgE-mediated food allergy (FA) and eosinophilic gastrointestinal disorders (EGID) are clinically distinct and treated differently, pathogenic effector Th2 (peTh2) cells are implicated in the pathogenesis of both FA and EGID. The aim of this study was to better characterize peTh2 cells in the context of FA and EGID and the overlap between these two conditions.

METHODS

Peripheral blood peTh2 cells (CD3+CD4+CD27-CD49d+CRTH2+CD161+) were profiled by intracellular cytokine flow cytometry in the following patient cohorts: patients with FA alone (n = 8), FA and food-triggered EGID (EGID+FA+FT, n = 7), food-triggered EGID alone (EGID+FT, n = 7), EGID without FA or specific food triggers (ONLY_EGID, n = 9), and healthy volunteers (HV, n = 7). Overnight peripheral blood mononuclear cell (PBMC) culture supernatants were assessed for cytokine production by multiplex analysis.

RESULTS

CRTH2+CD161+ (peTh2) memory CD4+ T cells were significantly increased in both patients with FA and those with ALL_EGID (inclusive of EGID+FA+FT, EGID+FT and ONLY_EGID) when compared to HV. However, ALL_EGID patients, particularly those with EGID+FA+FT, had significantly elevated IL-5+IL-13+ peTh2 cells, whereas FA patients had significantly elevated IFN-γ or IL-17A-expressing peTh2 cells. This finding was supported by increased spontaneous IL-5 and IL-13 production in overnight cultures of PBMC from EGID+FA+FT patients compared to spontaneous IL-10 and IFN-γ production by PBMC from FA patients. FA patients had increased IL-9, IL-10, IL-17A, and IFN-γ production in overnight cultures of stimulated PBMC.

CONCLUSIONS

EGID and IgE-mediated FA share a common cell subtype defined by specific surface markers and termed CRTH2+CD161+ (peTh2) memory CD4+ T cells. However, the cytokine profiles of these CRTH2+CD161+ (peTh2) memory CD4+ T cells are markedly different between the two disorders.

Updated guidance regarding the risk of allergic reactions to COVID-19 vaccines and recommended evaluation and management: A GRADE assessment and international consensus approach

This guidance updates 2021 GRADE (Grading of Recommendations Assessment, Development and Evaluation) recommendations regarding immediate allergic reactions following coronavirus disease 2019 (COVID-19) vaccines and addresses revaccinating individuals with first-dose allergic reactions and allergy testing to determine revaccination outcomes. Recent meta-analyses assessed the incidence of severe allergic reactions to initial COVID-19 vaccination, risk of mRNA-COVID-19 revaccination after an initial reaction, and diagnostic accuracy of COVID-19 vaccine and vaccine excipient testing in predicting reactions. GRADE methods informed rating the certainty of evidence and strength of recommendations. A modified Delphi panel consisting of experts in allergy, anaphylaxis, vaccinology, infectious diseases, emergency medicine, and primary care from Australia, Canada, Europe, Japan, South Africa, the United Kingdom, and the United States formed the recommendations. We recommend vaccination for persons without COVID-19 vaccine excipient allergy and revaccination after a prior immediate allergic reaction. We suggest against >15-minute postvaccination observation. We recommend against mRNA vaccine or excipient skin testing to predict outcomes. We suggest revaccination of persons with an immediate allergic reaction to the mRNA vaccine or excipients be performed by a person with vaccine allergy expertise in a properly equipped setting. We suggest against premedication, split-dosing, or special precautions because of a comorbid allergic history.

Dynamic chromatin accessibility licenses STAT5- and STAT6-dependent innate-like function of TH9 cells to promote allergic inflammation

Allergic diseases are a major global health issue. Interleukin (IL)-9-producing helper T (TH9) cells promote allergic inflammation, yet TH9 cell effector functions are incompletely understood because their lineage instability makes them challenging to study. Here we found that resting TH9 cells produced IL-9 independently of T cell receptor (TCR) restimulation, due to STAT5- and STAT6-dependent bystander activation. This mechanism was seen in circulating cells from allergic patients and was restricted to recently activated cells. STAT5-dependent Il9/IL9 regulatory elements underwent remodeling over time, inactivating the locus. A broader 'allergic TH9' transcriptomic and epigenomic program was also unstable. In vivo, TH9 cells induced airway inflammation via TCR-independent, STAT-dependent mechanisms. In allergic patients, TH9 cell expansion was associated with responsiveness to JAK inhibitors. These findings suggest that TH9 cell instability is a negative checkpoint on bystander activation that breaks down in allergy and that JAK inhibitors should be considered for allergic patients with TH9 cell expansion.

A genome catalog of the early-life human skin microbiome

Metagenome-assembled genomes have greatly expanded the reference genomes for skin microbiome. However, the current reference genomes are largely based on samples from adults in North America and lack representation from infants and individuals from other continents. Here we used ultra-deep shotgun metagenomic sequencing to profile the skin microbiota of 215 infants at age 2-3 months and 12 months who were part of the VITALITY trial in Australia as well as 67 maternally-matched samples. Based on the infant samples, we present the Early-Life Skin Genomes (ELSG) catalog, comprising 9,194 bacterial genomes from 1,029 species, 206 fungal genomes from 13 species, and 39 eukaryotic viral sequences. This genome catalog substantially expands the diversity of species previously known to comprise human skin microbiome and improves the classification rate of sequenced data by 25%. The protein catalog derived from these genomes provides insights into the functional elements such as defense mechanisms that distinguish early-life skin microbiome. We also found evidence for vertical transmission at the microbial community, individual skin bacterial species and strain levels between mothers and infants. Overall, the ELSG catalog uncovers the skin microbiome of a previously underrepresented age group and population and provides a comprehensive view of human skin microbiome diversity, function, and transmission in early life.

Multiomics integration of 22 immune-mediated monogenic diseases reveals an emergent axis of human immune health

Monogenic diseases are often studied in isolation due to their rarity. Here we utilize multiomics to assess 22 monogenic immune-mediated conditions with age- and sex-matched healthy controls. Despite clearly detectable disease-specific and "pan-disease" signatures, individuals possess stable personal immune states over time. Temporally stable differences among subjects tend to dominate over differences attributable to disease conditions or medication use. Unsupervised principal variation analysis of personal immune states and machine learning classification distinguishing between healthy controls and patients converge to a metric of immune health (IHM). The IHM discriminates healthy from multiple polygenic autoimmune and inflammatory disease states in independent cohorts, marks healthy aging, and is a pre-vaccination predictor of antibody responses to influenza vaccination in the elderly. We identified easy-to-measure circulating protein biomarker surrogates of the IHM that capture immune health variations beyond age. Our work provides a conceptual framework and biomarkers for defining and measuring human immune health.

The conundrum of COVID-19 mRNA vaccine-induced anaphylaxis

Novel messenger RNA (mRNA) vaccines have proven to be effective tools against coronavirus disease 2019, and they have changed the course of the pandemic. However, early reports of mRNA vaccine-induced anaphylaxis resulted in public alarm, contributing toward vaccine hesitancy. Although initial reports were concerning for an unusually high rate of anaphylaxis to the mRNA vaccines, the true incidence is likely comparable with other vaccines. These reactions occurred predominantly in young to middle-aged females, and many had a history of allergies. Although initially thought to be triggered by polyethylene glycol (PEG), lack of reproducibility of these reactions with subsequent dosing and absent PEG sensitization point away from an IgE-mediated PEG allergy in most. PEG skin testing has poor posttest probability and should be reserved for evaluating non-vaccine-related PEG allergy without influencing decisions for subsequent mRNA vaccination. Immunization stress-related response can closely mimic vaccine-induced anaphylaxis and warrants consideration as a potential etiology. Current evidence suggests that many individuals who developed anaphylaxis to the first dose of an mRNA vaccine can likely receive a subsequent dose after careful evaluation. The need to understand these reactions mechanistically remains critical because the mRNA platform is rapidly finding its way into other vaccinations and therapeutics.

Epithelial-intrinsic defects in TGFβR signaling drive local allergic inflammation manifesting as eosinophilic esophagitis

Allergic diseases are a global health challenge. Individuals harboring loss-of-function variants in transforming growth factor-β receptor (TGFβR) genes have an increased prevalence of allergic disorders, including eosinophilic esophagitis. Allergic diseases typically localize to mucosal barriers, implicating epithelial dysfunction as a cardinal feature of allergic disease. Here, we describe an essential role for TGFβ in the control of tissue-specific immune homeostasis that provides mechanistic insight into these clinical associations. Mice expressing a TGFβR1 loss-of-function variant identified in atopic patients spontaneously develop disease that clinically, immunologically, histologically, and transcriptionally recapitulates eosinophilic esophagitis. In vivo and in vitro, TGFβR1 variant-expressing epithelial cells are hyperproliferative, fail to differentiate properly, and overexpress innate proinflammatory mediators, which persist in the absence of lymphocytes or external allergens. Together, our results support the concept that TGFβ plays a fundamental, nonredundant, epithelial cell-intrinsic role in controlling tissue-specific allergic inflammation that is independent of its role in adaptive immunity.

Deep immune profiling uncovers novel associations with clinical phenotypes of Multisystem Inflammatory Syndrome in Children (MIS-C)

Multisystem Inflammatory Syndrome in Children (MIS-C) is a systemic inflammatory condition that follows SARS-CoV2 infection or exposure in children. Clinical presentations are highly variable and include fever, gastrointestinal (GI) disease, shock, and Kawasaki Disease-like illness (MIS-C/KD). Compared to patients with acute COVID, patients with MIS-C have a distinct immune signature and expansion of TRVB11 expressing T cells. However, the relationship between immunological and clinical phenotypes of MIS-C is unknown. Here, we measured serum biomarkers, TCR repertoire, and SARS-CoV2-specific T cell responses in a cohort of 76 MIS-C patients. Serum biomarkers associated with macrophage and Th1 activation were elevated in patients with shock, consistent with previous reports. Significantly increased SARS-CoV-2-induced IFN-γ, IL-2, and TNF-α production were seen in CD4 + T cells from patients with neurologic involvement and respiratory failure. Diarrhea was associated with a significant reduction in shock-associated serum biomarkers, suggesting a protective effect. TRVB11 usage was highly associated with MIS-C/KD and coronary aneurysms, suggesting a potential biomarker for these manifestations in MIS-C patients. By identifying novel immunologic associations with the different clinical phenotypes of MIS-C, this study provides insights into the clinical heterogeneity of MIS-C. These unique immunophenotypic associations could provide biomarkers to identify patients at risk for severe complications of MIS-C, including shock and MIS-C/KD.

Predictors of low bone density and fracture risk in Loeys-Dietz syndrome

PURPOSE

Loeys-Dietz syndrome (LDS) is a connective tissue disorder affecting multiple organ systems, including bone.

METHODS

We defined the bone phenotype and clinical predictors of low bone density and fracture risk in 77 patients with LDS type 1 to type 5.

RESULTS

Patients with LDS had dual-energy x-ray absorptiometry (DXA) Z-scores significantly < 0, and 50% of children and 9% of adults had Z-scores < -2. Sixty percent of patients had ≥1 fracture, and 24% of patients with spinal x-rays scans showed spinal compression fractures. Lower body mass index, asthma, male sex and eosinophilic gastrointestinal disease were correlated with lower DXA Z-scores. The count of 5 LDS-associated skeletal features (scoliosis, pes planus, arachnodactyly, spondylolisthesis, and camptodactyly) in patients with LDS was correlated with DXA Z-score. Adults with ≥1 skeletal features had DXA Z-scores significantly < 0, and children with >2 features had DXA Z-score significantly < -2. Bone turnover markers suggest accelerated bone resorption. Data from 5 patients treated with bisphosphonates suggest a beneficial effect.

CONCLUSION

All LDS types are associated with reduced bone density and increased risk of fracture, which may be due to increased bone resorption. Clinical features can predict a subgroup of patients at highest risk of low bone density and fracture risk.

Loeys-Dietz and Shprintzen-Goldberg syndromes: analysis of TGF-β-opathies with craniofacial manifestations using an innovative multimodality method

BACKGROUND

Elevated transforming growth factor-beta (TGF-β) signalling has been implicated in the pathogenesis of Loeys-Dietz syndrome (LDS) and Shprintzen-Goldberg syndrome (SGS). In this study, we provide a qualitative and quantitative analysis of the craniofacial and functional features among the LDS subtypes and SGS.

METHODS

We explore the variability within and across a cohort of 44 patients through deep clinical phenotyping, three-dimensional (3D) facial photo surface analysis, cephalometric and geometric morphometric analyses of cone-beam CT scans.

RESULTS

The most common craniofacial features detected in this cohort include mandibular retrognathism (84%), flat midface projection (84%), abnormal eye shape (73%), low-set ears (73%), abnormal nose (66%) and lip shape (64%), hypertelorism (41%) and a relatively high prevalence of nystagmus/strabismus (43%), temporomandibular joint disorders (38%) and obstructive sleep apnoea (23%). 3D cephalometric analysis demonstrated an increased cranial base angle with shortened anterior cranial base and underdevelopment of the maxilla and mandible, with evidence of a reduced pharyngeal airway in 55% of those analysed. Geometric morphometric analysis confirmed that the greatest craniofacial shape variation was among patients with LDS type 2, with distinct clustering of patients with SGS.

CONCLUSIONS

This comprehensive phenotypic approach identifies developmental abnormalities that segregate to mutation variants along the TGF-β signalling pathway, with a particularly severe phenotype associated with TGFBR2 and SKI mutations. Multimodality assessment of craniofacial anomalies objectively reveals the impact of mutations of the TGF-β pathway with perturbations associated with the cranium and cranial base with severe downstream effects on the orbit, maxilla and mandible with the resultant clinical phenotypes.

The Risk of Allergic Reaction to SARS-CoV-2 Vaccines and Recommended Evaluation and Management: A Systematic Review, Meta-Analysis, GRADE Assessment, and International Consensus Approach

Concerns for anaphylaxis may hamper severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) immunization efforts. We convened a multidisciplinary group of international experts in anaphylaxis composed of allergy, infectious disease, emergency medicine, and front-line clinicians to systematically develop recommendations regarding SARS-CoV-2 vaccine immediate allergic reactions. Medline, EMBASE, Web of Science, the World Health Organizstion (WHO) global coronavirus database, and the gray literature (inception, March 19, 2021) were systematically searched. Paired reviewers independently selected studies addressing anaphylaxis after SARS-CoV-2 vaccination, polyethylene glycol (PEG) and polysorbate allergy, and accuracy of allergy testing for SARS-CoV-2 vaccine allergy. Random effects models synthesized the data to inform recommendations based on the Grading of Recommendation, Assessment, Development, and Evaluation (GRADE) approach, agreed upon using a modified Delphi panel. The incidence of SARS-CoV-2 vaccine anaphylaxis is 7.91 cases per million (n = 41,000,000 vaccinations; 95% confidence interval [95% CI] 4.02-15.59; 26 studies, moderate certainty), the incidence of 0.15 cases per million patient-years (95% CI 0.11-0.2), and the sensitivity for PEG skin testing is poor, although specificity is high (15 studies, very low certainty). We recommend vaccination over either no vaccination or performing SARS-CoV-2 vaccine/excipient screening allergy testing for individuals without history of a severe allergic reaction to the SARS-CoV-2 vaccine/excipient, and a shared decision-making paradigm in consultation with an allergy specialist for individuals with a history of a severe allergic reaction to the SARS-CoV-2 vaccine/excipient. We recommend further research to clarify SARS-CoV-2 vaccine/vaccine excipient testing utility in individuals potentially allergic to SARS-CoV2 vaccines or their excipients.

Case Report: Rare Presentation of Dentin Abnormalities in Loeys-Dietz Syndrome Type I

Loeys-Dietz syndrome type 1 (LDS1) is caused by a mutation in the transforming growth factor-beta receptor 1 (TGFBR1) gene. We previously characterized the oral and dental anomalies in a cohort of individuals diagnosed with LDS and showed that LDS1 had a high frequency of oral manifestations, and most affected individuals had enamel defects. However, dentin anomalies were not apparent in most patients in the cohort. In this cohort, we had identified dentin anomalies in a patient with LDS1, harboring mutation TGFBR1 c.1459C&gt;T (p.Arg487Trp), and in this report, we present clinical and radiographic findings to confirm the dentin anomaly. The proband had gray-brown discoloration of most teeth typical for dentinogenesis imperfecta (DI). A radiographic exam revealed obliterated or very narrow pulp canals, with maxillary anterior teeth being affected more than the posterior teeth. The son of the proband, who also has the same mutation variant, had a history of DI affecting the primary teeth; however, his permanent teeth were normal in appearance at the time of exam. TGFBR1 is expressed by odontoblasts throughout tooth development and deletion of TGFBR1 in mouse models is known to affect dentin development. In this report, we present a rare case of abnormal dentin in two individuals with LDS1. These dental anomalies may be the first obvious manifestation of a life-threatening systemic disease and demonstrate the variable and multi-organ phenotypic effects in rare diseases.

Pathogenic effector TH2 cells discriminate between allergic and eosinophilic inflammation in food allergy and eosinophilic gastrointestinal disease

IgE-mediated food allergies (FA) and delayed food-triggered (FT) gastrointestinal tissue eosinophilia (EGID) have distinct clinical manifestations and are treated differently. Pathogenic effector TH2 (peTH2) cells are implicated in inappropriate TH2 responses in both of these diseases. Furthermore, EGID patients can have concomitant FA, and some EGID patients do not report any food triggers. To better understand the role of peTH2 cells in the context of FA and EGID and the overlap between these two conditions, peTH2 cells (CD3+CD4+CD27-CD49d+CRTH2+CD161+) from purified peripheral blood mononuclear cells (PBMC) were profiled by intracellular cytokine flow cytometry in these deeply-characterized patient cohorts: patients with FA alone (FA, n=5), EGID with FA and FT (EGID+FA+FT, n=7), EGID with FT (EGID+FT, n=7) and EGID without FA or FT (EGID, n=9). Patients with any food allergy or food trigger (FA, EGID+FA+FT, and EGID+FT) have increased peTH2 cells compared to healthy volunteers (HV). Interestingly, a greater percentage of peTH2 cells in patients with food triggers (EGID+FA+FT, EGID+FT) exhibit a trend toward IL5+IL13+ double positivity (P = 0.0556) than those from patients without food triggers (FA, EGID). In contrast, peTH2 cells from patients with FA had a greater percentage that were IL17A+ (P=0.009) or IFNγ+ (P=0.0444) than patients with eosinophilic disease (EGID+FA+FT, EGID+FT, EGID). Our studies indicate that while elevated levels of peTH2 cells are indicative of allergic inflammation of both immediate hypersensitivity and eosinophilic disease, the cytokine profile of each disorder may be distinct, where IL17A+ and IFNγ+ predominate in those without eosinophilic disease.

Dysregulated TGF-β Signaling Leads to Cell-Intrinsic Changes in T cell Development that Promote Allergic Inflammation

Variants in genes in the Transforming Growth Factor Beta (TGFβ) signaling pathway are associated with allergic diseases suggesting that this cytokine may be a central player in the allergic diathesis. The role of TGFβ in preserving T cell mediated self-tolerance is well appreciated but how disruption in this pathway promotes allergic inflammation is unclear. We previously demonstrated that patients with Loeys-Dietz Syndrome (LDS), an autosomal dominant disorder caused by mutations in TGFBR1 and TGFBR2, are highly predisposed to allergic disease. LDS patients and mice harboring a knock in allele (Tgfbr1mut) of an LDS mutation known to cause severe disease in humans exhibit higher levels of total and food specific IgE. These serologic changes were associated with higher frequencies of T follicular helper (Tfh) cells and lower T follicular regulatory (Tfr) cells. Using a mixed bone marrow and fetal liver chimera model, we showed that these alterations in T cell development are cell intrinsic. Chimera models also demonstrated that the TGFβ mutation drives higher IgE production despite the presence of wildtype Tregs. Furthermore OVA specific Tgfbr1mutOTII cells were more likely to accumulate in the peyers patch and differentiate into Tfh cells in response to orally ingested OVA. These findings correlated with increased AKT/pS6 signaling downstream of TCR in Tgfbr1mut T cells, and mTOR inhibition decreased Tgfbr1mut OTII Tfh cells in response to fed ova. Additionally, RNA sequence analysis of murine Tgfbr1mut Tfh cells revealed enhanced PI3K/AKT pathway activity. These findings suggest that TGFβ signaling plays an important role in T cell development and function via the PI3K/AKT pathway that when disrupted promotes allergic inflammation.

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.

Corneal thinning and cornea guttata in patients with mutations in TGFB2

OBJECTIVE

Human genome-wide association studies and animal models suggest a role for TGFB2 in contributing to the corneal thickness phenotype. No specific mutations, however, have been reported in this gene that affect corneal thickness. We sought to determine if haploinsufficiency of TGFB2 in humans associated with Loeys-Dietz syndrome type 4 is associated with corneal thinning.

DESIGN

Observational cohort study of families with Loeys-Dietz syndrome type 4, caused specifically by TGFB2 mutations, in a tertiary care setting.

PARTICIPANTS

Three probands with pathogenic mutations in TGFB2 and family members underwent comprehensive ophthalmic examination.

METHODS

Clinical assessment included Scheimpflug imaging, specular microscopy, and slit-lamp biomicroscopy. We measured visual acuity, axial length, refractive error, and central corneal thickness.

RESULTS

Clinical evaluation of 2 probands identified corneal thinning and cornea guttata, despite a young age and distinct mutations in TGFB2 (c.905G>A, p.Arg302His; c.988C>A, p.Arg330Ser). In the third family, corneal thinning co-segregated with a TGFB2 mutation (c.1103G>A, p.Gly368Glu), although without apparent guttae.

CONCLUSIONS

In this series, participants with TGFB2 mutations associated with Loeys-Dietz syndrome type 4 demonstrated decreased corneal thickness, and in 2 cases with splice site mutations, also demonstrated cornea guttata. The data demonstrate the importance of considering distinct phenotype-genotype correlations within this condition.

Safety and outcome of gastrostomy tube placement in patients with Loeys-Dietz syndrome

Background

Loeys-Dietz syndrome (LDS) is a systemic connective tissue disease (CTD) associated with a predisposition for intestinal inflammation, food allergy, and failure to thrive, often necessitating nutritional supplementation via gastrostomy tube. Poor wound healing has also been observed in in some patients with CTD, potentially increasing the risk of surgical interventions. We undertook to determine the safety and efficacy of gastrostomy tube placement in this population.

Methods

We performed a retrospective cohort study of 10 LDS patients who had a total of 12 gastrostomy tubes placed.

Results

No procedural complications occurred, although one patient developed buried bumper syndrome in the near post-procedural time period and one patient had a small abscess at a surgical stitch. Most patients exhibited improvements in growth, with a median immediate improvement in BMI Z-score of 0.2 per month following the institution of gastrostomy tube feedings. Those with uncontrolled inflammation due to inflammatory bowel disease or eosinophilic gastrointestinal disease showed the least benefit and in some cases failed to demonstrate significant weight gain despite nutritional supplementation.

Conclusions

Gastrostomy tube placement (surgical or endoscopic) is a generally safe and a reasonable therapeutic option for patients with LDS despite their underlying CTD.

Severity of oro-dental anomalies in Loeys-Dietz syndrome segregates by gene mutation

Background Loeys-Dietz syndrome (LDS), an autosomal dominant rare connective tissue disorder, has multisystemic manifestations, characterised by vascular tortuosity, aneurysms and craniofacial manifestations. Based on the associated gene mutations along the transforming growth factor-beta (TGF-β) pathway, LDS is presently classified into six subtypes. Methods We present the oro-dental features of a cohort of 40 patients with LDS from five subtypes. Results The most common oro-dental manifestations were the presence of a high-arched and narrow palate, and enamel defects. Other common characteristics included bifid uvula, submucous cleft palate, malocclusion, dental crowding and delayed eruption of permanent teeth. Both deciduous and permanent teeth had enamel defects in some individuals. We established a grading system to measure the severity of enamel defects, and we determined that the severity of the enamel anomalies in LDS is subtype-dependent. In specific, patients with TGF-β receptor II mutations (LDS2) presented with the most severe enamel defects, followed by patients with TGF-β receptor I mutations (LDS1). LDS2 patients had higher frequency of oro-dental deformities in general. Across all five subtypes, as well as within each subtype, enamel defects exhibited incomplete penetrance and variable expression, which is not associated with the location of the gene mutations. Conclusion This study describes, in detail, the oro-dental manifestations in a cohort of LDS, and we conclude that LDS2 has the most severely affected phenotype. This extensive characterisation, as well as some identified distinguishing features can significantly aid dental and medical care providers in the diagnosis and clinical management of patients with this rare connective tissue disorder.

Prevalence and diagnosis of sesame allergy in children with IgE-mediated food allergy

Sesame allergy is estimated to affect 17% of children with IgE-mediated food allergy, and often co-occurs with peanut/tree nut sensitization and allergy. Sesame-specific IgE levels may have utility in the clinical management of these patients.

Oral health-related quality of life in Loeys-Dietz syndrome, a rare connective tissue disorder: an observational cohort study

BACKGROUND

Loeys-Dietz syndrome (LDS) is a rare connective tissue disorder whose oral manifestations and dental phenotypes have not been well-characterized. The aim of this study was to explore the influence of oral manifestations on oral health-related quality of life (OHRQoL) in LDS patients.

MATERIAL AND METHODS

LDS subjects were assessed by the craniofacial team at the National Institutes of Health Clinical Center Dental Clinic between June 2015 and January 2018. Oral Health Impact Profile (OHIP-14) questionnaire, oral health self-care behavior questionnaire and a comprehensive dental examination were completed for each subject. OHRQoL was assessed using the OHIP-14 questionnaire with higher scores corresponding to worse OHRQoL. Regression models were used to determine the relationship between each oral manifestation and the OHIP-14 scores using a level of significance of p ≤ 0.05.

RESULTS

A total of 33 LDS subjects (51.5% female) aged 3-57 years (19.6 ± 15.1 years) were included in the study. The OHIP-14 scores (n = 33) were significantly higher in LDS subjects (6.30 [SD 6.37]) when compared to unaffected family member subjects (1.50 [SD 2.28], p < 0.01), and higher than the previously reported scores of the general U.S. population (2.81 [SD 0.12]). Regarding oral health self-care behavior (n = 32), the majority of LDS subjects reported receiving regular dental care (81%) and maintaining good-to-excellent daily oral hygiene (75%). Using a crude regression model, worse OHRQoL was found to be associated with dental hypersensitivity (β = 5.24; p < 0.05), temporomandibular joints (TMJ) abnormalities (β = 5.92; p < 0.01), self-reported poor-to-fair oral health status (β = 6.77; p < 0.01), and cumulation of four or more oral manifestations (β = 7.23; p < 0.001). Finally, using a parsimonious model, self-reported poor-to-fair oral health status (β = 5.87; p < 0.01) and TMJ abnormalities (β = 4.95; p < 0.01) remained significant.

CONCLUSIONS

The dental hypersensitivity, TMJ abnormalities, self-reported poor-to-fair oral health status and cumulation of four-or-more oral manifestations had significant influence on worse OHRQoL. Specific dental treatment guidelines are necessary to ensure optimal quality of life in patients diagnosed with LDS.

Recent developments in understanding the mechanisms of food allergy

PURPOSE OF REVIEW

The prevalence of food allergy is rising globally. This review will discuss recent discoveries regarding the immunologic mechanisms that drive the initial sensitization and allergic response to food antigens, which may inform prevention and treatment strategies.

RECENT FINDINGS

Tolerance to food antigens is antigen-specific and promoted by oral exposure early in life and maternal transfer of immune complexes via breast milk. IgG can inhibit both the initiation and effector phases of allergic responses to food antigens in mice, and high levels of food-specific IgG4 are associated with acquisition of tolerance in humans. Disruption of the skin barrier provides a route for food sensitization through the actions of mast cells, type 2 innate lymphoid cells, and IL-33 signaling. Regulatory T cells (Tregs) promote acquisition of oral tolerance, although defects in circulating allergen-specific Tregs are not evident in children with established food allergy. Certain microbes can offer protection against the development of IgE and food allergic responses, while dysbiosis increases susceptibility to food allergy.

SUMMARY

Tolerance to food antigens is antigen-specific and is promoted by oral exposure early in life, maternal transfer of immune complexes, food-specific IgG, Tregs, an intact skin barrier, and a healthy microbiome.

Genetic evidence for the role of transforming growth factor-β in atopic phenotypes

New evidence in humans and mice supports a role for transforming growth factor-β (TGF-β) in the initiation and effector phases of allergic disease, as well as in consequent tissue dysfunction. This pleiotropic cytokine can affect T cell activation and differentiation and B cell immunoglobulin class switching following initial encounter with an allergen. TGF-β can also act on mast cells during an acute allergic episode to modulate the strength of the response, in addition to driving tissue remodeling following damage caused by an allergic attack. Accordingly, genetic disorders leading to altered TGF-β signaling can result in increased rates of allergic disease.

IgE testing can predict food allergy status in patients with moderate to severe atopic dermatitis

BACKGROUND

Diagnosing food allergy in patients with atopic dermatitis (AD) is complicated by their high rate of asymptomatic sensitization to foods, which can lead to misdiagnosis and unnecessary food avoidance.

OBJECTIVE

We sought to determine whether food-specific (sIgE) or component immunoglobulin (Ig) E levels could predict allergic status in patients with moderate to severe AD and elevated total IgE.

METHODS

Seventy-eight children (median age, 10.7 years) with moderate to severe AD were assessed for a history of clinical reactivity to milk, egg, peanut, wheat, and soy. The IgE levels for each food and its components were determined by ImmunoCAP. The level and pattern of IgE reactivity to each food and its components, and their ratio to total IgE, were compared between subjects who were allergic and tolerant to each food.

RESULTS

Ninety-one percent of subjects were sensitized, and 51% reported allergic reactivity to at least 1 of the 5 most common food allergens. Allergy to milk, egg, and peanut were most common, and IgE levels to each of these foods were significantly higher in the allergic group. Component IgEs most associated with milk, egg, and peanut allergy were Bos d8, Gal d1, and Ara h2, respectively. The ratio of sIgE to total IgE offered no advantage to sIgE alone in predicting allergy.

CONCLUSION

Specific IgE levels and the pattern of IgE reactivity to food components can distinguish AD subjects allergic vs tolerant to the major food allergens and may therefore be helpful in guiding the clinical management of these patients.

Lineage-specific events underlie aortic root aneurysm pathogenesis in Loeys-Dietz syndrome

The aortic root is the predominant site for development of aneurysm caused by heterozygous loss-of-function mutations in positive effectors of the transforming growth factor-β (TGF-β) pathway. Using a mouse model of Loeys-Dietz syndrome (LDS) that carries a heterozygous kinase-inactivating mutation in TGF-β receptor I, we found that the effects of this mutation depend on the lineage of origin of vascular smooth muscle cells (VSMCs). Secondary heart field-derived (SHF-derived), but not neighboring cardiac neural crest-derived (CNC-derived), VSMCs showed impaired Smad2/3 activation in response to TGF-β, increased expression of angiotensin II (AngII) type 1 receptor (Agtr1a), enhanced responsiveness to AngII, and higher expression of TGF-β ligands. The preserved TGF-β signaling potential in CNC-derived VSMCs associated, in vivo, with increased Smad2/3 phosphorylation. CNC-, but not SHF-specific, deletion of Smad2 preserved aortic wall architecture and reduced aortic dilation in this mouse model of LDS. Taken together, these data suggest that aortic root aneurysm predisposition in this LDS mouse model depends both on defective Smad signaling in SHF-derived VSMCs and excessive Smad signaling in CNC-derived VSMCs. This work highlights the importance of considering the regional microenvironment and specifically lineage-dependent variation in the vulnerability to mutations in the development and testing of pathogenic models for aortic aneurysm.

Identification and analysis of peanut-specific effector T and regulatory T cells in children allergic and tolerant to peanut

BACKGROUND

Peanut allergy (PA) is potentially life-threatening and generally persists for life. Recent data suggest the skin might be an important route of initial sensitization to peanut, whereas early oral exposure to peanut is protective. In mice regulatory T (Treg) cells are central to the development of food tolerance, but their contribution to the pathogenesis of food allergy in human subjects is less clear.

OBJECTIVE

We sought to quantify and phenotype CD4⁺ peanut-specific effector T (ps-Teff) cells and peanut-specific regulatory T (ps-Treg) cells in children with and without PA or PS.

METHODS

ps-Teff and ps-Treg cells were identified from peripheral blood of children with PA, children with PS, and nonsensitized/nonallergic (NA) school-aged children and 1-year-old infants based on upregulation of CD154 or CD137, respectively, after stimulation with peanut extract. Expression of cytokines and homing receptors was evaluated by using flow cytometry. Methylation at the forkhead box protein 3 (FOXP3) locus was measured as a marker of Treg cell stability.

RESULTS

Differential upregulation of CD154 and CD137 efficiently distinguished ps-Teff and ps-Treg cells. A greater percentage of ps-Teff cells from infants with PA and infants with PS expressed the skin-homing molecule cutaneous lymphocyte antigen, suggesting activation after exposure through the skin, compared with NA infants. Although ps-Teff cells in both school-aged and infant children with PA produced primarily T_H2 cytokines, a T_H1-skewed antipeanut response was seen only in NA school-aged children. The frequency, homing receptor expression, and stability of ps-Treg cells in infants and school-aged children were similar, regardless of allergic status.

CONCLUSIONS

Exposure to peanut through the skin can prime the development of T_H2 ps-Teff cells, which promote sensitization to peanut, despite the presence of normal numbers of ps-Treg cells.

The Genetics of Food Allergy

PURPOSE OF REVIEW

Food allergy likely arises from a complex interplay between environmental triggers and genetic susceptibility. Here, we review recent studies that have investigated the genetic pathways and mechanisms that may contribute to the pathogenesis of food allergy.

RECENT FINDINGS

A heritability component of food allergy has been observed in multiple studies. A number of monogenic diseases characterized by food allergy have elucidated pathways that may be important in pathogenesis. Several population-based genetic variants associated with food allergy have also been identified. The genetic mechanisms that play a role in the development of food allergy are heterogeneous and complex. Advances in our understanding of the genetics of food allergy, and how this predisposition interacts with environmental exposures to lead to disease, will improve our understanding of the key pathways leading to food allergy and inform more effective prevention and treatment strategies.

Mechanistic correlates of clinical responses to omalizumab in the setting of oral immunotherapy for milk allergy

BACKGROUND

In our recent clinical trial, the addition of omalizumab to oral immunotherapy (OIT) for milk allergy improved safety, but no significant clinical benefit was detected.

OBJECTIVE

We sought to investigate mechanisms by which omalizumab modulates immunity in the context of OIT and to identify baseline biomarkers that predict subgroups of patients most likely to benefit from omalizumab.

METHODS

Blood was obtained at baseline and multiple time points during a placebo-controlled trial of OIT for milk allergy in which subjects were randomized to receive omalizumab or placebo. Immunologic outcomes included measurement of basophil CD63 expression and histamine release and casein-specific CD4⁺ regulatory T-cell proliferation. Biomarkers were analyzed in relationship to measurements of safety and efficacy.

RESULTS

Milk-induced basophil CD63 expression was transiently reduced in whole blood samples from both omalizumab- and placebo-treated subjects. However, IgE-dependent histamine release increased in washed cell preparations from omalizumab- but not placebo-treated subjects. No increase in regulatory T-cell frequency was evident in either group. Subjects with lower rates of adverse reactions, regardless of arm, experienced better clinical outcomes. Pre-OIT basophil reactivity positively associated with occurrence of symptoms during OIT, whereas the baseline milk IgE/total IgE ratio correlated with the likelihood of achieving sustained unresponsiveness. A combination of baseline basophil and serologic biomarkers defined a subset of patients in which adjunctive therapy with omalizumab was associated with attainment of sustained unresponsiveness and a reduction in adverse reactions.

CONCLUSIONS

Combining omalizumab therapy with milk OIT led to distinct alterations in basophil reactivity but not T-cell responses. Baseline biomarkers can identify subjects most likely to benefit from adjunctive therapy with omalizumab.

ERBIN deficiency links STAT3 and TGF-β pathway defects with atopy in humans

Lyons et al. show that STAT3 negatively regulates TGF-β signaling via ERBIN and that cell-intrinsic deregulation of TGF-β pathway activation promotes the IL-4/IL-4Rα/GATA3 axis to support atopic phenotypes in humans.

Nonimmunological connective tissue phenotypes in humans are common among some congenital and acquired allergic diseases. Several of these congenital disorders have been associated with either increased TGF-β activity or impaired STAT3 activation, suggesting that these pathways might intersect and that their disruption may contribute to atopy. In this study, we show that STAT3 negatively regulates TGF-β signaling via ERBB2-interacting protein (ERBIN), a SMAD anchor for receptor activation and SMAD2/3 binding protein. Individuals with dominant-negative STAT3 mutations (STAT3^mut) or a loss-of-function mutation in ERBB2IP (ERBB2IP^mut) have evidence of deregulated TGF-β signaling with increased regulatory T cells and total FOXP3 expression. These naturally occurring mutations, recapitulated in vitro, impair STAT3–ERBIN–SMAD2/3 complex formation and fail to constrain nuclear pSMAD2/3 in response to TGF-β. In turn, cell-intrinsic deregulation of TGF-β signaling is associated with increased functional IL-4Rα expression on naive lymphocytes and can induce expression and activation of the IL-4/IL-4Rα/GATA3 axis in vitro. These findings link increased TGF-β pathway activation in ERBB2IP^mut and STAT3^mut patient lymphocytes with increased T helper type 2 cytokine expression and elevated IgE.

Innate and adaptive dendritic cell responses to immunotherapy

PURPOSE OF REVIEW

In allergic disease, dendritic cells play a critical role in orchestrating immune responses to innate stimuli and promoting the formation of T helper 2 (TH2) effector versus T-regulatory cells. Here, we review recent advances in our understanding of how current forms of immunotherapy modulate dendritic cell responses. (Figure is included in full-text article.)

RECENT FINDINGS

Sublingual immunotherapy (SLIT) and oral immunotherapy (OIT) for peanut allergy alter the expression of costimulatory molecules on dendritic cells, which leads to reduced expression of TH2 effector cytokines in an antigen-nonspecific manner. SLIT and OIT also modulate dendritic cell innate immune responses to Toll-like receptor agonists, including enhanced production of interferon α and reduced expression of proinflammatory cytokines that may serve to promote the development of tolerance. Dendritic cells isolated from patients post-OIT promoted hypomethylation of the FOXP3 locus in effector T cells. Reduced methylation of the FOXP3 locus has been associated with more persistent clinical desensitization following OIT. Recent studies have additionally highlighted a role for B cells in inducing tolerogenic dendritic cell populations and T-regulatory cells during immunotherapy. Epicutaneous immunotherapy may also elicit immunosuppressive populations of cutaneous dendritic cells, although in some cases, antigen exposure through the skin can lead to sensitization. Finally, efforts have focused on identifying pharmacologic and/or antigen-independent strategies of altering dendritic cell function to enhance the immunosuppressive effects of immunotherapy.

SUMMARY

Dendritic cells are a critical target of immunotherapy. Alterations in both adaptive and innate immunity likely underlie the immunosuppressive effects of this treatment.

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.

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.

Modulation of dendritic cell innate and adaptive immune functions by oral and sublingual immunotherapy

Sublingual (SLIT) and oral immunotherapy (OIT) are promising treatments for food allergy, but underlying mechanisms are poorly understood. Dendritic cells (DCs) induce and maintain Th2-type allergen-specific T cells, and also regulate innate immunity through their expression of Toll-like receptors (TLRs). We examined how SLIT and OIT influenced DC innate and adaptive immune responses in children with IgE-mediated cow's milk (CM) allergy. SLIT, but not OIT, decreased TLR-induced IL-6 secretion by myeloid DCs (mDCs). SLIT and OIT altered mDC IL-10 secretion, a potent inhibitor of FcεRI-dependent pro-inflammatory responses. OIT uniquely augmented IFN-α and decreased IL-6 secretion by plasmacytoid DCs (pDCs), which was associated with reduced TLR-induced IL-13 release in pDC-T cell co-cultures. Both SLIT and OIT decreased Th2 cytokine secretion to CM in pDC-T, but not mDC-T, co-cultures. Therefore, SLIT and OIT exert unique effects on DC-driven innate and adaptive immune responses, which may inhibit allergic inflammation and promote tolerance.

Loeys-Dietz syndrome: a primer for diagnosis and management

Loeys-Dietz syndrome is a connective tissue disorder predisposing individuals to aortic and arterial aneurysms. Presenting with a wide spectrum of multisystem involvement, medical management for some individuals is complex. This review of literature and expert opinion aims to provide medical guidelines for care of individuals with Loeys-Dietz syndrome.

TGFβ receptor mutations impose a strong predisposition for human allergic disease

Transforming growth factor-β (TGFβ) is a multifunctional cytokine that plays diverse roles in physiologic processes as well as human disease, including cancer, heart disease, and fibrotic disorders. In the immune system, TGFβ regulates regulatory T cell (Treg) maturation and immune homeostasis. Although genetic manipulation of the TGFβ pathway modulates immune tolerance in mouse models, the contribution of this pathway to human allergic phenotypes is not well understood. We demonstrate that patients with Loeys-Dietz syndrome (LDS), an autosomal dominant disorder caused by mutations in the genes encoding receptor subunits for TGFβ, TGFBR1 and TGFBR2, are strongly predisposed to develop allergic disease, including asthma, food allergy, eczema, allergic rhinitis, and eosinophilic gastrointestinal disease. LDS patients exhibited elevated immunoglobulin E levels, eosinophil counts, and T helper 2 (TH2) cytokines in their plasma. They had an increased frequency of CD4(+) T cells that expressed both Foxp3 and interleukin-13, but retained the ability to suppress effector T cell proliferation. TH2 cytokine-producing cells accumulated in cultures of naïve CD4(+) T cells from LDS subjects, but not controls, after stimulation with TGFβ, suggesting that LDS mutations support TH2 skewing in naïve lymphocytes in a cell-autonomous manner. The monogenic nature of LDS demonstrates that altered TGFβ signaling can predispose to allergic phenotypes in humans and underscores a prominent role for TGFβ in directing immune responses to antigens present in the environment and foods. This paradigm may be relevant to nonsyndromic presentations of allergic disease and highlights the potential therapeutic benefit of strategies that inhibit TGFβ signaling.