The disease-specific clinical trial network for Primary Ciliary Dyskinesia (PCD-CTN)

Primary ciliary dyskinesia (PCD) is a rare genetic disorder characterised by impaired mucociliary clearance leading to irreversible lung damage. In contrast to other rare lung diseases like cystic fibrosis (CF), there are only few clinical trials and limited evidence-based treatments. Management is mainly based on expert opinions and treatment is challenging due to a wide range of clinical manifestations and disease severity. To improve clinical and translational research and facilitate development of new treatments, the clinical trial network for PCD (PCD-CTN) was founded in 2020 under the framework of the European Reference Network (ERN)-LUNG PCD Core. Applications from European PCD sites interested in participating in the PCD-CTN were requested. Inclusion criteria consisted of patient numbers, membership of ERN-LUNG PCD Core, use of associated standards of care, experience in PCD and/or CF clinical research, resources to run clinical trials, good clinical practice (GCP) certifications and institutional support. So far, applications from 22 trial sites in 18 European countries have been approved, including >1400 adult and >1600 paediatric individuals with PCD. The PCD-CTN is headed by a coordinating centre and consists of a steering and executive committee, a data safety monitoring board and committees for protocol review, training and standardisation. A strong association with patient organisations and industrial companies are further cornerstones. All participating trial sites agreed on a code of conduct. As CTNs from other diseases have demonstrated successfully, this newly formed PCD-CTN operates to establish evidence-based treatments for this orphan disease and to bring new personalised treatment approaches to patients.

The disease-specific clinical trial network for primary ciliary dyskinesia (PCD-CTN) was built under the framework of the European Reference Network (ERN)-LUNG PCD Core, and operates to establish evidence-based and new personalised treatment for PCDhttps://bit.ly/3sLtC8o

Lower airway clinical outcome measures for use in primary ciliary dyskinesia research: a scoping review

Objectives

Disease-specific, well-defined and validated clinical outcome measures are essential in designing research studies. Poorly defined outcome measures hamper pooling of data and comparisons between studies. We aimed to identify and describe pulmonary outcome measures that could be used for follow-up of patients with primary ciliary dyskinesia (PCD).

Methods

We conducted a scoping review by systematically searching MEDLINE, Embase and the Cochrane Database of Systematic Reviews online databases for studies published from 1996 to 2020 that included ≥10 PCD adult and/or paediatric patients.

Results

We included 102 studies (7289 patients). 83 studies reported on spirometry, 11 on body plethysmography, 15 on multiple-breath washout, 36 on high-resolution computed tomography (HRCT), 57 on microbiology and 17 on health-related quality of life. Measurement and reporting of outcomes varied considerably between studies (e.g. different scoring systems for chest HRCT scans). Additionally, definitions of outcome measures varied (e.g. definition of chronic colonisation by respiratory pathogen), impeding direct comparisons of results.

Conclusions

This review highlights the need for standardisation of measurements and reporting of outcome measures to enable comparisons between studies. Defining a core set of clinical outcome measures is necessary to ensure reproducibility of results and for use in future trials and prospective cohorts.

Update on Respiratory Fungal Infections in Cystic Fibrosis Lung Disease and after Lung Transplantation

Cystic fibrosis is the most common autosomal-recessive metabolic disease in the Western world. Impaired trans-membrane chloride transport via the cystic fibrosis transmembrane conductance regulator (CFTR) protein causes thickened body fluids. In the respiratory system, this leads to chronic suppurative cough and recurrent pulmonary infective exacerbations, resulting in progressive lung damage and respiratory failure. Whilst the impact of bacterial infections on CF lung disease has long been recognized, our understanding of pulmonary mycosis is less clear. The range and detection rates of fungal taxa isolated from CF airway samples are expanding, however, in the absence of consensus criteria and univocal treatment protocols for most respiratory fungal conditions, interpretation of laboratory reports and the decision to treat remain challenging. In this review, we give an overview on fungal airway infections in CF and CF-lung transplant recipients and focus on the most common fungal taxa detected in CF, Aspergillus fumigatus, Candida spp., Scedosporium apiospermum complex, Lomentospora species, and Exophiala dermatitidis, their clinical presentations, common treatments and prophylactic strategies, and clinical challenges from a physician’s point of view.

Proceedings of the COST action BM1407 inaugural conference BEAT-PCD: translational research in primary ciliary dyskinesia - bench, bedside, and population perspectives

Primary ciliary dyskinesia (PCD) is a rare heterogenous condition that causes progressive suppurative lung disease, chronic rhinosinusitis, chronic otitis media, infertility and abnormal situs. 'Better Experimental Approaches to Treat Primary Ciliary Dyskinesia' (BEAT-PCD) is a network of scientists and clinicians coordinating research from basic science through to clinical care with the intention of developing treatments and diagnostics that lead to improved long-term outcomes for patients. BEAT-PCD activities are supported by EU Framework Programme Horizon 2020 funded COST Action (BM1407). The Inaugural Conference of BEAT-PCD was held in December 2015 in Southampton, UK. The conference attracted ninety-six scientists, clinicians, allied health professionals, industrial partners and patient representatives from twenty countries. We aimed to identify the needs for PCD research and clinical care, particularly focussing on basic science, epidemiology, diagnostic testing, clinical management and clinical trials. The multidisciplinary conference provided an interactive platform for exchanging ideas through a program of lectures, poster presentations, breakout sessions and workshops. This allowed us to develop plans for collaborative studies. In this report, we summarize the meeting, highlight developments, and discuss open questions thereby documenting ongoing developments in the field of PCD research.

Accuracy of digital mRNA profiling of oesophageal biopsies as a novel diagnostic approach to eosinophilic oesophagitis

BACKGROUND

Quantification of tissue eosinophils remains the golden standard in diagnosing eosinophilic oesophagitis (EoE), but this approach suffers from poor specificity. It has been recognized that histopathological changes that occur in patients with EoE are associated with a disease-specific tissue transcriptome.

OBJECTIVE

We hypothesized that digital mRNA profiling targeted at a set of EoE-specific and Th2 inflammatory genes in oesophageal biopsies could help differentiate patients with EoE from those with reflux oesophagitis (RE) or normal tissue histology (NH).

METHODS

The mRNA expression levels of 79 target genes were defined in both proximal and distal biopsies of 196 patients with nCounter® (Nanostring) technology. According to clinicopathological diagnosis, these patients were grouped in a training set (35 EoE, 30 RE, 30 NH) for building of a three-class prediction model using the random forest method, and a blinded predictive set (n = 47) for model validation.

RESULTS

A diagnostic model built on ten differentially expressed genes was able to differentiate with 100% sensitivity and specificity between conditions in the training set. In a blinded predictive set, this model was able to correctly predict EoE in 14 of 18 patients in distal (sensitivity 78%, 95% CI 52-93%) and 16 of 18 patients in proximal biopsies (sensitivity 89%, 95% CI 64-98%), without false-positive diagnosis of EoE in RE or NH patients (specificity 100%, 95% CI 85-100%). Sensitivity was increased to 94% (95% CI 71-100%) when either the best predictive distal or proximal biopsy was used.

CONCLUSION AND CLINICAL RELEVANCE

We conclude that mRNA profiling of oesophageal tissue is an accurate diagnostic strategy in detecting EoE.

Update on paediatric obstructive sleep apnoea

Obstructive sleep apnoea (OSA) is one of the most common causes of sleep-disordered breathing (SDB) in children. It is associated with significant morbidity, potentially impacting on long-term neurocognitive and behavioural development, as well as cardiovascular outcomes and metabolic homeostasis. The low grade systemic inflammation and increased oxidative stress seen in this condition are believed to underpin the development of these OSA-related morbidities. The significant variance in degree of end organ morbidity in patients with the same severity of OSA highlights the importance of the interplay of genetic and environmental factors in determining the overall OSA phenotype. This review seeks to summarize the current understanding of the aetiology and mechanisms underlying OSA, its risk factors, diagnosis and treatment.

Preventive sublingual immunotherapy in preschool children: first evidence for safety and pro-tolerogenic effects

BACKGROUND

Prevention of new IgE sensitizations has been described during allergen-specific immunotherapy. However, prospective data using a preventive approach in very young children who would benefit most are missing. We initiated a prospective pilot study investigating the safety, immunomodulatory, and sensitization-preventive effect of sublingual immunotherapy (SLIT) in mono/oligoclonally sensitized, clinically asymptomatic children 2-5 yr of age.

METHODS

In this double-blinded, randomized, placebo-controlled pilot study, 31 mono-/oligosensitized children to house-dust mite or grass pollen were included. SLIT with the respective source (n = 15) or placebo (n = 16) was applied. After dose-up-phase therapy was continued for 2 yr. Parents recorded clinical events, vaccinations, and drug intake in a diary. Skin prick testing and specific IgE and IgG measurements were recorded at baseline, 12 and 24 months. At the same time, allergen-specific proliferation and IL10- and TGFβ-dependent Treg function were measured.

RESULTS

Preventive application of SLIT in young children was safe (no relevant side effects in 21,170 single applications). After 12 and 24 months of treatment, the rate of allergen-specific sensitization (specific IgE and SPT reactivity) was comparable in the treatment and the placebo group. However, verum-treated patients displayed a significant up-regulation of allergen-specific IgG (p < 0.05). Furthermore, IL10-dependent inhibition (p < 0.05) was observed in vitro in the treatment group but not in the placebo group.

CONCLUSION

Preventive SLIT is safe in children 2-5 yr of age and induces regulatory mechanisms involving allergen-specific IgG and IL10. Based on this pilot study, large-scale trials will need to investigate the modulation of sensitization and clinically relevant allergy.

Elevated levels of leukotriene C4 synthase mRNA distinguish a subpopulation of eosinophilic oesophagitis patients

BACKGROUND

Cysteinyl leukotrienes contribute to Th2-type inflammatory immune responses. Their levels in oesophageal tissue, however, do not distinguish patients with eosinophilic oesophagitis (EoE) from controls.

OBJECTIVE

We asked whether mRNA levels of leukotriene C4 synthase (LTC4 S), a key regulator of leukotriene production, could serve as a marker for EoE.

METHODS

Digital mRNA expression profiling (nCounter(®) Technology) was performed on proximal and distal oesophageal biopsies of 30 paediatric EoE patients and 40 non-EoE controls. Expression data were confirmed with RT-qPCR. LTC4 S mRNA levels were quantified in whole blood samples. Leukotriene E4 was measured in urine.

RESULTS

LTC4 S mRNA levels were elevated in proximal (2.6-fold, P < 0.001) and distal (2.9-fold, P < 0.001) oesophageal biopsies from EoE patients. Importantly, increased LTC4 S mRNA transcripts identified a subpopulation of EoE patients (28%). This patient subgroup had higher serum IgE levels (669 U/mL vs. 106 U/mL, P = 0.01), higher mRNA transcript numbers of thymic stromal lymphopoietin (TSLP) (1.6-fold, P = 0.009) and CD4 (1.4-fold, P = 0.04) but lower IL-23 mRNA levels (0.5-fold, P = 0.04). In contrast, elevated levels of IL-23 mRNA were found in oesophageal biopsies of patients with reflux oesophagitis. LTC4 S mRNA transcripts in whole blood and urinary excretion of leukotriene E4 were similar in EoE patient subgroups and non-EoE patients.

CONCLUSION & CLINICAL RELEVANCE

Elevated oesophageal expression of LTC4 S mRNA is found in a subgroup of EoE patients, concomitant with higher serum IgE levels and an oesophageal transcriptome indicative of a more-pronounced allergic phenotype. Together with TSLP and IL-23 mRNA levels, oesophageal LTC4 S mRNA may facilitate diagnosis of an EoE subpopulation for personalized therapy.

A Th17- and Th2-skewed cytokine profile in cystic fibrosis lungs represents a potential risk factor for Pseudomonas aeruginosa infection

RATIONALE

Cystic fibrosis (CF) is characterized by progressive pulmonary inflammation that is infection-triggered. Pseudomonas aeruginosa represents a risk factor for deterioration of lung function and reduced life expectancy.

OBJECTIVES

To assess T-cell cytokine/chemokine production in clinically stable children with CF and evaluate the association between T-cell subtypes and susceptibility for infection with P. aeruginosa.

METHODS

T-cell cytokine/chemokine profiles were measured in bronchoalveolar lavage fluid (BALF) from children with CF (n = 57; 6.1 ± 5.9 yr) and non-CF control subjects (n = 18; 5.9 ± 4.3 yr). Memory responses to Aspergillus fumigatus and P. aeruginosa were monitored. High-resolution computed tomography-based Helbich score was assessed. In a prospective observational trial the association between BALF cytokine/chemokine profiles and subsequent infection with P. aeruginosa was studied.

MEASUREMENTS AND MAIN RESULTS

Th1- (INF-γ), Th2- (IL-5, IL-13), Th17- (IL-17A), and Th17-related cytokines (IL-1β, IL-6) were significantly up-regulated in airways of patients with CF. IL-17A, IL-13, and IL-5 were significantly higher in BALF of symptomatic as compared with clinically asymptomatic patients with CF. IL-17A and IL-5 correlated with the percentage of neutrophils in BALF (r = 0.41, P < 0.05 and r = 0.46, P < 0.05, respectively). Th17- (IL-17A, IL-6, IL-1β, IL-8) and Th2-associated cytokines and chemokines (IL-5, IL-13, TARC/CCL17), but not IFN-γ levels, significantly correlated with high-resolution computed tomography changes (Helbich score; P < 0.05). P. aeruginosa- and A. fumigatus-specific T cells from patients with CF displayed significantly higher IL-5 and IL-17A mRNA expression. IL-17A and TARC/CCL17 were significantly augmented in patients that developed P. aeruginosa infection within 24 months.

CONCLUSIONS

We propose a role for Th17 and Th2 T cells in chronic inflammation in lungs of patients with CF. High concentrations of these cytokines/chemokines in CF airways precede infection with P. aeruginosa.

How to connect an IgE-driven response with CTL activity?

One of the goals of cell-based immune therapy in cancer is the induction of tumor-specific cytotoxic T-lymphocyte (CTL) responses. To achieve this objective, the ability of dendritic cells (DC) to cross-present tumor antigens can be exploited. One of the most efficient pathways for the induction of CTLs by cross-presentation is mediated by immunoglobulins of the IgG class, which are used by DCs to sample antigen in the form of immune complexes via Fc-gamma receptors. Could DCs use an IgE-mediated cross-presentation mechanism in a comparable manner to induce CTLs? We here discuss the potential of two human IgE Fc receptors, FcεRI and FcεRII, to serve as antigen uptake receptors for IgE-mediated cross-presentation. We conclude that the existence of an IgE-mediated cross-presentation pathway would provide a direct link between IgE-driven immune responses and CTL activity.

Development and validation of a standardized ELISA for the detection of soluble Fc-epsilon-RI in human serum

The aim of this study was to develop a standardized enzyme-linked immunosorbent assay (ELISA) for detection of human soluble Fc-epsilon-RI (sFcεRI), a serum isoform of the high affinity IgE receptor. A recombinant version of sFcεRI was produced in baculovirus and used as standard. ELISA plates were coated with anti-mouse IgG followed by incubation with the monoclonal capture antibody CRA1. This FcεRI-alpha-specific antibody binds to the stalk region of the protein and does not inhibit IgE-binding. After incubation with standards or serum samples, plates were incubated with chimeric IgE followed by detection with horseradish peroxidase conjugated anti-human IgE. Enzymatic activity was visualized with (3,3',5,5')-tetramethylbenzidine. Specificity was demonstrated by omission of capture or detection reagents. Units (U) of detection were established and the dynamic range of the assay was defined as 10-640 U/ml for a 1/5 serum dilution. Parameters of linearity (R(2)>0.999), matrix interference test (recovery of 70-110%), intra-assay variability (coefficient of variation (CV) <20%) and inter-assay variability (CV <20%) met acceptance criteria for immunoassay validation. Correlation analysis of serum units of sFcεRI measured with the new ELISA and serum IgE levels confirmed earlier published data describing a weak correlation of the two parameters in patients with elevated serum IgE while no correlation in patients with normal serum IgE or the total patient group was found. In summary, we established and validated a standardized ELISA for the detection of sFcεRI. This novel method now allows for comparative analysis of sFcεRI levels in health and disease.

High-affinity IgE receptors on dendritic cells exacerbate Th2-dependent inflammation

The IgE-mediated and Th2-dependent late-phase reaction remains a mechanistically enigmatic and daunting element of human allergic inflammation. In this study, we uncover the FcεRI on dendritic cells (DCs) as a key in vivo component of this form of allergy. Because rodent, unlike human, DCs lack FcεRI, this mechanism could be revealed only by using a new transgenic mouse model with human-like FcεRI expression on DCs. In the presence of IgE and allergen, FcεRI(+) DCs instructed naive T cells to differentiate into Th2 cells in vitro and boosted allergen-specific Th2 responses and Th2-dependent eosinophilia at the site of allergen exposure in vivo. Thus, FcεRI on DCs drives the cascade of pathogenic reactions linking the initial allergen capture by IgE with subsequent Th2-dominated T cell responses and the development of late-phase allergic tissue inflammation.

Allergic sensitization in kidney-transplanted patients prevails under tacrolimus treatment

BACKGROUND

Type I allergies have repeatedly been reported after solid organ transplantation despite T cell-targeted immunosuppressive therapy. A causal relationship with tacrolimus has been proposed.

OBJECTIVE

The present study directly compared the occurrence of allergic sensitization and disease under tacrolimus- vs. cyclosporin A-based immunosuppressive therapy.

METHODS

The prevalences of IgE-mediated sensitization and allergy were assessed in a cross-sectional study of kidney-transplanted adults receiving tacrolimus (n = 100) or cyclosporin A (n = 100).

METHODS

included a standardized questionnaire, skin prick test and measurement of total and specific IgE against common nutritive and inhalant allergens. Results The prevalence of sensitization was significantly higher in the tacrolimus- than in the cyclosporin A-treated group (34%, n = 34, vs. 20%, n = 20; P = 0.026). The rate of clinically relevant allergy in patients receiving tacrolimus was twice that in patients receiving cyclosporin A (15%, n = 15, vs. 8%, n = 8; P = 0.12). No other factor (age, serum drug level, concomitant immunosuppressive medication, time since transplantation, underlying disease) was found to have an influence on sensitization or allergy prevalence (logistic regression).

CONCLUSION AND CLINICAL RELEVANCE

Our results suggest that post-transplant immunosuppression with tacrolimus is associated with an increased occurrence of IgE-mediated sensitization and probably manifestation of allergic disease, which has to be treated specifically despite immunosuppressive therapy.

A soluble form of the high affinity IgE receptor, Fc-epsilon-RI, circulates in human serum

Soluble IgE receptors are potential in vivo modulators of IgE-mediated immune responses and are thus important for our basic understanding of allergic responses. We here characterize a novel soluble version of the IgE-binding alpha-chain of Fc-epsilon-RI (sFcεRI), the high affinity receptor for IgE. sFcεRI immunoprecipitates as a protein of ∼40 kDa and contains an intact IgE-binding site. In human serum, sFcεRI is found as a soluble free IgE receptor as well as a complex with IgE. Using a newly established ELISA, we show that serum sFcεRI levels correlate with serum IgE in patients with elevated IgE. We also show that serum of individuals with normal IgE levels can be found to contain high levels of sFcεRI. After IgE-antigen-mediated crosslinking of surface FcεRI, we detect sFcεRI in the exosome-depleted, soluble fraction of cell culture supernatants. We further show that sFcεRI can block binding of IgE to FcεRI expressed at the cell surface. In summary, we here describe the alpha-chain of FcεRI as a circulating soluble IgE receptor isoform in human serum.

Impact of systemic immuno-suppression after solid organ transplantation on allergen-specific responses

INTRODUCTION

  The immunosuppressive therapy in solid organ transplantation targets mainly the T- and B-cell-mediated immune response. However, there is evidence that it neither suppresses sensitization nor clinical manifestation of allergic diseases in organ-transplanted patients.

OBJECTIVE

  This study addresses the question whether allergen-specific responses are altered by systemic immunosuppression via negative effects on the T-regulatory cell compartment and a more pronounced suppression on Th1-type T-cell responses.

MATERIAL AND METHODS

  Peripheral blood mononuclear cells from 65 solid organ-transplanted (kidney, liver, lung) children, adolescents, and young adults and 18 healthy, matched controls were included, and their clinical and sensitization status assessed. Allergen-specific proliferation, intracellular cytokine production, frequency of forkhead box P3 (FOXP3)+ CD3+ CD4+ CD25(high) cells, mRNA expression of IL-10, transforming growth factor (TGF)-β and FOXP3 (real-time RT-PCR) of peripheral blood mononuclear cells or bronchoalveolar lavage fluid (BAL)-derived cells, and the inhibitory capacity of T-reg cells were investigated.

RESULTS

  Immunosuppression led to a significantly altered regulatory marker profile expressed by enhanced TGF-β mRNA production and a reduced frequency of FOXP3+ CD4+ CD3+ cells in solid organ transplanted individuals. FOXP3 expression in BAL cells of lung-transplanted patients was significantly decreased. Allergen-specific proliferation was not significantly altered despite long-term immunosuppression. However, suppression of allergen-specific responses via the T-regulatory cell fraction was deficient in immunosuppressed individuals.

CONCLUSION

  The results suggest an insufficient control of allergen-specific responses via the Treg-cell compartment under systemic immunosuppression.

Prebiotic oligosaccharides: in vitro evidence for gastrointestinal epithelial transfer and immunomodulatory properties

Prebiotic oligosaccharides are present in breast milk and evidence is pointing toward immunomodulatory properties of the acidic fraction. Recently, prebiotic supplements of infant formula [short-chain galacto (scGOS)-, long-chain fructo (lcFOS)-oligosaccharides] showed preventive effects on atopic disease development. We aimed to define the direct immunologic effects of these oligosaccharides and of human (aHMOS) and cows' milk (aCMOS) acidic oligosaccharides and to investigate the systemic uptake of prebiotic supplements of infant formula and a specific pectin-derived acidic oligosaccharide hydrolysate (pAOS) in vitro. After assurance of LPS-free conditions (limulus assay, toll like receptor-2, -4 transfected human embryonic kidney-cells), in vitro-transfer through a CaCo-2 cell monolayer was measured using high-pH anion exchange chromatography with pulsed amperometric detection. Direct effects on proliferation, cytokine-induction of cord blood mononuclear cells and modulation of allergen-specific CD4+ T-cell cytokine profiles from allergic and non-allergic individuals were investigated. Transfer of scGOS/lcFOS and pAOS in-vitro was detected with a rate of transfer of 4-14%, depending on the molecular size and structure. AHMOS induced IFN-γ and IL-10 but not the Th-2 cytokine IL-13 at physiologic concentrations (10-100 μg/ml) in cord blood, whereas aCMOS did not induce any of these cytokines. AHMOS significantly suppressed Th-2 type cytokine-production by Ara h1-specific CD4+ T cells (CFSE(low) CD3(+) CD4(+) cells) from peanut allergic patients. In conclusion, human milk-derived acidic oligosaccharides may modulate postnatal allergen-specific immune responses by the suppression of Th-2-type responses in atopy-prone individuals. Moreover, there is in vitro evidence for epithelial transport of prebiotic oligosaccharides.

The cystine/glutamate antiporter regulates dendritic cell differentiation and antigen presentation

The major cellular antioxidant glutathione is depleted during HIV infection and in obesity. Although the consequence of glutathione depletion on immune function is starting to emerge, it is currently not known whether glutathione dysregulation influences the differentiation and maturation of dendritic cells (DCs). Moreover, the effect of glutathione depletion on DC effector functions, such as Ag presentation, is poorly understood. Glutathione synthesis depends on the cystine/glutamate antiporter, which transports the rate-limiting precursor cystine into the cell in exchange for glutamate. In this paper, we present a detailed study of antiporter function in DCs and demonstrate a role for the antiporter in DC differentiation and cross-presentation. We show that the antiporter is the major mechanism for transport of cystine and glutamate and modulates the intracellular glutathione content and glutathione efflux from DCs. Blocking antiporter-dependent cystine transport decreases intracellular glutathione levels, and these effects correlate with reduced transcription of the functional subunit of the antiporter. We further demonstrate that blocking antiporter activity interferes with DC differentiation from monocyte precursors, but antiporter activity is not required for LPS-induced phenotypic maturation. Finally, we show that inhibiting antiporter uptake of cystine interferes with presentation of exogenous Ag to class II MHC-restricted T cells and blocks cross-presentation on MHC class I. We conclude that aberrant antiporter function disrupts glutathione homeostasis in DCs and may contribute to impaired immunity in the diseased host.

Relationships between levels of serum IgE, cell-bound IgE, and IgE-receptors on peripheral blood cells in a pediatric population

Background

Elevated serum immunoglobulin (Ig) E is a diagnostic marker of immediate-type allergic reactions. We hypothesize that serum IgE does not necessarily reflect total body IgE because in vivo IgE can be bound to cell surface receptors such as FcεRI and FcεRII (CD23). The aim of this study was to analyze the relationships between levels of serum IgE, cell-bound IgE, and IgE-receptors on peripheral blood cells in a pediatric population.

Methodology

Whole blood samples from 48 children (26 boys, 22 girls, mean age 10,3±5,4 years) were analyzed by flow cytometry for FcεRI, CD23, and cell-bound IgE on dendritic cells (CD11c+MHC class II+), monocytes (CD14+), basophils (CD123+MHC class II-) and neutrophils (myeloperoxidase+). Total serum IgE was measured by ELISA and converted into z-units to account for age-dependent normal ranges. Correlations were calculated using Spearman rank correlation test.

Principal Findings

Dendritic cells, monocytes, basophils, and neutrophils expressed the high affinity IgE-receptor FcεRI. Dendritic cells and monocytes also expressed the low affinity receptor CD23. The majority of IgE-receptor positive cells carried IgE on their surface. Expression of both IgE receptors was tightly correlated with cell-bound IgE. In general, cell-bound IgE on FcεRI+ cells correlated well with serum IgE. However, some patients carried high amounts of cell-bound IgE despite low total serum IgE levels.

Conclusion/Significance

In pediatric patients, levels of age-adjusted serum IgE, cell-bound IgE, and FcεRI correlate. Even in the absence of elevated levels of serum IgE, cell-bound IgE can be detected on peripheral blood cells in a subgroup of patients.

First evidence of a possible association between gastric acid suppression during pregnancy and childhood asthma: a population-based register study

BACKGROUND

Recent data in mice suggest that acid suppression during pregnancy yields offspring with type 2 T helper-dominant immunity, suggesting a predisposition for allergy.

OBJECTIVE

To determine the association of in utero exposure to acid-suppressive medications and the subsequent development of allergic diseases in children.

METHODS

We studied a population-based observational cohort formed by linking data from three Swedish national healthcare registers: the Medical Birth Register, the Hospital Discharge Register, and the Swedish Prescribed Drug Register. Main outcome measures included a hospital discharge diagnosis of an allergic disease or prescription for asthma medications, epinephrine auto-injectors, antihistamines or steroid ointments in children. Data were analysed using the Mantel-Haenszel procedure.

RESULTS

Twenty-nine thousand four hundred and ninety (5.03%) children had a discharge diagnosis of allergy or prescriptions for allergy medications. Five thousand six hundred and forty-five (0.96%) children had been exposed to acid suppression therapy during pregnancy; of these, 405 (0.07%) were treated for allergic diseases. Exposure to acid-suppressive medications in utero was associated with an increased odds ratio (OR) for developing allergy (OR 1.43, 95% confidence interval (95% CI) 1.29-1.59). We observed this association irrespective of the type of drug, time of exposure during pregnancy, and maternal history of allergy. The use of maternal acid-suppressive medication was associated with an increased OR for the development of childhood asthma (3.7% in the population at large vs. 5.6% in exposed children, OR 1.51, 95% CI 1.35-1.69), but not for other allergic diseases.

CONCLUSION

These data provide first evidence of a significant association between in utero exposure to acid-suppressive drugs and the risk of developing childhood asthma.

Allergen specific responses in cord and adult blood are differentially modulated in the presence of endotoxins

Background

Endotoxins are common contaminants in allergen preparations and affect antigen-specific cellular responses. Distinct effects of endotoxin on cells in human umbilical cord and adult blood are poorly defined.

Objectives

To examine the effect of endotoxins in allergen preparations on cellular responses in human cord and peripheral blood (PB).

Methods

The endotoxin content in β lactoglobulin (BLG), the peanut allergen Ara h 1 and the major birch pollen allergen Bet v 1 was assessed. Proliferation and cytokine response of mononuclear cells towards contaminated and lipopolysaccharide (LPS)-free allergens were evaluated at different time-points. Fractions of contaminated BLG were generated and assayed on their immuno-stimulatory capacity. The involvement of toll-like receptor (TLR) 2 and 4 was investigated by blocking antibodies and TLR-transfected human embryonic kidney cells.

Results

The proliferative response of cord blood (CB)-derived mononuclear cells towards allergen-preparations at day 3 was related to the level of LPS contamination. At day 7, proliferation was also detected in the absence of endotoxin. Cytokine production in CB was strongly affected by the content of endotoxin, TLR-4 dependent and not related to the allergen content. Allergen- and endotoxin-induced proliferative responses were generally significantly higher in CB than in adult blood.

Conclusion

Endotoxins in allergen preparations confound allergen-specific cellular responses. The impact of these contaminations varies with the blood source (CB vs. PB), the type of allergen and is time- and dose-dependent.

Cite this as: T. Eiwegger, E. Mayer, S. Brix, I. Schabussova, E. Dehlink, B. Bohle, V. Barkholt and Z. Szépfalusi, Clinical and Experimental Allergy, 2008 (38) 1627–1634.

Heat- and formalin-inactivated probiotic bacteria induce comparable cytokine patterns in intestinal epithelial cell-leucocyte cocultures

The mode of inactivation of probiotic bacteria may profoundly affect their immune-modulatory properties to the point of reversal of effects in in vitro human intestinal epithelial-like cell cultures (Caco-2). To further investigate the influence of inactivation treatment on cytokine production, three probiotic strains were evaluated-live, heat-inactivated, and formalin-inactivated strains-for their impact on interleukin (IL) 6, IL-8, and IL-10 production in Caco-2-leucocyte cocultures. The tested bacteria induced strain-specific production of IL-6, IL-8, and IL-10. No suppressive effects on cytokine synthesis were observed. Live microorganisms seemed to be slightly more potent inducers of cytokine production than nonviable strains, but differences to inactivated bacteria were not statistically significant. Our results indicate that heat and formalin treatments of probiotic microorganisms are equivalent inactivation methods in terms of induction of IL-6, IL-8, and IL-10 production in Caco-2-peripheral blood mononuclear cell cocultures and do not invert immune-modulatory effects.

Immunoglobulin E-Mediated Allergies in Lung-Transplanted Adults

BACKGROUND

Immunoglobulin E (IgE)-mediated allergy has repeatedly been reported after solid organ transplantation, apparently affecting approximately 10% of pediatric organ transplant recipients. Interestingly, type 1 allergy has not been described in transplanted adults, suggesting a particular propensity in childhood.

METHODS

The present cross-sectional study assessed the prevalence of type 1 allergy in 42 adult lung transplant recipients aged 25 to 50 years. Instruments included standardized interviews, skin prick tests, and serum IgE measurements.

RESULTS

Ten of 42 patients (23.8%) displayed elevated specific IgE levels or positive skin prick test results against one or more allergens. Five individuals (11.9%) additionally reported corresponding clinical symptoms of type 1 allergy. No statistically significant association of sensitization or allergy prevalence with patient age, kind of immunosuppressive therapy, and time since transplantation was found.

CONCLUSIONS

The phenomenon of transplantation-associated allergy is not age-restricted and thus should be assessed more thoroughly in all age groups.

Gastro-duodenal digestion products of the major peanut allergen Ara h 1 retain an allergenic potential

BACKGROUND

The process of gastro-duodenal digestion may play a role in determining the allergenic properties of food proteins. The sensitizing and allergenic potential of digestion products of highly degraded allergens, such as the major peanut allergen Ara h 1, is currently under debate. We evaluated the effect of in vitro gastro-duodenal digestion of Ara h 1 on T cell reactivity and basophil histamine release.

METHODS

An in vitro model of gastro-duodenal digestion was used to investigate changes in the allergenic properties of Ara h 1 using in vitro assays monitoring T cell reactivity (proliferation, cytokine production) and histamine release of basophils from peanut allergic individuals. The digestion process was monitored using an SDS-PAGE gel.

RESULTS

In vitro gastric digestion led to rapid degradation of Ara h 1 into small fragments M(r) L5600. Gastric digestion did not affect the ability of Ara h 1 to stimulate cellular proliferation. Gastro-duodenal digestion significantly reduced its ability to stimulate clonal expansion (P<0,05; Wilxocon's signed rank test). The Th-2 type cytokine polarization of T cells from peanut allergic donors (IFN-gamma/IL-13 ratio and IFN-gamma/IL-4 ratio of CFSE(low) CD4(+) T cells) remained unchanged regardless of the level of digestion. Histamine release of basophils from peanut allergic individuals was induced to the same extent by native Ara h 1 and its digestion products.

CONCLUSION

Gastro-duodenal digestion fragments of Ara h 1 retain T cell stimulatory and IgE-binding and cross-linking properties of the intact protein.

Early exposure to latex products mediates latex sensitization in spina bifida but not in other diseases with comparable latex exposure rates

BACKGROUND

The high prevalence of latex sensitization in patients with spina bifida (SB) has been attributed to repeated and early exposure to latex products. Other diseases such as gastroschisis/omphalocoele and post-haemorrhagic/congenital hydrocephalus are also associated with repeated and early latex exposure.

OBJECTIVE

The aim of the study was to evaluate whether the high prevalence of latex sensitization in patients with SB is rather related to the underlying disease itself than to disease-associated known risk factors.

METHODS

We compared children with SB (n=35), children with gastroschisis/omphalocoele (G/O, n=20) and children with post-haemorrhagic/congenital hydrocephalus (PH, n=45). All children with SB and PH had a ventriculo-peritoneal shunt since a very young age. Patients who underwent three or less surgical procedures matched in terms of age, number of operations, atopy and gender distribution, and were analysed for IgE sensitization rates to latex.

RESULTS

In the SB group, 16 of 35 patients (46%) showed elevated latex-specific IgE antibodies in contrast to one of 20 patients (5%) in the G/O group and four of 45 patients (8.9%) in the PH group (P<0.0005 and P<0.005, Fisher's exact test). Comparing matched control groups (<or=3 operations), the effects remained significant (P<0.05 and P<0.01).

CONCLUSION

This study suggests that the SB population bears a disease-associated propensity for latex sensitization. This effect cannot be explained exclusively by a higher number of operations and differences related to atopy, age or gender.

Exhaled nitric oxide in the management of childhood asthma: a prospective 6-months study

Fractional exhaled nitric oxide (FeNO) is elevated in asthma and reflects eosinophilic airway inflammation. The aim of this prospective, randomized, single-blind study was to examine whether the inclusion of repeated FeNO measurements into asthma monitoring leads to an improvement in asthma outcome. Forty-seven children with mild to moderate asthma were allocated to a FeNO group (n = 22) and to a control group (n = 25). In the FeNO group therapy was based on symptoms, beta-agonist use, lung function, and FeNO whereas in the control group therapy was based on symptoms, beta-agonist use and lung function only. Patients performed five visits in 6 weeks intervals. Frequency of respiratory symptoms, beta-agonist use, FEV(1)% predicted and the frequency of exacerbations were similar between groups. Patients in the FeNO group received higher doses of inhaled corticosteroids (ICS) (control group: median (interquartile range): 241 microg (26-607 microg); FeNo group: 316 microg (200-500 microg) and had significantly higher MEF(50)% predicted (control group: median (interquartile range): 68.5% (55.8-83.1%); FeNO group: 83.2% (62.9%-98.3%). At a cut-off point of 22.9 ppb FeNO the best predictive value for exacerbations with a sensitivity of 80% and specificity of 60% was found. Significant relationships were observed between FeNO and dose of ICS (beta = -8.77; P < 0.002), beta-agonist use 2 weeks prior to a visit (beta = 0.11; P < 0.05), asthma symptoms (beta = 0.02; P < 0.0001), and bronchial hyperresponsiveness (beta = 0.04; P = 0.02). In conclusion, FeNO was related to important markers of asthma control. A therapy regimen aimed at lowering FeNO in children with asthma improved parameters of small airway function, but was not able to improve clinical markers of asthma control.

Most of diaplacentally transferred allergen is retained in the placenta

BACKGROUND

Transplacental transfer of nutritive and inhalant allergens has been described being potentially responsible for a series of events leading to antigen-specific immune responses in the fetus. As such, cord blood T cell responses appear ubiquitously. However, studies failed to reveal a consistent dose-response relationship between antenatal allergen exposure and allergen-specific cellular reactivity in cord blood.

OBJECTIVE

To examine the transfer process of allergens (ovalbumin (OVA), beta-lactoglobulin (BLG), birch pollen allergen Bet v1) in placental tissue (BeWo cell line, ex vivo placenta model).

METHODS

The choriocarcinoma cell line BeWo was used to study the allergen uptake and transfer experiments in vitro. In the ex vivo placenta model the contribution of different placental compartments was evaluated. For this, immuno-histochemistry, immuno-electronmicroscopy and ELISA techniques were applied using monoclonal antibodies to Bet v1, OVA and -BLG.

RESULTS

In vitro transfer studies on a BeWo cell-layer revealed an intracellular allergen uptake and a trans-trophoblastic allergen transfer, which was temperature- and concentration dependent, pH sensitive and asymmetric. Allergen-specific staining of placental tissue after allergen perfusion (BLG) demonstrated bulk of the allergen in the syncytio-trophoblastic cell layer and minor staining in the villous stroma and in the endothelium of fetal vessels. Immunogold staining revealed an accumulation of the perfused allergen in the trophoblastic basement membrane.

CONCLUSION

In vitro/ex vivo trans-trophoblastic and trans-placental allergen transfer is shown with an accumulation of most of the allergen in placental tissues, potentially explaining the missing direct dose-response relationship between prenatal (maternal) allergen exposure and allergen-specific cellular reactivity in cord blood.

Immunosuppressive therapy does not prevent the occurrence of immunoglobulin E-mediated allergies in children and adolescents with organ transplants

BACKGROUND

Allogeneic organ transplantation has become a common procedure in acute and chronic organ failure. The major limitation, rejection of the allograft by the host's immune system, can be limited by various immunosuppressive drugs that target the adaptive T-cell response. Most of these drugs are used in the treatment of allergic diseases as well, suggesting that transplant recipients under long-term immunosuppressive therapy should not develop any sensitizations or at least not show any clinical signs of allergy. Surprisingly, organ-transplanted children and adults do report symptoms of type 1 allergies, such as allergic rhinoconjunctivitis, bronchial asthma, and food allergies. Thus far, mainly case reports and series on the occurrence of allergy after orthotopic liver transplantation exist.

OBJECTIVE

Our purpose with this study was to evaluate in a cross-sectional design the prevalence of immunoglobulin E-mediated sensitizations and type 1 allergies in solid organ-transplanted children and adolescents and to identify risk factors.

METHODS

Seventy-eight organ-transplanted subjects (50 kidney, 9 lung, 19 liver; mean age: 14.06 +/- 5.94 years; range 1.42 to 24.25 years) were studied by standardized interviews (modified International Study of Asthma and Allergies in Childhood [ISAAC] criteria), skin-prick tests, and measurement of specific and total serum immunoglobulin E.

RESULTS

Nineteen patients (24.4%) were found to be sensitized to > or = 1 common inhalant or food allergens, as reflected by elevated specific immunoglobulin E levels and/or positive skin-prick test results, and 8 subjects (10.3%) additionally reported a corresponding present history of atopic diseases. No severe anaphylactic reactions were reported. No statistically significant associations with gender, kind of transplanted organ, distinct immunosuppressive therapies, and age at time of transplantation or age at investigation were found (chi2 test, Fisher's exact test, and Wilcoxon rank-sum test, respectively). Multiple logistic-regression analysis did not identify any independent risk factor either.

CONCLUSION

This study demonstrates that therapeutic immunosuppression does not control sensitizations and clinical manifestation of type 1 allergies in organ-transplanted children and adolescents.

Absence of systemic immunologic changes during dose build-up phase and early maintenance period in effective specific sublingual immunotherapy in children

BACKGROUND

Sublingual immunotherapy (SLIT) has been reported to be a safe treatment for inhalant allergies in children. Yet the immunologic mechanisms resulting in clinical improvement are poorly understood.

OBJECTIVE

To identify early systemic immunologic changes during the first 8 weeks of clinically effective SLIT to grass pollen, tree pollen or house dust mite in paediatric patients with allergic rhinoconjunctivitis and/or asthma.

METHODS

Peripheral blood mononuclear cells and plasma samples of 13 children with reduced symptoms after 1 year of SLIT were obtained before therapy and at 2 and 8 weeks after the initiation of SLIT. Allergen-specific lymphocyte proliferation assays were performed, and allergen-induced cytokine production (IL-2, IL-4, IL-10, IFN-gamma, and TGF-beta(1)) was measured by ELISA and flow cytometry. Allergen-specific IgE, IgG1, IgG4, and IgA levels in plasma samples were determined in ELISA.

RESULTS

During the first 8 weeks of successful SLIT, allergen-specific lymphoproliferation (n=13) as well as levels of allergen-specific intracellular (n=8) and secreted cytokines (n=9) did not change significantly. In addition, no alterations in levels of allergen-specific Igs (n=7) were observed.

CONCLUSION

We could not find any early systemic immunologic changes during the first 8 weeks of clinically effective SLIT to inhalant allergens in paediatric patients with allergic rhinoconjunctivitis and/or asthma.

[Cow's milk allergy: guidelines for the diagnostic evaluation]

About 2% of the general population and up to 6% of children suffer from food allergy. Cow's milk is charged with a important role in infancy after weaning, since conventional formula are based on its procession. IgE-mediated and Non-IgE- mediated allergic reactions, which are different in manifestation and pathogenesis, can be distinguished. A special role play the exacerbation of atopic dermatitis and the gastrointestinal-food-hypersensitivity-reactions. Skin-prick-test and determination of specific IgE are important diagnostic tools beside medical history. The golden standard of diagnosis is the double-blind-placebo-controlled-food- challenge. The clear result from food-challenge allows to verify suspected food allergies or, on the other hand, to avoid unnecessary diets. Extensively-hydrolysed-formula or Amino-acidformula are a high nutritional value alternative in case of proved cow's milk allergy in infancy.

Human milk--derived oligosaccharides and plant-derived oligosaccharides stimulate cytokine production of cord blood T-cells in vitro

Human milk contains large amounts of free oligosaccharides (HMOs). HMOs have been shown to exert antiinflammatory properties, and evidence for their immunomodulatory effects is increasing. The purpose of this study was to evaluate influences of two human breast milk-derived oligosaccharide samples (neutral and acidic oligosaccharides), and of a low-molecular-weight fucoidan on cytokine production and activation of cord blood mononuclear cells. Cord blood mononuclear cells from randomly chosen healthy newborns were co-cultured with the oligosaccharide samples. By means of flow cytometry, intracellular cytokine production (d 20) and surface marker expression of T cells (d 5) were measured. In vitro-induced Ig levels were quantified nephelometrically (total IgG1) and by ELISA (total IgE) in the supernatant of cell cultures. The acidic oligosaccharide fraction increased the percentage of interferon-gamma producing CD3+CD4+ and CD3+CD8+ cells (p < 0.05) and the IL-13 production in CD3+CD8+ cells (p < 0.05). In acidic oligosaccharide cultures, CD25+ expression on CD3+CD4+ cells was significantly elevated (p < 0.05). Low-molecular-weight fucoidan induced IL-4 production in CD3+CD4+ T cells (p < 0.05) and IL-13 production in CD3+CD8+ T cells (p < 0.05), whereas interferon-gamma production remained unaffected in both T-cell populations. Ig production (total IgE and total IgG1) remained unaffected. Human milk-derived oligosaccharides and plant-derived oligosaccharides affect the cytokine production and activation of cord blood derived T cells in vitro. Therefore, oligosaccharides and, in particular, acidic oligosaccharides may influence lymphocyte maturation in breast-fed newborns.

Increased prevalence of latex-sensitization among children with chronic renal failure

BACKGROUND

Type-I-allergy to natural rubber latex (NRL) has been shown to be more prevalent among certain groups of patients. Children suffering from chronic renal failure (CRF) could be a suspected risk group because of their intense exposure to latex through catheters, gloves and anesthetic equipment during frequent hospitalizations from early life on. We investigated the prevalence of latex-sensitization among this group of patients and sought to identify risk factors.

METHODS

Ninety-three patients (mean age 10.5 years) suffering from CRF were assessed by questionnaire-based history (details on renal disease, number and kind of surgical procedures, family and personal history of atopic diseases, allergic reactions to NRL, and the use of pacifiers) and by measurement of total and latex-specific serum immunoglobulin (Ig)E.

RESULTS

Ten of 93 (10.8%) patients showed elevated latex-specific IgE-levels. One of 10 patients reported clinical symptoms to latex-allergen, but no allergic reactions to NRL during medical care were reported. Sensitized patients were significantly more likely to be atopic, reflected by a positive history of other allergies as well as elevated total serum IgE-levels, and had a significantly higher number of urogenital surgeries (P = 0.02 in all cases, Fisher's exact and Wilcoxon test, respectively).

CONCLUSION

This study demonstrates that children with CRF are at increased risk of latex-hypersensitivity. Significant associations with atopy and repeated surgeries were observed. Larger studies are required to elucidate whether these children are also at increased risk of anaphylaxis and therefore deserve preventive measures.