Advances in asthma, allergy mechanisms, and genetics in 2006

Genomic evidence for shared common ancestry of East African hunting-gathering populations and insights into local adaptation

Anatomically modern humans arose in Africa ∼300,000 years ago, but the demographic and adaptive histories of African populations are not well-characterized. Here, we have generated a genome-wide dataset from 840 Africans, residing in western, eastern, southern, and northern Africa, belonging to 50 ethnicities, and speaking languages belonging to four language families. In addition to agriculturalists and pastoralists, our study includes 16 populations that practice, or until recently have practiced, a hunting-gathering (HG) lifestyle. We observe that genetic structure in Africa is broadly correlated not only with geography, but to a lesser extent, with linguistic affiliation and subsistence strategy. Four East African HG (EHG) populations that are geographically distant from each other show evidence of common ancestry: the Hadza and Sandawe in Tanzania, who speak languages with clicks classified as Khoisan; the Dahalo in Kenya, whose language has remnant clicks; and the Sabue in Ethiopia, who speak an unclassified language. Additionally, we observed common ancestry between central African rainforest HGs and southern African San, the latter of whom speak languages with clicks classified as Khoisan. With the exception of the EHG, central African rainforest HGs, and San, other HG groups in Africa appear genetically similar to neighboring agriculturalist or pastoralist populations. We additionally demonstrate that infectious disease, immune response, and diet have played important roles in the adaptive landscape of African history. However, while the broad biological processes involved in recent human adaptation in Africa are often consistent across populations, the specific loci affected by selective pressures more often vary across populations.

Galectin-3: One Molecule for an Alphabet of Diseases, from A to Z

Galectin-3 (Gal-3) regulates basic cellular functions such as cell-cell and cell-matrix interactions, growth, proliferation, differentiation, and inflammation. It is not surprising, therefore, that this protein is involved in the pathogenesis of many relevant human diseases, including cancer, fibrosis, chronic inflammation and scarring affecting many different tissues. The papers published in the literature have progressively increased in number during the last decades, testifying the great interest given to this protein by numerous researchers involved in many different clinical contexts. Considering the crucial role exerted by Gal-3 in many different clinical conditions, Gal-3 is emerging as a new diagnostic, prognostic biomarker and as a new promising therapeutic target. The current review aims to extensively examine the studies published so far on the role of Gal-3 in all the clinical conditions and diseases, listed in alphabetical order, where it was analyzed.

Resolving the etiology of atopic disorders by using genetic analysis of racial ancestry

Atopic dermatitis (AD), food allergy, allergic rhinitis, and asthma are common atopic disorders of complex etiology. The frequently observed atopic march from early AD to asthma, allergic rhinitis, or both later in life and the extensive comorbidity of atopic disorders suggest common causal mechanisms in addition to distinct ones. Indeed, both disease-specific and shared genomic regions exist for atopic disorders. Their prevalence also varies among races; for example, AD and asthma have a higher prevalence in African Americans when compared with European Americans. Whether this disparity stems from true genetic or race-specific environmental risk factors or both is unknown. Thus far, the majority of the genetic studies on atopic diseases have used populations of European ancestry, limiting their generalizability. Large-cohort initiatives and new analytic methods, such as admixture mapping, are currently being used to address this knowledge gap. Here we discuss the unique and shared genetic risk factors for atopic disorders in the context of ancestry variations and the promise of high-throughput "-omics"-based systems biology approach in providing greater insight to deconstruct their genetic and nongenetic etiologies. Future research will also focus on deep phenotyping and genotyping of diverse racial ancestry, gene-environment, and gene-gene interactions.

Association between thromboxane A2 receptor polymorphisms and asthma risk: A meta-analysis

OBJECTIVE

To determine whether there is an association between thromboxane A2 receptor (TBXA2R) gene polymorphisms (+924C/T and +795C/T) and asthma risk by conducting a meta-analysis.

DATA SOURCES

Pubmed, Embase, Chinese National Knowledge Infrastructure (CNKI) and Wanfang database were searched (updated May 1, 2015).

STUDY SELECTIONS

Articles evaluating the association between TBXA2R gene polymorphisms and asthma risk were selected.

RESULTS

A total of 7 studies on +924C/T polymorphism and 6 studies on +795C/T polymorphism were included in this meta-analysis. There was a significant association between TBXA2R +924C/T polymorphism and asthma risk in the recessive model (OR = 1.33, 95% CI = 1.01-1.75, P = 0.045). No significant association between +795C/T polymorphism and asthma risk in the overall population was demonstrated. In subgroup analyzes, significant association was observed in atopic asthma risk in the recessive model (OR = 1.43, 95% CI = 1.01-2.01, P = 0.043), but no significant association was found between TBXA2R +924C/T polymorphism and asthma risk in Asians (OR = 1.14, 95% CI = 0.80-1.63, P = 0.457). TBXA2R +795C/T polymorphism was associated with aspirin-intolerant asthma (AIA) risk when stratified by asthma subphenotype in the allelic model (OR = 1.30, 95% CI = 1.05-1.60, P = 0.014) and dominant model (OR = 1.50, 95% CI = 1.11-2.03, P = 0.008).

CONCLUSION

Our results suggested that TBXA2R +924C/T polymorphism is associated with asthma risk, and +795C/T polymorphism may be a risk factor for AIA. Larger-scale and well-designed studies are required to validate the association identified in the current meta-analysis.

DNA Microarray Analysis of Submandibular Glands in IgG4-Related Disease Indicates a Role for MARCO and Other Innate Immune-Related Proteins

IgG4-related disease (IgG4-RD) is a novel systemic disease entity characterized by elevated serum IgG4 and tissue infiltration of IgG4-positive plasma cells accompanied by severe fibrosis. Although recent studies demonstrated that innate immune cells including monocytes and macrophages might promote local fibrosis and IgG4 production, the pathological mechanism remains unclear. In this study, we sought to identify the disease-associated genes, especially innate immune molecules. Gene expression was analyzed by DNA microarray in submandibular glands (SMGs) from patients with IgG4-RD (n = 5), chronic sialoadenitis (CS) (n = 3), and controls (n = 3). Differentially expressed genes (DEGs) were validated by real-time polymerase chain reaction (PCR) and immunohistochemical staining in IgG4-RD (n = 18), CS (n = 4), Sjögren syndrome (n = 11), and controls (n = 10). Gene expression patterns in the 3 groups were quite different from each other by the pvclust method and principal components analysis. In IgG4-RD, 1028 upregulated genes and 692 downregulated genes were identified as DEGs (P < 0.05). Gene Ontology (GO) term analysis indicated that the upregulated DEGs in IgG4-RD encoded proteins involved in T/B cell activation and chemotaxis. PCR validated significantly higher expression of macrophage receptor with collagenous structure (MARCO), a pattern-recognition receptor, in IgG4-RD compared with the other groups (P < 0.01). Immunohistochemical analysis confirmed that the expression pattern of MARCO was similar to that of the M2 macrophage marker CD163. MARCO was identified as a disease-associated molecule in IgG4-RD by DNA microarray. Moreover, M2 macrophages might contribute to the initiation of IgG4-RD via MARCO.

Human IgE against the major allergen Bet v 1--defining an epitope with limited cross-reactivity between different PR-10 family proteins

Background

The interaction between IgE and allergen is a key event at the initiation of an allergic response, and its characteristics have substantial effects on the clinical manifestation. Despite this, the molecular details of the interaction between human IgE and the major birch allergen Bet v 1, one of the most potent tree allergens, still remain poorly investigated.

Objective

To isolate Bet v 1-specific human monoclonal IgE and characterize their interaction with the allergen.

Methods

Recombinant human IgE were isolated from a combinatorial antibody fragment library and their interaction with Bet v 1 assessed using various immunological assays. The structure of one such IgE in the single-chain fragment variable format was determined using X-ray crystallography.

Results

We present four novel Bet v 1-specific IgE, for one of which we solve the structure, all with their genetic origin in the IGHV5 germline gene, and demonstrate that they target two non-overlapping epitopes on the surface of Bet v 1, thereby fulfilling the basic criteria for FcεRI cross-linkage. We further define these epitopes and for one epitope pinpoint single amino acid residues important for the interaction with human IgE. This provides a potential explanation, at the molecular level, for the differences in recognition of isoforms of Bet v 1 and other allergens in the PR-10 protein family displayed by IgE targeting this epitope. Finally, we present the first high-resolution structure of a human allergen-specific IgE fragment in the single-chain fragment variable (scFv) format.

Conclusions and Clinical Relevance

We here display the usefulness of allergen-specific human monoclonal IgE as a tool in studies of the crucial molecular interaction taking place at the initiation of an allergic response. Such studies may aid us in development of better diagnostic tools and guide us in the development of new therapeutic compounds.

Novel genes in Human Asthma Based on a Mouse Model of Allergic Airway Inflammation and Human Investigations

Purpose

Based on a previous gene expression study in a mouse model of asthma, we selected 60 candidate genes and investigated their possible roles in human asthma.

Methods

In these candidate genes, 90 SNPs were genotyped using MassARRAY technology from 311 asthmatic children and 360 healthy controls of the Hungarian (Caucasian) population. Moreover, gene expression levels were measured by RT PCR in the induced sputum of 13 asthmatics and 10 control individuals. t-tests, chi-square tests, and logistic regression were carried out in order to assess associations of SNP frequency and expression level with asthma. Permutation tests were performed to account for multiple hypothesis testing.

Results

The frequency of 4 SNPs in 2 genes differed significantly between asthmatic and control subjects: SNPs rs2240572, rs2240571, rs3735222 in gene SCIN, and rs32588 in gene PPARGC1B. Carriers of the minor alleles had reduced risk of asthma with an odds ratio of 0.64 (0.51-0.80; P=7×10^-5) in SCIN and 0.56 (0.42-0.76; P=1.2×10^-4) in PPARGC1B. The expression levels of SCIN, PPARGC1B and ITLN1 genes were significantly lower in the sputum of asthmatics.

Conclusions

Three potentially novel asthma-associated genes were identified based on mouse experiments and human studies.

A range of Cℇ3-Cℇ4 interdomain angles in IgE Fc accommodate binding to its receptor CD23

The antibody IgE plays a central role in allergic disease, functioning principally through two cell-surface receptors: FcℇRI and CD23. FcℇRI on mast cells and basophils mediates the immediate hypersensitivity response, whilst the interaction of IgE with CD23 on B cells regulates IgE production. Crystal structures of the lectin-like `head' domain of CD23 alone and bound to a subfragment of IgE consisting of the dimer of Cℇ3 and Cℇ4 domains (Fcℇ3-4) have recently been determined, revealing flexibility in the IgE-binding site of CD23. Here, a new crystal form of the CD23-Fcℇ3-4 complex with different molecular-packing constraints is reported, which together with the earlier results demonstrates that conformational variability at the interface extends additionally to the IgE Fc and the quaternary structure of its domains.

Immunopathogenesis of allergic disorders: current concepts

Allergic disorders are a group of immune-mediated disorders that are associated with considerable morbidity and ill health. There has been significant rise in the prevalence of allergy in the last few years. This has heightened interest in uncovering the novel mechanisms involved in etiopathogenesis of allergic disorders. Understanding the pathways underlying allergy will help in developing effective modalities for its prevention and treatment. This review focuses primarily on common IgE-mediated allergic conditions and recent developments in their immunopathogenesis, especially those involving respiratory mucosa.

Ca2+-dependent structural changes in the B-cell receptor CD23 increase its affinity for human immunoglobulin E

Immunoglobulin E (IgE) antibodies play a fundamental role in allergic disease and are a target for therapeutic intervention. IgE functions principally through two receptors, FcϵRI and CD23 (FcϵRII). Minute amounts of allergen trigger mast cell or basophil degranulation by cross-linking IgE-bound FcϵRI, leading to an inflammatory response. The interaction between IgE and CD23 on B-cells regulates IgE synthesis. CD23 is unique among Ig receptors in that it belongs to the C-type (calcium-dependent) lectin-like superfamily. Although the interaction of CD23 with IgE is carbohydrate-independent, calcium has been reported to increase the affinity for IgE, but the structural basis for this activity has previously been unknown. We have determined the crystal structures of the human lectin-like head domain of CD23 in its Ca²⁺-free and Ca²⁺-bound forms, as well as the crystal structure of the Ca²⁺-bound head domain of CD23 in complex with a subfragment of IgE-Fc consisting of the dimer of Cϵ3 and Cϵ4 domains (Fcϵ3-4). Together with site-directed mutagenesis, the crystal structures of four Ca²⁺ ligand mutants, isothermal titration calorimetry, surface plasmon resonance, and stopped-flow analysis, we demonstrate that Ca²⁺ binds at the principal and evolutionarily conserved binding site in CD23. Ca²⁺ binding drives Pro-250, at the base of an IgE-binding loop (loop 4), from the trans to the cis configuration with a concomitant conformational change and ordering of residues in the loop. These Ca²⁺-induced structural changes in CD23 lead to additional interactions with IgE, a more entropically favorable interaction, and a 30-fold increase in affinity of a single head domain of CD23 for IgE. Taken together, these results suggest that binding of Ca²⁺ brings an extra degree of modulation to CD23 function.

Prevalence of allergic sensitization versus allergic rhinitis symptoms in an unselected population

BACKGROUND

Allergic rhinitis (AR) is the most common allergic disorder and its prevalence has significantly increased worldwide, nowadays affecting up to 40% of the population in young adults. The objective of the present survey was to evaluate the prevalence of allergic sensitization and the prevalence of clinically diagnosed AR in a sample of the Belgian population, and to estimate the effect of age and gender.

METHODS

We performed a cross-sectional population-based study at an annual public fair in Ghent. Participants underwent a skin prick test (SPT) to 3 aeroallergens: a mix of trees (hazel, alder, and birch), grass pollen, and house dust mite (HDM). The clinical relevance of sensitization was assessed by relating relevant symptoms of AR to the corresponding SPT.

RESULTS

A total of 2,320 participants (1,475 females, median age 44.7 years, range 3-86) were included in this study. The standardized prevalence rates of sensitization were 13.2% for tree mix, 25.9% for grass pollen, and 25.9% for HDM. Sensitization to at least one of the allergens was present in 40.3% of the subjects. Symptomatic sensitization related to trees was reported in 9.7% of cases, grass-related AR was 17.6%, and HDM-related AR was 17.1%. The overall prevalence of AR was 30.9%.

CONCLUSION

In this study we demonstrated a 40.3% prevalence of a positive SPT to one or more common aeroallergens. A clinical diagnosis of AR was present in 30.9% of cases, peaking in the third and fourth decades of life. It is to be expected that in the next decades, when this generation grows older, the general AR prevalence will further increase.

Interleukin 12 receptor deficiency in a child with recurrent bronchopneumonia and very high IgE levels

Interleukin-12 (IL-12) is involved in cellular immune responses against intracellular pathogens by promoting the generation of T naive in T helper 1 (Th1) cells and by increasing interferon-gamma (IFN-gamma) production from T and natural killer (NK) cells. A defective induction of a Th1 response may lead to a higher risk of infections, and, in particular, infections due to typical and atypical Mycobacteria. We report on the case of a girl with suffering from recurrent bronchopneumonia associated with very high serum IgE levels, who exhibited a profound impairment of the Th1 generation associated with a novel mutation in the exon 5 of the IL-12R β1 gene (R156H). Our data suggest that in children with severe and recurrent infections, even in the absence of a mycobacterial infection, functional and/or genetic alterations of the molecular mechanisms governing Th1/Th2 homeostasis might be responsible for an atypical immunodeficiency and, therefore, should be investigated in these patients.

Gene-gene interactions between candidate gene polymorphisms are associated with total IgE levels in Korean children with asthma

OBJECTIVE

To investigate associations between total serum immunoglobulin E (IgE) levels and single nucleotide polymorphisms (SNPs) from eight candidate genes (IL-4 rs2243250, IL-4Rα rs1805010, IL-13 rs20541, IL-13Rα1 rs2495636, CD14 rs2569190, tumor necrosis factor-alpha (TNF-α) rs1800629, cytotoxic T lymphocyte-associated antigen (CTLA4) rs231775, FCER1B rs1441585) in children with asthma and to evaluate gene-gene interactions.

METHODS

A total of 669 Korean children with asthma (n = 544 atopic n = 125 non-atopic) were included. Asthma phenotypes, total serum IgE levels, and methacholine challenge test results were evaluated. SNPs were genotyped using the polymerase chain reaction-restriction fragment length polymorphisms (PCR-RFLP) method. Multi-factor dimensionality reduction (MDR) was used to analyze gene-gene interactions.

RESULTS

The combination of the IL-13, IL-13Rα1, and CTLA4 polymorphisms was selected through MDR analysis of the data pertaining to children with atopic and non-atopic asthma (accuracy = 0.5459, cross validation consistency (CVC) = 10/10). The IL-4Rα, IL-13, IL-13Rα1, CD14, and CTLA4 polymorphisms were selected as the best model of increased total serum IgE levels in non-atopic and atopic asthma (asthma: accuracy = 0.4726, CVC = 10/10; atopic asthma: accuracy = 0.4573, CVC = 10/10). Both the IL-4Rα and the IL-13 polymorphisms were correlated with the IgE level. ANOVA analysis revealed that the combinations of the CTLA4 and IL-13, IL-13 and IL-13Rα1, IL-4Rα and IL-13, and CD14 and IL-13 polymorphisms were all significantly associated with increased total serum IgE levels.

CONCLUSIONS

The best model of increased IgE level included the IL-4Rα, IL-13, IL-13Rα1, CD14, and CTLA4 polymorphisms. Of the various interactions between these polymorphisms, the combinations of the CTLA4 and IL-13 polymorphisms and the IL-13 and IL-13Rα1 polymorphisms showed synergistic effects in terms of increased total serum IgE levels in the present cohort.

Th2 and regulatory immune reactions contribute to IgG4 production and the initiation of Mikulicz disease

OBJECTIVE

Mikulicz disease has been considered to be a subtype of Sjögren's syndrome (SS). However, recent studies have suggested that Mikulicz disease is an IgG4-related disease and is distinguishable from SS. In addition, it has been reported that both interleukin-4 (IL-4) and IL-10 induce IgG4 production and inhibit IgE. This study was undertaken to examine the expression of these cytokines in patients with Mikulicz disease and patients with SS.

METHODS

Labial salivary gland (LSG) sections from 15 patients with Mikulicz disease and 18 patients with SS were examined for subsets of the infiltrating lymphocytes, expression patterns of messenger RNA (mRNA) for cytokines/chemokines, and relationships between the IgG4:IgG ratio and the expression of mRNA for IL-4 or IL-10.

RESULTS

Immunohistochemical analysis showed lymphocyte infiltration of various subsets in the LSGs of SS patients, and the selective infiltration of IgG4-positive plasma cells and Treg cells in the LSGs of Mikulicz disease patients. The levels of mRNA for both Th1 and Th2 cytokines and chemokines in LSGs from patients with SS were significantly higher than in controls, while the expression of both Th2 and Treg cells was significantly higher in the patients with Mikulicz disease than in controls. Furthermore, the expression of IL-4 or IL-10 in the LSGs was correlated with the IgG4:IgG ratio.

CONCLUSION

These results suggest that the pathogenesis of Mikulicz disease is different from that of SS. Mikulicz disease is a unique inflammatory disorder characterized by Th2 and regulatory immune reactions that might play key roles in IgG4 production.

TBX21 and HLX1 polymorphisms influence cytokine secretion at birth

BACKGROUND

TBX21 (T cell specific T-box transcription factor) and HLX1 (H.20-like homeobox 1) are crucial transcription factors of T(H)1-cells, inducing their differentiation and suppressing T(H)2 commitment, particularly important for early life immune development. This study investigated the influence of TBX21 and HLX1 single nucleotide polymorphisms (SNPs), which have previously been shown to be associated with asthma, on T(H)1/T(H)2 lineage cytokines at birth.

METHODS AND FINDINGS

Cord blood mononuclear cells (CBMCs) of 200 neonates were genotyped for two TBX21 and three HLX1 SNPs. CBMCs were stimulated with innate (Lipid A, LpA; Peptidoglycan, Ppg), adaptive stimuli (house dust mite Dermatophagoides pteronyssinus 1, Derp1) or mitogen (phytohemagglutinin, PHA). Cytokines, T-cells and mRNA expression of T(H)1/T(H)2-related genes were assessed. Atopic diseases during the first 3 years of life were assessed by questionnaire answered by the parents. Carriers of TBX21 promoter SNP rs17250932 and HLX1 promoter SNP rs2738751 showed reduced or trendwise reduced (p≤0.07) IL-5, IL-13 and TNF-α secretion after LpA-stimulation. Carriers of HLX1 SNP rs2738751 had lower IL-13 levels following Ppg-stimulation (p = 0.08). Carriers of HLX1 exon 1 SNP rs12141189 showed increased IL-5 (LpA, p = 0.007; Ppg, p = 0.10), trendwise increased IL-13 (LpA), higher GM-CSF (LpA/Ppg, p≤0.05) and trendwise decreased IFN-γ secretion (Derp1+LpA-stimulation, p = 0.1). Homozygous carriers of HLX1 promoter SNP rs3806325 showed increased IL-13 and IL-6 (unstimulated, p≤0.03). In carriers of TBX21 intron 3 SNP rs11079788 no differences in cytokine secretion were observed. mRNA expression of T(H)1/T(H)2-related genes partly correlated with cytokines at protein level. TBX21 SNP rs11079788 carriers developed less symptoms of atopic dermatitis at 3 years of age (p = 0.03).

CONCLUSIONS

Polymorphisms in TBX21 and HLX1 influenced primarily IL-5 and IL-13 secretion after LpA-stimulation in cord blood suggesting that genetic variations in the transcription factors essential for the T(H)1-pathway may contribute to modified T(H)2-immune responses already early in life. Further follow-up of the cohort is required to study the polymorphisms' relevance for immune-mediated diseases such as childhood asthma.

Impairment of lung function might be related to IL-10 and IFN-γ defective production in allergic children

A functional defect of T regulatory cells (Tregs) has been proposed as pathogenic mechanism of allergic reaction. Impairment of lung function frequently occurs in children with respiratory allergy. This study aimed at investigating the possible role of IL-10 and IFN-γ on lung function deterioration in allergic children. Forty children with mild asthma, monosensitized to house dust mites, were evaluated and followed-up for 2 years. Spirometry was performed in all children. IL-10 and IFN-γ were evaluated in in vitro experiments. FEV(1), FVC, and FEF(25-75), evaluated as percent of predicted, significantly diminished over time (p<0.0001, p=0.03, and p<0.0001 respectively). There was a strong relationship between changes in spirometric parameters and IL-10 production and between changes in FEV(1) values and IFN-γ production over time. This preliminary study provided evidence that IL-10 and IFN-γ production could be defective in allergic children prone to develop functional impairment.

Diversity of immunoglobulin E-encoding transcripts in sinus mucosa of subjects diagnosed with non-allergic fungal eosinophilic sinusitis

BACKGROUND

The role of allergy in the aetiopathogenesis of chronic rhinosinusitis (CRS) remains controversial. For example, in some cases with sinus fungal infections allergy can be demonstrated by standard tests. In other cases, such signs can be absent despite elevated levels of IgE-positive cells in sinus tissue and the presence of IgE and eosinophils in the sinus mucous.

OBJECTIVE

To define the nature of molecular diversity in antibodies of the IgE isotype at the site of local inflammation in subjects diagnosed with non-allergic fungal eosinophilic sinusitis (NAFES).

METHODS

The local occurrence and sequence characteristics of IgE-encoding transcripts in NAFES patients were investigated and compared with sequences found in subjects diagnosed with CRS featuring systemic allergy. These sequences have also been compared with other reported IgE-encoding transcriptomes. Results IGHV genes derived from major subgroups 1, 3, 4 and 5 and a diverse set of IGHD and IGHJ genes were shown to create the IgE repertoire in patients diagnosed with NAFES and CRS. The average lengths of the third hypervariable loop in these populations were 15.8 and 14.6 residues. The sequences showed evidence of extensive somatic hypermutation (mutation frequency: NAFES, 6.4 ± 3.2%; CRS, 7.0 ± 4.4%) with substitutions targeted to complementarity-determining regions. These sequence collections thus show extensive similarities to those found in other polyclonal Ig repertoires including those encoding IgE.

CONCLUSION AND CLINICAL RELEVANCE

We conclude that sinus IgE-encoding transcripts in subjects diagnosed with NAFES show evidence of conventional IgE responses and we suggest that allergens with characteristics of classical antigens should be investigated for a role in the local response occurring in NAFES. This investigation illustrates that assessment of local immunity might be an important diagnostic tool in conditions like NAFES with no systemic signs of allergy to identify or rule out an allergic component of the patient's disease.

Maternal C-reactive protein levels in pregnancy are associated with wheezing and lower respiratory tract infections in the offspring

OBJECTIVE

We assessed whether maternal C-reactive protein (CRP) levels during pregnancy and CRP gene variations are associated with wheezing and lower respiratory tract infections (LRTIs) in offspring.

STUDY DESIGN

Information on wheezing and LRTIs in the offspring at 6 and 14 months of age, and maternal CRP levels and genotype was obtained from a population-based birth cohort.

RESULTS

A total of 63 children (12.5%) experienced recurrent wheezing and 61 (12.4%) a recurrent diagnosis of LRTIs. Children in the highest tertile of maternal CRP levels had a higher risk of experiencing recurrent wheezing (adjusted odds ratio, 2.87; 95% confidence interval, 1.23-6.71) and being diagnosed with recurrent LRTIs (odds ratio, 2.37; 95% confidence interval, 1.01-5.55), as compared with children in the lowest tertile. The rs1205 polymorphism influenced maternal serum CRP levels but not the risk of the offspring outcomes.

CONCLUSION

Higher CRP levels in pregnancy are associated with wheezing and LRTIs in offspring. However, genetic variation in CRP influencing maternal levels is not related to these phenotypes.

Immunoglobulin Production Pattern in Allergic and Non-Allergic Subjects

Allergic rhinitis (AR) is characterized by Th2 polarized immune response, such as increased IL-4 and reduced IFN-γ production, and by a functional defect of T regulatory cells. This impaired immune response profile influences the pattern of immunoglobulin (Ig) production in allergic patients. However, no studies have compared the pattern of inhalant allergen-specific Ig classes between allergic patients and normal subjects. The aim of this study is to therefore investigate the allergen-specific IgE, IgG, IgG4, and IgA serum level pattern in a group of patients with pollen allergy and in non-allergic healthy subjects. One hundred and two allergic patients (evaluated both out of and in the pollen season) were enrolled. In addition, 50 healthy non-allergic subjects were recruited during the whole year. Serum allergen-specific IgE, IgG, IgG4, and IgA for Parietaria, grasses, and birch were quantitatively determined by the ImmunoCAP System method. Allergen-specific IgE, IgG, IgG4, and IgA serum levels were significantly different for each tested allergen (p=0.0001 for each class) among groups. Allergic patients, mainly during pollen season, showed the highest IgG, IgG4, and IgA levels. The present study therefore provides the preliminary evidence that Ig production pattern toward inhalant allergens may depend on the specificity of the allergenic response both in non-allergic subjects and allergic patients Allergic patients do not show a defect of IgG and IgA classes. In addition, this study is the first that quantitatively evaluates the Ig classes. However, further studies should include non-allergic subjects evaluated both during and out of the pollen season.

Altered signaling through IL-12 receptor in children with very high serum IgE levels

An alteration of Th1/Th2 homeostasis may lead to diseases in humans. In this study, we investigated whether an impaired IL-12R signaling occurred in children with elevated serum IgE levels divided on the basis of the IgE levels (group A: >2000kU/l; group B: <2000kU/l). We evaluated the integrity of the IL-12R signaling through the analysis of phosphorylation/activation of STAT4, and mRNA expression and membrane assembly of the receptor chains. At a functional level, a proliferative defect of lymphocytes from group A patients was observed. In these patients, an abnormal IL-12R signaling was documented, and this finding was associated with abnormal expression of the IL-12Rbeta2 chain. Our data indicate that in patients with very high IgE levels the generation of Th1 response is impaired, and that this abnormality associates with abnormal IL-12R signaling.

Interferon-gamma and IL-10 may protect from allergic polysensitization in children: preliminary evidence

BACKGROUND

A functional defect of T regulatory cells (Treg) has been proposed as pathogenic mechanism of allergic reaction. Polysensitization is a common feature of allergic patients.

AIM OF THE STUDY

It was to investigate the possible role of Treg-Th1 cytokines, in the development of new sensitizations in childhood.

METHODS

Forty monosensitized (MS) children with allergic rhinitis were evaluated and followed-up for 2 years. New sensitizations were investigated. IL-10 and IFN-gamma were evaluated in in vitro experiments.

RESULTS

Children remaining MS showed significant higher production of both IL-10 and IFN-gamma.

CONCLUSION

This preliminary study provided evidence that IL-10 and IFN-gamma production could be defective in allergic children prone to develop polysensitization.

Regulation of T cells in airway disease by beta-agonist

It is widely recognized that Th2 cytokines derived from T cells play a major role in the development of allergic lung inflammation that causes most asthma. Beta-agonists are important rescue and maintenance therapies for asthma, yet our understanding of beta-agonist effects on T cell biology is surprisingly poor. Recent studies using both cell culture and more integrative models are beginning to reveal beta-agonist regulation of T cell signaling and function that may be important in the pathogenesis and treatment of asthma and possibly other inflammatory diseases. Here we provide a comprehensive review of the literature concerning beta-agonist effects on T cells, and discuss the relevance of emerging paradigms of beta-adrenergic receptor signaling to T cell function.

Association between reduced copy-number at T-cell receptor gamma (TCRgamma) and childhood allergic asthma: A possible role for somatic mosaicism

Asthma is a chronic inflammatory disease of the lungs which affects more than 6.5 million American children. A family-based genome-wide association study of copy-number variation identified an association between decreased copy-number at TCRgamma and childhood allergic asthma. TCRgamma encodes the T-cell receptor gamma glycoprotein, a cell-surface protein found on T-cells and involved in cell-mediated immunity. Using quantitative real-time PCR, we sought to determine if copy-number variation at TCRalpha, TCRbeta or TCRgamma was associated with childhood allergic asthma in an independent cohort of 94 cases and 455 controls using DNA from buccal swabs. Copy-number variation at these loci is well-known, but appears to be dominated by somatic mutations. Genotyping results indicated that copy-number variants at these genes are largely somatic mutations, as inheritance did not show Mendelian consistency. In these mosaic cell populations, copy-number was significantly reduced among asthmatic children at TCRgamma (p=0.0199), but was not associated at TCRalpha or TCRbeta (p=0.7972 and 0.8585, respectively). These findings support the association between reduced copy-number at TCRgamma and childhood allergic asthma. Further work is needed to resolve whether reduced copy-number at TCRgamma predisposes individuals to asthma, or whether deletion of this gene is a somatic response to the disease.

Elispot and Elisa Assessment of Interferon-Gamma after Sublingual Immunotherapy

Allergic rhinitis (AR) is characterized by a Th2 polarized immune response, and specific immunotherapy modifies this arrangement, restoring a physiologic Th1 profile. Sublingual immunotherapy (SLIT) is widely prescribed. The aim of the study is to evaluate two different methods for assessing IFN-γ, namely ELISPOT and ELISA, before and after a pre-seasonal SLIT course as marker for Th1 response. Thirty-eight AR patients with pollen allergy assumed pre-seasonal SLIT for 3 months. Patients' blood samples for assessing IFN-γ serum levels were collected before initiating SLIT (baseline – T0), after 3 months pre-seasonal SLIT course (T1), and three months after completion of SLIT (T2). IFN-γ-specific producing cells, after allergen stimulation, were assessed by cytokine ELISPOT at the same time points. IFN-γ-specific producing cells significantly increased after SLIT both at T1 and T2 (p=0.0002). On the contrary, ELISA assessment did not reveal an increase in IFN-γ serum levels at any time point. In conclusion, these results demonstrate that ELISA assessment of serum IFN-γ is not suitable for identifying an early response.

Effects of food processing on food allergens

Food allergies are on the rise in Western countries. With the food allergen labeling requirements in the US and EU, there is an interest in learning how food processing affects food allergens. Numerous foods are processed in different ways at home, in institutional settings, and in industry. Depending on the processing method and the food, partial or complete removal of the offending allergen may be possible as illustrated by reduction of peanut allergen in vitro IgE immunoreactivity upon soaking and blanching treatments. When the allergen is discretely located in a food, one may physically separate and remove it from the food. For example, lye peeling has been reported to produce hypoallergenic peach nectar. Protein denaturation and/or hydrolysis during food processing can be used to produce hypoallergenic products. This paper provides a short overview of basic principles of food processing followed by examples of their effects on food allergen stability. Reviewed literature suggests assessment of processing effects on clinically relevant reactivity of food allergens is warranted.

A randomized study comparing the effect of loratadine added to montelukast with montelukast, loratadine, and beclomethasone monotherapies in patients with chronic asthma

BACKGROUND

Loratadine added to montelukast has been suggested to improve endpoints of asthma.

OBJECTIVE

This study investigated the additive effects of concomitant montelukast and loratadine when compared with montelukast, loratadine, and inhaled beclomethasone monotherapies in asthma. Methods. Patients (N = 406) were 15 to 65 years of age with a forced expiratory volume in 1 second (FEV(1))-predicted of 50% to 85%, FEV(1) reversibility > or = 15%, and a minimal level of daytime symptoms and beta -agonist use. This three-part 2X2 crossover-study consisted of two double-blind 6-week treatment periods where patients were administered once daily oral montelukast 10 mg, loratadine 10 mg, montelukast 10 mg + loratadine 10 mg, or twice daily inhaled beclomethasone 200 mu g. A subsequent 48-week extension study compared montelukast + loratadine with beclomethasone. The primary endpoint was the percentage change from baseline in FEV(1).

RESULTS

Over 6 weeks of double-blind treatment, significant improvements (p < 0.05) in the primary endpoint of FEV(1) were seen for montelukast + loratadine versus loratadine (least-square mean percentage-point difference of 5.8%), beclomethasone versus montelukast + loratadine (2.35%), montelukast versus loratadine (5.94%), and beclomethasone versus montelukast (4.65%); a numerical improvement (p = 0.054) was seen for montelukast + loratadine versus montelukast (1.60%). Significant improvements for montelukast + loratadine versus montelukast were seen in some secondary endpoints (evening peak expiratory flow, nocturnal asthma symptom score, nocturnal awakenings, and asthma-specific quality of life) but not others. Significant improvements in most endpoints except daytime asthma symptoms score were seen for montelukast + loratadine versus loratadine. In the extension study, both montelukast + loratadine and beclomethasone improved several endpoints. All treatments were generally comparable in the percentage of patients with clinical and laboratory adverse experiences.

CONCLUSION

In this study, the addition of loratadine to montelukast produced a small numerical, but not statistically significant, improvement in FEV(1) and, in general, no consistent improvement in other asthma endpoints. No improvement of montelukast + loratadine versus beclomethasone was seen in any endpoint.

Immunoglobulin production pattern is allergen-specific in polysensitized patients

Allergic rhinitis (AR) is characterized by Th2 polarized immune response, such as increased IL-4 and reduced IFN-gamma production, and by a functional defect of T regulatory cells. This impaired immune response profile influences the pattern of immunoglobulin production in allergic patients. Therefore, the aim of this study is firstly to investigate the allergen-specific IgE, IgG, IgG4, and IgA serum level pattern in polysensitized AR patients with the same skin prick test positivity to some pollen allergens. Secondly, this study aims at relating immunoglobulin (Ig) values with some clinical and immunological parameters. Eighty polysensitized patients with AR were enrolled. Serum allergen-specific IgE, IgG, IgG4, and IgA for mites, Parietaria, grasses, and birch, TGF-beta and sHLA-G were determined by the ELISA method. Allergic symptoms and drugs use were also assessed. Allergen-specific IgE, IgG, IgG4, and IgA serum levels were significantly different for each tested allergen (p=0.0001). There was a significant correlation between IgE levels and allergy severity, whereas IgA had an antagonistic behaviour, considering mite-specific immunoglobulins. In conclusion, the present study provides the first evidence that immunoglobulin production pattern depends on the specificity of the allergenic response.

Inhibitory effect of Platycodi Radix on ovalbumin-induced airway inflammation in a murine model of asthma

Asthma is a chronic inflammatory disease of the airways characterized by an associated increase in airway responsiveness. In this study, we investigated the inhibitory effect of an aqueous extract from the root of Platycodi Radix (Changkil: CK) on airway inflammation in a murine model of asthma. Mice were sensitized and challenged by ovalbumin (OVA) inhalation to induce chronic airway inflammation and airway remodeling. CK markedly decreased the number of infiltrated inflammatory cells and the levels of Th1 and Th2 cytokines and chemokines compared with those in the OVA-induced group. In addition, CK reduced OVA-specific IgE levels in bronchoalveolar lavage (BAL) fluid. Based on lung histopathological studies, inflammatory cell infiltration and mucus hypersecretion were inhibited by CK administration compared to that in the OVA-induced group. Lung weight was reduced after CK administration. Also, increased generation of ROS in BAL fluid, as well as NF-kappaB nuclear translocation, by inhalation of OVA was diminished by CK. Moreover, CK reduced the OVA-induced upregulation of matrix metalloproteases activity. These findings indicate that oxidative stress may play a crucial role in the pathogenesis of bronchial asthma induced by OVA and that CK may be useful as an adjuvant therapy for the treatment of bronchial asthma.

Maternal cytokine production during pregnancy and the development of childhood wheezing and allergic disease in offspring three years of age

Allergic diseases are multifactorial; they develop from complex interactions between genes and the environment. The immunological bias toward atopy and asthma might be established during in utero development of the fetal immune system. We prospectively investigated the association between maternal cytokine changes during pregnancy and the development of childhood wheezing and atopy at three years of age. Blood samples from 90 pregnant women were assayed for TNF-alpha, TGF-beta, IFN-gamma, IL-4, IL-6, and IL-2 at 18 weeks of gestation and at 6 weeks after delivery. Telephone interviews were performed and a questionnaire administered to assess wheezing and allergic disease in the children. The serum total IgE and specific IgE to eggs, milk and dust mites were measured. Maternal IFN-gamma, TNF-alpha and TGF-beta levels significantly decreased during pregnancy compared to the levels after delivery. However, the IL-4 levels did not change. Maternal TNF-alpha and IFN-gamma levels were decreased both before and after delivery in children with reported wheezing. Individual maternal IL-4 levels, before delivery, were higher than after delivery in the children that developed wheezing. There were no significant differences in maternal cytokine levels between children with and without asthma. In children with atopy, the maternal IFN-gamma /IL-4 ratio, during the first trimester, had a tendency to decrease compared to the children without atopy, whereas the maternal IL-2 levels at 6 weeks after delivery were increased. A first pregnancy showed higher concentrations of IL-4 before and after delivery than did women with multiple pregnancies. Maternal cytokine levels begin to change toward a Th2 immunity starting in the first trimester. A stronger Th2 immune response during the first trimester of pregnancy is associated with childhood wheezing and atopy at three years of age, and a first pregnancy.

Distinct regulation of IgE, IgG4 and IgA by T regulatory cells and toll-like receptors

BACKGROUND

Allergic diseases are characterized by the activation of the immune system and formation of immunoglobulin (Ig)E antibodies against normally innocuous environmental antigens, whereas IgG4 and IgA represent noninflammatory and blocking antibody isotypes. The T helper 2 (Th2) cells induce and T regulatory (Treg) cells suppress several features of allergic inflammation. Our aim was to investigate the role of allergen-specific T regulatory type 1 (Tr1) cells and CD4(+)CD25(+) Treg cells and toll-like receptors (TLRs) on IgE, IgG4 and IgA production.

METHODS

Germline or productive Ig-transcripts are determined by real-time reverse transcriptase-polymerase chain reaction, secreted Igs are measured by enzyme-linked immunosorbent assay and the frequency of Ig-producing plasma cells is investigated by enzyme-linked immunosorbent spot. Circulating CD4(+)CD25(+) Treg cells and allergen-specific Tr1 cells are used.

RESULTS

Both allergen-specific, interleukin-10-secreting Tr1 cells and CD4(+)CD25(+) Treg cells from healthy individuals induced IgG4 and suppressed IgE production in peripheral blood mononuclear cells and purified B-cell cultures. In contrast, induction of IgA production is independent of T-cell help and the role of Tr1 or Treg cells is very limited, whereas it was highly induced by direct B-cell activation via TLR7 and 9.

CONCLUSIONS

These data suggest that T regulatory cells may contribute to the suppression of allergic diseases by suppression of IgE and induction of IgG4, whereas IgA production is enhanced by B-cell activation via TLR7 and TLR9.

An association study of 13 SNPs from seven candidate genes with pediatric asthma and a preliminary study for genetic testing by multiple variants in Taiwanese population

INTRODUCTION

Asthma is one of the most common chronic diseases in children. It is caused by complex interactions between various genetic factors and exposures to environmental allergens and irritants. Because of the heterogeneity of the disease and the genetic and cultural differences among different populations, a proper association study and genetic testing for asthma and susceptibility genes is difficult to perform.

MATERIALS AND METHODS

We assessed 13 single-nucleotide polymorphisms (SNPs) in seven well-known asthma susceptibility genes and looked for association with pediatric asthma using 449 asthmatic subjects and 512 non-asthma subjects in Taiwanese population.

RESULTS

CD14-159 C/T and MS4A2 Glu237Gly were identified to have difference in genotype/allele frequencies between the control group and asthma patients. Moreover, the genotype synergistic analysis showed that the co-contribution of two functional SNPs was riskier or more protective from asthma attack. Our study provided a genotype synergistic method for studying gene-gene interaction on polymorphism basis and genetic testing using multiple polymorphisms.

Heritability of self-reported asthma and allergy: a study in adult Dutch twins, siblings and parents

The present study assessed the prevalence of asthma and allergy, and estimated the importance of genetic and environmental influences on asthma and allergy liability and their association. Longitudinal data on self-reported, doctor-diagnosed asthma and allergy were collected in over 14,000 individuals registered with the Netherlands Twin Register. Structural equation modeling was used for univariate and bivariate genetic analyses on data from twins, their siblings, and parents. Results showed no sex, age, and minimal birth cohort effects for asthma prevalence (11.8%). For allergy, prevalence was higher in women (19.8%) than in men (13.9%). Allergy prevalence at ages 22, 23, and 24 years increased from the 1970 to the 1980 birth cohort. The prevalence of allergy, but not of asthma, was higher in nontwin siblings than in twins. No assortative mating was observed. High (broad-sense) heritabilities were found for asthma (75%) and allergy (66%), with evidence for nonadditive genetic effects in asthma. The association between asthma and allergy (correlation=.65) was largely due to common genes (70%). No sex differences in genetic architecture were found. In conclusion, the prevalence of allergy but not of asthma increased in recent years. Individual differences in the liability to asthma, allergy and their co-occurrence are for a large part accounted for by differences in genetic background. Nonadditive gene action is important, which may have consequences for gene hunting strategies.

IgE in allergy and asthma today

The spreading epidemic of allergies and asthma has heightened interest in IgE, the central player in the allergic response. The activity of IgE is associated with a network of proteins; prominent among these are its two principal receptors, FcepsilonRI (high-affinity Fc receptor for IgE) and CD23, as well as galectin-3 and several co-receptors for CD23, notably CD21 and various integrins. Here, we review recent progress in uncovering the structures of these proteins and their complexes, and in our understanding of how IgE exerts its effects and how its expression is regulated. The information that has emerged suggests new therapeutic directions for combating allergic disease.

Interaction between GATA-3 and the transcriptional coregulator Pias1 is important for the regulation of Th2 immune responses

Th2 cytokine expression is dependent on the transcription factor GATA-3. However, the molecular interactions of GATA-3 leading to Th2 cytokine gene activation have not been well characterized. Here, we reported a number of GATA-3 associated proteins in Th2 cells, and one of such proteins Pias1 functioned as a positive transcriptional coregulator for GATA-3. When overexpressed in Th2 cells, Pias1 enhanced the expression of IL-13, and to lesser degrees, IL-4 and -5. Conversely, Pias1 siRNA down-regulated the Th2 cytokine expression. In Leishmania major infection, manipulating Pias1 expression in parasite-reactive CD4 T cells altered severity of disease caused by Th2 responses. Mechanistically, Pias1 markedly potentiated GATA-3-mediated activation of the IL-13 promoter by facilitating the recruitment of GATA-3 to the promoter. In contrast, IL-5 promoter was modestly enhanced by Pias1 and no effect was observed on IL-4 promoter. Thus, both promoter activation and additional mechanisms are responsible for regulation by Pias1.