Pteronyssinus Allergen Research Articles

Mite Molecular Profile in the Th2-Polarized Moderate-to-Severe Persistent Asthma Endotype Subjected to High Allergen Exposure

Background: The association among the IgE responses to prevailing groups of house dust mite (HDM) allergens in the concurrent asthma phenotypes has not been determined. Objective: The aim of the present study lays on a component-resolved diagnosis (CRD) model to investigate the mite molecular signature in subjects with type-2 inflammation asthma. Methods: We selected patients showing a clinically relevant sensitization to HDMs with moderate-to-severe persistent asthma. Skin prick test (SPT) with standardized mite extracts, a broad customized CRD serum sIgE panel including 9 Dermatophagoides pteronyssinus allergens and the related protein allergenic characterization, was investigated in all serum samples. Results: Ninety out of 93 (96.77%) patients with a positive SPT to HDM showed a concordant sIgE (≥0.35 kU_A/L) to the crude extract of D. pteronyssinus. Major allergens (Der p 2, Der p 23, and Der p 1) were present in >70% of all subjects, with mid-tier allergens (Der p 5, Der p 7, and Der p 21) reaching up to 51% in the present cohort. A complex pleomorphic repertoire of HDM molecules recognized by IgE was depicted, including 38 distinct profiles. Conclusions and Clinical Relevance: The proposed CRD panel approach, containing the most prevalent HDM allergens, appeared to be sufficient to obtain a precise D. pteronyssinus molecular diagnosis in asthmatics with a climate-dependent high-mite allergen exposure and coexisting sensitization. A dominant role of both major and mid-tier allergens has been confirmed in moderate and severe persistent asthmatics with the preponderant Th2-high endotype.

Korean Modification of the Nasal Provocation Test With House Dust Mite Antigen Following the EAACI Guidelines.

ObjectivesWe evaluated the usefulness of the standardized nasal provocation test (NPT) protocol recently published by the European Academy of Allergy and Clinical Immunology (EAACI) and compared the utility of several parameters for diagnosing allergic rhinitis (AR) caused by house dust mites (HDM). Subjective parameters were nasal and ocular symptoms measured using a visual analog scale (VAS), and objective parameters were peak nasal inspiratory flow (PNIF), minimal cross-sectional area (MCA), and total nasal volume (TNV).MethodsBefore and after spraying Dermatophagoides pteronyssinus (DP) allergen (1,000 AU/mL, 100 μL) into both nostrils of 13 patients with AR (AR group) and 22 patients with non-AR (NAR group), we used VAS scores to measure nasal symptoms (nasal obstruction, rhinorrhea, sneezing, and itching) and ocular symptoms and assessed PNIF, MCA, and TNV.ResultsThe AR group had significantly worse symptoms than the NAR group 15 minutes after DP challenge (P<0.001). After 30 minutes, nasal obstruction and rhinorrhea remained worse in the AR group (P<0.001); a similar but less marked difference was seen for sneezing (P=0.012) and itching (P=0.039). Ocular symptoms, PNIF, MCA, and TNV differed between groups after both 15 and 30 minutes (P<0.05). The area under the receiver operating characteristic curve was higher for nasal obstruction (0.977), rhinorrhea (0.906), and TNV (0.979) than for sneezing (0.755), itching (0.673), and MCA (0.836).ConclusionNPT performed according to the EAACI guidelines could help diagnose AR caused by HDM. TNV and VAS changes in nasal obstruction and rhinorrhea had higher diagnostic accuracy than other parameters.

Sensitization to major Dermatophagoides pteronyssinus allergens in house dust mite allergic patients from North Eastern Poland developing rhinitis or asthma

PurposeRecognition of individual allergens by IgE is crucial for triggering symptoms in allergic rhinitis (AR) or asthmatic (AA) patients. House dust mite (HDM) allergy is frequent around the world, the sensitization profile to individual HDM allergens varies in individual HDM-allergic patients (APs). The aim of this study was to evaluate the pattern of IgE sensitization to three major Dermatophagoides pteronyssinus (Dp) allergens among patients from North Eastern Poland suffering from HDM-AR and/or AA. Patients and methodsThe study was performed on 323 HDM-AR and/or AA patients and 106 controls (CG) including 30 healthy non-atopic subjects, 32 AR patients not sensitized to Dp and 44 non-atopic asthmatics. IgE levels to natural (n)Der p 1, nDer p 2, recombinant (r)Der p 2.0101 and rDer p 23 allergens were measured by ELISA. ResultsThe majority of HDM-APs were sensitized to nDer p 1 (72.1%), nDer p 2 (81.7%), rDer p 2.0101 (78.3%) and rDer p 23 (70.9%). The frequency of positive results to individual allergens depended on clinical manifestations and the level of IgE to the whole Dp extract. In HDM-AA patients, reactivity to nDer p 1 and rDer p 23 was detected more frequently than in HDM-AR patients. The whole Dp extract completely inhibited IgE binding to nDer p 1 and nDer p 2 but only partially to rDer p 23. ConclusionsHDM-APs from North-Eastern Poland display sensitization profile to major allergens which is similarly observed in western Europe. HDM-based diagnostic and therapeutic products should include all major allergens.

Comparison of diagnostic parameters of methods for determination of sensitization to allergen D. pteronyssinus in patients with respiratory allergic diseases

The aim of the study was to evaluate the diagnostic parameters of various methods for determining allergy sensitization to the dust mite allergen Dermatophagoides pteronyssinus in patients with respiratory allergic diseases – allergic rhinitis and bronchial asthma. Materials and methods: During the study, 88 patients with allergic rhinitis and / or atopic asthma were examined with three different methods of specific allergic diagnosis (in vivo and in vitro) according to the recommendations of the ethics committee of the Pirogov Vinnitsa National Medical University, all of which were out of acute period. Inclusion criteria were a diagnosis of allergic rhinitis (both intermittent and persistent) and / or atopic asthma. The prick-test was conducted according to the classic test method by normative documents with commercial allergen extracts. Western blots for the determination of IgE levels were performed using RIDA AllergyScreen test systems (R-Biopharm AG, Darmstadt, Germany) and Euroline (Euroimmun). Results and discussion: The results of two systems for the determination of specific IgE to D. Pteronyssinus by the Rida AllergyScreen and Euroline methods have a systematic difference of values (-1.27 kU / l). There is a good agreement between the results of skin testing with D. Pteronyssinus allergens and the detection of specific IgE by the Rida AllergyScreen method, and there is a satisfactory agreement between the results of skin testing with D. Pteronyssinus allergens and detection of specific IgE by the Euroline method. According to the results of the curve of detection of specific IgE by AllergyScreen method for determination of sensitization to allergen D. Pteronyssinus has excellent diagnostic significance (AUC=0,953), detection of specific IgE by Euroline method for determination of sensitization to allergen D. Pteronyssinus – good AUC=0,7.

In Vivo Allergen-Activated Eosinophils Promote Collagen I and Fibronectin Gene Expression in Airway Smooth Muscle Cells via TGF-β1 Signaling Pathway in Asthma.

Eosinophils infiltration and releasing TGF-β1 in the airways has been implicated in the pathogenesis of asthma, especially during acute episodes provoked by an allergen. TGF-β1 is a major mediator involved in pro-inflammatory responses and fibrotic tissue remodeling in asthma. We aimed to evaluate the effect of in vivo allergen-activated eosinophils on the expression of COL1A1 and FN in ASM cells in asthma. A total of 12 allergic asthma patients and 11 healthy subjects were examined. All study subjects underwent bronchial challenge with D. pteronyssinus allergen. Eosinophils from peripheral blood were isolated before and 24 h after the bronchial allergen challenge using high-density centrifugation and magnetic separation. Individual co-cultures of blood eosinophils and immortalized human ASM cells were prepared. The TGF-β1 concentration in culture supernatants was analyzed using ELISA. Gene expression was analyzed using qRT-PCR. Eosinophils integrins were suppressed with linear RGDS peptide before co-culture with ASM cells. Results: The expression of TGF-β1 in asthmatic eosinophils significantly increased over non-activated asthmatic eosinophils after allergen challenge, p < 0.001. The TGF-β1 concentration in culture supernatants was significantly higher in samples with allergen-activated asthmatic eosinophils compared to baseline, p < 0.05. The effect of allergen-activated asthmatic eosinophils on the expression of TGF-β1, COL1A1, and FN in ASM cells was more significant compared to non-activated eosinophils, p < 0.05, however, no difference was found on WNT-5A expression. The incubation of allergen-activated asthmatic eosinophils with RGDS peptide was more effective compared to non-activated eosinophils as the gene expression in ASM cells was downregulated equally to the same level as healthy eosinophils.

Determination of sensitization to dust mite allergens D. pteronyssinus and D. farinae in patients with respiratory allergic diseases using immunoblot and multiplex component testing

Objective — to evaluate the diagnostic parameters of the immunoblot and ImmunoCAP ISAC methods for determining sensitization to allergens of the house dust mite Dermatophagoides pteronyssinus and Dermatophagoides farinae in patients with respiratory allergic diseases — allergic rhinitis and bronchial asthma.Materials and methods. In the process of this study, 40 patients with bronchial asthma and/or allergic rhinitis were examined using two different methods of specific allergological diagnosis (in vitro). The study was open, randomized, comparative. The quantitative determination of specific IgE in blood serum was carried out using the RIDA® AllergyScreen immunoblot method (R-Biopharm AG, Germany) at the private laboratory of the Allergo-Immunological Center CPR LLC. Examination by the method of ImmunoCAP ISAC was performed in the Clinic of Allergology and Immunology «Forpost».Results and discussion. Sensitization to D. farinae allergen was 35.0 % (14 people) with specific IgE by the Rida AllergyScreen method, 42.5 % (17 people) with specific IgE by the ImmunoCAP ISAC method; sensitization to D. рteronyssinus allergen was 35.0 % (14 people) with specific IgE by the Rida AllergyScreen method, 40.0 % (16 people) with specific IgE by the ImmunoCAP ISAC method.Conclusions. As a method for the quantitative determination of specific IgE to the D. farinae allergen, the immunoblot compared with ImmunoCAP ISAC has high specificity and predictability of a positive result (100 %), but the sensitivity and predictability of a negative result are 82.35 % (95 % CI: 56.57—96.20) and 88.46 % (95 % CI: 73.30—95.54), respectively, and the accuracy of the method is 92.5 % (95 % CI: 79.61—98.43).As a method for the quantitative determination of specific IgE to the D. pteronyssinus allergen, the immunoblot compared with ImmunoCAP ISAC, similar to the results of preliminary testing, has high specificity and predictability of a positive result (100 %), however, the sensitivity and predictability of a negative result have a value of 75.00 % (95 % CI: 47.62—92.73) and 85.71 % (95 % CI: 71.97—93.34), respectively, and the accuracy of the method is 90.00 % (95 % CI: 76.34; 97.21).

Antibody blockade of Dectin-2 suppresses house dust mite-induced Th2 cytokine production in dendritic cell- and monocyte-depleted peripheral blood mononuclear cell co-cultures from asthma patients

BackgroundDectin-2, which is a C-type lectin, interacts with the house dust mite (HDM) Dermatophagoides pteronyssinus allergen. This study aimed to investigate whether Dectin-2 blockade by antagonistic monoclonal antibodies (MoAbs) attenuates HDM-induced allergic responses.MethodsTwo anti-Dectin-2 MoAbs were generated and validated for specific binding to Dectin-2 Fc fusion protein (Dectin-2.Fc) and inhibition of Dectin-2.Fc/HDM interaction. Patients with asthma exhibiting high titers of anti-D. pteronyssinus IgE were enrolled. Peripheral blood mononuclear cells with depleted CD14+ monocytes were obtained from these patients and co-cultured with autologous monocyte-derived conventional dendritic cells in the presence of D. pteronyssinus or its group 2 allergens (Der p 2). Interleukin (IL)-5 and IL-13 levels in the culture supernatants were determined using ELISA in the presence or absence of anti-Dectin-2 MoAbs.ResultsTwo MoAbs, 6A4G7 and 17A1D10, showed specific binding to recombinant Dectin-2.Fc and inhibited HDM binding to Dectin-2.Fc. Both anti-Dectin-2 MoAbs inhibited IL-5 and IL-13 production in co-cultures with Der p 2 stimulation in a dose-dependent manner. 6A4G7 and 17A1D10 (3 μg/mL) significantly inhibited Der p 2-induced (3 μg/mL) IL-5 production by 69.7 and 86.4% and IL-13 production by 84.0 and 81.4%, respectively. Moreover, this inhibitory effect of the two MoAbs remained significant in the presence of D. pteronyssinus.ConclusionsAnti-Dectin-2 MoAbs significantly inhibited HDM-induced allergic responses in vitro and therefore have the potential to become therapeutic agents in mite-induced allergic diseases.

An Engineered Hybrid Protein from Dermatophagoides pteronyssinus Allergens Shows Hypoallergenicity.

The house dust mite (HDM) Dermatophagoides pteronyssinus is an important risk factor for asthma and rhinitis. Allergen specific immunotherapy that is based on recombinant proteins has been proposed for the safer and more efficient treatment of allergic diseases. The aim of this study was to design and obtain a hybrid protein (DPx4) containing antigenic regions of allergens Der p 1, Der p 2, Der p 7, and Der p 10 from this mite. DPx4 was produced in Escherichia coli and its folding was determined by circular dichroism. Non-denaturing dot-blot, ELISA, basophil activation test, dot blot with monoclonal antibodies, ELISA inhibition, and cysteine protease activity assays were performed. Mice that were immunized with DPx4 were also analyzed. We found that DPx4 had no cysteine protease activity and it showed significantly lower IgE reactivity than Der p 1, Der p 2, and D. pteronyssinus extract. DPx4 induced lower basophil activation than Der p 2 and the allergen extract. Immunized mice produced IgG antibodies that inhibited the binding of allergic patient’s IgE to the allergen extract and induced comparatively higher levels of IL-10 than the extract in peripheral blood mononuclear cells (PBMC) culture. These results suggest that DPx4 has immunological properties that are useful for the development of a mite allergy vaccine.

Synergistic effect of Dermatophagoides pteronyssinus allergens and dexamethasone on the expression of CD163 by peripheral blood mononuclear cells

BackgroundThe CD163 is a marker of monocyte/macrophage anti-inflammatory function. Its soluble form (sCD163) also exert anti-inflammatory activities including inhibition of T cell proliferation. ObjectiveTo evaluate the effect of dexamethasone (Dx) and Dermatophagoides pteronyssinus (Dp) on ex vivo production of sCD163 by peripheral blood mononuclear cells (PBMCs). MethodsPBMCs from 26 allergic asthma patients (AAs) and 12 non-atopic healthy controls (HCs) were cultured with Dp, Dx, Dp + Dx or without any stimulation for up to 144 h (T144). Concentration of sCD163, interleukin (IL) -6 and IL-10 in PMBC culture supernatants was evaluated using ELISA. The mRNA expression of CD163 by PBMCs was estimated using quantitative PCR (qPCR). ResultsAt T144 the median concentration of CD163 in unstimulated PBMC cultures of AAs was greater than that in HCs (p = 0.008). Concomitant application of Dp and Dx resulted in a synergistic effect reflected by a dramatic increase of sCD163 concentration both in HCs (p = 0.0002) and AAs (p < 0.0001). Also a synergistic effect of Dp and Dx on CD163 mRNA expression was seen at T24 and T48 but not at T6 or T12. Among asthmatic patients the effect of Dx on sCD163 production was attenuated in severe in comparison to mild-to-moderate AAs (p = 0.0007). Moreover, Dp-induced production of IL-6 but not IL-10 was inhibited by Dx (p < 0.0001). Inhibition of IL-10 decreased sCD163 concentration by more than 50%. ConclusionsDx-triggered upregulation of anti-inflammatory CD163 expression by monocytes is synergistic with endogenous mechanisms involved in the resolution of Dp-induced inflammation. This effect is impaired in severe asthma patients.

Preventive sublingual immunotherapy with House Dust Mite extract modulates epitope diversity in pre‐school children

The preventive effect of allergen immunotherapy (AIT) on allergy and asthma development is currently assessed using primary and secondary AIT approaches. Knowledge of the immunological effects of these interventions is limited and the impact on epitope diversity remains to be defined. We used high-density peptide arrays that included all known Dermatophagoides pteronyssinus (Der p) and Dermatophagoides farinae (Der f) allergens and the whole proteome of Der f to study changes in House Dust Mite (HDM) linear peptide recognition during a 2-year preventive double-blind placebo-controlled sublingual HDM AIT pilot study in 2-5-year-old children with sensitization to HDM but without symptoms. Preventive AIT-treated patients showed significantly higher IgG epitope diversity to HDM allergens compared to placebo-treated individuals at 24months of treatment (P<0.05), while no increase in IgE diversity was seen. At 24months of treatment, IgG4 diversity for HDM allergens was significantly higher in the pAIT-treated patients compared to placebo group (P<0.05). Potentially beneficial changes in epitope recognition throughout the treatment are also seen in peptides derived from Der f proteome. These data suggest a beneficial immunomodulation of preventive sublingual immunotherapy at a molecular level by favoring a broader blocking repertoire and inhibiting epitope spreading.

Adoptive cell therapy of tolerogenic dendritic cells as inducer of regulatory T cells in allergic rhinitis.

Regulatory T cells (Tregs) have become promising candidates for immunotherapy in allergic rhinitis (AR). The contributing role of tolerogenic dendritic cells (tDCs) in the augmentation of Tregs in AR remains to be determined. The properties of tDCs in expanding Tregs and their potential to ameliorate AR were evaluated in vitro and in vivo. Monocyte-derived tDCs stimulated with Dermatophagoides pteronyssinus allergen 1 favored the generation of activated Tregs (aTregs) and suppressed effector T-cell responses in a transforming growth factor-beta/interleukin-10 (TGF-β/IL-10)-dependent manner in vitro. The adoptive transfer of tDCs inhibited allergic airway inflammation in the mouse model, whereas depletion of CD25+ cells or blocking TGF-β/IL-10 signaling eliminated the inhibitory effect, indicating that Tregs were involved in the anti-inflammatory activity of tDCs. Our data show that tDCs are a potential therapeutic target in AR.

Underestimation of house dust mite–specific IgE with extract-based ImmunoCAPs compared with molecular ImmunoCAPs

Underestimation of house dust mite–specific IgE with extract-based ImmunoCAPs compared with molecular ImmunoCAPs

Characterization of a hybrid protein designed with segments of allergens from Blomia tropicalis and Dermatophagoides pteronyssinus

BackgroundSensitization to allergens of the house dust mites Dermatophagoides pteronyssinnus and Blomia tropicalis is an important risk factor for asthma and allergic diseases. Allergen-specific immunotherapy is currently based on natural allergen extracts, however, in the last years recombinant allergens with different modifications have shown promising immunological properties that may be advantageously applied for developing novel allergy vaccines. MethodsA hybrid molecule (MAVAC-BD-2) containing epitopes of B. tropicalis (Blo t 5, Blo t 8 and Blo t 10) and D. pteronyssinus (Der p 1, Der p 2, Der p 7 and Der p 8) allergens was constructed, expressed in Escherichia coli and purified by affinity chromatography. Its folding was analyzed by circular dichroism. Antibody reactivities were evaluated by ELISA and non-denaturing dot blot assays using a battery of sera from mite allergic patients and non-allergic subjects. ELISA inhibition and dot blot assays with monoclonal antibodies were used to detect B-cell epitopes. Human basophil activation and induction of IgG-blocking antibodies in mice immunized with the hybrid protein were also evaluated. ResultsMAVAC-BD-2, expressed as a 22.8 kDa protein, showed a lower frequency and strength of IgE reactivity compared to Blo t 5, Der p 1, Der p 2 and the extracts of B. tropicalis and D. pteronyssinus. MAVAC-BD-2 inhibited 26% of IgE reactivity to Der p 2 and Blo t 5, reacted with anti-Der p 1 and anti-Der p 2 monoclonal antibodies and did not induce relevant basophil activation. MAVAC-BD-2 immunized mice produced specific antibodies that reacted against mite extracts and the purified allergens, as well as IgG antibodies that blocked the human IgE reactivity to mite extracts. ConclusionMAVAC-BD-2 has hypoallergenic characteristics and in mice induces IgG antibodies that block the human IgE reactivity to mite extracts.

High-quality assembly of Dermatophagoides pteronyssinus genome and transcriptome reveals a wide range of novel allergens

House dust mites (HDM) are a predominant source of inhalant allergens that attribute to over 50% of worldwide allergy cases, while the full spectrum of HDM allergens remains unknown. Here we sequenced a high-quality genome of Dermatophagoides (D.) pteronyssinus to find known canonical allergens and allergen orthologs inferred from D. farinae genome. The D. pteronyssinus genome was assembled by a hybrid assembly approach using PacBio, Illumina and Ion Torrent reads. Transcriptomes of D. pteronyssinus and D. farinae were compared using Cufflinks. Allergens were identified by two-dimensional gel electrophoresis and MALDI-ToF MS. Allergenicities of the novel allergens were detected by ELISA using patients’ sera against bacteria expressing recombinant proteins. Genomic, transcriptomic, and proteomic approaches revealed full gene structures of 21 known allergens, and uncovered 11 putative allergen homologs. A high-quality D. pteronyssinus genome of 66.8 Mb was constructed. This genome assembly represented 98.2% of estimated genome size, with contig N50 being 80kb. The first comprehensive transcriptomic analysis of D. pteronyssinus and D. farinae revealed distinctively expressed allergen genes between the two dust mites, in which Der p 1, 5, 10, 21 and 24 were highly expressed in D. pteronyssinus, while Der f 10, 13, 21, 26 and 31 expressed higher in D. farinae. From ELISA, IgE binding rates of Der p 25, 26, 28, 32, and 33 were 38.5-65.3%, in which Der p 33 had the highest allergenicity. Bioinformatics and experimental characterizations of D. pteronyssinus genome and allergens provide important resources for future investigation of HDM allergens.

Anaphylaxis due to food-related anaphylaxis treated with omalizumab

Anaphylaxis is a systemic allergic reaction that is acute and could be life-threatening. Once diagnosed, avoidance of allergen and carrying an epinephrine auto-injector are recommended. Most anaphylactic reactions are immunoglobulin E (IgE)-mediated and the major triggers include food, medication, insect stings, exercise and vaccines. Here, we present a case of a 38-year-old male, a surgeon, diagnosed as food-related anaphylaxis with a convincing clinical history and the positive serum-specific IgE level to Dermatophagoides pteronyssinus and Dermatophagoides farina allergens. This patient was treated with omalizumab administered subcutaneously. Routine lymphocyte subsets and CD23+ B cells of this patient were evaluated monthly for the consecutive ten months and one year after the last treatment. Our data showed that there was a correlation between the level of CD23+ B cells and the efficacy of omalizumab treatment. The patient had higher percentage of CD23+ B cells and CD23 expression level (86.5 % and MFI 371.9, respectively) during the onset of anaphylaxis. With the omalizumab treatment, both CD23+ B cells and CD23 expression level decreased gradually. The basal levels of CD23+ B cells and CD23 expression dropped to 25.1% and 72.6 MFI, respectively when the patient became recovered one year after the last treatment. Our findings highlight the potential of CD23+ B cells to be the useful parameter to predict the treatment effect of omalizumab in food-related anaphylaxis.

Local Allergic Rhinitis in Adult Patients with Chronic Nasal Symptoms

Background: Local allergic rhinitis (LAR) remains an underdiagnosed condition characterized by the local production of IgE antibodies during the natural exposure to aeroallergens. The prevalence of LAR in adult patients with a previous diagnosis of non-AR was assessed. Material and Methods: Eighty-four patients with perennial nasal allergy symptoms but a negative skin prick test and specific IgE antibodies against common inhalant allergens were included in the study. Nasal provocation tests were performed with the inhalant allergens Dermatophagoides pteronyssinus, Alternaria, and cat allergen, followed by the detection of nasal-specific IgE antibodies in the lavage during the challenge. Results: LAR was confirmed in 21 (25%) study patients. In the remaining 63 (75%) patients, non-AR was diagnosed. In addition, LAR was found following exposure to D. pteronyssinus in 19 (22.6%) patients, Alternaria in 3 (3.6%) patients, and the cat allergen in 1 (1.2%) patient. In 2 patients, concomitant allergies to D. pteronyssinus and Alternaria were observed. Conclusion: LAR can be a form of chronic perennial rhinitis that has previously been considered to be non-AR.

Dissociation between skin test reactivity and anti-aeroallergen IgE: Determinants among urban Brazilian children.

BackgroundThe dissociation between specific IgE and skin prick test reactivity to aeroallergens, a common finding in populations living in low and middle-income countries, has important implications for the diagnosis and treatment of allergic diseases. Few studies have investigated the determinants of this dissociation. In the present study, we explored potential factors explaining this dissociation in children living in an urban area of Northeast Brazil, focusing in particular on factors associated with poor hygiene.MethodsOf 1445 children from low income communities, investigated for risk factors of allergies, we studied 481 with specific IgE antibodies to any of Blomia tropicalis, Dermatophagoides pteronyssinus, Periplaneta americana and Blatella germanica allergens. Data on demographic, environmental and social exposures were collected by questionnaire; serum IgG and stool examinations were done to detect current or past infections with viral, bacterial, protozoan and intestinal helminth pathogens. We measured atopy by skin prick testing (SPT) and specific IgE (sIgE) to aerollergens in serum (by ImmunoCAP). SIgE reactivity to B. tropicalis extract depleted of carbohydrates was measured by an in-house ELISA. Total IgE was measured by in house capture ELISA. SNPs were typed using Illumina Omni 2.5.ResultsNegative skin prick tests in the presence of specific IgE antibodies were frequent. Factors independently associated with a reduced frequency of positive skin prick tests were large number of siblings, the presence of IgG to herpes simplex virus, Ascaris lumbricoides and Trichuris trichiura infections, living in neighborhoods with infrequent garbage collection, presence of rodents and cats in the household and sIgE reactivity to glycosylated B. tropicalis allergens. Also, SNP on IGHE (rs61737468) was negatively associated with SPT reactivity.ConclusionsA variety of factors were found to be associated with decreased frequency of SPT such as unhygienic living conditions, infections, total IgE, IgE response to glycosylated allergens and genetic polymorphisms, indicating that multiple mechanisms may be involved. Our data, showing that exposures to an unhygienic environment and childhood infections modulate immediate allergen skin test reactivity, provide support for the “hygiene hypothesis”.

Alteration of -656(G/T) and -607(C/A) polymorphisms in interleukin-18 (IL-18) gene in house dust mite-sensitive allergic rhinitis patients in Thailand.

Allergic rhinitis (AR) is an IgE-mediated inflammation of the nasal membranes, which is naturally triggered by aeroallergens. House dust mites (HDM) are the most common inhalant allergens. Interleukin-18 (IL-18) has been established as an essential cytokine that can activate the generation of IgE. This randomized controlled study aimed to identify the possible relationship of the genetic variations in the IL-18 gene with AR in mite-sensitive Thai patients. Study subjects consisted of 150 AR patients and 50 normal participants. Genomic DNA of 30 randomized AR patients and 30 randomized controls were screened by sequencing for the selection of candidate single nucleotide polymorphisms (SNPs), and further analyzed by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) assay for all subjects. The following five SNPs were detected in the IL-18 gene: -656 G/T, -607 C/A, and -137 G/C in promoter 1 and -920 C/T and -373 C/G in promoter 2. The results showed that -656 G/T and -607 C/A SNPs were significantly correlated with IgE levels specific to Dermatophagoides pteronyssinus (Der p) allergen (P = 0.045 and P = 0.045, respectively), and significant differences were observed in the genotype distribution of AR patients when compared with controls [P = 0.044 and P = 0.044, respectively; odds ratios (ORs): 1.941 (95%CI, 1.014-3.715) and 1.941 (95%CI, 1.014-3.715), respectively]. Our findings indicate that the IL-18 alleles, -656T (rs1946519) and -607A (rs1946518), might be associated with the higher production of Der p allergen-specific IgE in mite-sensitive AR patients.

Evolution and predictive value of IgE responses toward a comprehensive panel of house dust mite allergens during the first 2 decades of life

The evolution of the IgE response to the numerous allergen molecules of Dermatophagoides pteronyssinus is still unknown. We sought to characterize the evolutionary patterns of the IgE response to 12 molecules of D pteronyssinus from birth to adulthood and to investigate their determinants and clinical relevance. We investigated the clinical data and sera of 722 participants in the German Multicenter Allergy Study, a birth cohort started in 1990. Diagnoses of current allergic rhinitis (AR) related to mite allergy and asthma were based on yearly interviews at the ages of 1 to 13years and 20years. IgE to the extract and 12 molecules of D pteronyssinus were tested by means of ImmunoCAP and microarray technology, respectively, in sera collected at ages 1, 2, 3, 5, 6, 7, 10, 13, and 20years. Exposure to mites at age 6 and 18months was assessed by measuring Der p 1 weight/weight concentration in house dust. One hundred ninety-one (26.5%) of 722 participants ever had IgE to D pteronyssinus extract (≥0.35 kUA/L). At age 20years, their IgE recognized most frequently Der p 2, Der p 1, and Der p 23 (group Amolecules; prevalence, >40%), followed by Der p 5, Der p 7, Der p 4, and Der p 21 (group B molecules; prevalence, 15% to 30%) and Der p 11, Der p 18, clone 16, Der p 14, and Der p 15 (group C molecules; prevalence, <10%). IgE sensitization started almost invariably with group Amolecules and expanded sequentially first to group B and finally to group C molecules. Early IgE sensitization onset, parental hay fever, and higher exposure to mites were associated with a broader polymolecular IgE sensitization pattern. Participants reaching the broadest IgE sensitization stage (ie, ABC) had significantly higher risk of mite-related AR and asthma than unsensitized participants. IgE to Der p 1 or Der p 23 at age 5years or less predicted asthma at school age. Parental hay fever and early exposure to D pteronyssinus allergens promote IgE polysensitization to several D pteronyssinus molecules, which in turn predicts current mite-related AR and current/future asthma. These results might inspire predictive algorithms and prevention strategies against the progression of IgE sensitization to mites toward AR and asthma.

High-dose cutaneous exposure to mite allergen induces IgG-mediated protection against anaphylaxis.

The relationship among natural allergen exposure, induction of blocking antibody and the occurrence of atopic allergy-particularly in the presence of IgE production-is debatable. To clarify the relationship between the dose of cutaneous exposure to dust mite allergen and susceptibility to the IgE-mediated allergic response in relation to IgG production. NC/Nga mice were epicutaneously exposed to various doses of Dermatophagoides pteronyssinus allergen to induce atopic dermatitis-like skin lesions. We then evaluated the skin lesions, induction of mite-specific immune responses, and susceptibility to anaphylaxis. Dose-dependent exacerbation of atopic dermatitis-like skin lesions and increases in mite-specific IgG and IgE production were observed. However, mice exposed to relatively low doses of mite allergen showed hypersusceptibility to mite allergen-specific anaphylaxis. We also showed that adoptive transfer of total IgG from Dp-sensitized mice rescued mice from the hypersusceptibility seen in those exposed to low doses of mite allergen. High-dose cutaneous exposure to dust mites induced effective blocking IgG production, even if accompanied by IgE production. Our data might support the concept that an increase in IgG titre, not a decrease in IgE titre, is a marker of clinical improvement in allergen-specific immunotherapy.