Dermatophagoides Pteronyssinus Extract Research Articles

IgE Abs to Der p 1 and Der p 2 as diagnostic markers of house dust mite allergy as defined by a bronchoprovocation test

BackgroundLimited information is available regarding the clinical usefulness of measuring the levels of IgE to allergen components from house dust mites (HDMs) in the diagnosis of genuine HDM allergy. MethodsTo evaluate the diagnostic usefulness of measuring levels of serum IgE antibodies (Abs) to allergen components from Dermatophagoides pteronyssinus (DP) as a predictor of immediate asthmatic response (IAR) to bronchoprovocation, we studied 55 DP-sensitized asthmatic patients who underwent a bronchoprovocation test using crude DP extract. The levels of IgE Abs to crude DP, nDer p 1, rDer p 2, and rDer p 10 in patients who showed IAR (n = 41) were compared with those in patients who showed no IAR (n = 14). ResultsWhile the frequencies of positivity for IgE Abs to nDer p 1 and rDer p 2 among the entire study population were 89 and 86%, respectively, all patients with IAR tested positive for both of them with high IgE concentrations. The areas under the receiver operating characteristic curves for IgE to nDer p 1 and rDer p 2 as predictors of IAR were 0.913 and 0.906, respectively. The specificity of IgE to nDer p 1 and rDer p 2 was higher than IgE to crude DP even at low cut-off points. ConclusionsIgE to nDer p 1 and/or rDer p 2 was highly predictive of allergen-induced IAR. These findings validate the clinical usefulness of measuring the levels of IgE to nDer p 1 and rDer p 2 as a diagnostic tool for genuine HDM allergy.

Sensitivity to Five Types of House Dust Mite in a Group of Allergic Egyptian Children.

Background: The published data on house dust mite (HDM) sensitization from Egypt are scanty. We sought to investigate the sensitization to five different types of HDM among a group of allergic children in a trial to outline the most frequent sensitizing strains in the Cairo Province. Methods: We consecutively enrolled 100 asthmatic patients, aged 1-7 years, of whom 22 had concomitant skin allergy. Skin prick testing was performed using allergen extracts of Dermatophagoides pteronyssinus, Dermatophagoides farinae, Lepidoglyphus destructor, Tyrophagus putrescentiae, and Acarus siro. Results: Twenty-four patients (24%) were sensitized to one or more strains of HDM. Sensitization to one strain was revealed in 12% of the studied sample, while sensitization to two or three strains was detected in 8% and 4% respectively. Twelve percent of the enrolled children were sensitive to D. pteronyssinus, 11% to D. farinae, 7% to L. destructor, 6% to T. putrescentiae, and 4% to A. siro. Eight out of the 12 (66%) children sensitive to one strain had mild intermittent asthma, while five out of eight (62.5%) sensitive to two strains had moderate persistent asthma. All children sensitized to three strains of HDM had persistent rather than intermittent asthma. HDM sensitization did not correlate significantly to the history of sun exposure, bed mattresses and pillows, living in farms, or exposure to stored grains. The co-existence of atopic dermatitis tended to have a higher rate of HDM sensitization. Conclusion:D. pteronyssinus and D. farinae represent the most common sensitizing strains in the studied sample. Wider-scale population-based studies are needed to assess the prevalence of HDM allergy and its clinical correlates in our country.

Fast onset of action of sublingual immunotherapy in house dust mite‐induced allergic rhinitis: A multicenter, randomized, double‐blind, placebo‐controlled trial

To investigate how quickly an allergic rhinitis (AR) patients' symptoms will improve with sublingual immunotherapy (SLIT). Double-blind placebo study. This is a multicenter, randomized, double-blind, placebo-controlled study of SLIT used to treat house dust mite-induced AR. A total of 120 AR patients, aged 4 to 60 years, were treated for 6 months and randomized into two groups: 1) SLIT with Dermatophagoides pteronyssinus (D.p.) and Dermatophagoides farina (D.f.) extract (n = 60) ; and 2) matched placebo controls (n = 60). Symptom, medications received, and a visual analog scale score were recorded during the whole study. Serum-specific IgE and IgG4 to D. p. and D. f. were assessed before and after the treatment. Eighty-five patients (70.8%) completed the study. Twelve patients (20%) chose to withdraw from the SLIT group, but none because of serious adverse effects. The total symptom and visual analog scores VAS in the SLIT group decreased significantly when compared to the placebo controls (P <0.05) after week 14, as well as for the significant (P <0.05) improvement of all individual AR symptoms in the SLIT group (e.g., sneezing, nasal discharge, itching, and nasal obstruction) after week 22. There was a significant (P <0.05) increase of IgG4 to both D.f. and D.p. in the SLIT, but not in the placebo group after treatment. SLIT with a mixture of D.f. and D.p. extract is an effective and safe treatment for patients with house dust mite-induced AR. Its onset of action can be observed as early as 14 weeks after treatment.

Multi-allergen Challenge Stimulates Steriod-Resistant Airway Inflammation via NF-κB-Mediated IL-8 Expression

Neutrophilic airway inflammation associated with multiple allergens has been related to steroid-resistant asthma. However, most animal models use only one allergen, which cannot simulate asthma closely as seen in patients. To determine the mechanism of inflammatory process involved in this severe condition, BALB/c mice were repetitively challenged with the pooled extract of dust mite, ragweed, and Aspergillus species (DRA). We found that DRA increased interleukin (IL)-10 and TGF-β levels and neutrophil recruitment in bronchial alveolar lavage fluid. We also found that although dexamethasone suppressed the release of these two cytokines, mast cells recruitment, and mucus hypersecretion, it actually increased neutrophil infiltration and the level of keratinocyte-derived chemokine (mKC), a functional homolog of human IL-8. Treatment of human lung alveolar A549 cells with Der p1, an extract of house dust mite Dermatophagoides pteronyssinus, increased the expression of IL-8 and activity of NF-κB. The elevated IL-8 level was suppressed by BAY11-7082, a selective NF-κB inhibitor, but not by dexamethasone. These results suggest that increased IL-8 (mKC) levels may be involved in steroid-resistant neutrophilic airway inflammation through an NF-κB-dependent pathway.

Varying Allergen Composition and Content Affects the in vivo Allergenic Activity of Commercial Dermatophagoides pteronyssinus Extracts

Background: Diagnosis and immunotherapy of house-dust mite (HDM) allergy is still based on natural allergen extracts. The aim of this study was to analyze commercially available Dermatophagoides pteronyssinus extracts from different manufacturers regarding allergen composition and content and whether variations may affect their allergenic activity. Methods: Antibodies specific for several D. pteronyssinus allergens (Der p 1, 2, 5, 7, 10 and 21) were used to analyze extracts from 10 different manufacturers by immunoblotting. Sandwich ELISAs were used to quantify Der p 1 and Der p 2 in the extracts. Mite-allergic patients (n = 45) were skin-tested with the extracts and tested for immunoglobulin E (IgE) reactivity to a panel of 10 mite allergens (Der p 1, 2, 4, 5, 7, 8, 10, 14, 20 and 21) by dot blot. Results: Only Der p 1 and Der p 2 were detected in all extracts but their concentrations and ratios showed high variability (Der p 1: 6.0–40.8 µg ml^–1; Der p 2: 1.7–45.0 µg ml^–1). At least 1 out of 4 allergens (i.e. Der p 5, 7, 10 and 21) was not detected in 8 of the studied extracts. Mite-allergic subjects showed different IgE reactivity profiles to the individual mite allergens, the extracts showed different allergenic activity in skin-prick tests and false-negative results. Conclusions: Commercially available D. pteronyssinus extracts lack important allergens, show great variability regarding allergen composition and content and some gave false-negative diagnostic test results in certain patients.

372 Skin Prick Test Reactivity Compared to Serum Specific IGE by ISAC in Patients With Rhinitis

BackgroundMicroarray technique is promising in allergy diagnosis. The aim of this study was to compare SPT with specific-IgE by microarray in a group of patients with rhinitis.MethodsCross-sectional study, 101 participants with rhinitis diagnosed according to ARIA (89.1% with asthma); age range 6 to 15 years. SPT was done with Dermatophagoides pteronyssinus (Dp), Blattella germanica (Bg), cat and dog allergenic extracts (IPI ASAC Brasil); a mean wheal diameter of ≥2 mm greater than the negative control was considered positive. Sera were analysed for allergen specific IgE antibodies to Dp (Der p 1, Der p 2), Bg (Bla g 1, Bla g 2, Bla g 4, Bla g 5), cat (Fel d 1, Fel d 2) and dog (Can f 1, Can f 2) allergens using a microarray system (ImmunoCAP ISAC, PMD, Austria), considered positive ≥0.3 ISU (ISAC standardized units). Categorical variables were shown as percentage and differences between the 2 methods verified by chi-square test; P < 0.05 was considered significant.ResultsSPT was positive to Dp in 88.1% whereas ISAC was positive to Der p 1 in 74.2% (P < 0.001) and Der p 2 in 73.3% (P < 0.01) respectively. Sensitivity of SPT was 97% and specificity was 38%. The remaining allergens caused less SPT reactions (cockroach 25.7%, cat 22.8%, dog 27.7%) and these were associated with lower detection of specific-IgE by ISAC respectively Bla g 1 (0.9%, P = 0.09), Bla g 2 (0%), Bla g 4 (0%), Bla g 5 (0.9%, P = 0.55); Fel d 1 (16.8%, P < 0.01), Fel d 2 (0.9%, P = 0.06); Can f 1 (4.9%, P = 0.53), Can f 2 (2.9%, P < 0.001).ConclusionsSPT remains the favored method to detect IgE-mediated sensitivity to aeroallergens. SPT was highly sensitive for Dp though less specific in comparison with the IgE microarray to Der p 1 and Der p 2 allergens.

Comparative Immunomodulatory Activity of Ascaris Suum Eggs and Dermatophagoides pteronyssinus Extract in BALB/C Mice: Cytokine and Immunoglobulin Regulations

Allergy is highly prevalent in well-developed countries; hygiene hypothesis suggests that this is due to exposure to previous bacterial infection eliciting Th1-response that suppresses Th2-mediated responses. Aside from Th2 suppressing Th1-responses, Th2-mediated infections such as parasitism, appear to lower the risk of developing allergy. This study investigates the effects of Ascaris suum infection in Dermatophagoides pteronyssinus-induced allergic BALB/c mice. Ninety BALB/c mice divided into three trials were randomly grouped into: normal control (1), A. suum infected mice (2), D. pteronyssinus exposed mice (3), A. suum infected mice and then exposed to D. pteronyssinus (4), D. pteronyssinus exposed mice and then infected with A. suum (5), and mice exposed and infected with D. pteronyssinus and A. suum, simultaneously (6). Blood and fecal samples were collected at days 0, 36, and 72 for the measurement of cytokines and immunoglobulins through ELISA, and for fecal analysis. Results showed that A. suum infection suppressed D. pteronyssinus-induced allergy morphologically and histologically and downregulated the production of D. pteronyssinus-specific IgE. A. suum and D. pteronyssinus upregulated the production of IL-4 and IL-5, and only A. suum eggs enhanced the production of IL-10. D. pteronyssinus enhanced production of both D. pteronyssinus-specific and A. suum-specific IgE and IgG and may be accounted to crossreacting antigens present in D. pteronyssinus and A. suum. IL-10 is upregulated in mice with A. suum infection and appears to protect mice against D. pteronyssinus-induced allergy. The possible role of IL-10 production in response to A. suum infection and against D. pteronyssinus-induced allergy needs further investigation.

Modulation of the Humoral Response to Dermatophagoides pteronyssinus Allergens in BALB/c Mice by Extract Modification and Adjuvant Use

Background: Currently, several strategies are being used in order to improve the safety and efficacy of allergen-specific immunotherapy; these strategies include the use of modified hypoallergenic extracts as well as different adjuvants with immunomodulatory properties in combination with native or modified extracts. The objectives of this study were to investigate the humoral response generated in mice to modified Dermatophagoides pteronyssinus extracts in the presence or absence of two different adjuvants. Methods: BALB/c mice were inoculated either with native, depigmented or depigmented-polymerised D. pteronyssinus without adjuvants or combined with aluminium hydroxide or oligodeoxinucleotides containing CpG motifs. IgE concentration, specific total IgG, IgG1 and IgG2a titres were measured in mice sera and cross-reactivity inhibition experiments were performed. IgG antigenic profiles were obtained by immunoblotting for all formulations. Results: Inoculation of depigmented-polymerised extract induced statistically significant lower IgE levels than the native extract even when adsorbed onto aluminium hydroxide. When this extract was inoculated in the presence of oligodeoxinucleotides containing CpG motifs, it elicited high IgG levels, a high IgG2a/lgG1 ratio and low IgE production. Furthermore, the antigenic profiles observed after extract inoculation showed punctual differences between the depigmented-polymerised extract and the native or depigmented extracts. Conclusions: Our results suggest that the depigmentation and polymerisation process modifies the native extract’s antigenic and immunogenic properties and converts the depigmented-polymerised extract into a better choice for allergen-specific immunotherapy.

Evaluation of therapeutic sublingual vaccines in a murine model of chronic house dust mite allergic airway inflammation

Second generation therapeutic vaccines based upon recombinant allergens or natural extracts, potentially formulated in vector systems or adjuvants, are being developed. To this aim, preclinical studies in relevant animal models are needed to select proper allergens, formulations and administration schemes. To develop a chronic house dust mite (HDM) allergy model to evaluate sublingual therapeutic vaccine candidates. The BABL/c mice that were used were sensitized with Dermatophagoides pteronyssinus (Dpte) and Dermatophagoides farinae (Dfar) mite extracts by intraperitoneal injections followed by aerosol exposures. Animals subsequently underwent sublingual immunotherapy (SLIT) with either Dpte, Dfar or Dpte/Dfar extracts, twice a week for 8weeks. SLIT efficacy was assessed by whole body plethysmography, lung histology and broncho-alveolar lavages cell counts. Specific T cell and antibody responses to major and minor HDM allergens were monitored in tissues and serum/saliva, respectively. Mice sensitized to Dpte and Dfar allergens exhibited strong airway hyperresponsiveness (AHR) and lung inflammatory infiltrates including eosinophils. Sensitized animals mounted Th2-biased cellular and humoral responses specific for group 1 and 2 major allergens, as well as group 5, 7 and 10 minor allergens. This phenotype was sustained for at least 2months, allowing the evaluation of immunotherapeutic protocols with HDM extracts-based vaccines. In this model, SLIT decreased AHR and Th2 responses and induced HDM-specific IgAs in saliva. The Dpte/Dfar mix proved the most efficacious when compared to Dpte or Dfar extracts alone. The efficacy of a sublingual vaccine based on a Dpte/Dfar allergen extract mix was demonstrated in a well standardized murine model of chronic allergic airway inflammation based on clinically relevant mite allergens. The latter will be used as a benchmark for evaluation of future vaccines, including recombinant allergens. This HDM allergic airway inflammation animal model is a useful tool to design and select candidate vaccines to be tested in humans.

Mite allergen decreases DC-SIGN expression and modulates human dendritic cell differentiation and function in allergic asthma

AbstractHouse dust mites (HDMs) induce allergic asthma in sensitized individuals, although how HDMs activate immature mucosal dendritic cells (DCs) to render the T helper cell type 2 (Th2)-mediated immune response is unclear. In this study, our results showed a significant calcium-dependent lectin binding of Dermatophagoides pteronyssinus (Der p) extracts to DC-specific intercellular adhesion molecule-3-grabbing nonintegrin (DC-SIGN), the C-type lectin receptors (CLRs) of DCs. Moreover, monocyte-derived DCs (MDDCs) of Der p-sensitized asthmatics (AS) exhibited decreased expression of DC-SIGN, increased endocytosis, and impaired differentiation of DC precursors. The Der p-induced downregulation of DC-SIGN expression in the differentiation of immature MDDCs may be because of the internalization of Der p-DC-SIGN complex. MDDCs of AS produced more interleukin (IL)-6 and less IL-12p70 cytokines when stimulated with lipopolysaccharide (LPS) or Der p than those of nonallergic controls (NC). In the co-culture experiments, MDDCs pretreated with Der p induced GATA-3 expression and IL-4 cytokine productions in naive CD4+ T cells. These effects of Der p on the differentiation and function of MDDCs could be partially blocked by anti-DC-SIGN antibodies. In conclusion, our results suggest a critical step of allergen sensitization that involves CLRs in the innate immune response of DCs, which may provide a therapeutic or preventive potential for allergic asthma.

Assessment of Short-Term Changes Induced by a Dermatophagoides pteronyssinus Extract on Asthmatic Patients. Randomised, Double-Blind, Placebo-Controlled Trial

Once the optimal dose is reached, subcutaneous immunotherapy [SCIT] with mite extract is capable of reducing symptoms and the need for rescue medication. To assess the capacity of a subcutaneous extract of mites [D. pteronyssinus] to bring about a reduction in concomitant medication as well as in vivo and in vitro changes in just 2-3 months of treatment in patients with allergic asthma. A total of 45 patients with persistent mild-moderate allergic asthma due to sensitisation to D. pteronyssinus were included in a multi-centre, double-blind, placebo-controlled trial. Length of treatment was 4 months. After a period for adjusting medication in order to classify asthma severity appropriately, patients were commenced on treatment of 400 or 800 g/day of budesonide as concomitant medication. After 4 months of treatment there were no significant changes in the budesonide dose between the active group and the placebo group. In the active group there was a significant difference between active and placebo group in sIgG4 [p=.0003], as well as a significant increase in the cutaneous tolerance index [2.81, CI 95%: 1.29 - 7.48, which was significant with a Confidence Interval of 95%]. These changes were not observed in the placebo group. After just 4 months of treatment, SCIT was capable of inducing in vivo and in vitro changes, but these changes were not reflected in improved clinical outcome within the first 4 months of therapy.

Safety of specific immunotherapy using a depigmented and polymerised extract of Dermatophagoides pteronyssinus in children under five years of age

Background Different opinion documents point to a patient age of under five years as a relative contraindication to specific immunotherapy, arguing that this age group has a greater risk of developing anaphylaxis, and that specially trained personnel are needed to deal with the problem if it occurs. However, insufficient evidence exists to support such an affirmation. Patients and methods A retrospective follow-up observational study was made of patients aged 60 months or younger who had been subjected to specific immunotherapy. We included 77 children with a diagnosis of extrinsic bronchial asthma (n = 68), extrinsic spasmodic cough (n = 5) and allergic rhinitis (n = 4) confirmed by clinical criteria and prick-test, with specific IgE positivity to Dermatophagoides pteronyssinus. All patients received specific immunotherapy with an extract of depigmented D. pteronyssinus polymerised with glutaraldehyde, involving an initial cluster protocol of two weeks and monthly maintenance doses. All observed adverse reactions were recorded, and classified according to European Academy of Allergy and Clinical Immunology (EAACI) criteria. Results A total of 1837 doses were administered to the 77 patients, with four adverse reactions being observed in three patients. Three reactions (0.16% of the administered doses) were local and immediate, while one was systemic and of grade 2 (0.05% of the administered doses) – consisting of an episode of nocturnal wheezing. Conclusions Specific immunotherapy in children under five years of age with the extract used is safe. We consider that further studies are needed, involving other types of extracts, to allow reconsideration of the relative contraindication of patient age for the administration of immunotherapy.

Change of Th17 and expression of RORγt in a murine model of allergic rhinitis after a stimulation of allergen and corticosteroid

To study the effects of allergen and corticosteroid on T help 17 (Th17) and orphan nuclear receptor gammat (RORγt) in allergic-rhinitis mice. Experimental allergic rhinitis (AR) was induced by the extract of dermatophagoides pteronyssinus (DP) including 2% ovalbumin (OVA) sensitization in 30 male mice with DP allergen group (n = 10), intranasal corticosteroid (budesonide, BUD) group (n = 10) or without treatment (model group, n = 10). And another 10 were included into the normal control group. The murine levels of Th17 were measured by flow cytometry (FCM). The expression of RORγt mRNA was measured by reverse transcription-polymerase chain reaction (RT-PCR) while that of RORγt protein in nasal mucosa detected by immunohistochemical staining. The expression of RORγt in nasal mucosa of AR model was higher than that in the control group (25 ± 5 vs 48 ± 10, P < 0.01). But its expression declined significantly after the administration of local corticosteroid (48 ± 10 vs 31 ± 6, P < 0.01). The levels of RORγt mRNA and Th17 in the AR model group were significantly higher than those in the control group (18.4% ± 1.3% vs 27.5% ± 1.6%, 0.43 ± 0.04 vs 0.64 ± 0.05, both P < 0.01). The levels of RORγt mRNA and Th17 in the spleen of AR mice were significantly reduced by allergen dosing (27.5% ± 1.6% vs 20.0% ± 2.1%, 0.64 ± 0.05 vs 0.54 ± 0.03, both P < 0.01) but not by corticosteroid (P > 0.05). Allergen may affect the systemic immunity to inhibit the RORγt expression and block the Th17 differentiation in AR model. Local steroid only produces a marked effect through a down-regulated RORγt expression in nasal mucosa.

Detection of Allergenic Compounds Using an IL-4/Luciferase/CNS-1 Transgenic Mice Model

The interleukin-4 (IL-4) signaling cascade has been identified as a potentially important pathway in the development of allergies. The principal objective of this study was to produce novel transgenic (Tg) mice harboring the luciferase gene under the control of the human IL-4 promoter and the enhancer of IL-4 (CNS-1), in an effort to evaluate three types of allergens including a respiratory sensitizer, vaccine additives, and crude extracts of natural allergens in vivo. A new lineage of Tg mice was generated by the microinjection of pIL-4/Luc/CNS-1 constructs into a fertilized mice egg. The luciferase activity was successfully regulated by the IL-4 promoter in splenocytes cultured from IL-4/Luc/CNS-1 Tg mice. From the first five founder lines, one (#57) evidencing a profound response to ovalbumin was selected for use in evaluating the allergens. Additionally, the lungs, thymus, and lymph nodes of IL-4/Luc/CNS-1 Tg mice evidenced high luciferase activity in response to allergens such as phthalic anhydride (PA), trimellitic anhydride, ovalbumin, gelatin, Dermatophagoides pteronyssinus extracts, and Japanese cedar pollen, whereas key allergy-related indicators including ear thickness, Immunoglobulin E concentration, and the infiltration of inflammatory leukocytes in response to PA were unaltered in the Tg mice relative to the non-Tg mice. Furthermore, the expression levels of endogenous type 2 helper T cells cytokines and proinflammatory cytokines were similarly increased in these organs of IL-4/Luc/CNS-1 Tg mice in response to allergens. These results indicate that IL-4/Luc/CNS-1 Tg mice may be used as an animal model for the evaluation and prediction of the human body response to a variety of allergens originating from the environment and from certain industrial products.

European and Mexican vs US diagnostic extracts of Bermuda grass and cat in skin testing

Laboratory testing of various diagnostic extracts has shown lower potencies for several European and Mexican extracts relative to the US Food and Drug Administration (FDA) reference (10,000 BAU/mL). Quantitative skin prick testing (QSPT) with Dermatophagoides pteronyssinus extracts have previously shown a similar picture. To compare European and Mexican Bermuda grass (BG) and cat diagnostic extracts against an FDA-validated extract using QSPT. Six diagnostic BG and cat extracts (1 reference FDA extract, 3 European extracts, 1 imported nonstandardized extract from the United States, and 1 Mexican extract) were tested with quadruplicate QSPT, as a concentrate and as 2 serial 2-fold dilutions, in cat and BG allergic individuals. BG showed good dose response in wheal size for the concentrate (1:2-1:4 dilutions; steep part of the curve). Cat showed poorer dose response. The Wilcoxon test for linked random samples was used to investigate whether the distribution of the reference differed from each of the test extracts to a statistically significant degree (2-sided asymptotic significance, α = .05). All BG and 2 cat extracts were statistically less potent than the 10,000 BAU/mL US reference. European BG extracts were 7,700, 4,100, and 1,600 BAU/mL, and cat extracts were 12,500, 4,400, and 5,100 BAU/mL. The potency of some diagnostic extracts of BG and cat used in Europe, Mexico, and the United States differs, with the US extracts being generally more potent. On the basis of provocation tests, optimal diagnostic concentrations should be determined. Similar comparisons using other manufacturers and therapeutic extracts might be interesting.

Flaky Tail Mouse Denotes Human Atopic Dermatitis in the Steady State and by Topical Application with Dermatophagoides pteronyssinus Extract

The barrier abnormality, a loss-of-function mutation in the gene encoding filaggrin (FLG), which is linked to the incidence of atopic dermatitis (AD), is a recently discovered but important factor in the pathogenesis of AD. Flaky tail (Flg(ft)) mice, essentially deficient in filaggrin, have been used to investigate the role of filaggrin on AD. However, the relevancy of Flg(ft) mice to human AD needs to be determined further. In this study, we observed the clinical manifestations of Flg(ft) mice in the steady state and their cutaneous immune responses against external stimuli, favoring human AD. Under specific pathogen-free conditions, the majority of Flg(ft) mice developed clinical and histological eczematous skin lesions similar to human AD with outside-to-inside skin barrier dysfunction evaluated by newly devised methods. In addition, cutaneous hapten-induced contact hypersensitivity as a model of acquired immune response and a mite extract-induced dermatitis model physiologically relevant to a human AD were enhanced in Flg(ft) mice. These results suggest that the Flg(ft) mouse genotype has potential as an animal model of AD corresponding with filaggrin mutation in human AD.

Clinical Efficacy of House Dust Mite-specific Immunotherapy in Asthmatic Children

Immunotherapy has been widely used in the treatment of allergic diseases. We evaluated the clinical efficacy of specific immunotherapy with extracts of Dermatophagoides pteronyssinus (Dp) and Dermatophagoides farinae (Df) in children with asthma. All 40 children had moderate-to-severe asthma and positive allergen tests for Dp and Df. All required daily medication. They were randomly assigned to two groups: Half of them received immunotherapy with subcutaneous injections of Dp and Df extracts, while the other half were not given immunotherapy. Participants were followed up for more than 6 months. Children in both groups had apparent improvements in medication use and symptoms after 6 months. The mean medication scores declined from 3.6 +/- 1.14 to 1.7 +/- 0.66 in the immunotherapy group (p < 0.01) and from 3.35 +/- 0.87 to 2.4 +/- 1.09 in the control group (p < 0.01). There was a significant difference between the two groups (mean difference 0.95; p < 0.01). The symptom score improved in the immunotherapy group from 2.65 +/- 0.98 to 1.20 +/- 1.00 (p < 0.01) and in the control group from 2.55 +/- 0.99 to 1.40 +/- 0.88 (p < 0.01), with a significant difference between the two groups (mean difference 0.3; p < 0.01). The number of office visits in the immunotherapy group was greater than that of the controls, but the frequencies of emergency room visits and hospitalization decreased. Our study showed that specific immunotherapy with Dp and Df was beneficial for asthmatic children.

Allergen immunotherapy

Specific immunotherapy (SIT) involves the administration of allergen extracts to achieve clinical tolerance of those allergens that cause symptoms in patients with allergic conditions. Immunotherapy is effective in patients with mild forms of allergic disease and also in those who do not respond well to standard drug therapy. Most SIT is given by means of injection, but there is increasing interest in performing SIT through the sublingual route. SIT remains the treatment of choice for patients with systemic allergic reactions to wasp and bee stings and should be considered as an option in patients with allergic rhinitis, asthma, or both. SIT can modify the course of allergic disease by reducing the risk of new allergic sensitizations and inhibiting the development of clinical asthma in children treated for allergic rhinitis. The precise mechanisms responsible for the beneficial effects of SIT remain a matter of research and debate. An effect on regulatory T cells seems most probable and is associated with switching of allergen-specific B cells toward IgG4 production. Few direct comparisons of SIT and drug therapy have been made. Existing data suggest that the effects of SIT take longer to develop, but once established, SIT achieves long-lasting relief of allergic symptoms, whereas the benefits of drugs only last as long as they are continued.

IgE cross‐reactivity between Ascaris and domestic mite allergens: the role of tropomyosin and the nematode polyprotein ABA‐1

Analysis of cross-reactivity between the nematode Ascaris ssp. and dust mites, two important allergen sources in the tropics, will contribute in understanding their influence on asthma and atopy. The objective of this study was to investigate immunoglobulin E (IgE) cross-reactivity between Ascaris and two domestic mites in the tropics. Sera from 24 asthmatic patients were used in ELISA and immunoblotting IgE-binding inhibition assays using Ascaris, Blomia tropicalis and Dermatophagoides pteronyssinus extracts and the recombinants Blo t 10, ABA-1 and Blo t 13 as competitors. Identification of Ascaris allergens was confirmed by mass spectrometry (LC-MS/MS). We detected at least 12 human IgE-binding components in Ascaris extract. Blomia tropicalis and D. pteronyssinus inhibited 83.3% and 79% of IgE-binding to Ascaris, while Ascaris inhibited 58.3% and 79.3% to B. tropicalis and D. pteronyssinus respectively. Mite tropomyosin inhibited 85% of IgE-binding to Ascaris. Affinity-purified human IgE to rBlo t 10 identified an allergen of 40 kDa in Ascaris extract, further confirmed as tropomyosin by LC-MS/MS. We found no evidence of IgE cross-reactivity between rABA-1 and any allergen component in mite extracts, including rBlo t 13. There is cross-reactivity between Ascaris and mites, determined by several allergens including tropomyosin and glutathione-S-transferase. In addition to its potential impact on asthma pathogenesis, Ascaris infection and mite allergy diagnosis relying on the determination of specific IgE could be affected by this cross-reactivity. ABA-1 has no cross-reactive counterpart in mite extracts, suggesting its usefulness as a more specific marker of Ascaris infection.

Interference of Dermatophagoides' Specific Immunoglobulins G in the Quantification of Mite's Specific Immunoglobulins E

In order to investigate the interference of specific IgG in the quantification of specific IgE, using the ImmunoCAP 250® system, we studied, in parallel, the interference by total adsorption of interferent and the classical method of adding interferent increasingly. Furthermore, to evaluate if the interference is affected by different solid phases, total extract of Dermatophagoides pteronyssinus and recombinant allergens of Dermatophagoides farinae were used. The results showed a statistical significant interference by IgG in the quantification of the specific IgE, but neither analytical nor clinical significant interference were observed. Therefore, this analytical system provides an accurate method for determination of the specific IgE concentration contributing to the allergic disease diagnosis quality.