Early Allergic Response Research Articles

Effect of Biologic Therapies on Airway Hyperresponsiveness and Allergic Response: A Systematic Literature Review.

Airway hyperresponsiveness (AHR) is a key feature of asthma. Biologic therapies used to treat asthma target specific components of the inflammatory pathway, and their effects on AHR can provide valuable information about the underlying disease pathophysiology. This review summarizes the available evidence regarding the effects of biologics on allergen-specific and non-allergen-specific airway responses in patients with asthma. We conducted a systematic review in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines, including risk-of-bias assessment. PubMed and Ovid were searched for studies published between January 1997 and December 2021. Eligible studies were randomized, placebo-controlled trials that assessed the effects of biologics on AHR, early allergic response (EAR) and/or late allergic response (LAR) in patients with asthma. Thirty studies were identified for inclusion. Bronchoprovocation testing was allergen-specific in 18 studies and non-allergen-specific in 12 studies. Omalizumab reduced AHR to methacholine, acetylcholine or adenosine monophosphate (3/9 studies), and reduced EAR (4/5 studies) and LAR (2/3 studies). Mepolizumab had no effect on AHR (3/3 studies), EAR or LAR (1/1 study). Tezepelumab reduced AHR to methacholine or mannitol (3/3 studies), and reduced EAR and LAR (1/1 study). Pitrakinra reduced LAR, with no effect on AHR (1/1 study). Etanercept reduced AHR to methacholine (1/2 studies). No effects were observed for lebrikizumab, tocilizumab, efalizumab, IMA-638 and anti-OX40 ligand on AHR, EAR or LAR; benralizumab on LAR; tralokinumab on AHR; and Ro-24-7472 on AHR or LAR (all 1/1 study each). No dupilumab or reslizumab studies were identified. Omalizumab and tezepelumab reduced EAR and LAR to allergens. Tezepelumab consistently reduced AHR to methacholine or mannitol. These findings provide insights into AHR mechanisms and the precise effects of asthma biologics. Furthermore, findings suggest that tezepelumab broadly targets allergen-specific and non-allergic forms of AHR, and the underlying cells and mediators involved in asthma.

Allergen provocation tests in respiratory research: building on 50 years of experience.

Allergen provocation of the airways identifies novel inflammatory pathways and guides our understanding about efficacy of new therapies. Testing of the upper or lower airways may affect the other compartment but cannot be substituted for each other. https://bit.ly/3FuT1qt

Dibutyl Phthalate Augments Allergen-induced Lung Function Decline and Alters Human Airway Immunology. A Randomized Crossover Study.

Rationale: Phthalates are a group of chemicals used in common commercial products. Epidemiological studies suggest that phthalate exposure is associated with development or worsening of allergic diseases such as asthma. However, effects of dibutyl phthalate (DBP) or other phthalates found in high concentrations in indoor air have never been examined in allergic individuals in a controlled exposure setting.Objectives: To investigate the airway effects in humans caused by inhalation of a known concentration of a single phthalate, DBP.Methods: In a randomized crossover study, 16 allergen-sensitized participants were exposed to control air or DBP for 3 hours in an environmental chamber followed immediately by an allergen inhalation challenge. Bronchoalveolar wash and lavage were obtained 24 hours after exposure. Lung function, early allergic response, airway responsiveness, inflammation, immune mediators, and immune cell phenotypes were assessed after DBP exposure.Measurements and Main Results: DBP exposure increased the early allergic response (21.4% decline in FEV1 area under the curve, P = 0.03). Airway responsiveness was increased by 48.1% after DBP exposure in participants without baseline hyperresponsiveness (P = 0.01). DBP increased the recruitment of BAL total macrophages by 4.6% (P = 0.07), whereas the M2 macrophage phenotype increased by 46.9% (P = 0.04). Airway immune mediator levels were modestly affected by DBP.Conclusions: DBP exposure augmented allergen-induced lung function decline, particularly in those without baseline hyperresponsiveness, and exhibited immunomodulatory effects in the airways of allergic individuals. This is the first controlled human exposure study providing biological evidence for phthalate-induced effects in the airways.Clinical trial registered with www.clinicaltrials.gov (NCT02688478).

Vaccination Against Measles, Mumps, and Rubella in the Light of Current Epidemic Threats: Unjustified Postponement.

A worrying increase in the number of measles cases has been noted recently in Poland, which may have to do with a decreasing proportion of children vaccinated against measles, mumps, and rubella (MMR) in the second year of life (<95%). For many years, MMR vaccination in children has been associated with a fear of allergy to eggs. This study seeks to define the reason and justification for postponing MMR vaccination in a population of children referred to the outpatient specialist immunization clinic. One hundred and thirty eight (138) children, mean 24.5±26.6months, with a history of past allergies, in whom the first-time MMR vaccination was delayed by family doctors for fear of allergic reactions, were enrolled into the study. The mean delay in a vaccine shot was 12.3±26.9months. There were 101 children who displayed a distinct allergy to the egg proteins, among other accompanying types of allergy. All of the 138 children were found eligible to receive MMR vaccine at the visit to the clinic. No early allergic responses were noticed in any of the children. There were negligible delayed allergic responses in six children, all from the egg allergy group. We conclude that MMR vaccination in children with egg allergy is safe and can be conducted on the outpatient basis without any specific precautions or safety measures. Delays in vaccination were unjustified and may jeopardize children's health. There is a need for insightful education of primary care doctors concerning of MMR vaccination safety, particularly when allergy is suspected, to avoid unduly and potentially harmful delays.

Allergic Bronchopulmonary Aspergillosis–A Luminal Hypereosinophilic Disease With Extracellular Trap Cell Death

Allergic bronchopulmonary aspergillosis (ABPA) is characterized by an early allergic response and late-phase lung injury in response to repeated exposure to Aspergillus antigens, as a consequence of persistent fungal colonization of the airways. Here, we summarize the clinical and pathological features of ABPA, focusing on thick mucus plugging, a key observation in ABPA. Recent findings have indicated that luminal eosinophils undergo cytolytic extracellular trap cell death (ETosis) and release filamentous chromatin fibers (extracellular traps, ETs) by direct interaction with Aspergillus fumigatus. Production of ETs is considered to be an innate immune response against non-phagocytable pathogens using a “trap and kill” mechanism, although eosinophil ETs do not promote A. fumigatus damage or killing. Compared with neutrophils, eosinophil ETs are composed of stable and condensed chromatin fibers and thus might contribute to the higher viscosity of eosinophilic mucus. The major fate of massively accumulated eosinophils in the airways is ETosis, which potentially induces the release of toxic granule proteins and damage-associated molecular patterns, epithelial damage, and further decreases mucus clearance. This new perspective on ABPA as a luminal hypereosinophilic disease with ETosis/ETs could provide a better understanding of airway mucus plugging and contribute to future therapeutic strategies for this challenging disease.

Subcutaneous immunotherapy with purified Der p1 and 2 suppresses type 2 immunity in a murine asthma model.

BackgroundAllergen‐specific immunotherapy can induce long‐term suppression of allergic symptoms, reduce medication use, and prevent exacerbations of allergic rhinitis and asthma. Current treatment is based on crude allergen extracts, which contain immunostimulatory components such as β‐glucans, chitins, and endotoxin. Use of purified or recombinant allergens might therefore increase efficacy of treatment.AimsHere, we test application of purified natural group 1 and 2 allergens from Dermatophagoides pteronyssinus (Der p) for subcutaneous immunotherapy (SCIT) treatment in a house dust mite (HDM)‐driven mouse model of allergic asthma.Materials and methods HDM‐sensitized mice received SCIT with crude HDM extract, a mixture of purified Der p1 and 2 (DerP1/2), or placebo. Upon challenges, we measured specific immunoglobulin responses, allergen‐induced ear swelling response (ESR), airway hyperresponsiveness (AHR), and inflammation in bronchoalveolar lavage fluid (BAL) and lung tissue.Results ESR measurement shows suppression of early allergic response in HDM‐SCIT– and DerP1/2‐SCIT–treated mice. Both HDM‐SCIT and DerP1/2‐SCIT are able to suppress AHR and eosinophilic inflammation. In contrast, only DerP1/2‐SCIT is able to significantly suppress type 2 cytokines in lung tissue and BAL fluid. Moreover, DerP1/2‐SCIT treatment is uniquely able suppress CCL20 and showed a trend toward suppression of IL‐33, CCL17 and eotaxin levels in lung tissue.DiscussionTaken together, these data show that purified DerP1/2‐SCIT is able to not only suppress AHR and inflammation, but also has superior activity toward suppression of Th2 cells and HDM‐induced activation of lung structural cells including airway epithelium.ConclusionsWe postulate that treatment with purified natural major allergens derived from HDM will likely increase clinical efficacy of SCIT.

Spirodela polyrhiza and its Chemical Constituent Vitexin Exert Anti-Allergic Effect via ORAI1 Channel Inhibition.

Intracellular calcium signaling cascades are integral to early and late allergic responses involving mast cell degranulation and type 2 helper T cell activation, respectively. Both the responses are accompanied by the movement of calcium through the calcium release-activated calcium (CRAC) channel, encoded by the ORAI1 gene. Spirodela polyrhiza (L.) Schleid (SP) has anti-inflammatory and anti-allergic effects, but its effect on calcium signaling has not been reported. This study investigated whether a 30% ethanolic SP extract (SPEtOH) and its constituents can reduce CRAC currents ([Formula: see text]), and thus inhibit mast cell degranulation and T cell activation. In Jurkat T lymphocytes, we found that 3[Formula: see text]mg/mL SPEtOH inhibited the [Formula: see text] by [Formula: see text]%, whereas one of its constituents vitexin (100[Formula: see text][Formula: see text]M) inhibited the [Formula: see text] by [Formula: see text]%. Furthermore, in the RBL-2H3 mast cell, the [Formula: see text] was inhibited by 3[Formula: see text]mg/mL SPEtOH ([Formula: see text]%) and 100[Formula: see text][Formula: see text]M vitexin ([Formula: see text]%). Investigation of human primary T cell proliferation induced by co-stimulation with antibodies to cluster of differentiation 3 and 28, and of RBL-2H3 mast cell degranulation following IgE-antigen complex stimulation revealed that 100[Formula: see text][Formula: see text]M vitexin inhibited both T-cell proliferation (by [Formula: see text]%) and mast cell degranulation (by [Formula: see text]%). These effects were concentration-dependent, and no cytotoxicity was observed. Our findings suggest that vitexin is a promising candidate compound for the development of therapeutic agents to prevent and treat allergic diseases.

Small airway involvement in the late allergic response in asthma.

Allergy and asthma are closely linked. Inhalation of allergen induces an early allergic response (EAR) within the airways of allergic asthmatic subjects, which is followed by a late allergic response (LAR) in approximately 50% of the subjects. The LAR is defined as a drop in forced expiratory volume in 1 second (FEV1 ) from baseline usually occurring 4-8 hours after exposure and is believed to affect small airways. However, FEV1 is insensitive to changes in small airway physiology. Our aim was to investigate and compare the pathophysiological processes in large and small airways during the EAR and the LAR and to characterize subjects with both an EAR and a LAR (dual responders) versus those with an EAR only (single responders). Thirty-four subjects with allergic asthma underwent an inhaled allergen challenge. Lung physiology was assessed by spirometry, impulse oscillometry (IOS), body plethysmography, inert gas washout, single breath methane dilution carbon monoxide diffusion and exhaled breath temperature (EBT), at baseline and repeatedly for 23 hours post-allergen challenge. Peripheral airway resistance, air trapping and ventilation heterogeneity were significantly increased in dual responders (n = 15) compared to single responders (n = 19) 6-8 hours post-challenge. Parameters of peripheral airway resistance and ventilation heterogeneity, measured with IOS and inert gas washout, respectively, correlated at baseline and during the allergic airway response in all subjects. The LAR involves increased resistance and ventilation defects within the peripheral airways. Alternative definitions of the LAR including small airways pathophysiology could be considered. Small airway dysfunction during the LAR suggests that dual responders may have more extensive airway pathology and underscores the relevance of small airways assessment in asthma.

Omalizumab effectively protects against early and late allergic responses in asthma after 4 weeks.

Omalizumab is licensed for therapy in severe allergic asthma with an effect demonstrated after 8 weeks or longer treatment. As new applications for omalizumab demand precise knowledge of the onset of effects, the objective of this study was to determine the time course of the early (EAR) and late allergic reaction (LAR). Ten patients (IgE>300 IU/mL and <700 IU/mL) with a significant response to allergen challenge were treated with omalizumab according to the approved dosing table. Bronchial allergen provocations (BAP) were repeated at weeks 1, 2, 4, and 8. EAR was significantly reduced after 4 weeks (ΔFEV1 28% vs 11%; P<.001), eNO (86 vs 53 ppb; P<.05) and basophil activation after 2 weeks (CD63 expression 79% vs 32%, P<.05) and LAR already after 1 week (ΔFEV1 26% vs 13%, P<.05). These results demonstrate the onset of protective effects earlier than previously determined, potentially improving seasonal utilization and combination with immunotherapy.

Mucosal Type 2 Innate Lymphoid Cells Are a Key Component of the Allergic Response to Aeroallergens.

Newly characterized type 2 innate lymphoid cells (ILC2s) display potent type 2 effector functionality; however, their contribution to allergic airways inflammation and asthma is poorly understood. Mucosal biopsy used to characterize the airway mucosa is invasive, poorly tolerated, and does not allow for sequential sampling. To assess the role of ILC2s during nasal allergen challenge in subjects with allergic rhinitis using novel noninvasive methodology. We used a human experimental allergen challenge model, with flow cytometric analysis of nasal curettage samples, to assess the recruitment of ILC2s and granulocytes to the upper airways of subjects with atopy and healthy subjects after allergen provocation. Soluble mediators in the nasal lining fluid were measured using nasosorption. After an allergen challenge, subjects with atopy displayed rapid induction of upper airway symptoms, an enrichment of ILC2s, eosinophils, and neutrophils, along with increased production of IL-5, prostaglandin D2, and eosinophil and T-helper type 2 cell chemokines compared with healthy subjects. The most pronounced ILC2 recruitment was observed in subjects with elevated serum IgE and airway eosinophilia. The rapid recruitment of ILC2s to the upper airways of allergic patients with rhinitis, and their association with key type 2 mediators, highlights their likely important role in the early allergic response to aeroallergens in the airways. The novel methodology described herein enables the analysis of rare cell populations from noninvasive serial tissue sampling.

Davallia mariesii Moore Improves FcεRI-Mediated Allergic Responses in the Rat Basophilic Leukemia Mast Cell Line RBL-2H3 and Passive Cutaneous Anaphylaxis in Mice.

Davallia mariesii Moore (Drynaria rhizome extract (DRE)) is widely known for its efficacy in treating inflammation, arteriosclerosis, and bone injuries. This study evaluated whether treatment with DRE inhibited FcɛRI-mediated allergic responses in the RBL-2H3 mast cells and investigated the early- and late-phase mechanisms by which DRE exerts its antiallergic effects. IgE anti-DNP/DNP-HSA-sensitized RBL-2H3 mast cells were tested for cytotoxicity to DRE, followed by the assessment of β-hexosaminidase release. We measured the amounts of inflammatory mediators (e.g., histamine, PGD2, TNF-α, IL-4, and IL-6) and examined the expression of genes involved in arachidonate and FcεRI signaling pathways. In addition, we confirmed the antiallergic effects of DRE on passive cutaneous anaphylaxis (PCA) in mice. DRE inhibited RBL-2H3 mast cell degranulation and production of allergic mediators in them. In early allergic responses, DRE reduced expression of FcεRI signaling-related genes (e.g., Syk, Lyn, and Fyn) and extracellular signal-regulated kinase phosphorylation in mast cells. In late allergic responses, DRE reduced PGD2 release and COX-2 expression and cPLA2 phosphorylation in FcɛRI-mediated mast cells. Lastly, 250–500 mg/kg DRE significantly attenuated the IgE-induced PCA reaction in mice. These findings provide novel information on the molecular mechanisms underlying the antiallergic effects of DRE in FcɛRI-mediated allergic responses.

The histone deacetylase inhibitor trichostatin A suppresses murine innate allergic inflammation by blocking group 2 innate lymphoid cell (ILC2) activation

BackgroundGroup 2 innate lymphoid cells (ILC2) are an important source of the type 2 cytokines interleukin (IL)-5 and IL-13 that are critical to the allergic airway phenotype. Previous studies reported...

Anti-IgE treatment, airway inflammation and remodelling in severe allergic asthma: current knowledge and future perspectives.

Asthma is a disorder of the airways involving various inflammatory cells and mediators and characterised by bronchial hyperresponsiveness, chronic inflammation and structural alterations in the airways, also known as remodelling. IgE is an important mediator of allergic reactions and has a central role in allergic asthma pathophysiology, as it is implicated in both the early and late phase allergic response. Moreover, clinical and mechanistic evidence has lately emerged, implicating IgE in the development of airway remodelling. The use of monoclonal antibodies targeting IgE, such as omalizumab, has proven very effective in improving respiratory symptoms and quality of life, while reducing asthma exacerbations, emergency room visits and the use of systemic corticosteroids in allergic severe asthma. These effects are believed to be mainly mediated by omalizumab's inhibitory effect on the initiation and further propagation of the allergic inflammation cascade. However, there is evidence to suggest that anti-IgE treatment remains effective long after it has been discontinued. In part, these findings could be attributed to the possible ameliorating effects of anti-IgE treatment on airway remodelling. In this review, we discuss recent findings supporting the notion that anti-IgE treatment modulates the complex immune responses that manifest clinically as asthma and ameliorates airway remodelling changes often observed in allergic severe asthma phenotypes.

Roflumilast for asthma: Efficacy findings in mechanism of action studies

BackgroundThe efficacy profile of roflumilast, a phosphodiesterase-4 inhibitor used for the treatment of chronic obstructive pulmonary disease (COPD), is well known. In asthma treatment, much less is understood about the role of roflumilast, particularly its mechanism of action and potential bronchodilatory effects. AimTo evaluate the therapeutic efficacy and mechanism of action of roflumilast in patients with asthma using data from eight placebo-controlled, double-blind phase I–III studies. MethodsThe studies were conducted at 14 sites in Europe, North America and South Africa from 1997 to 2005. The effect of treatment with 250 μg, 500 μg or 1000 μg roflumilast was compared with placebo in seven cross-over studies and one parallel-group study in 197 patients 18–70 years of age. Primary endpoints focused on the extent of the late allergic response after an allergen challenge, change in sputum cell eosinophil counts or exhaled nitric oxide (eNO), forced expiratory volume in 1 s (FEV1) and exercise-induced bronchoconstriction. Secondary endpoints included the extent of the early allergic response and measurements of tumour necrosis factor α (TNFα), sputum cells and inflammatory markers. ResultsRoflumilast attenuated allergen-induced bronchoconstriction (FEV1) in patients with asthma. Significant reductions in allergen-induced airway inflammation, including a reduction in both eosinophil and neutrophil counts were also observed and physiologic responses to allergen-induced challenge were confirmed by a significant reduction in TNFα. Side effects were similar to COPD, but did not include weight loss. ConclusionsThe results from these studies indicate that the anti-inflammatory effects of roflumilast observed in COPD are also seen in asthma and advance our understanding of its mechanism of action.All studies were funded by Takeda. Trial registration numbers available on ClinicalTrials.gov: NCT01365533.

9α,11β-PGF2, a Prostaglandin D2 Metabolite, as a Marker of Mast Cell Activation in Bee Venom-Allergic Patients.

Mast cell (MC) mediators, among them prostaglandin D2 (PGD2) and 9α,11β-PGF2, PGD2’s metabolite, play a key role in allergic reactions, including bee venom anaphylaxis (BVA). Assessment of these mediators has never been performed in BVA. The aim of the study was to assess the activation of MC during in vivo provocation with bee venom (BV) and to measure PGD2 and 9α,11β-PGF2 in the course of an allergen challenge. The second aim was to determine if assessment of these mediators could be useful for predicting adverse events during venom immunotherapy (VIT). In 16 BV-VIT patients and 12 healthy subjects, levels of PGD2 and 9α,11β-PGF2 were assessed during BV provocation by means of the skin chamber method. Chamber fluids, collected at 5 and 15 min, were analyzed for both mediators by gas chromatography mass spectrometry negative ion chemical ionization. BVA in comparison to non-allergic patients had a significantly higher ratio of 9α,11β-PGF2 in allergen-challenged chambers to 9α,11β-PGF2 in allergen-free chambers after 15 min of provocation (p = 0.039). Allergen challenge resulted in a significant increase of 9α,11β-PGF2 levels between 5 and 15 min after provocation only in BVA patients (p < 0.05). Analysis of log-transformed PGD2 levels showed significant difference between changes in PGD2 concentration between BVA and healthy subjects. No study patient developed adverse reactions during. 9α,11β-PGF2 is actively generated during the early allergic response to BV. Skin chamber seems to be a promising, non-invasive and safe model of in vivo allergen provocation in BV-allergic patients. High or low levels of both mediators do not predict occurrence of adverse events during VIT.

MIG (CXCL9), IP-10 (CXCL10) and I-TAC (CXCL11) concentrations after nasal allergen challenge in patients with allergic rhinitis

IntroductionThe role of monokine induced by interferon-γ (IFN-γ, MIG/CXCL9), IFN-γ-inducible protein (IP-10/CXCL10), and IFN-inducible T cell α chemoattractant (I-TAC/CXCL11) in allergic inflammation has not been explored in detail in vivo. The aim of the study was to examine the changes in concentrations of MIG/CXCL9, IP-10/CXCL10 and I-TAC/CXCL11 in nasal lavages collected from healthy and allergic subjects during nasal allergen challenge.Material and methodsSubjects allergic to grass pollen and healthy controls were included. Nasal allergen challenge preceded by placebo administration was performed outside the pollen season. Nasal lavages were collected before and 30 min after application of the placebo and 30 min after allergen administration. Concentrations of chemokines were determined using ELISA.ResultsWe observed significantly higher concentrations of IP-10/CXCL10 in allergic patients compared to the healthy subjects before (354.49 ±329.24 vs. 164.62 ±175.94 pg/ml; p = 0.036), 30 min after placebo (420.3 ±421.28 vs. 246.88 ±353.24 pg/ml; p = 0.021) and 30 min after allergen administration (403.28 ±359.29 vs. 162.68 ±148.69 pg/ml; p = 0.025). IP-10/CXCL10 levels did not change 30 min after allergen provocation. In contrast, MIG/CXCL9 levels were similar in both groups before and after placebo. However, a significant rise in MIG/CXCL9 concentration was noted in allergic patients 30 min after the allergen (138.88 ±109.59 vs. 395.8 ±301.2 pg/ml; p = 0.00026). I-TAC/CXCL11 concentrations increased after placebo as well as the allergen in both groups.ConclusionsIP-10/CXCL10 concentrations are elevated in nasal lavages from allergic patients and this chemokine may play a role in chronic allergic inflammation. MIG/CXCL9 levels increase rapidly after allergen application, which may suggest its role in the early allergic response. Results on I-TAC/CXCL11 concentrations remain inconclusive.

Modulation of antigen-induced responses by serotonin and prostaglandin E2 via EP1 and EP4 receptors in the peripheral rat lung

The cyclooxygenase (COX) pathway and prostanoids may critically contribute to the early allergic airway response. In the rat lung, serotonin (5-HT) is a major mediator of antigen-induced contractions. The aim of this study was therefore to examine the relative role of the COX pathway and serotonin for antigen-induced contractions in the rat lung. Airway responses were studied in rat precision-cut lung slices (PCLS). Lung slices were stimulated with ovalbumin or serotonin after pretreatment with COX inhibitors or specific TP or EP receptor antagonists. Changes in airway size (contractions/relaxations) were measured by a digital video camera. The supernatants were analysed for changes in prostaglandin and serotonin release. Airway contractions to ovalbumin were attenuated by the unselective COX inhibitor indomethacin, the selective COX-1 inhibitor FR-122047 and COX-2 inhibitor celecoxib. The EP1 receptor antagonist ONO-8713 reduced the contractions, whereas the EP4 receptor antagonist L-161,982 significantly increased the contractile response to ovalbumin. The 5-HT2A receptor antagonist ketanserin completely inhibited the ovalbumin-induced contractions. The different COX inhibitors decreased the production of prostaglandins but did not affect the synthesis of serotonin. The serotonin-induced bronchoconstriction was attenuated by celecoxib and ONO-8713, but not by methacholine. Taken together, our data indicate that PGE2 is the main prostanoid involved in the early allergic airway response in the rat lung. PGE2 appears to act both as a primary mediator of antigen-induced airway contraction via the EP4 receptor and as a downstream modulator of serotonin-induced bronchoconstriction via the EP1 receptor.

Inhibitory effect of topical adelmidrol on antigen-induced skin wheal and mast cell behavior in a canine model of allergic dermatitis.

BackgroundAdelmidrol is a semisynthetic derivative of azelaic acid and analogue of the anti-inflammatory compound palmitoylethanolamide (PEA). Based upon its physicochemical properties, adelmidrol is suitable for topical application. The main objective of the present study was to evaluate the efficacy of a topical adelmidrol emulsion on early and late inflammatory responses in hypersensitive dogs. Repeated intradermal injections of Ascaris suum extract were performed in both lateral thoracic areas of six conscious hypersensitive Beagle dogs, topically treated during 8 consecutive days. Adelmidrol (2%) was applied to one side and vehicle to the other. 24 hours after the last antigen challenge, two biopsies (adelmidrol- and vehicle-treated side) were obtained for each dog at the antigen injection site.ResultsA significant reduction in the antigen-induced wheal areas was observed on the 4th and 7th day of adelmidrol treatment. Moreover, cutaneous mast cell numbers were significantly decreased in biopsies obtained after 8 consecutive days of topical adelmidrol treatment.ConclusionsThe results obtained in the present study show that topical treatment with adelmidrol might represent a new therapeutic tool in controlling the early and late allergic inflammatory skin responses in companion animals.

자소엽(紫蘇葉) 에탄올 추출물이 RBL-2H3 비만세포에서 제 1형 알레르기 반응 조절에 미치는 효과

Objectives Perillae Folium (PF) has been widely used in Korean herbal medicines used for treatment of acute and chronic inflammatory diseases, such as rhinitis, asthma, and enteritis. In this study, to investigate the protective effect of PF on type 1 allergic response, we determined whether PF inhibits early or late allergic responses. Methods The effect of PF was analyzed by ELISA,. RT-PCR and Western blot in RBL-2H3 cells. Levels of <TEX>${\beta}$</TEX>-hexosaminidase, interleukin (IL)-4 and TNF-<TEX>${\alpha}$</TEX> were measured using enzyme-linked immunosorbent assays (ELISAs). mRNA levels of cytokines and enzymes were analyzed with RT-PCR. Signal transduction was analyzed with Western blot. Results We found that PF suppressed <TEX>${\beta}$</TEX>-hexosaminidase release in RBL-2H3 by the IgE-DNP-HSA stimulation. PF also significantly inhibited enzymes level, such as COX-1, COX-2, iNOS, and HDC2, along with reduced cytokine levels, such as IL-2, IL-3, IL-4, IL-6, IL-13, and TNF-<TEX>${\alpha}$</TEX> in RBL-2H3. In addition, PF suppressed the phospholyation of ERK1/2, JNK1/2, and <TEX>$I{\kappa}B{\alpha}$</TEX>. Conclusions Our results indicate that PF protects against type 1 allergic response and exert an anti-inflammatory effect through the inhibition of degranulation and expression of cytokines and enzymes via the suppression of signal transduction.

97 Grass Pollen Allergen-induced Surface Expression of CD203C, CD63 and CD107A on CRTH2+ Basophils

BackgroundGrass pollen immunotherapy is associated with reduction in symptoms, the need for rescue medication and improvement of quality of life in patients with severe seasonal pollinosis. Although, the suppression of the early allergic response following in vivo cutaneous allergen challenge is associated with inhibition of basophil histamine release, the effects of immunotherapy on basophil reactivity is yet to be fully determined. We hypothesized that basophil reactivity as measured by increased expression of surface activation markers CD203c, CD63 and CD107a on CRTH2+ basophils is increased in grass pollen allergic individuals following in vitro allergen stimulation. We further hypothesized that this hypereactivity is reduced in immunotherapy-treated patients.MethodsHeparinized blood obtained from grass pollen allergics (n = 7), immunotherapy treated patients (n = 6) and non-atopic controls (n = 9) was incubated with 0, 0.1, 1, 10 and 100 ng/mL of P. Pratense extract at 37°C for 15 minutes. Cells were stained with anti-CD3, CRTh2, CD123, CD303, CD203c, CD63 and CD107a. Additionally, whole blood basophil histamine release was measured pre/post immunotherapy by ELISA (n = 6).ResultsA dose-dependent increase in the proportion of CD203c+, CD63+ and CD107a+ CRTH2+ basophils was observed following in vitro grass pollen stimulation in allergics but not in non-atopic controls. At 100 ng/mL of P. Pratense extract, CD203c+, CD63+ and CD107a+CRTH2+ basophils were significantly elevated in allergics compare to non-topics (P < 0.001, P < 0.001 and P < 0.009). This increase in CD203c+, CD63+CRTH2+ basophils in allergic individuals significantly correlated with timothy-specific IgE (r = 0.84, P < 0.0001; r = 0.85, P < 0.0001). Interestingly, 10- to 100-fold more allergen was required for CRTH2+ basophils to express CD203c, CD63 and CD107a in immunotherapy-treated patients compare to grass pollen allergics. At suboptimal allergen-concentration (10 ng/mL), CD203c+, CD63+ and CD107a+CRTH2+ basophils were significantly reduced in immunotherapy treated subjects compare to allergics (P < 0.001, P < 0.001 and P < 0.002). Basophil histamine release measured after treatment was significantly reduced compared to pre-treatment levels (P < 0.03).ConclusionsBasophil reactivity and histamine release is significantly reduced following grass pollen immunotherapy. The use of surface activation markers CD203c, CD63 and CD107a on basophils for monitoring clinical efficacy requires further investigations.