Timothy Grass Pollen Research Articles

Dupilumab Improves Clinical Symptoms and Biomarkers in Comorbid Seasonal Timothy Grass Pollen Allergic Rhinitis in Patients With CRSwNP.

Dupilumab Improves Clinical Symptoms and Biomarkers in Comorbid Seasonal Timothy Grass Pollen Allergic Rhinitis in Patients With CRSwNP.

The cytoskeletal protein profilin is an important allergen in saltwort (Salsola kali).

Pollen from Salsola kali, i.e., saltwort, Russian thistle, is a major allergen source in the coastal regions of southern Europe, in Turkey, Central Asia, and Iran. S. kali-allergic patients mainly suffer from hay-fever (i.e., rhinitis and conjunctivitis), asthma, and allergic skin symptoms. The aim of this study was to investigate the importance of individual S. kali allergen molecules. Sal k 1, Sal k 2, Sal k 3, Sal k 4, Sal k 5, and Sal k 6 were expressed in Escherichia coli as recombinant proteins containing a C-terminal hexahistidine tag and purified by nickel affinity chromatography. The purity of the recombinant allergens was analyzed by SDS-PAGE. Their molecular weight was determined by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, and their fold and secondary structure were studied by circular dichroism (CD) spectroscopy. Sera from clinically well-characterized S. kali-allergic patients were used for IgE reactivity and basophil activation experiments. S. kali allergen-specific IgE levels and IgE levels specific for the highly IgE cross-reactive profilin and the calcium-binding allergen from timothy grass pollen, Phl p 12 and Phl p 7, respectively, were measured by ImmunoCAP. The allergenic activity of natural S. kali pollen allergens was studied in basophil activation experiments. Recombinant S. kali allergens were folded when studied by CD analysis. The sum of recombinant allergen-specific IgE levels and allergen-extract-specific IgE levels was highly correlated. Sal k 1 and profilin, reactive with IgE from 64% and 49% of patients, respectively, were the most important allergens, whereas the other S. kali allergens were less frequently recognized. Specific IgE levels were highest for profilin. Of note, 37% of patients who were negative for Sal k 1 showed IgE reactivity to Phl p 12, emphasizing the importance of the ubiquitous cytoskeletal actin-binding protein, profilin, for the diagnosis of IgE sensitization in S. kali-allergic patients. rPhl p 12 and rSal k 4 showed equivalent IgE reactivity, and the clinical importance of profilin was underlined by the fact that profilin-monosensitized patients suffered from symptoms of respiratory allergy to saltwort. Accordingly, profilin should be included in the panel of allergen molecules for diagnosis and in molecular allergy vaccines for the treatment and prevention of S. kali allergy.

Clinical validation of grass pollen exposure chamber in patients with allergic rhinitis triggered by timothy grass.

The fluctuation in concentrations of airborne allergens frequently presents a challenge to assessing the efficacy of allergen immunotherapy (AIT) in 'field' studies. Allergen exposure chambers (AECs) are specialized medical installations developed to expose individuals to allergens at defined and consistent concentrations under a controlled environment. The aim of the study was to validate the provocation test with timothy grass pollen as well as to assess its safety in the AEC in patients with allergic rhinitis. In the ALLEC® AEC, varying concentrations of timothy grass pollen were dispersed. Allergic symptoms were measured by total nasal symptom score (TNSS), acoustic rhinometry, peak nasal inspiratory flow (PNIF) and nasal discharge volume. Lung function, assessed through peak expiratory flow rate (PEFR) and forced expiratory volume in the first second (FEV1), was used to evaluate safety. The consistency of the test was proved by the stability of environmental conditions, including temperature, humidity and CO2 levels, as well as constant concentrations of grass pollen at predetermined levels ranging from 1000 to 10,000 particles per cubic meter (p/m3). Allergic individuals developed symptoms at concentrations of 3000 p/m3 and above, across all measured endpoints. Lung function was not affected throughout all the challenges. The reproducibility of symptoms was confirmed throughout the tests. The concentration of 8000 p/m3 together with a challenge duration of 120 min was found to be optimal. The study demonstrates that the ALLEC® grass pollen exposure chamber provides a reliable and safe method for inducing repeatable symptoms in patients with allergic rhinitis. This approach can be effectively applied for allergy diagnostics and clinical endpoint determination during AIT.

Sensitization to genuine markers of timothy grass pollen (Phleum pratense) in the North-Central region of Portugal.

Background. Pollen is the main cause of respiratory allergy and its prevalence is increasing. Timothy grass (Phleum pratense) is one of the most common pollen sources, and one of the best characterized allergenic grasses. The major allergens Phl p1, Phl p2, Phl p5 and Phl p6 are considered markers of genuine grass pollen sensitization. Methods. Retrospective study. IgE levels of Phl p1 and Phl p5 in patients living in the North-Central region of Portugal were analyzed, considering age and area of residence (inland or costal). Results. Among the 188 patients with IgE results for Phl p1 and Phl p5, sensitization to Phl p1 and Phl p5b was observed in 97.87% and 63.83%, respectively. The majority demonstrated co-sensitization to both Phl p1 and Phl p5b, while 68 patients were monosensitized to Phl p1 and 4 patients were monosensitized to Phl p5b. Either patients living in costal or inland areas showed IgE levels of Phl p1 higher than Phl p5b. Conclusions. Regarding genuine grass pollen sensitization, Phl p1 sensitization is more prevalent than Phl p5b in the North-Central region of Portugal.

Adoptive transfer of allergen-expressing B cells prevents IgE-mediated allergy.

Prophylactic strategies to prevent the development of allergies by establishing tolerance remain an unmet medical need. We previously reported that the transfer of autologous hematopoietic stem cells (HSC) expressing the major timothy grass pollen allergen, Phl p 5, on their cell surface induced allergen-specific tolerance in mice. In this study, we investigated the ability of allergen-expressing immune cells (dendritic cells, CD4+ T cells, CD8+ T cells, and CD19+ B cells) to induce allergen-specific tolerance in naive mice and identified CD19+ B cells as promising candidates for allergen-specific cell therapy. For this purpose, CD19+ B cells were isolated from Phl p 5-transgenic BALB/c mice and transferred to naive BALB/c mice, pre-treated with a short course of rapamycin and an anti-CD40L antibody. Subsequently, the mice were subcutaneously sensitized three times at 4-week intervals to Phl p 5 and Bet v 1 as an unrelated control allergen. Allergen-expressing cells were followed in the blood to monitor molecular chimerism, and sera were analyzed for Phl p 5- and Bet v 1-specific IgE and IgG1 levels by RBL assay and ELISA, respectively. In vivo allergen-induced lung inflammation was measured by whole-body plethysmography, and mast cell degranulation was determined by skin testing. The transfer of purified Phl p 5-expressing CD19+ B cells to naive BALB/c mice induced B cell chimerism for up to three months and prevented the development of Phl p 5-specific IgE and IgG1 antibody responses for a follow-up period of 26 weeks. Since Bet v 1 but not Phl p 5-specific antibodies were detected, the induction of tolerance was specific for Phl p 5. Whole-body plethysmography revealed preserved lung function in CD19+ B cell-treated mice in contrast to sensitized mice, and there was no Phl p 5-induced mast cell degranulation in treated mice. Thus, we demonstrated that the transfer of Phl p 5-expressing CD19+ B cells induces allergen-specific tolerance in a mouse model of grass pollen allergy. This approach could be further translated into a prophylactic regimen for the prevention of IgE-mediated allergy in humans.

Assessing IgE sensitization profiles to birch and timothy grass pollen allergens in birch pollen allergic blood donors using an oligoplex specific IgE assay

IgE sensitization profiles to single birch allergens in birch-sensitized patients differ among European countries. The aim of this study was to determine the distribution of specific IgE antibodies to major and minor birch pollen allergens in a population of allergic Norwegian individuals by using a birch allergic blood donor population as a surrogate sample. Sixty blood donors were recruited and sampled based on birch allergy symptoms such as rhinitis, rhinoconjunctivitis and/or mild asthma in previous seasons. All sera were collected before start of the pollen season and tested using a line blot assay (Euroimmun AG, Lübeck, Germany) for IgE to birch and timothy pollen. Both extracts, single allergens, and cross-reacting carbohydrate determinants (CCD) were analysed. Only donors with specific IgE to birch and/or timothy grass were further evaluated. Specific IgE to birch pollen extract was found in 52 sera, and sensitization to timothy grass in 40 sera. Specific IgE to Bet v 1 was predominant in contrast to Bet v 4 which was absent. However, sensitization to the minor allergens Bet v 2 and 6 was always found together with high levels of IgE to Bet v 1. Subjects sensitized to the profilin Bet v 2 from birch were also sensitized to Phl p 12 from timothy grass. In conclusion, there was predominantly Bet v 1 sensitization in this cohort and low sensitization to minor allergens and cross-reactive allergens (Bet v 2, Bet v 4, Phl p 7 and Phl p 12).

Pollen allergen products: current standardisation issues

Scientific relevance. Pollen allergen medicines are in high demand, and their therapeutic benefits directly correlate with their standardisation. Better diagnosis and treatment of allergic diseases require state-of-the-art procedures for assessing the allergenic activity of pollen allergen products using reference standards and physicochemical testing methods.Aim. The study aimed at developing methodological approaches to the standardisation of pollen allergen products in order to shift to measuring their potency in allergenic activity units (AAU) and bring their quality in line with the requirements of the State Pharmacopoeia of the Russian Federation.Materials and methods. The study used pollen allergen reference standards by Microgen, the WHO International Standard for timothy grass (Phleum pratense) pollen extract, a gel filtration standard kit of molecular weight markers ranging from 1.35 to 670 kDa, bovine serum albumin, serum samples with specific IgE obtained from donors sensitised to the study pollen allergens, labelled anti-human IgE antibodies, and reference standards for determining residual volatile solvents by gas chromatography. The identification of in-house reference standards for the potency of pollen allergens involved Western blotting (for allergenic components). The total protein content was determined by Bradford’s assay. In addition, the authors used high-performance liquid chromatography to study protein fractions and gas–liquid chromatography to determine the content of residual organic solvents.Results. To substitute the existing method of non-specific characterisation of allergenic activity in protein nitrogen units (PNU), the authors developed and tested a new method to control allergenic activity in allergenic activity units (AAU) based on an in vitro competitive enzyme-linked immunosorbent assay (ELISA) procedure developed and validated in this study. Furthermore, the authors developed and certified 15 primary in-house reference standards with allergenic activity established in AAU/mL using skin tests in vivo. The experimental data were analysed to standardise the allergenic activity of the pollen allergens manufactured by Microgen. The authors developed physicochemical methods for the certification of in-house reference standards and validated these methods in accordance with the State Pharmacopoeia of the Russian Federation. The study involved selecting chromatographic separation conditions for residual organic solvents (acetone and diethyl ether) and establishing system suitability criteria for the chromatographic system. The allergenic activity of secondary in-house reference standards was certified against that of primary in-house reference standards using competitive ELISA. Thus, the authors managed to shift to the standardisation of pollen allergen products in vitro.Conclusions. The authors developed their competitive ELISA-based method to standardise pollen allergen products by comparing the inhibition of immune responses to a product and a standard. The study demonstrated the feasibility of substituting allergenic activity quantification (in AAU) for protein nitrogen content determination (in PNU) and showed the first example of using AAU for the certification of in-house reference standards. Additionally, the authors developed and validated an analytical procedure for determining the content of residual organic solvents in pollen allergen products by gas–liquid chromatography.

Molecular allergy diagnosis is sensitive and avoids misdiagnosis in patients sensitized to seasonal allergens.

The specificity of extract-based pollen allergy diagnosis is decreased due to cross-reactivity via cross-reactive carbohydrate determinants (CCDs) or panallergens such as profilins or polcalcins. This study aimed to explore the prevalence of sensitization to seasonal extracts, CCDs, profilin and polcalcin and investigate the sensitivity and specificity of seasonal molecular allergy diagnosis (MAD) using commercially available test methods. 2948 patients were screened for specific immunoglobulin E to ash, birch, mugwort, ragweed and timothy grass pollen extracts and grouped according to the number of positive tests (1-5). 100 patients from each group and a control group were randomly selected to calculate the prevalence of CCD and panallergen sensitization. With 742 patients, sensitivity and specificity of MAD (Alt a 1, Fra/Ole e 1, Bet v 1, Phl p 1, Art v 1, and Amb a 1) was determined. 1627 patients (55.2%) were positive to at least one, and 1002 patients (34.0%) were positive to multiple of the five pollen allergens investigated; 18.5% of the pollen-sensitized patients had sensitization to CCDs or panallergens. Specifically, sensitization to CCDs, profilins, and polcalcins was observed in 8.7%, 10.9%, and 2.9% of these patients, respectively. The sensitivity of MAD was high, with sensitivities between 96.2% and 100% using ImmunoCAP and 91.5% and 100% using ALEX2 . Specificity was 100% for both assays. Due to cross-reactivity, about one-fifth of pollen-sensitized patients is at risk of misdiagnosis. However, MAD is sensitive, specific and helps to avoid misdiagnosis and select primary allergen sources for immunotherapy.

Extract-Shaped Immune Repertoires as Source for Nanobody-Based Human IgE in Grass Pollen Allergy.

The presence of allergen-specific IgE in serum is a biomarker for allergic disease. Specific IgE antibodies for research and diagnostics, however, remain scarce. In contrast to prototypic antibodies, camelid species have evolved single domains as moiety for antigen recognition. These so-called nanobodies represent a versatile platform for the development of diagnostic and therapeutic approaches. In this study, we aimed for generating nanobodies and derived IgE formats from an extract-shaped immune repertoire. Timothy grass pollen represents a complex, but well-defined mixture of individual allergens. Therefore, a repertoire library from a timothy grass pollen extract immunised llama was established. The selection by phage display yielded 3 nanobodies with immunoreactivity to the extract. IgE-like nanobody-based human IgE (nb-hIgE) antibodies were produced in mammalian cells and assessed in different immunoassays and commercial platforms. Immunoblotting and diagnostic ImmunoCap analysis of single timothy grass pollen allergens identified the major allergens Phl p 6 and Phl p 4 as targets. Assessment of immunoreactivity further documented significant molecular cross-reactivity with pollen extract of different grass species and variant presence of allergens within extracts of Pooideae grasses. In summary, our study shows that extract-based immunisation enables the generation of allergen-specific nanobodies and derived nb-hIgE formats linking nanobody technologies with allergological applications.

Effects of fiber electrostatic cling and moisture regain on timothy grass pollen attraction

The purposes of this study are to determine if there is a relationship between fabric parameters such as electrostatic charge and moisture regain on the attraction of Timothy grass pollen, and to determine the effects of various fabric treatments on their pollen attraction. Half of the fabrics were treated with acidic acid (vinegar), basic (ammonia), and fabric softener. Both untreated and treated fabrics were exposed to Timothy grass pollen. The pollen counts of both untreated and treated fabrics were then determined. The results showed that untreated wool was found to be the least attraction to Timothy grass pollen while nylon was the most attracted to this pollen. The relationship between electrostatic cling time and pollen attraction was not established in the fibers studied except nylon, which had the highest cling time and the highest pollen count. When examining the relationship between fiber moisture regain and their pollen attraction, the results showed that other than wool, which had the highest MR and the lowest pollen count, no consistency was found between the MR and pollen count for the rest of the fibers tested. For fabric treatments, the results showed that dilute acidic acid was found to be most effective in reducing the pollen counts in all fiber fabrics except made no change in wool. Fabric softener was found to be the least effective treatment in lowering the fabric pollen attraction on all fiber fabrics except nylon.

253 Protective and cleansing effect of a skin care product against pollen allergen accumulation in the hair follicle

Environmental airborne elements such as pollutant matters, chemicals, or allergens, such as pollen allergens accumulate on the skin and more particularly in the infundibula of the hair follicle due to its specific form and function. This accumulation can lead to irritation, discomfort or even sensitization and allergic reactions. Thereby, prevention of accumulation or cleansing of these elements within the infundibulum is a key challenge to protect skins submitted to environmental factors. A new study model was set up to mimic pollen allergen deposit onto the skin and test the effect of a skin care product to prevent or cleanse the allergen accumulation. Explants from a hairy abdominoplasty were prepared and placed on Perfex vivo culture supports (Bio-EC). Recombinant allergen Phl p 5b from Timothy grass pollen (abcam) was applied on the surface of explants for 6 hours and the explants were proceeded for immunohistochemistry to visualize the allergen accumulation. Pretreatment with the skin care product was used to evaluate the preventive effect or a cleansing protocol was used to quantify the curative efficacy. The skin care product was able to completely prevent accumulation along the hair follicle when applied on the explant prior to allergen exposition. A strong removal (-83%) of accumulated allergens was observed when explants were cleansed using the same product. In conclusion, a study model was set up to mimic pollen allergens accumulation in the infundibulum. Protective effect thanks to the film forming capacity of the tested skin care product or its cleansing ability could be demonstrated. The product displayed a great double effect, making it an ally to protect skin from environmental airborne elements allowing sensitization processes prevention.

POLLEN INDUCED ANAPYLAXIS THROUGH SKIN ABRASION

<h3>Introduction</h3> Anaphylaxis is an acute, potentially lethal, multisystem syndrome resulting from the sudden release of mast cell- and basophil-derived mediators into the circulation. We present an unusual case of anaphylaxis to pollen exposure through abraded skin secondary to a skateboard accident. <h3>Case Description</h3> A 19- year-old women with past medical history of mild allergic rhinitis treated with OTC antihistamines as needed had a skate board accident that led to large abrasion" road rash" on the right posterior thigh and buttocks. She notices the abrasion occurred on ground where there was a significant degree of pollen dust which contaminated her abrasion significantly. One hour later, she developed diffuse urticaria, dyspnea and wheezing. She went to emergency room and was treated with epinephrine intramuscular injection, methylprednisolone, diphenhydramine IV and albuterol. She was admitted overnight for observation with no biphasic reaction. No clear source for the anaphylaxis was immediately noted as there had been no new foods, medications, insect sting or history of exercise induced anaphylaxis. On subsequent evaluation she was found to have markedly elevated timothy grass pollen IgE (96.7 kU/L) known to be pollinating at the time. <h3>Discussion</h3> Grass pollens hypersensitivity is common allergic rhinitis trigger, however, anaphylaxis from exposure via a skin abrasion is not reported to the best of our knowledge. We would like to draw attention that grass pollen sensitization as a potential source of anaphylaxis following exposure to the blood stream via significant abraded skin.

A new way forward? Examining the potential of quantitative analysis of IgE datasets

BackgroundAllergies constitute an important public health problem, and epidemiological data is crucial to developing strategies for its prevention and therapy. Few population-based studies are available for data on allergies and sensitization. However, as these studies are expensive and time-consuming, novel approaches are searched for.ObjectivesA large monocentric IgE dataset was used to analyse quantitative sensitization data in different age and gender groups and compared the results to available epidemiological data.MethodsA total of 14,370 patients who sought medical care at the Department for Dermatology and Allergology at the Technical University of Munich, Germany was analysed. Total IgE and sensitization measured in specific IgE levels to common food allergens and aeroallergens were compared between females and males, age groups, and the year of testing (2003–2021).Results8283 females (57.6%) and 6087 males (42.4%) were tested. The average number of specific IgE tests per patient was 12.3 ± 11.4. Total IgE increased after birth with age and reached a peak between 4–6 years in males and 10–12 years in females. Males had higher specific IgE for all common aeroallergens (house dust mite, birch, mugwort and timothy grass pollen) and food allergens (milk protein, chicken egg white, peanut, wheat flour, cod) except for cat epithelia. Data closely reflected results of population-based studies in the literature.ConclusionThis study shows that, despite potential patient and test selection bias, the results of the quantitative IgE-dataset analysis closely reflect results of population-based data. Thus, as large cohorts can be examined with a minute amount of effort, this surrogate method appears promising to supplement epidemiology research.

The association of timothy grass allergy and cat ownership on cat sensitization.

Background: Pollen hypersensitivity might be a determining factor for other nonseasonal allergens because it may indicate deviation of the immune system toward T-helper type 2 activity and immunoglobulin E sensitivity. Objective: To investigate whether timothy grass pollen allergy may be a predictive factor for cat sensitization and whether there is an association between sensitivity to both allergens. Method: A retrospective review was made of patients with symptoms of rhinitis. The skin-prick test results and cat ownership status of the patients were analyzed. On the basis of the skin-prick test results with Phleum pratense (timothy grass) and other pollens, the patients were analyzed in two groups: "timothy allergic" and "non-timothy allergic." Results: A total of 383 patients with the diagnosis of rhinitis were included in the study, which comprised 213 (55.6%) in the timothy allergic group and 170 (44.4%) in the non-timothy allergic group. The frequency of cat sensitization was significantly higher in the patients in the timothy allergic group compared with those without timothy grass allergy (33.8% versus 12.3%; p < 0.001). No significant difference was determined between the two groups in terms of cat ownership (p = 0.63). In the logistic regression analysis, cat ownership (adjusted odds ratio [OR] 23.07 [95% confidence interval {CI}, 7.72-68.91]) and timothy allergy (adjusted OR 7.72 [95% CI, 3.16-18.86]) were associated with an increased risk of cat sensitization. Conclusion: Timothy grass allergy may play a role in the development of cat sensitization; however, further research is needed to clarify these associations and the underlying mechanisms.

Timothy Grass Pollen Induces Spatial Reorganisation of F-Actin and Loss of Junctional Integrity in Respiratory Cells.

Grass pollens have been identified as mediators of respiratory distress, capable of exacerbating respiratory diseases including epidemic thunderstorm asthma (ETSA). It is hypothesised that during thunderstorms, grass pollen grains swell to absorb atmospheric water, rupture, and release internal protein content to the atmosphere. The inhalation of atmospheric grass pollen proteins results in deadly ETSA events. We sought to identify the underlying cellular mechanisms that may contribute towards the severity of ETSA in temperate climates using Timothy grass (Phleum pratense). Respiratory cells exposed to Timothy grass pollen protein extract (PPE) caused cells to undergo hypoxia ultimately triggering the subcellular re-organisation of F-actin from the peri junctional belt to cytoplasmic fibre assembly traversing the cell body. This change in actin configuration coincided with the spatial reorganisation of microtubules and importantly, decreased cell compressibility specifically at the cell centre. Further to this, we find that the pollen-induced reorganisation of the actin cytoskeleton prompting secretion of the pro-inflammatory cytokine, interleukin-8. In addition, the loss of peri-junctional actin following exposure to pollen proteins was accompanied by the release of epithelial transmembrane protein, E-cadherin from cell-cell junctions resulting in a decrease in epithelial barrier integrity. We demonstrate that Timothy grass pollen regulates F-actin dynamics and E-cadherin localisation in respiratory cells to mediate cell-cell junctional integrity highlighting a possible molecular pathway underpinning ETSA events.

Allergy-induced systemic inflammation impairs tendon quality.

SummaryBackgroundTreatment of degenerating tendons still presents a major challenge, since the aetiology of tendinopathies remains poorly understood. Besides mechanical overuse, further known predisposing factors include rheumatoid arthritis, diabetes, obesity or smoking all of which combine with a systemic inflammation.MethodsTo determine whether the systemic inflammation accompanying these conditions contributes to the onset of tendinopathy, we studied the effect of a systemic inflammation induced by an allergic episode on tendon properties. To this end, we induced an allergic response in mice by exposing them to a timothy grass pollen allergen and subsequently analysed both their flexor and Achilles tendons. Additionally, we analysed data from a health survey comprising data from more than 10.000 persons for an association between the occurrence of an allergy and tendinopathy.FindingsBiomechanical testing and histological analysis revealed that tendons from allergic mice not only showed a significant reduction of both elastic modulus and tensile stress, but also alterations of the tendon matrix. Moreover, treatment of 3D tendon-like constructs with sera from allergic mice resulted in a matrix-remodelling expression profile and the expression of macrophage-associated markers and matrix metalloproteinase 2 (MMP2) was increased in allergic Achilles tendons. Data from the human health study revealed that persons suffering from an allergy have an increased propensity to develop a tendinopathy.InterpretationOur study demonstrates that the presence of a systemic inflammation accompanying an allergic condition negatively impacts on tendon structure and function.FundingThis study was financially supported by the Fund for the Advancement of Scientific Research at Paracelsus Medical University (PMU-FFF E-15/22/115-LEK), by the Land Salzburg, the Salzburger Landeskliniken (SALK, the Health Care Provider of the University Hospitals Landeskrankenhaus and Christian Doppler Klinik), the Paracelsus Medical University, Salzburg and by unrestricted grants from Bayer, AstraZeneca, Sanofi-Aventis, Boehringer-Ingelheim.

Sensitization Profiles of Timothy Grass Pollen in Northern China.

PurposeGrass pollen is an important cause of IgE-mediated allergy in countries worldwide, especially within Europe. However, there has been no research on grass pollen allergy in northern China. We aimed to determine the status of grass pollen allergy and the sensitization patterns to Phleum pratense (P. pratense) in northern China.Patients and MethodsPollen data were collected for three geographic areas (Beijing, Shenmu, Shizuishan) in northern China. The study enrolled 101 patients (62 men; age range, 1–64 years; median age, 10 years) who had allergic rhinoconjunctivitis and/or asthma during the grass pollen season and positive skin prick test results positive to P. pratense. Serum-specific IgE (sIgE) against Phl p 1, Phl p 2, Phl p 5, Phl p 6, Phl p 7, Phl p 12 was measured by ImmunoCAP.ResultsThe pollen season of P. pratense was from June to September in Beijing, May to September in Shenmu and July to August in Shizuishan. P. pratense pollen accounted for 2–3% of the annual pollen index of total pollen counts. Among 101 patients with positive skin prick test results to P. pratense, 72% had detectable sIgE to P. pratense. Phl p 12 was the most frequently recognized component (45%), followed by Phl p 1 (22%), Phl p 5 (14%), Phl p 6 (8%) and Phl p 7 (3%). No patients had sIgE to Phl p 2. Ten sensitization patterns to the six components were observed. High rate of sIgE to Phl p 12 was positively correlated with co-sensitization to weed or tree pollen.ConclusionConsidering the pollen concentration, P. pratense was a minor pollen allergen in northern China and its pollen season overlapped with that of weed pollen. IgE sensitization to P. pratense was likely to be induced by cross-reactivity between grass pollen allergy and weed/tree pollen allergy.

Pollen Sensitization in Association with Allergic Rhinitis in preschool asthmatic Children

Abstract Background Grass pollens are significant elicitors of IgE-mediated allergic disease in the world and timothy grass (Phleum pratense) is an important pollen in allergy induction. Objective We sought to determine the rate of pollen sensitization in group of Egyptian asthmatic children with allergic rhinitis using timothy grass pollen as a potential triggering factor for allergic rhinitis. Patients and Methods This analytical cross sectional study was conducted on a group of preschool children following up at the Pediatric Allergy and Immunology Clinic, Children's Hospital, Ain Shams University during the period from December 2018 to April 2019. We enrolled 52 asthmatic children with concomitant allergic rhinitis sampled in a consecutive manner. They were subjected to skin prick testing for timothy grass pollen, positive histamine control and negative control. Results The study revealed high frequency of timothy grass pollen(TGP) sensitization occurring in 60.3% of patients with concomitant allergic rhinitis .wheal diameters pointed to sensitization only rather than actual allergy to TGP. TGP sensitization showed no significant correlation to disease duration. Children with rhinosinsuitis had comparable rates of TGP sensitization to those without rhinosinsuitis. Conclusion It is concluded from our results that sensitization to timothy grass pollen (TGP) is common in allergic rhinitis. The findings are limited by the sample size and consecutive manner of sampling. Wider scale studies are needed to accurately evaluate the frequency of timothy grass pollen (TGP) sensitization in our country.

Standardisation of allergen products: 4. Validation of a candidate European Pharmacopoeia standard method for quantification of major grass pollen allergen Phl p 5.

The aim of the BSP090 project is the establishment of European Pharmacopoeia Chemical Reference Substances (CRSs) in combination with corresponding standard ELISA methods for quantification of major allergens in allergen products. Here, we present data of a Phlp5-specific sandwich ELISA that proved suitable for the quantification of Phlp5, one of the major Timothy grass (Phleum pratense) pollen allergens. A Phlp5-specific ELISA system was assessed with respect to accuracy, precision, inter-assay (within laboratory) and inter-laboratory variations, in a ring trial including 14laboratories in Europe and the USA. Model samples containing recombinant Phlp5a CRS as well as native grass pollen extracts were analysed. Each participant was instructed to perform at least one preliminary assay to familiarise with the protocol, followed by three independent assays. The candidate standard ELISA proved suitable to quantify recombinant and native Phlp5 with satisfactory precision (93% of results within ±30% acceptance range). Inter-assay variation (max. GCV 24%) and especially inter-laboratory variation (max. GCV 13%) showed conclusive results. When assessing accuracy by means of recovery of recombinant spikes from a grass pollen extract matrix, similarly satisfactory spike recovery results were observed for the two spikes with higher concentrations (all within ±30% acceptance range), whereas recovery of the lowest concentration spike was slightly poorer with mean results of six laboratories exceeding acceptance range. Based on the collaborative study results, the assessed Phlp5-specific immunoassay is appropriate to be proposed as European Pharmacopoeia standard method.

Differential induction of allergen-specific IgA responses following timothy grass subcutaneous and sublingual immunotherapy

There is no detailed comparison of allergen-specific immunoglobulin responses following sublingual immunotherapy (SLIT) and subcutaneous immunotherapy (SCIT). We sought to compare nasal and systemic timothy grass pollen (TGP)-specific antibody responses during 2 years of SCIT and SLIT and 1 year after treatment discontinuation in a double-blind, double-dummy, placebo-controlled trial. Nasal fluid and serum were obtained yearly (per-protocol population, n= 84). TGP-specific IgA1, IgA2, IgG4, IgG, and IgE were measured in nasal fluids by ELISA. TGP-specific IgA1, IgA2, and Phleum pratense (Phl p)1, 2, 4, 5b, 6, 7, 11, and 12 IgE and IgG4 were measured in sera by ELISA and ImmunoCAP, respectively. At years 2 and 3, TGP-IgA1/2 levels in nasal fluid were elevated in SLIT compared with SCIT (4.2- and 3.0-fold for IgA1, 2.0- and 1.8-fold for IgA2, respectively; all P< .01). TGP-IgA1 level in serum was elevated in SLIT compared with SCIT at years 1, 2, and 3 (4.6-, 5.1-, and 4.7-fold, respectively; all P<.001). Serum TGP-IgG level was higher in SCIT compared with SLIT (2.8-fold) at year 2. Serum TGP-IgG4 level was higher in SCIT compared with SLIT at years 1, 2, and 3 (10.4-, 27.4-, and 5.1-fold, respectively; all P< .01). Serum IgG4 levels to Phl p1, 2, 5b, and 6 were increased at years 1, 2, and 3 in SCIT and SLIT compared with placebo (Phl p1: 11.8- and 3.9-fold; Phl p2: 31.6- and 4.4-fold; Phl p5b: 135.5- and 5.3-fold; Phl p6: 145.4- and 14.7-fold, respectively, all at year 2 when levels peaked; P< .05). IgE to TGP in nasal fluid increased in the SLIT group at year 2 but not at year 3 compared with SCIT (2.8-fold; P= .04) and placebo (3.1-fold; P= .02). IgA to TGP and IgE and IgG4 to TGP components stratified participants according to treatment group and clinical response. The observed induction of IgA1/2 in SLIT and IgG4in SCIT suggest key differences in the mechanisms of action.