Atmospheric exposure to the major Artemisia pollen allergen (Art v 1): Seasonality, impact of weather, and clinical implications

Immunoproteomic analysis and identification of possible allergenic proteins in Artemisia annua pollen

BACKGROUND

Artemisia annua (A. annua) is a wind-pollinated weed and a major allergen responsible for allergic respiratory diseases in Northern China.

METHODS

This study involved the separation of pollen proteins from A. annua utilizing SDS-PAGE and Coomassie Blue staining techniques. The effectiveness of extracting allergens from Artemisia annua pollen (AAP) were confirmed both in vivo and in vitro. A mouse model was established using A. annua pollen (AAP) extracts. In vitro, the interaction between allergenic proteins in the AAP extract and specific IgE antibodies present in patients' sera was analyzed, using IgE-immunoblotting and ELISA methods. Protein bands were subsequently analyzed by mass spectrometry. The recombinant Art an 3 (rArt an 3) protein was obtained via recombination, expression, and purification. Finally, the binding activity of rArt an 3 specific IgE was subsequently examined using Western blot and inhibition ELISA (iELISA).

RESULTS

The electrophoretic profiles of AAP showed band patterns ranging from 10 to 70 kDa, with the most prominet IgE-binding pollen proteins detected at approximately 12 kDa. After stimulation of AAP, the sensitized group of mice exhibited significant allergic symptoms compared to the control group. Mass spectrometry analysis identified 7 proteins, including putative aldehyde oxidase Art an 7, Art v 1-like protein, Art an 3.0101 allergen precursor, Art an 3.0102 allergen precursor, Art an 3.0201 allergen precursor, lipid transfer protein 3, and non-specific lipid-transfer protein. The results of immunoblotting and iELISA showed that rArt an 3 could bind to IgE antibodies in the patient sera, and co-incubation of rArt an 3 with serum, the binding serum significantly inhibited IgE binding to the crude AAP.

CONCLUSIONS

The Art an 3 is a key allergenic protein in AAP with a high IgE sensitization rate in the studied population sample. These findings enhance our understanding of the sensitization components of AAP and its sensitization characteristics within the Chinese population, thereby promoting the development of precise molecular diagnostics and therapeutic interventions.

Influence of meteorological and ambient air quality factors on Artemisia pollen counts in Urumqi, Northwest China

The exposure of Artemisia pollen in the air to humans causes adverse allergenic effects on the respiratory system. However, the relationship between Artemisia pollen counts and meteorological and air quality factors in the arid and semiarid cities of northwest China has not attracted significant attention. Here, we observed the seasonal pollen counts of Artemisia, as well as the main meteorological variables (temperature/T, relative humidity/RH, and wind speed/WS, and ambient air quality factors (PM2.5, PM10, and CO2). This was conducted from May to September 2021 at three sampling sites in Urumqi, Xinjiang. The results showed that Artemisia pollen counts gradually increased from May (121 grains/1000 mm2) to August (563 grains/1000 mm2) and decreased till the end of the sampling period in September (247 grains/1000 mm2). Pearson correlation analysis revealed a significant positive correlation between the variation in Artemisia pollen counts and PM2.5 (R = 0.545, P < 0.01), the average temperature (R = 0.424, P < 0.05), and PM10 (R = 0.466, P < 0.05). Oppositely, a significant negative correlation was observed between the RH (R = 0.503, P < 0.01) and WS (R = 0.653, P < 0.01). Variation partitioning analysis showed that meteorological factors contributed the highest (44 %) to the variation in pollen counts. The study results provide basic information for future case studies on allergenic plant pollen in Urumqi and serve as a reference for the development of sustainable healthy cities in arid regions.

Outdoor airborne allergens: Characterization, behavior and monitoring in Europe

Aeroallergens or inhalant allergens, are proteins dispersed through the air and have the potential to induce allergic conditions such as rhinitis, conjunctivitis, and asthma. Outdoor aeroallergens are found predominantly in pollen grains and fungal spores, which are allergen carriers. Aeroallergens from pollen and fungi have seasonal emission patterns that correlate with plant pollination and fungal sporulation and are strongly associated with atmospheric weather conditions. They are released when allergen carriers come in contact with the respiratory system, e.g. the nasal mucosa. In addition, due to the rupture of allergen carriers, airborne allergen molecules may be released directly into the air in the form of micronic and submicronic particles (cytoplasmic debris, cell wall fragments, droplets etc.) or adhered onto other airborne particulate matter. Therefore, aeroallergen detection strategies must consider, in addition to the allergen carriers, the allergen molecules themselves. This review article aims to present the current knowledge on inhalant allergens in the outdoor environment, their structure, localization, and factors affecting their production, transformation, release or degradation. In addition, methods for collecting and quantifying aeroallergens are listed and thoroughly discussed. Finally, the knowledge gaps, challenges and implications associated with aeroallergen analysis are described.

Pollen grading prediction scale for patients with Artemisia pollen allergy in China: A 3-day moving predictive model

BACKGROUND

Artemisia pollen is the most prevalent outdoor aeroallergen causing respiratory allergies in Beijing, China. Pollen allergen concentrations have a direct impact on the quality of life of those suffering from allergies. Artemisia pollen deposition grading predictions can provide early warning for the protection and treatment of patients as well as provide a scientific basis for allergen specific clinical immunotherapy.

OBJECTIVE

To develop a model of Artemisia pollen grading to predict development in patients with pollen allergy.

METHODS

Artemisia pollen data from four pollen monitoring stations in Beijing as well as the number of Artemisia pollen allergen serum specific immunoglobulin E positive cases in Beijing Tongren Hospital from 2014 to 2016 were used to develop a statistical model of pollen deposition and provide optimised threshold values.

RESULTS

A logarithmic correlation existed between the number of patients with Artemisia pollen allergy and Artemisia pollen deposition, and the average pollen deposition for three consecutive days was most correlated with the number of allergic patients. Based on the threshold of the number of patients and the characteristics of Artemisia pollen, a five-stage pollen deposition grading model was developed to predict the degree of pollen allergy.

CONCLUSIONS

Graded prediction of pollen deposition may help pollen allergic populations benefit from preventive interventions before onset.

A recombinant Artemisia vulgaris pollen adjuvanted Art v 1 protein-based vaccine treats allergic rhinitis and bronchial asthma using pre- and co-seasonal ultrashort immunotherapy regimens in sensitized mice

Allergic rhinitis is an important risk factor for bronchial asthma. Allergen-specific immunotherapy (ASIT) is the gold standard for treatment of allergic rhinitis, conjunctivitis, and asthma. A disadvantage of current ASIT methods is the length of therapy which requires numerous allergen administrations. The success of ASIT is determined by its schedule, which, depending on the vaccine and type of allergy, can be pre-seasonal (before the allergy season begins), combined pre/co-seasonal (during the allergy season) etc. The aim of the present study was to evaluate a vaccine based on recombinant Artemisia vulgaris pollen major Art v 1 protein formulated with ISA-51 adjuvant for therapy of allergic rhinitis and bronchial asthma in Artemisia-sensitized mice in an ultrashort (4 subcutaneous injections at weekly intervals) pre- and co-seasonal ASIT regimen. To simulate co-seasonal ASIT in mice, mice were regularly challenged with intranasal and nebulized Artemisia vulgaris pollen extract at the same time as receiving subcutaneous ASIT. For comparison, we used a previous Art v 1 protein vaccine formulated with SWE adjuvant, which in this study was modified by adding CpG oligonucleotide (Th1-biasing synthetic toll-like receptor 9 agonist), and a commercial vaccine containing a modified Artemisia vulgaris extract with aluminum hydroxide adjuvant. The therapeutic potential of Art v 1 based vaccine formulations with different ASIT regimens was evaluated in high and low (10 times lower) dose regimens. The ISA-51-adjuvanted vaccine formulations were the only ones among those studied in the ultrashort pre- and co-seasonal ASIT regimens to provide significant reduction in both signs of allergic rhinitis and bronchial asthma in sensitized mice (vs. positive control). In the ISA-51 adjuvanted group, immune response polarization toward Th1/Treg was observed in pre-seasonal ASIT, as reflected in a significant decrease in the serum level of total and Art v 1-specific IgE and increased ratios of allergen-specific IgG2a/IgG1 and IFN-γ/IL-4. The high dose SWE-CpG-adjuvanted vaccine had similar efficacy to the ISA-51 adjuvanted groups whereas the commercial vaccine showed significantly less effectiveness. The findings support further preclinical safety studies of the Art v 1-based vaccine formulated with ISA-51 adjuvant.

Drivers of the release of the allergens Bet v 1 and Phl p 5 from birch and grass pollen

The drivers affecting the Pollen Allergen Potency (PAP, amount of allergen released per pollen) are sparsely known. Betula and Poaceae airborne pollen are the two main allergenic pollen in the World. Airborne pollen and their allergens Bet v 1 and Phl p 5 were simultaneously measured from 2010 to 2015 in Davos (Switzerland) and Munich (Germany) by using volumetric traps and ChemVol cascade impactors. Daily variations in PAP were analysed in PM_>10 and PM_2.5-10 air fractions and generalized additive models were created to explain which factors determine PAP, including meteorological parameters and inorganic pollutants. 87.1 ± 13.9% of Bet v 1 and 88.8 ± 15.5% of Phl p 5 was detected in the fraction PM_>10 where most pollen grains were collected. Significantly higher PAP for grasses (3.5 ± 1.9 pg Phl p 5/pollen grain) were observed in Munich than in Davos (2.4 ± 1.5 pg/pollen grain, p < 0.001), but not for Betula (2.5 ± 1.6 pg Bet v 1/pollen grain in Munich and 2.3 ± 1.7 in Davos, N.S.). PAP varied between days, years and location, and increased along the pollen season for Poaceae, but remaining constant for Betula. Free allergens (allergens observed in the fraction with limited pollen, PM_{2.5- 10}) were recorded mostly at the beginning or at the end of the pollen season, being linked to higher humidity and rainy days. Also, PAP was higher when the airborne pollen concentrations increased rapidly after one day of low/moderate levels. Our findings show that pollen exposure explains allergen exposure only to a limited extend, and that day in the season, geographic location and some weather conditions need to be considered also to explain symptoms of allergic individuals.

Risk factors of chronic cough in China: a systematic review and meta-analysis

OBJECTIVES

Risk factors of chronic cough in China have not been systematically analyzed and we hypothesized that risk factors of chronic cough might have distinct characteristics in China. Hence, we performed this meta-analysis focusing on the potential risk factors of chronic cough in China.

METHODS

We searched 7 databases for studies published before May 8, 2021. This systematic review was performed in accordance with the PRISMA checklist.

RESULTS

A total of 33 eligible articles were identified and included in this systematic review, and 28 studies were included in the meta-analysis. Our results showed that allergy (OR: 3.72; 95% CI: 1.85-7.47), nasal/sinusitis diseases (OR: 3.56; 95% CI: 2.02-6.29), family history of allergy (OR = 1.74; 95% CI: 1.59-1.90), family history of chronic respiratory diseases (OR = 1.67; 95% CI: 1.47-1.91), exposure to pollutants (OR = 1.60; 95% CI: 1.26-2.04), passive smoking (OR = 1.44; 95% CI: 1.32-1.57), and exposure to pets (OR = 1.37; 95% CI: 1.18-1.58) were risk factors for chronic cough in China.

CONCLUSIONS

Our study indicated some potential risk factors of chronic cough in China, which provides useful epidemiological information for managing chronic cough in China and is worthy as a reference for future global investigations.

Establishing the twig method for investigations on pollen characteristics of allergenic tree species

The twig method in climate chambers has been shown to successfully work as a proxy for outdoor manipulations in various experimental setups. This study was conducted to further establish this method for the investigation of allergenic pollen from tree species (hazel, alder, and birch). Direct comparison under outdoor conditions revealed that the cut twigs compared to donor trees were similar in the timing of flowering and the amount of pollen produced. Cut twigs were able to flower in climate chambers and produced a sufficient amount of pollen for subsequent laboratory analysis. The addition of different plant or tissue fertilizers in the irrigation of the twigs did not have any influence; rather, the regular exchange of water and the usage of fungicide were sufficient for reaching the stage of flowering. In the experimental setup, the twigs were cut in different intervals before the actual flowering and were put under warming conditions in the climate chamber. An impact of warming on the timing of flowering/pollen characteristics could be seen for the investigated species. Therefore, the twig method is well applicable for experimental settings in pollen research simulating, e.g., accelerated warming under climate change.

Characterization of allergenicity of Platanus pollen allergen a 3 (Pla a 3) after exposure to NO2 and O3

Pollen allergens, widely present in the atmosphere, are the main cause of seasonal respiratory diseases that affect millions of people worldwide. Although previous studies have reported that nitrogen dioxide (NO₂) and ozone (O₃) promote pollen allergy, the specific biological processes and underlying mechanisms remain less understood. In this study, Platanus pollen grains were exposed to gaseous pollutants (NO₂ and O₃). We employed environmental electron microscopy, flow cytometry, western blot assay, enzyme-linked immunoassay, ultraviolet absorption spectrometry, circular dichroism, and protein mass spectrometry to characterise the subpollen particles (SPPs) released from pollen grains. Furthermore, we determined the immunogenicity and pathogenicity induced by Platanus pollen allergen a 3 (Pla a 3). Our results demonstrated that NO₂ and O₃ could damage the pollen cell membranes in SPPs and increase the amount of Pla a 3 allergen released into the atmosphere. Additionally, NO₂ and O₃ altered the structure of Pla a3 protein through nitrification and oxidation, which not only enhanced the immunogenicity of allergens but also increased the stability of the protein. In vivo analysis using an animal model indicated that NO₂ and O₃ greatly aggravated pollen-induced pneumonia. Thus, our study provides guidance for the prevention of pollen allergic diseases.

Research Advances on Health Effects of Edible Artemisia Species and Some Sesquiterpene Lactones Constituents

The genus Artemisia, often known collectively as "wormwood", has aroused great interest in the scientific community, pharmaceutical and food industries, generating many studies on the most varied aspects of these plants. In this review, the most recent evidence on health effects of edible Artemisia species and some of its constituents are presented and discussed, based on studies published until 2020, available in the Scopus, Web of Sciences and PubMed databases, related to food applications, nutritional and sesquiterpene lactones composition, and their therapeutic effects supported by in vivo and clinical studies. The analysis of more than 300 selected articles highlights the beneficial effect on health and the high clinical relevance of several Artemisia species besides some sesquiterpene lactones constituents and their derivatives. From an integrated perspective, as it includes therapeutic and nutritional properties, without ignoring some adverse effects described in the literature, this review shows the great potential of Artemisia plants and some of their constituents as dietary supplements, functional foods and as the source of new, more efficient, and safe medicines. Despite all the benefits demonstrated, some gaps need to be filled, mainly related to the use of raw Artemisia extracts, such as its standardization and clinical trials on adverse effects and its health care efficacy.

Variation in IgE binding potencies of seven Artemisia species depending on content of major allergens

BACKGROUND

Artemisia weed pollen allergy is important in the northern hemisphere. While over 350 species of this genus have been recorded, there has been no full investigation into whether different species may affect the allergen diagnosis and treatment. This study aimed to evaluate the variations in amino acid sequences and the content of major allergens, and how these affect specific IgE binding capacity in representative Artemisia species.

METHODS

Six representative Artemisia species from China and Artemisia vulgaris from Europe were used to determine allergen amino acid sequences by transcriptome, gene sequencing and mass spectrometry of the purified allergen component proteins. Sandwich ELISAs were developed and applied for Art v 1, Art v 2 and Art v 3 allergen quantification in different species. Aqueous pollen extracts and purified allergen components were used to assess IgE binding by ELISA and ImmunoCAP with mugwort allergic patient serum pools and individual sera from five areas in China.

RESULTS

The Art v 1 and Art v 2 homologous allergen sequences in the seven Artemisia species were highly conserved. Art v 3 type allergens in A. annua and A. sieversiana were more divergent compared to A. argyi and A. vulgaris. The allergen content of Art v 1 group in the seven extracts ranged from 3.4% to 7.1%, that of Art v 2 from 1.0% to 3.6%, and Art v 3 from 0.3% to 10.5%. The highest IgE binding potency for most Chinese Artemisia allergy patients was with A. annua pollen extract, followed by A. vulgaris and A. argyi, with A. sieversiana significantly lower. Natural Art v 1-3 isoallergens from different species have almost equivalent IgE binding capacity in Artemisia allergic patients from China.

CONCLUSION AND CLINICAL RELEVANCE

There was high sequence similarity but different content of the three group allergens from different Artemisia species. Choice of Artemisia annua and A. argyi pollen source for diagnosis and immunotherapy is recommended in China.

Relationship between Poaceae pollen and Phl p 5 allergen concentrations and the impact of weather variables and air pollutants on their levels in the atmosphere

The sensitization to grass pollen is a known problem in European countries. Phl p 5 is an important allergen recognized by the majority of grass sensitized individuals. In this study, we evaluated daily variation in airborne Poaceae pollen and Phl p 5 allergen concentrations to determine whether airborne pollen concentrations alone are sufficient to reflect the actual allergenic potential of the air. The relationships between the mentioned pollen and allergen concentrations and associated environmental variables were also examined. The airborne particles were collected during the Poaceae flowering season in Bratislava in 2019. Pollen sampling was performed using a Hirst-type sampler, while a cyclone sampler was used for the aeroallergen capturing. Allergenic molecules were quantified by ELISA assay. The associations between pollen and allergen concentrations showed that these two variables are positively correlated; however, the correlation was not significant. We observed the concurrent occurrence of airborne pollen and allergen peaks on the same day. Nevertheless, during some days of the pollen season, the allergen concentrations did not correspond to the airborne pollen values. Moreover, the days with low pollen concentration but high pollen potency and vice versa were observed. The effect of selected environmental variables on daily pollen and allergen concentrations was evaluated through Spearman's correlation analysis. Of all meteorological variables considered, air temperature, precipitation, and relative air humidity were significantly correlated with airborne pollen and/or allergen concentrations. The association with air temperature was positive, while the negative association was observed with precipitation and relative air humidity. Among the atmospheric pollutants, O3 and PM10 were significantly and positively associated with both pollen and allergen concentrations, whereas CO and PM2.5 were significantly and positively associated only with pollen concentration.

Particle size distribution of the major Alternaria alternata allergen, Alt a 1, derived from airborne spores and subspore fragments

Fungal fragments are abundant immunoreactive bioaerosols that may outnumber the concentrations of intact spores in the air. To investigate the importance of Alternaria fragments as sources of allergens compared to Alternaria spores, we determined the levels of Alternaria spores and Alt a 1 (the major allergen in Alternaria alternata spores) collected on filters within three fractions of particulate matter (PM) of different aerodynamic diameter: (1) PM_>10, (diameter>10 μm); (2) PM_2.5-10 (2.5-10μm); (3) PM_2.5 (0.12-2.5 μm). The airborne particles were collected using a three stage high-volume ChemVol cascade impactor during the Alternaria sporulation season in Poznań, Poland (30 d between 6 July and 22 September 2016). The quantification of Alt a 1 was performed using the enzyme-linked immunosorbent assay. High concentrations of Alt a 1 were recorded during warm and dry d characterized by high sunshine duration, lack of clouds and high dew point values. Atmospheric concentrations of Alternaria spores correlated significantly (r = 0.930, p < 0.001) with Alt a 1 levels. The highest Alt a 1 was recorded in PM_2.5-10 (66.8 % of total Alt a 1), while the lowest in PM_2.5 (<1.0 %). Significantly more Alt a 1 per spore (>30 %) was observed in PM_2.5-10 than in PM_>10. This Alt a 1 excess may be derived from sources other than spores, e.g. hyphal fragments. Overall, in outdoor air the major source of Alt a 1 are intact Alternaria spores, but the impact of other fungal fragments (hyphal parts, broken spores, conidiophores) cannot be neglected, as they may increase the total atmospheric Alt a 1 concentration.