The perfect storm: temporal analysis of air during the world's most deadly epidemic thunderstorm asthma (ETSA) event in Melbourne.

BACKGROUND: There have been 26 epidemic thunderstorm asthma (ETSA) events worldwide, with Melbourne at the epicentre of ETSA with 7 recorded events, and in 2016 experienced the deadliest ETSA event ever recorded. Health services and emergency departments were overwhelmed with thousands requiring medical care for acute asthma and 10 people died. OBJECTIVES: This multidisciplinary study was conducted across various health and science departments with the aim of improving our collective understanding of the mechanism behind ETSA. DESIGN: This study involved time-resolved analysis of atmospheric sampling of the air for pollen and fungal spores, and intact and ruptured pollen compared with different weather parameters, pollution levels and clinical asthma presentations. METHODS: Time-resolved pollen and fungal spore data collected by Deakin AirWATCH Burwood, underwent 3-h analysis, to better reflect the 'before', 'during' and 'after' ETSA time points, on the days leading up to and following the Melbourne 2016 event. Linear correlations were conducted with atmospheric pollution data provided by the Environment Protection Authority (EPA) of Victoria, weather data sourced from Bureau of Meteorology (BOM) and clinical asthma presentation data from the Victorian Agency for Health Information (VAHI) of Department of Health. RESULTS: Counts of ruptured grass pollen grains increased 250% when the thunderstorm outflow reached Burwood. Increased PM10, high relative humidity, decreased temperature and low ozone concentrations observed in the storm outflow were correlated with increased levels of ruptured grass pollen. In particular, high ozone levels observed 6 h prior to this ETSA event may be a critical early indicator of impending ETSA event, since high ozone levels have been linked to increasing pollen allergen content and reducing pollen integrity, which may in turn contribute to enhanced pollen rupture. CONCLUSION: The findings presented in this article highlight the importance of including ruptured pollen and time-resolved analysis to forecast ETSA events and thus save lives.

Epidemic Thunderstorm Asthma: Lessons Learned from the Storm Down-Under.

Epidemic thunderstorm asthma (ETSA) is a global health problem that can strike without sufficient warning and can have catastrophic consequences. Because of climate change, future events are likely to become more common, more disastrous, and more unpredictable. To prevent loss of life and avoid surge events on health care infrastructure, identifying at-risk individuals and their potential biomarkers is the most prophylactic approach that can be taken to mitigate the deadly consequences of ETSA. In this review, we provide an update on the clinical mechanism, global prevalence, and characteristics of those patients moderately or severely at risk of ETSA. Identifying these patient characteristics will aid clinical professionals to provide suitable and personalized treatment plans and, in turn, avoid future loss of life.

The Melbourne epidemic thunderstorm asthma event 2016: an investigation of environmental triggers, effect on health services, and patient risk factors.

BACKGROUND: A multidisciplinary collaboration investigated the world's largest, most catastrophic epidemic thunderstorm asthma event that took place in Melbourne, Australia, on Nov 21, 2016, to inform mechanisms and preventive strategies. METHODS: Meteorological and airborne pollen data, satellite-derived vegetation index, ambulance callouts, emergency department presentations, and data on hospital admissions for Nov 21, 2016, as well as leading up to and following the event were collected between Nov 21, 2016, and March 31, 2017, and analysed. We contacted patients who presented during the epidemic thunderstorm asthma event at eight metropolitan health services (each including up to three hospitals) via telephone questionnaire to determine patient characteristics, and investigated outcomes of intensive care unit (ICU) admissions. FINDINGS: Grass pollen concentrations on Nov 21, 2016, were extremely high (>100 grains/m3). At 1800 AEDT, a gust front crossed Melbourne, plunging temperatures 10°C, raising humidity above 70%, and concentrating particulate matter. Within 30 h, there were 3365 (672%) excess respiratory-related presentations to emergency departments, and 476 (992%) excess asthma-related admissions to hospital, especially individuals of Indian or Sri Lankan birth (10% vs 1%, p<0·0001) and south-east Asian birth (8% vs 1%, p<0·0001) compared with previous 3 years. Questionnaire data from 1435 (64%) of 2248 emergency department presentations showed a mean age of 32·0 years (SD 18·6), 56% of whom were male. Only 28% had current doctor-diagnosed asthma. 39% of the presentations were of Asian or Indian ethnicity (25% of the Melbourne population were of this ethnicity according to the 2016 census, relative risk [RR] 1·93, 95% CI 1·74-2·15, p <0·0001). Of ten individuals who died, six were Asian or Indian (RR 4·54, 95% CI 1·28-16·09; p=0·01). 35 individuals were admitted to an intensive care unit, all had asthma, 12 took inhaled preventers, and five died. INTERPRETATION: Convergent environmental factors triggered a thunderstorm asthma epidemic of unprecedented magnitude, tempo, and geographical range and severity on Nov 21, 2016, creating a new benchmark for emergency and health service escalation. Asian or Indian ethnicity and current doctor-diagnosed asthma portended life-threatening exacerbations such as those requiring admission to an ICU. Overall, the findings provide important public health lessons applicable to future event forecasting, health care response coordination, protection of at-risk populations, and medical management of epidemic thunderstorm asthma. FUNDING: None.

Exploring the Effects of Omega-3 and Omega-6 Fatty Acids on Allergy Using a HEK-Blue Cell Line.

BACKGROUND: Allergic reactions can result in life-threatening situations resulting in high economic costs and morbidity. Therefore, more effective reagents are needed for allergy treatment. A causal relationship has been suggested to exist between the intake of omega-3/6 fatty acids, such as docosahexanoic acid (DHA), eicosapentanoic acid (EPA), docosapentanoic acid (DPA) and arachidonic acid (AA), and atopic individuals suffering from allergies. In allergic cascades, the hallmark cytokine IL-4 bind to IL-4 receptor (IL-4R) and IL-13 binds to IL-13 receptor (IL-13R), this activates the STAT6 phosphorylation pathway leading to gene activation of allergen-specific IgE antibody production by B cells. The overall aim of this study was to characterize omega-3/6 fatty acids and their effects on STAT6 signaling pathway that results in IgE production in allergic individuals. METHODS: The fatty acids were tested in vitro with a HEK-Blue IL-4/IL-13 reporter cell line model, transfected with a reporter gene that produces an enzyme, secreted embryonic alkaline phosphatase (SEAP). SEAP acts as a substitute to IgE when cells are stimulated with bioactive cytokines IL-4 and/or IL-13. RESULTS: We have successfully used DHA, EPA and DPA in our studies that demonstrated a decrease in SEAP secretion, as opposed to an increase in SEAP secretion with AA treatment. A statistical Student's t-test revealed the significance of the results, confirming our initial hypothesis. CONCLUSION: We have successfully identified and characterised DHA, EPA, DPA and AA in our allergy model. While AA was a potent stimulator, DHA, EPA and DPA were potential inhibitors of IL-4R/IL-13R signalling, which regulates the STAT6 induced pathway in allergic cascades. Such findings are significant in the future design of dietary therapeutics for the treatment of allergies.

Fishy business: effect of omega-3 fatty acids on zinc transporters and free zinc availability in human neuronal cells.

Omega-3 (ω-3) fatty acids are one of the two main families of long chain polyunsaturated fatty acids (PUFA). The main omega-3 fatty acids in the mammalian body are α-linolenic acid (ALA), docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA). Central nervous tissues of vertebrates are characterized by a high concentration of omega-3 fatty acids. Moreover, in the human brain, DHA is considered as the main structural omega-3 fatty acid, which comprises about 40% of the PUFAs in total. DHA deficiency may be the cause of many disorders such as depression, inability to concentrate, excessive mood swings, anxiety, cardiovascular disease, type 2 diabetes, dry skin and so on. On the other hand, zinc is the most abundant trace metal in the human brain. There are many scientific studies linking zinc, especially excess amounts of free zinc, to cellular death. Neurodegenerative diseases, such as Alzheimer's disease, are characterized by altered zinc metabolism. Both animal model studies and human cell culture studies have shown a possible link between omega-3 fatty acids, zinc transporter levels and free zinc availability at cellular levels. Many other studies have also suggested a possible omega-3 and zinc effect on neurodegeneration and cellular death. Therefore, in this review, we will examine the effect of omega-3 fatty acids on zinc transporters and the importance of free zinc for human neuronal cells. Moreover, we will evaluate the collective understanding of mechanism(s) for the interaction of these elements in neuronal research and their significance for the diagnosis and treatment of neurodegeneration.

Peanut allergens alter intestinal barrier permeability and tight junction localisation in Caco-2 cell cultures.

BACKGROUND/AIMS: Allergen absorption by epithelia may play an important role in downstream immune responses. Transport mechanisms that can bypass Peyer's patches include transcellular and paracellular transport. The capacity of an allergen to cross via these means can modulate downstream processing of the allergen by the immune system. The aim of this study was to investigate allergen-epithelial interactions of peanut allergens with the human intestinal epithelium. METHODS: We achieved this using the human Caco-2 cell culture model, exposed to crude peanut extract. Western and immunofluorescence analysis were used to identify the cellular and molecular changes of peanut extract on the intestinal epithelium. RESULTS: Following exposure of Caco-2 cells to peanut extract, binding of the peanut allergens Ara h 1 and Ara h 2 to the apical cellular membrane and transcytosis across the monolayers were observed. Additionally, the co-localisation of the transmembrane tight junction proteins occludin, JAM-A and claudin-1, with the intracellular adhesion protein ZO-1 was modified. CONCLUSION: Disruption of Caco-2 barrier integrity through tight junction disruption may enable movement of peanut proteins across the intestinal epithelium. This accounts for peanut's increased allergenicity, compared to other food allergens, and provides an explanation for the potency of peanut allergens in immune response elicitation.

DHA protects against zinc mediated alterations in neuronal cellular bioenergetics.

Zinc accumulation may impair cellular bioenergetics, which is associated with neuronal apoptosis. We simultaneously assessed anaerobic and aerobic metabolism in live cells to characterise this effect and hypothesised that the omega 3 fatty acid docosahexaenoic acid (DHA) would protect against any zinc mediated alterations in bioenergetics. In this study we observed a decrease in cellular oxygen consumption, but not glycolytic rate, following chronic zinc exposure, which was specific for neuronal cells. This was due to impaired ATP turnover, without any other effects on mitochondrial function, and was restored by DHA. DHA had no further effects on bioenergetics. These data suggest that zinc disrupts bioenergetics at a point distal to the respiratory chain, which is restored by DHA.

Molecular cloning and characterization of hazel pollen protein (70 kD) as a luminal binding protein (BiP): a novel cross-reactive plant allergen.

BACKGROUND: Tree pollen contains many allergens showing cross-reactivity to proteins from pollen, seeds, and fruits of different plant species. Amongst Fagales, responsible for several allergenic responses, hazel provides the best material to study pollen as well as food allergens in one species. The aim of this study was to identify and characterize the physiological function of an allergen from hazel pollen and to determine possible cross-reactivity to proteins from hazelnut. METHODS: Monoclonal antibodies (mAbs) against hazel pollen crude extract were produced. On the basis of IgE binding, demonstrated by sera from patients allergic to hazel pollen, one mAb indicating the best correlation has been selected, and the putative allergen was purified by preparative gel electrophoresis. Isoforms were investigated by two-dimensional PAGE, and for molecular identification a hazel pollen cDNA library was constructed. In situ localization of the allergen during pollen development was performed by immunofluorescence labelling. RESULTS: Immunological staining of crude hazel pollen extract with specific IgE and mAb revealed a 70-kD protein. Immunoblot studies with mAb showed cross-reactive proteins of 70-72 kD in different plant tissues and species. After protein purification, the IgE-binding reactivity of the allergen has been reconfirmed, and two isoforms were detected. Molecular cloning identified the allergen as a luminal binding protein (BiP) of the Hsp70 family with 88-92% sequence identity in various plants. Further immunocytological studies indicated involvement of BiP during pollen development. CONCLUSIONS: Chaperons like BiP play an important role in protein synthesis and in the protection of cellular structures during stress-related processes. Because of their highly conserved protein sequences, we propose that such allergens could be responsible for at least a part of the allergenic cross-reactivity between proteins from different pollens and plant foods.

Oligoclonal analysis of the atopic T cell response to the group 1 allergen of Cynodon dactylon (bermuda grass) pollen: pre- and post-allergen-specific immunotherapy.

BACKGROUND: Bermuda grass pollen (BGP) is an increasingly important seasonal aeroallergen in Australia and other subtropical and temperate regions. BGP shares minimal allergenic cross-reactivity with pollens of rye grass or other Pooideae grasses often used for desensitization regimens in grass pollen allergy. Current allergen immunotherapy is seldom used in asthmatic patients due to IgE-mediated side effects. Since clinically effective immunotherapy is linked with altered allergen-specific T cell response, characterisation of human T cell reactivity to Cyn d 1, the major B cell allergen of BGP, should permit the design of effective and safe immunotherapy for BGP allergy. METHODS: Short-term BGP-specific CD4+ T cell lines were established from peripheral blood of 14 BGP-sensitive patients before and after conventional 50% BGP and 50% 7-grass mix subcutaneous specific allergen immunotherapy (SIT). T cell diversity of antigen specificity and function was assessed by proliferation and cytokine production to BGP, Cyn d 1 and Cyn d 1 peptides. RESULTS: Three highly immunogenic regions of Cyn d 1 were identified in 13/14 patients pre-SIT: Cyn d 1 (109-128), (181-209) and (217-241). The SIT regimen was clinically efficacious. Following SIT, decreased proliferation to BGP, Cyn d 1 and Cyn d 1 peptides was observed with a marked decrease in the IL-5:IFN-gamma ratio. CONCLUSIONS: Cyn d 1 is a major T cell allergen of BGP. Decreased Cyn d 1-specific IL-5 dominant T cell responses were observed in association with clinically effective treatment with the 50% BGP and 50% 7-grass mix. Identified dominant T cell regions of Cyn d 1 should facilitate safer vaccine development for BGP-induced asthma in addition to rhinitis.