Total transcriptome, proteome, and allergome of Johnson grass pollen, which is important for allergic rhinitis in subtropical regions.

BACKGROUND: Genomic data are lacking for many allergen sources. To circumvent this limitation, we implemented a strategy to reveal the repertoire of pollen allergens of a grass with clinical importance in subtropical regions, where an increasing proportion of the world's population resides. OBJECTIVE: We sought to identify and immunologically characterize the allergenic components of the Panicoideae Johnson grass pollen (JGP; Sorghum halepense). METHODS: The total pollen transcriptome, proteome, and allergome of JGP were documented. Serum IgE reactivities with pollen and purified allergens were assessed in 64 patients with grass pollen allergy from a subtropical region. RESULTS: Purified Sor h 1 and Sor h 13 were identified as clinically important allergen components of JGP with serum IgE reactivity in 49 (76%) and 28 (43.8%), respectively, of patients with grass pollen allergy. Within whole JGP, multiple cDNA transcripts and peptide spectra belonging to grass pollen allergen families 1, 2, 4, 7, 11, 12, 13, and 25 were identified. Pollen allergens restricted to subtropical grasses (groups 22-24) were also present within the JGP transcriptome and proteome. Mass spectrometry confirmed the IgE-reactive components of JGP included isoforms of Sor h 1, Sor h 2, Sor h 13, and Sor h 23. CONCLUSION: Our integrated molecular approach revealed qualitative differences between the allergenic components of JGP and temperate grass pollens. Knowledge of these newly identified allergens has the potential to improve specific diagnosis and allergen immunotherapy treatment for patients with grass pollen allergy in subtropical regions and reduce the burden of allergic respiratory disease globally.

Specific IgE recognition of pollen allergens from subtropic grasses in patients from the subtropics.

BACKGROUND: Pollens of subtropical grasses, Bahia (Paspalum notatum), Johnson (Sorghum halepense), and Bermuda (Cynodon dactylon), are common causes of respiratory allergies in subtropical regions worldwide. OBJECTIVE: To evaluate IgE cross-reactivity of grass pollen (GP) found in subtropical and temperate areas. METHODS: Case and control serum samples from 83 individuals from the subtropical region of Queensland were tested for IgE reactivity with GP extracts by enzyme-linked immunosorbent assay. A randomly sampled subset of 21 serum samples from patients with subtropical GP allergy were examined by ImmunoCAP and cross-inhibition assays. RESULTS: Fifty-four patients with allergic rhinitis and GP allergy had higher IgE reactivity with P notatum and C dactylon than with a mixture of 5 temperate GPs. For 90% of 21 GP allergic serum samples, P notatum, S halepense, or C dactylon specific IgE concentrations were higher than temperate GP specific IgE, and GP specific IgE had higher correlations of subtropical GP (r = 0.771-0.950) than temperate GP (r = 0.317-0.677). In most patients (71%-100%), IgE with P notatum, S halepense, or C dactylon GPs was inhibited better by subtropical GP than temperate GP. When the temperate GP mixture achieved 50% inhibition of IgE with subtropical GP, there was a 39- to 67-fold difference in concentrations giving 50% inhibition and significant differences in maximum inhibition for S halepense and P notatum GP relative to temperate GP. CONCLUSION: Patients living in a subtropical region had species specific IgE recognition of subtropical GP. Most GP allergic patients in Queensland would benefit from allergen specific immunotherapy with a standardized content of subtropical GP allergens.

An immunodiagnostic assay for quantitation of specific IgE to the major pollen allergen component, Pas n 1, of the subtropical Bahia grass.

BACKGROUND: Pollens of the Panicoideae subfamily of grasses including Bahia (Paspalum notatum) are important allergen sources in subtropical regions of the world. An assay for specific IgE to the major molecular allergenic component, Pas n 1, of Bahia grass pollen (BaGP) would have immunodiagnostic utility for patients with pollen allergy in these regions. METHODS: Biotinylated Pas n 1 purified from BaGP was coated onto streptavidin ImmunoCAPs. Subjects were assessed by clinical history of allergic rhinitis and skin prick test (SPT) to aeroallergens. Serum total, BaGP-specific and Pas n 1-specific IgE were measured. RESULTS: Pas n 1 IgE concentrations were highly correlated with BaGP SPT (r = 0.795, p < 0.0001) and BaGP IgE (r = 0.915, p < 0.0001). At 0.23 kU/l Pas n 1 IgE, the diagnostic sensitivity (92.4%) and specificity (93.1%) for the detection of BaGP allergy was high (area under receiver operator curve 0.960, p < 0.0001). The median concentrations of Pas n 1 IgE in non-atopic subjects (0.01 kU/l, n = 67) and those with other allergies (0.02 kU/l, n = 59) showed no inter-group difference, whilst grass pollen-allergic patients with allergic rhinitis showed elevated Pas n 1 IgE (6.71 kU/l, n = 182, p < 0.0001). The inter-assay coefficient of variation for the BaGP-allergic serum pool was 6.92%. CONCLUSIONS: Pas n 1 IgE appears to account for most of the BaGP-specific IgE. This molecular component immunoassay for Pas n 1 IgE has potential utility to improve the sensitivity and accuracy of diagnosis of BaGP allergy for patients in subtropical regions.

Season of birth and childhood food allergy in Australia.

BACKGROUND: Recent studies suggest a possible role for low ultraviolet radiation exposure and low vitamin D status as a risk factor for food allergy. We hypothesized that children born in autumn/winter months (less sun exposure) might have higher food allergy rates than those born in spring/summer. METHODS: We compared IgE-mediated food allergy rates by season of birth in 835 children aged 0-4 yr assessed 1995-2009 in a specialist referral clinic, using population births as controls. To address potential concerns about generalizability, we also examined national prescriptions for adrenaline autoinjectors (2007) and infant hypoallergenic formula (2006-2007). RESULTS: Although live births in the general ACT population showed no seasonal pattern (50% autumn/winter vs. 50% spring/summer), autumn/winter births were more common than spring/summer births among food allergy patients (57% vs. 43%; p < 0.001). The same seasonal pattern was observed with peanut (60% vs. 40%; p < 0.001) and egg (58% vs. 42%; p = 0.003). Regional UVR intensity was correlated with relative rate of overall food allergy (ß, -1.83; p = 0.05) and peanut allergy (ß, -3.27; p = 0.01). National data showed that autumn/winter births also were more common among children prescribed EpiPens (54% vs. 46%; p < 0.001) and infant hypoallergenic formula (54% vs. 46%; p < 0.001). CONCLUSIONS: The significantly higher rates of food allergy in children born autumn/winter (compared to spring/summer), the relationship between relative food allergy rates and monthly UVR, combined with national adrenaline autoinjector and infant hypoallergenic formula prescription data, suggest that ultraviolet light exposure/vitamin D status may be one of many potential factors contributing to childhood food allergy pathogenesis.

Causes of ant sting anaphylaxis in Australia: the Australian Ant Venom Allergy Study.

OBJECTIVE: To determine the Australian native ant species associated with ant sting anaphylaxis, geographical distribution of allergic reactions, and feasibility of diagnostic venom-specific IgE (sIgE) testing. DESIGN, SETTING AND PARTICIPANTS: Descriptive clinical, entomological and immunological study of Australians with a history of ant sting anaphylaxis, recruited in 2006-2007 through media exposure and referrals from allergy practices and emergency physicians nationwide. We interviewed participants, collected entomological specimens, prepared reference venom extracts, and conducted serum sIgE testing against ant venom panels relevant to the species found in each geographical region. MAIN OUTCOME MEASURES: Reaction causation attributed using a combination of ant identification and sIgE testing. RESULTS: 376 participants reported 735 systemic reactions. Of 299 participants for whom a cause was determined, 265 (89%; 95% CI, 84%-92%) had reacted clinically to Myrmecia species and 34 (11%; 95% CI, 8%-16%) to green-head ant (Rhytidoponera metallica). Of those with reactions to Myrmecia species, 176 reacted to jack jumper ant (Myrmecia pilosula species complex), 18 to other jumper ants (15 to Myrmecia nigrocincta, three to Myrmecia ludlowi) and 56 to a variety of bulldog ants, with some participants reacting to more than one type of bulldog ant. Variable serological cross-reactivity between bulldog ant species was observed, and sera from patients with bulldog ant allergy were all positive to one or more venoms extracted from Myrmecia forficata, Myrmecia pyriformis and Myrmecia nigriceps. CONCLUSION: Four main groups of Australian ants cause anaphylaxis. Serum sIgE testing enhances the accuracy of diagnosis and is a prerequisite for administering species-specific venom immunotherapy.

Biogeographical variation in specific IgE recognition of temperate and subtropical grass pollen allergens in allergic rhinitis patients.

OBJECTIVE: Globally, grass pollens (GP) are major aeroallergen triggers of allergic rhinitis (AR) and asthma. However, patterns of allergic sensitisation to pollen of temperate (Pooideae: Lolium perenne) and subtropical (Chloridoideae: Cynodon dactylon and Panicoideae: Paspalum notatum) subfamilies in diverse climates remain unclear. This study aims to evaluate the level of allergic sensitisation and IgE specificity for major GP allergens representing the three subfamilies in biogeographically distinct regions. METHODS: Participants (GP-allergic with AR, 330; non-atopic, 29; other allergies, 54) were recruited in subtropical: Queensland, and temperate: New South Wales, Western and South Australia, regions. Clinical history, skin prick test (SPT), total and specific IgE to GP and purified allergens (ImmunoCAP) were evaluated. Cross-inhibition of sIgE with Pas n 1, Cyn d 1 and Lol p 1 by GP extracts was investigated. RESULTS: Queensland participants showed higher sensitisation to P. notatum and C. dactylon than L. perenne GP. sIgE was higher to Pas n 1 and Cyn d 1, and sIgE to Pas n 1 and Cyn d 1 was inhibited more by Panicoideae and Chloridoideae, respectively, than Pooideae GP. Conversely, participants from temperate regions showed highest sensitisation levels to L. perenne GP and Lol p 1, and sIgE to Lol p 1 was inhibited more by Pooideae than other GP. CONCLUSION: Levels and patterns of sensitisation to subtropical and temperate GP in AR patients depended on biogeography. Knowledge of the specificity of sensitisation to local allergens is important for optimal diagnosis and choice of allergen-specific immunotherapy to maximise benefit.

Optimising the management of allergic rhinitis: an Australian perspective.

Allergic rhinitis (AR) is one of the most prevalent medical conditions. It has significant effects on quality of life and can have considerable socioeconomic effects. The traditional classification of perennial and seasonal rhinitis does not distinguish between provoking factors, nor does it indicate the most appropriate treatment. A more useful classification is based on symptoms, which may be intermittent or persistent, and vary widely in severity. The goal of management is to achieve optimal symptom control. Therapeutic options include allergen avoidance, pharmacotherapy and immunotherapy. Antihistamines and intranasal corticosteroids (INCS) have become the cornerstones of therapy. A variety of effective treatments are available for consumers to self-select, without the advice of a doctor or pharmacist. INCS are widely recognised as the most effective pharmacotherapy for AR, in both adults and children. The efficacy of various preparations is similar, but those with low systemic bioavailability are preferred for children and for patients who are also receiving inhaled, topical or systemic corticosteroids.

Stinging and biting insect allergy: an Australian experience.

BACKGROUND: Stings and bites from various insects are responsible for many anaphylactic events. OBJECTIVE: To document the clinical features of specific forms of anaphylaxis and investigate clinical concerns regarding stinging and biting insect allergy. METHODS: All patients presenting for evaluation of adverse reactions to insect stings or bites between December 1980 and December 1997 had the clinical details of their reactions recorded and their reactions classified. RESULTS: The spectrum of clinical symptoms and signs is similar to that seen in anaphylaxis from other sources; stings on the head or neck are not more likely to cause life-threatening reactions than stings elsewhere on the body; a lesser reaction will not necessarily lead to a more serious reaction from a future sting; asthmatic patients do appear to have an increased risk of asthma as a feature of their anaphylactic response; anaphylaxis is usually confined to a particular insect species for the individual patient; patients who have had multiple stings at one time may have experienced true anaphylaxis and not a "toxic" response; and patients who have had anaphylaxis from other sources are at no greater risk than that of the general population of reacting similarly to insect stings or bites. CONCLUSIONS: Anaphylactic events from insect stings show the same clinical features as those from other sources. Systemic reactions seem confined to a specific insect species. Patients who experience RXN3 reactions from multiple stings at one time should undergo specific venom testing, because many have experienced true anaphylaxis and not a toxic response. Future consideration should be given to the role of beta-adrenergic antagonists and ACE inhibitors in patients with systemic reactions.

Anaphylaxis due to Red Imported Fire Ant sting.

The invasive Red Imported Fire Ant (Solenopsis invicta Buren) is well established at two locations in the Brisbane area, and we report a patient with anaphylaxis after a sting. The potential for anaphylactic events in Australia due to S. invicta will be greater than for native ants because of its unusual venom, its habit of forming supercolonies in grassy areas, and its aggressive group territorial defence, which can result in multiple stings.