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

Abstract

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.

Cyn d 1 airborne allergen in a Southern Brazilian city

“…The second hypothesis for this result was that the presence of Cyn d 1 serum-speci ic IgE antibodies may occur at low levels in individuals with high positivity to Phl p 1 due to cross-reactivity to group 1, without representing proper sensitization to Cynodon dactylon [18]. In addition, the allergenic component used in this test is a natural allergen (nCyn d 1) glycosylated in the amino-terminal portion, which may imply a speci ic IgE response to nCyn d 1 in populations not exposed to Cynodon dactylon.…”

5-grass-pollen SLIT effectiveness in seasonal allergic rhinitis: Impact of sensitization to subtropical grass pollen

“…In temperate regions of Australia, and in similar climatic regions globally, pollens from temperate grasses (such as ryegrass) are major drivers of seasonal allergic rhinitis (SAR) and asthma risks, including epidemic thunderstorm asthma. [1][2][3][4] The effectiveness of temperate grass pollen allergen immunotherapy (AIT) has been wellcharacterized in SAR populations from the northern hemisphere, with evidence available from a number of large, double-blind, placebocontrolled, randomized trials for the short-and long-term treatment benefits of standardized AIT products. 5 However, there have been comparatively few studies of the effectiveness of temperate grass pollen AIT treatments in SAR patients from the southern hemisphere, who are frequently polysensitized to both temperate and subtropical grass pollens.…”

“…5 However, there have been comparatively few studies of the effectiveness of temperate grass pollen AIT treatments in SAR patients from the southern hemisphere, who are frequently polysensitized to both temperate and subtropical grass pollens. 1,2 To date, one controlled study of grass pollen AIT effectiveness in Australian SAR patients has been performed, which was an open-label, controlled study conducted with 300 IR 5-grass pollen sublingual immunotherapy tablet (300 IR 5-grass SLIT), which contains a homologous mixture of temperate grass pollens including ryegrass pollen. 6 This study by O'Hehir et al was conducted over 2-3 consecutive pollen seasons in Melbourne, Australia (2014-2016) and confirmed that 300 IR 5-grass SLIT is effective from the first pollen season in SAR patients with primary allergy to temperate grass (ryegrass) pollen.…”

“…Addressing this specific area of uncertainty is of considerable practical importance for informing optimal approaches to AIT for SAR patients in temperate regions of Australia, and similar regions globally, where temperate grass pollen is a major driver of SAR disease burdens and risks and polysensitization to subtropical grass pollen is prevalent. [1][2][3][4] In the present study, patient treatment satisfaction during treatment with 300 IR 5-grass SLIT over 3 consecutive pollen seasons was evaluated in a real-life setting in SAR patients with primary allergy to temperate grass pollen in temperate regions of Australia. In a pre-specified subgroup analysis, the impact of patient polysensitization status to subtropical grass pollen on changes in SAR symptom intensity during 300 IR 5-grass SLIT treatment was evaluated.…”

“…In temperate regions of Australia, and in similar climatic regions globally, pollens from temperate grasses (such as ryegrass) are major drivers of seasonal allergic rhinitis (SAR) and asthma risks, including epidemic thunderstorm asthma. 1 , 2 , 3 , 4 …”