Creating A Risk Assessment Tool for Thunderstorm Asthma: the CARISTA Study

Thunderstorm asthma is a recurring public health emergency in South-Eastern Australia with increasing risks due to climate change. Yet thunderstorm asthma is only the "tip of the iceberg" of documented seasonal surges in emergency asthma presentations due to ryegrass pollen allergy - an escalating challenge to healthcare provision in South-Eastern Australia. The CARISTA (Creating A Risk assessment biomarker tool to prevent Seasonal allergic and Thunderstorm Asthma) study aims to address these profound health impacts.

The CARISTA study will recruit adults at high risk of seasonal allergic asthma and thunderstorm asthma who will be monitored using a customised secure data platform for asthma and allergic rhinitis symptoms over two consecutive spring seasons (2025/2026/2027). Participants with self-reported or diagnosed seasonal allergic rhinitis and/or seasonal allergic asthma will be recruited before springtime and their baseline allergic rhinitis and/or asthma symptoms, respiratory function and blood biomarkers (allergy or sensitisation to ryegrass pollen, levels of inflammatory cells [eosinophils]) will be measured.

The key symptoms of interest are moderate or severe asthma exacerbations which are defined as an increase in asthma symptoms requiring intervention with an emergency medical visit, use of oral corticosteroid therapy or of regular preventive asthma therapy. These asthma exacerbations will be used to establish a biomarker-based estimate of risk for seasonal allergic asthma exacerbations to inform preventive clinical practice. The key biomarker will be the threshold of serum specific IgE (sp-IgE) to ryegrass pollen and its allergen sub-components, but other biomarkers such as lung function, eosinophil levels, and allergen component sensitisation will be simultaneously assessed.

This study brings together a team of world-leading multidisciplinary and cross-sectoral clinicians and researchers in Respiratory Medicine, Allergy, Primary Health Care, Epidemiology, Public Health, Statistical modelling and Botany from multiple health and academic institutions.

Overall, CARISTA will test a new approach to predict risk for seasonal allergic asthma to identify treatable traits for preventing seasonal allergic asthma exacerbations to reduce the recurrent annual health threat of seasonal and thunderstorm asthma, address community and health care provider concerns and uncertainty regarding preventive treatment and management.

Inclusion criteria

Consenting adults aged 18 to 70 years with seasonal allergic rhinitis

willing to undertake:

• Lung function testing
• Blood sample collection for risk factor identification, -Prospectively logging their symptoms and medications through the springtime season using the CARISTA symptom monitoring platform . -

Exclusion criteria

• Individuals unable to provide informed consent
• Individuals who do not suffer from symptoms of seasonal allergic rhinitis
• Individuals who do not consent to lung function testing and blood sample collection - Individuals with unstable asthma (FEV1 by spirometry less than 70% predicted), a recent exacerbation or change of asthma preventive medication use (within one month) would be excluded, although re-screening would be permitted after one month, time permitting.
• Individuals with severe asthma requiring the use of continuous oral corticosteroids or biological medication for severe asthma.
• The presence of any medical illness, such as cardiac disease, pre-existing illness or immunomodulatory therapy that, in the opinion of the Investigators, would compromise participant safety or the derivation of biomarkers during the study.