Department of Biodiversity and Environmental Management (Botany), University of León, León, Spain.
Department of Biological, Geological and Environmental Sciences, University of Bologna, Bologna, Italy.
Sci Total Environ. 2024 Mar 20;917:170597. doi: 10.1016/j.scitotenv.2024.170597. Epub 2024 Feb 1.
Fungal spores, commonly found in the atmosphere, can trigger important respiratory disorders. The glycoprotein Alt a 1 is the major allergen present in conidia of the genus Alternaria and has a high clinical relevance for people sensitized to fungi. Exposure to this allergen has been traditionally assessed by aerobiological spore counts, although this does not always offer an accurate estimate of airborne allergen load. This study aims to pinpoint the key factors that explain the presence and variation of Alt a 1 concentration in the atmosphere in order to establish exposure risk periods and improve forecasting models. Alternaria spores were sampled using a Hirst-type volumetric sampler over a five-year period. The allergenic fraction from the bioaerosol was collected using a low-volume cyclone sampler and Alt a 1 quantified by Enzyme-Linked ImmunoSorbent Assay. A cluster analysis was executed in order to group days with similar environmental features and then analyze days with the presence of the allergen in each of them. Subsequently, a quadratic discriminant analysis was performed to evaluate if the selected variables can predict days with high Alt a 1 load. The results indicate that higher temperatures and absolute humidity favor the presence of Alt a 1 in the atmosphere, while time of precipitation is related to days without allergen. Moreover, using the selected parameters, the quadratic discriminant analysis to predict days with allergen showed an accuracy rate between 67 % and 85 %. The mismatch between daily airborne concentration of Alternaria spores and allergen load can be explained by the greater contribution of medium-to-long distance transport of the allergen from the major emission sources as compared with spores. Results highlight the importance of conducting aeroallergen quantification studies together with spore counts to improve the forecasting models of allergy risk, especially for fungal spores.
真菌孢子广泛存在于大气中，可能引发重要的呼吸道疾病。半乳甘露聚糖蛋白 Alt a 1 是交链孢属分生孢子中的主要过敏原，对真菌致敏人群具有很高的临床相关性。传统上通过空气生物学孢子计数来评估这种过敏原的暴露情况，但这并不总是能准确估计空气传播过敏原的负荷。本研究旨在确定解释大气中 Alt a 1 浓度存在和变化的关键因素，以便确定暴露风险期并改进预测模型。在五年的时间里，使用 Hirst 型容量采样器采集Alternaria 孢子。使用小体积旋风采样器采集生物气溶胶中的过敏原部分，并通过酶联免疫吸附测定法定量 Alt a 1。进行聚类分析，以便将具有相似环境特征的日子分组，然后分析每组日子中过敏原的存在情况。随后，进行二次判别分析，以评估所选变量是否可以预测高 Alt a 1 负荷的日子。结果表明，较高的温度和绝对湿度有利于大气中 Alt a 1 的存在，而降水时间与无过敏原的日子有关。此外，使用所选参数进行二次判别分析预测有过敏原的日子，准确率在 67%至 85%之间。空气中 Alternaria 孢子的日浓度与过敏原负荷之间的不匹配可以用过敏原从中等距离到远距离从主要排放源输送的贡献较大来解释，而不是孢子。研究结果强调了在进行过敏风险预测模型时，同时进行空气变应原定量研究和孢子计数的重要性，尤其是对于真菌孢子。
