Epidemiological Study of Common Allergens Sensitizing Hay Fever Patients in Different Regions of Mainland China

Pollen is a significant allergen worldwide, and the management of allergic rhinitis (AR) varies regionally [1]. In China, geographical diversity and cross-reactivity between pollen and food allergens complicate the development of a unified guideline for allergy testing [2]. This study involved 200 AR patients from northern, southern, and northwestern China, testing them with 300 food and inhalant allergens and components by the Allergy Explorer2 (ALEX2) to analyze regional sensitization profiles and epidemiological characteristics. Seventeen inhalant allergens used in the skin prick test (SPT) were selected based on their prevalence and relevance in China [3]. The SPT results indicate that the most common allergen in the southern region is house dust mite (Dermatophagoides pteronyssinus), while the sensitization rate to mugwort is significantly higher in the northern and northwestern regions, consistent with previous studies [4]. Results revealed that environmental, climate, and dietary factors may contribute to distinct regional differences in sensitization patterns. Northern patients had higher rates of eye and skin allergies, while the northwestern group experienced more asthma. A significant correlation was found between the number of positive allergens and elevated total serum IgE levels (p < 0.0001), suggesting that the number of positive tests can serve as an indirect marker for IgE levels [5] (Table 1). VAS scores indicated that northern patients had more severe nasal symptoms (running nose and anosmia, Figure 1B,E), with higher eye symptom scores than those from the northwestern region (Figure 1G–K). Among the study population, 76.5% were sensitized to at least one pan-allergen (nsLTP, PR-10, or profilin), with nsLTP showing the highest sensitization rate (66%), followed by profilin (44%) and PR-10 (41.5%). Sensitization to nsLTP and PR-10 was mostly to single components, while multiple component sensitization was more common for profilin (Table 1). This differs from the sensitization patterns in northern Europe, where profilin and PR-10 sensitization are more common, and single-component nsLTP sensitization is rarer [6]. Interestingly, the northwestern region had a significantly higher sensitization rate to nsLTP than the other regions, with about 30% of patients sensitized to over 10 nsLTP components. Further analysis showed that sensitization to nsLTP and profilin was more prevalent in the northern and northwestern regions compared to the southern region. In the northern region, common nsLTP allergens included Mal d 3, Ole e 7, and Cor a 8, while in the northwestern region, Art v 3, Cor a 8, Mal d 3, and Pla a 3 were predominant. PR-10 sensitization, particularly to Bet v 1, was more common in the northern region. Profilin allergens such as Cuc m 2 and Mer a 1 were prevalent in the northern regions, while in the northwestern region, they were Cuc m 2 and Pho d 2 (Table S1). This study also highlighted the most common inhalant and food allergens. Northern and northwestern regions shared similar inhalant allergen profiles, including mugwort (Art v 1/Art v 3), timothy grass (Phl p 12), and birch (Bet v 2). Indoor allergens like dust mites (Der f 2/Der f 1/Der p 2/Der p 1) and cat hair (Fel d 1) had higher sensitization rates in both northern and southern regions. Common food allergens across regions include melons, dates, strawberries, peaches, apples, and hazelnuts, with milk and locust showing higher sensitization rates in the southern region. Notably, sensitization to hazelnuts and apples varies by region. In the northern and northwestern regions, hazelnut sensitization was primarily to Cor a 8, while in the southern region, Cor a 1.0103 was more common. The northwestern region also exhibited higher sensitization to fruit and vegetable allergens (Zea m 14/Api g 2/Vit v 1/Act d 10) and nuts (Jug r 3). Based on these findings, we propose a regional-specific diagnostic workflow (Table 2, Figure S1) to guide the selection of specific IgE tests for pollen allergy patients and recommend considering region-specific allergens for testing. However, considering variations in regional economic conditions and healthcare facility capabilities, we recommend different testing methodologies—such as (SPT and/or serum IgE tests—providing flexibility in selection based on local contexts). This study was approved by the ethics committee of the First Affiliated Hospital of Guangzhou Medical University (GYFYY-2017-18). Written informed consent was signed by each patient or his/her guardians before the study. The authors declare no conflicts of interest. The data that supports the findings of this study are available in the Supporting Information of this article. Table S1. Pan-allergen sensitization rate of Chinese pollinosis patients. Table S2. Ranking of inhaled, food, and other allergens of pollinosis patients in northern regions. Table S3. Ranking of inhaled, food, and other allergens of pollinosis patients in southern regions. Table S4. Ranking of inhaled, food, and other allergens of pollinosis patients in northwestern regions. Figure S1. Regional atlas of high-prevalence allergens (> 30% sensitization) in Chinese pollinosis patients. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.