Supplementary Material for: Do Plantago lanceolata Skin Prick Test-Positive Patients Display IgE to Genuine Plantain Pollen Allergens? Investigation of Pollen Allergic Patients from the North-East of France

Background: English plantain (Plantago lanceolata) is an important weed pollen allergen source triggering allergic symptoms during summer. To elucidate genuine versus cross-reactive sensitization, we investigated IgE reactivity patterns and inhibition capacities of plantain-sensitized patients. Methods: Sera of 35 rhinoconjunctivitis patients from the north-east of France with positive skin prick tests (SPT) to Plantago lanceolata pollen were tested with clinically relevant allergen sources using ELISA, ImmunoCAP, and immunoblot inhibition. Results: The patients were multisensitized with additional reactivity to grass (94.3%), ash (74.3%), birch (71.4%), and mugwort (55.2%) pollen in SPT. Sensitization prevalence to allergen molecules was 34.3% (Pla l 1), 94.3% (Phl p 1/5), 60.0% (Ole e 1), 65.7% (Bet v 1), 37.1% (profilin), and 40.0% (CCD). In immunoblot, IgE reactivity to plantain pollen was inhibited with relevant pollen extracts and purified rPla l 1. Two sera did not reveal any IgE cross-reactivity, while reactivity to plantain was efficiently inhibited by grass pollen in the sera of 10 patients. The sera from 17 different patients could be inhibited by grass, birch, or ash pollen to varying degrees. Thus, only 37.1% of our patients demonstrated true plantain pollen sensitization, while 62.9% were solely positive due to IgE cross-reactive molecules from other clinically relevant pollen. Conclusions: Plantain pollen-sensitized patients are multi-reactors demonstrating varying and complex IgE-reactivity profiles. In vivo and in vitro tests using extracts are typically blurred due to the presence of homologous allergens or CCD in grass, birch, or ash pollen. So far, Pla l 1 represents the only indicative marker allergen for the diagnosis of genuine plantain pollen sensitization.

背景：长叶车前草（Plantago lanceolata）是夏季引发过敏症状的重要杂草花粉变应原来源。为明确真正致敏与交叉反应性致敏的区别，本研究针对车前草致敏患者的IgE反应模式及抑制能力展开了探究。
方法：选取法国东北部35名对长叶车前草花粉皮肤点刺试验（SPT）结果呈阳性的鼻结膜炎患者血清，采用酶联免疫吸附试验（ELISA）、ImmunoCAP及免疫印迹抑制试验，对临床相关变应原来源进行检测。
结果：受试患者均为多致敏体质，皮肤点刺试验显示其对禾本科花粉（94.3%）、白蜡树花粉（74.3%）、桦树花粉（71.4%）及艾蒿花粉（55.2%）均存在额外反应性。各变应原分子的致敏率分别为：Pla l 1（34.3%）、Phl p 1/5（94.3%）、Ole e 1（60.0%）、Bet v 1（65.7%）、前纤维蛋白（profilin，37.1%）及交叉反应性碳水化合物决定簇（CCD，40.0%）。免疫印迹实验结果显示，车前草花粉的IgE反应可被相关花粉提取物及纯化重组Pla l 1抑制。其中2份血清未检测到任何IgE交叉反应性；在10名患者的血清中，禾本科花粉可有效抑制其对车前草的反应；另有17名不同患者的血清反应可被禾本科、桦树或白蜡树花粉不同程度地抑制。综上，本研究中仅37.1%的患者呈现真正的车前草花粉致敏，而62.9%的患者血清阳性仅源于其他临床相关花粉中存在的IgE交叉反应性分子。
结论：车前草花粉致敏患者均为多反应体质，呈现出多样化且复杂的IgE反应谱。由于禾本科、桦树或白蜡树花粉中存在同源变应原或交叉反应性碳水化合物决定簇，基于提取物的体内及体外试验通常会出现结果模糊的情况。截至目前，Pla l 1是唯一可用于诊断真正车前草花粉致敏的标志性变应原。