Kelly Vanessa J, Winkler Tilo, Venegas Jose G, Kone Mamary, Hamilos Daniel L, Afshar Roshi, Cho Josalyn L, Luster Andrew D, Medoff Benjamin D, Harris R Scott
Divisions of Pulmonary and Critical Care and Rheumatology, Allergy and Immunology, Department of Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, United States of America.
Department of Anaesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, United States of America.
PLoS One. 2015 Dec 7;10(12):e0143976. doi: 10.1371/journal.pone.0143976. eCollection 2015.
Allergic non-asthmatic (ANA) adults experience upper airway symptoms of allergic disease such as rhinorrhea, congestion and sneezing without symptoms of asthma. The aim of this study was to utilize PET-CT functional imaging to determine whether allergen challenge elicits a pulmonary response in ANA subjects or whether their allergic disease is truly isolated to the upper airways.
In 6 ANA subjects, bronchoalveolar lavages (BAL) were performed at baseline and 24h after instillation of an allergen and a diluent in separate lung lobes. After instillation (10h), functional imaging was performed to quantify and compare regional perfusion, ventilation, fractional gas content (Fgas), and glucose uptake rate (Ki) between the baseline, diluent and allergen lobes. BAL cell counts were also compared.
In ANA subjects, compared to the baseline and diluent lobes, perfusion and ventilation were significantly lower in the allergen lobe (median [inter-quartile range], baseline vs. diluent vs. allergen: Mean-normalized perfusion; 0.87 [0.85-0.97] vs. 0.90 [0.86-0.98] vs. 0.59 [0.55-0.67]; p<0.05. Mean-normalized ventilation 0.89 [0.88-0.98] vs. 0.95 [0.89-1.02] vs. 0.63 [0.52-0.67], p<0.05). In contrast, no significant differences were found in Fgas between baseline, diluent and allergen lobes or in Ki. Total cell counts, eosinophil and neutrophil cell counts (cells/ml BAL) were significantly greater in the allergen lobe compared to the baseline lobe (all P<0.05).
Despite having no clinical symptoms of a lower airway allergic response (cough and wheeze) allergic non-asthmatic subjects have a pulmonary response to allergen exposure which manifests as reduced ventilation and perfusion.
过敏性非哮喘（ANA）成人有过敏性疾病的上呼吸道症状，如鼻漏、鼻塞和打喷嚏，但无哮喘症状。本研究的目的是利用PET-CT功能成像来确定变应原激发是否会在ANA受试者中引发肺部反应，或者他们的过敏性疾病是否真的仅局限于上呼吸道。
对6名ANA受试者在基线时以及在不同肺叶分别注入变应原和稀释剂后24小时进行支气管肺泡灌洗（BAL）。注入后（10小时），进行功能成像以量化和比较基线、稀释剂和变应原肺叶之间的区域灌注、通气、气体分数含量（Fgas）和葡萄糖摄取率（Ki）。还比较了BAL细胞计数。
在ANA受试者中，与基线和稀释剂肺叶相比，变应原肺叶的灌注和通气显著降低（中位数[四分位间距]，基线与稀释剂与变应原：平均标准化灌注；0.87[0.85 - 0.97]对0.90[0.86 - - 0.98]对0.59[0.55 - 0.67]；p<0.05。平均标准化通气0.89[0.88 - 0.98]对0.95[0.89 - 1.02]对0.63[0.52 - 0.67]，p<0.05）。相比之下，基线、稀释剂和变应原肺叶之间的Fgas或Ki没有显著差异。与基线肺叶相比，变应原肺叶的总细胞计数、嗜酸性粒细胞和中性粒细胞细胞计数（细胞/ml BAL）显著更高（所有P<0.05）。
尽管没有下呼吸道过敏反应（咳嗽和喘息）的临床症状，但过敏性非哮喘受试者对变应原暴露有肺部反应，表现为通气和灌注降低。
