Riccio Anna Maria, Mauri Pierluigi, De Ferrari Laura, Rossi Rossana, Di Silvestre Dario, Benazzi Louise, Chiappori Alessandra, Dal Negro Roberto Walter, Micheletto Claudio, Canonica Giorgio Walter
Respiratory Diseases and Allergy Unit, IRCCS AOU San Martino-IST, University of Genoa, Genoa, Italy.
Proteomics and Metabolomics Unit, Institute for Biomedical Technologies, CNR, Milan, Italy.
Clin Transl Allergy. 2017 Mar 9;7:6. doi: 10.1186/s13601-017-0143-1. eCollection 2017.
Bronchial asthma is a heterogeneous disease characterized by three cardinal features: chronic inflammation, variable airflow obstruction, and airway hyperresponsiveness. Asthma has traditionally been defined using nonspecific clinical and physiologic variables that encompass multiple phenotypes and are treated with nonspecific anti-inflammatory therapies. Based on the modulation of airway remodeling after 12 months of anti-immunoglobulin E (IgE) treatment, we identified two phenotypes (omalizumab responder, OR; and non-omalizumab responder, NOR) and performed morphometric analysis of bronchial biopsy specimens. We also found that these two phenotypes were correlated with the presence/absence of galectin-3 (Gal-3) at baseline (i.e., before treatment). The aims of the present study were to investigate the histological and molecular effects of long-term treatment (36 months) with anti-IgE and to analyze the behavior of OR and NOR patients.
All patients were treated with the monoclonal antibody anti-IgE omalizumab for 36 months. The bronchial biopsy specimens were evaluated using morphometric, eosinophilic, and proteomic analysis (MudPIT). New data were compared with previous data, and unsupervised cluster analysis of protein profiles was performed.
After 36 months of treatment with omalizumab, reduction of reticular basement membrane (RBM) thickness was confirmed in OR patients (Gal-3-positive at baseline); similarly, the protein profiles (over 500 proteins identified) revealed that, in the OR group, levels of proteins specifically related to fibrosis and inflammation (e.g., smooth muscle and extracellular matrix proteins (including periostin), Gal-3, and keratins decreased by between 5- and 50-fold. Eosinophil levels were consistent with molecular data and decreased by about tenfold less in ORs and increased by twofold to tenfold more in NORs. This tendency was confirmed (p < 0.05) based on both fold change and DAVE algorithms, thus indicating a clear response to anti-IgE treatment in Gal-3-positive patients.
Our results showed that omalizumab can be considered a disease-modifying treatment in OR. The proteomic signatures confirmed the presence of Gal-3 at baseline to be a biomarker of long-term reduction in bronchial RBM thickness, eosinophilic inflammation, and muscular and fibrotic components in omalizumab-treated patients with severe asthma. Our findings suggest a possible relationship between Gal-3 positivity and improved pulmonary function.
支气管哮喘是一种异质性疾病，具有三个主要特征：慢性炎症、可变气流受限和气道高反应性。传统上，哮喘是根据包含多种表型的非特异性临床和生理变量来定义的，并采用非特异性抗炎疗法进行治疗。基于抗免疫球蛋白E（IgE）治疗12个月后气道重塑的调节情况，我们确定了两种表型（奥马珠单抗反应者，OR；和非奥马珠单抗反应者，NOR），并对支气管活检标本进行了形态计量分析。我们还发现，这两种表型与基线时（即治疗前）半乳糖凝集素-3（Gal-3）的存在与否相关。本研究的目的是调查抗IgE长期治疗（36个月）的组织学和分子效应，并分析OR和NOR患者的行为。
所有患者均接受单克隆抗体抗IgE奥马珠单抗治疗36个月。使用形态计量学、嗜酸性粒细胞和蛋白质组学分析（多维蛋白质鉴定技术）对支气管活检标本进行评估。将新数据与先前数据进行比较，并对蛋白质谱进行无监督聚类分析。
用奥马珠单抗治疗36个月后，证实OR患者（基线时Gal-3阳性）的网状基底膜（RBM）厚度降低；同样，蛋白质谱（鉴定出500多种蛋白质）显示，在OR组中，与纤维化和炎症特异性相关的蛋白质水平（如平滑肌和细胞外基质蛋白（包括骨膜蛋白）、Gal-3和角蛋白）降低了5至50倍。嗜酸性粒细胞水平与分子数据一致，在OR患者中降低了约10倍，在NOR患者中增加了2至10倍。基于倍数变化和DAVE算法均证实了这种趋势（p<0.05），从而表明Gal-3阳性患者对抗IgE治疗有明显反应。
我们的结果表明，奥马珠单抗可被视为OR患者的疾病修饰治疗。蛋白质组学特征证实，基线时Gal-3的存在是奥马珠单抗治疗的重症哮喘患者支气管RBM厚度、嗜酸性粒细胞炎症以及肌肉和纤维化成分长期降低的生物标志物。我们的研究结果提示Gal-3阳性与肺功能改善之间可能存在关联。
