过敏性肺炎的诊断和治疗进展

Progress in diagnosis and treatment of hypersensitivity pneumonitis

过敏性肺炎(hypersensitivity pneumonitis,HP)是在易感人群中由已知或未知吸入抗原引起的一种免疫介导性疾病,主要属于Ⅲ型和Ⅳ型超敏反应[1]。HP是一种影响肺实质和小气道的炎性和(或)纤维化疾病,曾称“外源性过敏性肺泡炎”,并被分为急性、亚急性和慢性。基于影像学或组织病理学上的纤维化是预后的主要决定因素,2020版ATS/ERS最新成人HP指南将HP分为纤维化型(混合炎症性合并纤维化或纯纤维化)或非纤维化型(纯炎症性)。HP以间质性肺炎、淋巴细胞性细支气管炎和肉芽肿为病理特征。HP与吸入抗原相关,许多刺激因子都与其有关,但仍有60%的患者难以识别暴露的抗原,导致HP未被广泛认识,临床诊断的HP远低于实际的HP。2020版ATS/ERS最新成人HP的诊断指南对HP新分类等诸多方面进行了阐述和更新。临床医生及时识别非纤维化型HP和纤维化型HP意义重大,从而避免环境因素持续存在,影响HP的疾病进程及其预后。

Hypersensitivity pneumonitis(HP)is an immune-mediated disease caused by known or unknown inhaled antigens in susceptible populations,mainly belonging to typeⅢand typeⅣhypersensitivity reactions.HP is an inflammatory and/or fibrotic disease that affects the lung parenchyma and small airways.It has been called“exogenous allergic alveolitis”and is classified as acute,subacute and chronic one.Based on imaging or histopathological fibrosis being a major determinant of prognosis,the new 2020 ATS/ERS guidelines for adult HP classify HP as fibrotic type(i.e.mixed inflammatory with fibrosis or pure fibrosis)or non-fibrotic type(i.e.pure inflammation).The pathological features of HP is characterized by interstitial pneumonia,lymphocytic bronchiolitis and granuloma.HP is associated with inhaled antigens,and many citing antigens are associated with HP.However,60%of patients still have difficulty in recognizing exposed antigens,leading to the fact that HP is not widely recognized and clinically diagnosed HP is far lower than the actual HP.The 2020 ATS/ERS guidelines for the diagnosis of adult HP describe and update the new classification of adult HP.It is of great significance for clinicians to identify non-fibrotic HP and fibrotic HP in time,so as to avoid the persistence of environmental factors and change the disease progression and prognosis of HP.