Proud David, Chow Chung-Wai
Department of Physiology & Biophysics, University of Calgary, HSC 1627, 3330 Hospital Drive NW, Calgary, AB, T2N 4N1 Canada.
Am J Respir Cell Mol Biol. 2006 Nov;35(5):513-8. doi: 10.1165/rcmb.2006-0199TR. Epub 2006 Jun 15.
Substantial evidence implicates common respiratory viral infections in the pathogenesis of asthma and chronic obstructive pulmonary disease (COPD). Children who experience recurrent virally induced wheezing episodes during infancy are at greater risk for developing asthma. In addition, respiratory viral infections are a major trigger for acute exacerbations of both asthma and COPD. Despite the importance of viral infections in asthma and COPD, the mechanisms by which viruses predispose to, or cause exacerbations of, these diseases remain poorly understood. It is clear that viral infections lead to enhanced airway inflammation and can cause airways hyperresponsiveness. The epithelial cell is the principal site of viral infection in the airways and plays a central role in viral modulation of airway inflammation via release of a variety of cytokines, chemokines, and growth factors. The mechanisms by which viral infections modulate epithelial function, therefore, is a topic of intense investigation. The epithelium also contributes to the host innate defense response to viral infection by releasing products that are antiviral and/or can lead to increased recruitment of dendritic cells and lymphocytes. Some evidence supports a role for the epithelial cell in specific immunity, although the response of more conventional cells of the immune system to viral infections is likely the dominant factor in this regard. Although current therapies may help combat virally induced disease exacerbations, they are less than ideal. A better understanding of the mechanisms underlying viral modulation of these diseases, therefore, may lead to new therapeutic approaches.
大量证据表明，常见的呼吸道病毒感染与哮喘和慢性阻塞性肺疾病（COPD）的发病机制有关。在婴儿期经历反复病毒诱发喘息发作的儿童患哮喘的风险更高。此外，呼吸道病毒感染是哮喘和COPD急性加重的主要诱因。尽管病毒感染在哮喘和COPD中很重要，但病毒导致这些疾病易感性增加或加重的机制仍知之甚少。很明显，病毒感染会导致气道炎症增强，并可引起气道高反应性。上皮细胞是气道中病毒感染的主要部位，通过释放多种细胞因子、趋化因子和生长因子，在病毒对气道炎症的调节中起核心作用。因此，病毒感染调节上皮功能的机制是一个深入研究的课题。上皮细胞还通过释放具有抗病毒作用和/或可导致树突状细胞和淋巴细胞募集增加的产物，参与宿主对病毒感染的固有防御反应。一些证据支持上皮细胞在特异性免疫中的作用，尽管在这方面，免疫系统中更传统的细胞对病毒感染的反应可能是主导因素。虽然目前的治疗方法可能有助于对抗病毒诱发的疾病加重，但并不理想。因此，更好地了解这些疾病的病毒调节机制可能会带来新的治疗方法。
