Clinical immune response to rhinovirus challenge in human asthmatics

描述（由申请人提供）：儿童和年轻人的大多数哮喘加重是由鼻病毒（RV）感染引起的。作为哮喘相关发病的最重要原因，在人类中进行临床调查以确定其潜在机制是必要的。我们假设哮喘患者鼻子中产生的免疫反应是随后免疫系统系统调节的基础，并且在易感个体（那些先前患有哮喘的人）中，这种改变的鼻腔环境是哮喘恶化的原因。具体来说，我们认为这种修饰在哮喘患者的上呼吸道中产生了一种独特的对RV的免疫反应模式，从而触发Th2细胞因子“特征”状态的发展，从而驱动哮喘患者下呼吸道RV感染的不良后果。此外，我们认为这种th2诱导的鼻气道环境的强度在这些过敏性哮喘患者中进一步被放大，这是由于有效的抗RV免疫反应的发育和表达的缺陷，导致对RV的易感性更大。确定鼻病毒引起的哮喘发作的病因将确定预防和治疗这些发作的具体目标。特异性目标1将解决变应性气道疾病演变过程中鼻上皮细胞（EC）发生表观遗传变化的假设，这是鼻腔EC的结果

DESCRIPTION (provided by applicant): Most asthma exacerbations in children and young adults result from rhinovirus (RV) infections. As the most important cause of asthma-related morbidity it is essential that clinical investigations be performed in humans to define the underlying mechanisms. We hypothesize that the immune responses generated in the nose of asthmatics underlie subsequent systemic modulation of the immune system, and that - in susceptible individuals (those with pre-existing asthma) - this modified nasal milieu is responsible for the asthma exacerbation. Specifically, we propose that this modification produces a distinct pattern of immune responsiveness to RV in the upper airway of asthmatics, which triggers the development of a Th2 cytokine "signature" state that drives the adverse outcome of RV infection in the lower airway of asthmatics. In addition, we propose that the intensity of this Th2-inducing nasal airway milieu is further exaggerated in these allergic asthmatics, by a concomitant defect in the development and expression of effective anti-RV immune responses, leading to greater susceptibility to RV. Determining the etiology of rhinovirus-induced asthma exacerbations will identify specific targets to prevent and treat these episodes. Specific Aim 1 will address the hypothesis that epigenetic changes develop in nasal epithelial cells (EC) during the evolution of allergic airway disease as a result of which nasal EC are programmed to produce cytokines central to orchestrating an allergic inflammatory immune response. We will primarily determine whether nasal epithelium from allergic asthmatics, when infected with RV, is programmed to secrete cytokines that promote a Th2 cytokine "signature" (IL-25, IL- 33, and TSLP). Specific Aim 2 will interrogate the complementary hypothesis that increased susceptibility to RV and extent of nasal infections in asthmatics amplifies the consequences of this Th2-inducing bias. Specifically we propose that over time nasal epithelium in asthmatics is epigenetically re-programmed, resulting in the greater susceptibility of EC to RV infection. Initially we will analyze nasal EC ex vivo to test the hypothesis that EC from asthmatics will be more susceptible to RV infection as manifested by a greater magnitude of RV replication, a more rapid tempo of infection and overall greater death of RV-infected cells. We will then corroborate this in vitro analysis with in vivo studies by infecting asthmatics and controls with RV, monitoring viral load over time as a measure of the pace of infection. Most importantly, we will perform nasal biopsies at the peak of infection to determine the extent of viral infection and whether this represents cytopathic (necrotic) or apoptotic cell death. And, finally, Specific Aim 3 will address the molecular and cellular basis for the defect in anti-viral immunity in asthma. We will establish primary cultures of EC from control and asthmatic individuals prior to RV infection and examine them for baseline- and RV infection- induced expression of cytokines central to anti-viral immunity (IFNs-α, -ß, and λ and IL-15). We expect that anti-viral mediator expression will correlate inversely with the susceptibility, tempo, and severity of RV infection.