Immune reconstitution to Aspergillus

描述（由申请人提供）：侵袭性曲霉菌病（IA）的年发病率在异基因造血干细胞（HCT）接受者中为10 - 15%，死亡率约为80%;因此，这种感染已成为HCT后感染相关死亡的主要原因。现在感染主要发生在异基因HCT过程的晚期，即中性粒细胞植入后。流行病学与最近的认识是一致的，即在动物模型中有效的免疫需要强大的CD 4 + T辅助细胞1型（Th 1）的反应。然而，尚未进行大型研究来评价铜绿假单胞菌特异性免疫重建。我们已经开发了测量细胞对曲霉菌抗原的反应的方法，并在健康志愿者中证明了可重复的可变反应。我们提出了一项纵向免疫重建研究，以评估这一假设，即CD 4 + T细胞重建是重要的，以保护从IA后，同种异体HCT，多种因素，包括供体转移免疫，可能影响免疫重建。具体目标是：1.确定重建的细胞免疫是否可预测IA的风险和结局。患者将入组一项纵向研究，以评价重组细胞数量（DC 1、DC 2、T细胞亚型、NK细胞和B细胞）和对A.烟曲霉菌丝抗原预测IA的风险和结局。在目标2中，研究将确定健康供体中反应性CD 4 + T细胞和细胞因子模式的可变频率的意义。将评价供体应答，以检验健康人群中产生IFN-γ的CD 4 + T细胞的低频率与MHC等位基因相关的假设，可能包括特定的II类单倍型和/或III类区域（TNF-α基因）的多态性。将评估供体反应对受体重建的影响。目标3中的研究将鉴定呈递给健康人CD 4 + T细胞的烟曲霉抗原。通过用菌丝抗原连续刺激，从健康受试者中产生曲霉特异性CD 4 + T细胞克隆。经典HLA限制性CD 4+克隆将用于筛选A.烟曲霉cDNA，用顺序筛选鉴定单个T细胞抗原。本研究的目的是确定针对曲霉属物种的移植后免疫保护机制。这一信息将是有价值的发展战略，以预防和治疗真菌感染的免疫功能低下的人。

DESCRIPTION (provided by applicant): The annual incidence of invasive aspergillosis (IA) ranges from 10 to15% in allogeneic hematopoietic stem cell (HCT) recipients, with mortality approximating 80%; as such, this infection has become a prominent cause of infection-related death after HCT. Infection now occurs primarily late in the course of allogeneic HCT, after neutrophil engraftment. Epidemiology is consistent with the recent recognition that effective immunity in animal models requires robust CD4+ T helper type-1 (Th1) responses. However, no large studies have been performed to evaluate Aspergillus-specific immune reconstitution. We have developed the methods to measure cellular responses to Aspergillus antigens, and demonstrated reproducibly variable responses in healthy volunteers. We propose a longitudinal immune-reconstitution study to evaluate the hypothesis that CD4+ T cell reconstitution is important to protect from IA late after allogeneic HCT, with multiple factors, including donor transferred immunity, potentially impacting immune reconstitution. Specific aims will be to: 1. Determine if reconstituted cellular immunity predicts risks for, and outcomes of IA. Patients will be enrolled in a longitudinal study to evaluate whether reconstituted cell numbers (DC1, DC2, T cell subtypes, NK cells and B cells) and functional responses to A. fumigatus hyphal antigen predict risks for, and outcomes of IA. In Aim 2, studies will determine the significance of variable frequencies of reactive CD4+ T cells and cytokine patterns in healthy donors. Donor responses will be evaluated to test the hypothesis that low frequencies of IFN-gamma producing CD4+ T cells in healthy people are associated with MHC alleles, potentially including specific Class II haplotypes and/or polymorphism(s) in the Class III region (TNF-alpha gene). The impact of donor responses on recipient reconstitution will be evaluated. Studies in Aim 3 will identify Aspergillus fumigatus antigens presented to healthy human CD4+ T cells. Aspergillus-specific CD4+ T cell clones will be generated from healthy subjects by sequential stimulation with hyphal antigens. Classical HLA-restricted CD4+ clones will be used to screen pooled libraries of A. fumigatus cDNA, with sequential screens identifying individual T-cell antigens. This study will be performed with the goal of defining the mechanisms of post-transplant immune protection against Aspergillus species. This information will be valuable for development of strategies to prevent and treat fungal infections in immunocompromised people.