Uncontrolled diabetes, immune dysregulation and tuberculosis

描述(申请人提供)：日益流行的2型糖尿病(DM)越来越被认为是对结核病(TB)控制的威胁。流行病学研究一直表明，糖尿病患者更容易感染结核病，但其潜在机制尚不清楚。我们最近发现，糖尿病和结核病患者在用结核分枝杆菌提取物刺激白细胞后，有1型细胞因子的高表达。尽管增加了这种明显的保护性反应，但在治疗过程中，患有糖尿病的结核病患者比非糖尿病患者需要更长的时间来清除结核分枝杆菌。干扰素水平越高？已经确诊的结核分枝杆菌感染和慢性糖尿病小鼠体内的水平(和更高的细菌负荷)被认为是先天反应延迟的结果。这些观察使我们假设，在患有DM的人类中，低效的细菌遏制是由于免疫功能障碍，包括无法发起及时的反应，和/或特定的免疫缺陷导致的反应效率较低。为了探索这些可能性，我们提出了一项前瞻性的病例对照研究，考察新诊断的糖尿病控制不佳的结核病患者(TB-DMP)与没有糖尿病和正常血糖的患者(TB-noDM)对分枝杆菌抗原的回忆反应是否不同。参与者的全血将与结核分枝杆菌全细胞裂解液孵育，在召回反应的前24小时内，将在5个时间点收集他们被刺激的血浆和白细胞。我们将在三个阶段的背景下评估细胞因子和趋化因子分泌的动态(AIM 1)和一组扩展的免疫系统组件(AIM 2)的差异mRNA表达：i)单核细胞的激活和分化为抗原提呈细胞(先天反应)，ii)记忆T淋巴细胞的激活，可能表达与保护或加重TB(适应性反应)相关的细胞因子，以及iii)巨噬细胞或细胞毒性T淋巴细胞表达效应器，最终杀死MTB(效应器反应)。TB-DMP患者回忆反应的时间和/或类型的改变将通过使用广义估计方程的纵向分析来确定。最终的模型将考虑可能的混杂因素和效果修饰符。这些结果将进一步提供在TB-DMP患者中表达发生变化的候选分子的列表，并为在未来的研究中选择最佳时间点来研究每一阶段的反应奠定基础。长期目标是了解解释结核病和糖尿病之间联系的机制，为改善糖尿病患者的结核病管理和预防提出新的建议。我们有能力提出对影响全球数百万患者的疾病进行研究，这取决于我们能否接触到36%患有糖尿病的结核病患者，以及我们靠近结核病诊所的最先进的实验室。公共卫生相关性：随着2型糖尿病大流行的加速，越来越多的文献报告这些患者对肺结核病的易感性增加。在这个项目中，我们将探索糖尿病控制不善是否会影响对分枝杆菌的免疫反应。这是了解这两种疾病之间联系的生物学基础的第一步，从而设计出更有效地管理这些患者的策略。

DESCRIPTION (provided by applicant): The growing pandemic of type 2 diabetes (DM) is being increasingly recognized as a threat to tuberculosis (TB) control. Epidemiological studies consistently show DM patients are more susceptible to TB, but the underlying mechanism is unclear. We recently showed that patients with DM and TB have hyperexpression of type 1 cytokines after stimulating white blood cells with a Mycobacterium tuberculosis extract. Despite mounting this apparently protective response, TB patients with DM take longer to clear M. tuberculosis during the course of treatment than non-DM patients. The higher IFN- ? levels (and higher bacterial burden) seen in mice with established M. tuberculosis infection and chronic diabetes is thought to be the consequence of a delayed innate response. These observations led us to hypothesize that inefficient bacterial containment in humans with DM is due to dysfunctional immunity that involves either an inability to mount a timely response, and/or a less effective response resulting from a specific immune defect. To explore these possibilities we propose a prospective case-control study examining whether newly-diagnosed TB patients with poorly- controlled DM (TB-DMp) differ in the recall response to a mycobacterial antigen from those with no DM and euglycemia (TB-noDM). Whole blood from participants will be incubated with M. tuberculosis whole cell lysate, and their stimulated plasma and white blood cells will be harvested at five time points during the first 24h of this recall response. We will evaluate the dynamics of cytokine and chemokine secretion (Aim 1) and the differential mRNA expression of an extended panel of immune system components (Aim 2) in the context of three stages: i) monocyte activation and differentiation into antigen presenting cells (innate response), ii) activation of memory T lymphocytes that may express cytokines associated with protection or exacerbation of TB (adaptive response), and iii) expression of effectors by macrophages or cytotoxic T lymphocytes that ultimately kill MTB (effector response). Alterations in the timing and/or type of recall response in TB-DMp patients will be established by longitudinal analysis using generalized estimating equations. The final model will take into account possible confounders and effect modifiers. These results will further provide a list of candidate molecules with altered expression in TB-DMp patients and the basis for selection of optimal time points to study each stage of response in future studies. The long-term goal is to understand the mechanisms explaining the association between TB and DM, to develop new recommendations for improved management and prevention of TB in DM patients. Our ability to propose studies on diseases that affects millions of patients worldwide rests on our access to a population of TB patients where 36% present DM, and our state-of-the art laboratory which is close to the TB clinics. PUBLIC HEALTH RELEVANCE: As the type 2 DM pandemic accelerates, there is a growing body of literature reporting increased susceptibility of these patients to pulmonary TB. In this project we will explore whether poor diabetes control compromises the immune response to mycobacteria. This is the first step towards understanding the biological basis of the association between these two diseases, and therefore designing strategies to manage these patients more efficiently.