Keratoconjunctivitis Sicca and Conjunctival Antigen-Presenting Cells

干燥性角膜结膜炎（KCS），也称为干眼综合征，是一种慢性进行性炎性眼部疾病，其特征是角膜和结膜表面的慢性干燥和炎症。KCS是最常见的眼病之一。发病机制包括干燥激活眼表应激通路，导致上皮细胞、上皮内淋巴细胞和浸润性CD4+ T细胞产生炎性细胞因子。最近有报道称，在干燥综合征相关的KCS患者中，成熟抗原提呈细胞（APCs）的数量与疾病严重程度和结膜杯状细胞损失相关。然而，这是否也适用于更常见的KCS，还有待确定。该研究项目的目的是验证结膜中成熟apc的数量与KCS患者疾病严重程度相关的假设。主要目的是比较来自KCS患者和对照组的印象细胞学样本中成熟APCs的数量，并将这些发现与临床严重程度的标志物联系起来。次要目的是(1)比较apc单个亚群（树突状细胞、巨噬细胞、单核细胞）的数量，并将其与临床结果相关联；(2)比较KCS患者和对照组印象细胞学样本中泪MUC5AC（粘蛋白5AC，杯状细胞的主要分泌粘蛋白）的浓度和杯状细胞的数量，并将结果与疾病标志物相关联。中度至重度KCS患者和健康对照者将使用既定问卷对症状进行检查。泪膜的数量和质量将通过Schirmer试验、泪膜半月板高度测量和荧光素泪膜破裂时间来确定。采用ELISA法测定Schirmer试纸条提取的泪液蛋白MUC5AC浓度。用荧光素和丽丝胺绿染色评价眼表质量。此外，结膜细胞将通过印迹细胞学收集，以测量结膜杯状细胞密度，并通过流式细胞术评估趋化因子受体在免疫细胞中的表达。通过确定某些APC群体的成熟是否与杯状细胞丢失和临床严重程度相关，该研究结果将增强我们对KCS病理生理学的理解。发现具有更大疾病特异性的生物标志物将代表诊断分类的重大进展。此外，研究结果可能有助于监测疾病进展，并验证治疗方案的疗效或可能的毒性。

Keratoconjunctivitis sicca (KCS), also known as dry eye syndrome, is a chronic, progressive, inflammatory ocular disease characterized by chronic dryness and inflammation of the corneal and conjunctival surfaces. KCS is one of the most prevalent eye diseases. The pathogenesis includes activation of stress pathways on the ocular surface by desiccation resulting in production of inflammatory cytokines by epithelial cells, intraepithelial lymphocytes and infiltrating CD4+ T cells. It has recently been reported that the number of mature antigen presenting cells (APCs) correlated with disease severity and conjunctival goblet cell loss in patients with KCS related to Sjogren’s syndrome. However, it remains to be established, whether this also applies to more common forms of KCS.The goal of the research project is to test the hypothesis that the number of mature APCs in the conjunctiva correlates with disease severity in patients with KCS. The primary objective is to compare the number of mature APCs in impression cytology samples from patients with KCS and controls and to correlate the findings with markers of clinical severity. Secondary objectives are (1) to compare the numbers of individual subgroups of APCs (dendritic cells, macrophages, monocytes) and correlate these with clinical findings and (2) to compare tear MUC5AC (Mucin 5AC, a major secreted mucin of goblet cells) concentration and the number of goblet cells in impression cytology samples from patients with KCS and controls and to correlate the findings with disease markers.Patients with moderate to severe KCS and healthy control subjects will be examined with regard to symptoms using established questionnaires. Quantity and quality of tear film will be determined by Schirmer’s test, tear meniscus height measurement and fluorescein tear break-up time. MUC5AC concentration in tear protein extracted from Schirmer test strips will be measured by ELISA. Quality of the ocular surface will be assessed by fluorescein and lissamine green staining. Moreover, conjunctival cells will be harvested by impression cytology to measure conjunctival goblet cell density and to evaluate chemokine receptor expression in immune cells with flow cytometry.The findings of the study will enhance our understanding of the pathophysiology of KCS by determining if maturation of certain APC populations is associated with goblet cell loss and clinical severity. Discovering biomarkers with greater disease specificity will represent a major advance in diagnostic classification. Moreover, the findings of the study may become helpful to monitor disease progression and to verify the efficacy or the possible toxicity of the therapeutic regimen.