Postnikoff Cameron K, Huisingh Carrie, McGwin Gerald, Nichols Kelly K
a School of Optometry , University of Alabama at Birmingham , Birmingham , Alabama , USA.
Curr Eye Res. 2018 Oct;43(10):1253-1259. doi: 10.1080/02713683.2018.1500611. Epub 2018 Aug 9.
Leukocytes accumulate in the eye with sleep, but little is known about the presence or absence of leukocytes in awake, open eye tears. This study sought to compare normal and dry eye subjects for daily variation in open eye leukocyte composition.
Ten normal subjects and nine dry eye subjects were enrolled. Subjects were trained for self-collection of tear samples using an ocular surface wash with 5 mL of phosphate buffered saline per eye. Subjects performed washes at awakening, between 8 and 9 am, between 11 am and 12 pm, and between 4 pm and 5 pm on four separate days. Leukocytes were isolated from the wash and were counted with a cell counter before staining with an anti-CD45 antibody and viability stain. Stained leukocytes were then analyzed via flow cytometry. Side scatter characteristics were used to distinguish granulocytes from lymphocytes. Results were interpreted both by time of wash as well as time from awakening.
At awakening, dry eye subjects had approximately twice as many recovered leukocytes and had a statistically significantly higher granulocyte-to-lymphocyte ratio as compared to normals. Leukocytes were rapidly cleared from the eye with a significant decrease in leukocyte counts at the 8 am time point as compared to awakening. Leukocyte counts across all open eye time points appeared to be consistent, with no differences between normal and dry eye subjects.
There is a low level, constitutively expressed population of leukocytes in the open eye tears of normal and dry eye subjects. Higher levels of granulocytes in dry eye disease subjects warrants further investigation into this population of cells, and their role in homeostasis and dysregulation.
睡眠时白细胞会在眼部积聚，但对于清醒状态下睁眼时泪液中白细胞的存在与否知之甚少。本研究旨在比较正常人和干眼患者睁眼时白细胞组成的每日变化情况。
招募了10名正常受试者和9名干眼受试者。训练受试者使用每只眼睛5毫升磷酸盐缓冲盐水进行眼表冲洗以自行采集泪液样本。受试者在四个不同日期的觉醒时、上午8点至9点之间、上午11点至12点之间以及下午4点至5点之间进行冲洗。从冲洗液中分离白细胞，在用抗CD45抗体和活力染料染色前用细胞计数器进行计数。然后通过流式细胞术分析染色后的白细胞。利用侧向散射特性区分粒细胞和淋巴细胞。结果根据冲洗时间以及觉醒后的时间进行解读。
觉醒时，干眼受试者回收的白细胞数量约为正常人的两倍，且粒细胞与淋巴细胞的比例在统计学上显著高于正常人。白细胞从眼部迅速清除，与觉醒时相比，上午8点时白细胞计数显著下降。所有睁眼时间点的白细胞计数似乎一致，正常人和干眼受试者之间没有差异。
正常人和干眼受试者的睁眼泪液中存在低水平的、组成性表达的白细胞群体。干眼疾病受试者中粒细胞水平较高，值得进一步研究这群细胞及其在体内稳态和失调中的作用。
