Shenzhen Key Laboratory of Reproductive Immunology for Peri-implantation, Shenzhen Zhongshan Institute for Reproduction and Genetics, Shenzhen Zhongshan Urology Hospital, Shenzhen, China.
Department of Paediatrics & Adolescent Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China.
Am J Reprod Immunol. 2021 Jun;85(6):e13388. doi: 10.1111/aji.13388. Epub 2021 Jan 27.
Unexplained recurrent miscarriage (uRM) is defined as two or more spontaneous abortions prior to 20 weeks of gestation with unknown etiology. Peripheral blood natural killer (pNK) cells contact with the villus and exert important role in normal pregnancy. However, it is still controversial about the association between pNK cytotoxicity and uRM, and the underlying mechanism remains unknown so far.
In this study, we aim to compare the percentage, immunophenotype, and function of pNK cells between patients with uRM and fertile controls. The peripheral blood was collected from 49 patients with uRM and 11 fertile women in their middle luteal phase of the menstrual cycle. pNK cells were co-cultured with K562 cells at different cell ratios to measure the cytotoxicity. The percentage of CD3 CD56 , CD3 CD56 , and CD3 CD56 pNK was analyzed by flow cytometry and quantified to evaluate the expression of cytotoxic granules (granzyme B, granulysin, and perforin), and the cell surface receptors related to pNK cell cytotoxicity (NKG2D, NKp30, NKp46, CD158a, and CD158b) were also detected.
The general linear model analysis showed that pNK cell cytotoxicity in patients with uRM was significantly lower than that in fertile controls. In addition, the ratios of NKG2D/CD158a, NKp30/CD158a, and NKp46/CD158a in CD3 CD56 pNK subsets were significantly lower in uRM group than that in fertile control. The logistical regression analysis showed that the reduced NKp30/CD158a, NKp46/CD158a ratios in CD3 CD56 pNK subsets were significantly associated with uRM.
Our results suggested that a low pNK cytotoxicity, which is mediated by inhibitory signals, might be associated with uRM.
不明原因的反复性流产（uRM）定义为两次或两次以上发生在妊娠 20 周之前的自发性流产，且病因不明。外周血自然杀伤（pNK）细胞与绒毛接触，并在正常妊娠中发挥重要作用。然而，pNK 细胞的细胞毒性与 uRM 之间的相关性仍存在争议，其潜在机制至今仍不清楚。
在这项研究中，我们旨在比较 uRM 患者和生育能力正常的对照组之间 pNK 细胞的百分比、免疫表型和功能。采集 49 例 uRM 患者和 11 例生育中期妇女的外周血，将 pNK 细胞与 K562 细胞以不同的细胞比例共培养，以测量细胞毒性。用流式细胞术分析 CD3 CD56 、CD3 CD56 、CD3 CD56 pNK 细胞的百分比，并进行量化以评估细胞毒性颗粒（颗粒酶 B、颗粒溶素和穿孔素）的表达，同时还检测与 pNK 细胞细胞毒性相关的细胞表面受体（NKG2D、NKp30、NKp46、CD158a 和 CD158b）。
一般线性模型分析显示，uRM 患者的 pNK 细胞毒性明显低于生育能力正常的对照组。此外，CD3 CD56 pNK 亚群中 NKG2D/CD158a、NKp30/CD158a 和 NKp46/CD158a 的比值在 uRM 组明显低于对照组。逻辑回归分析显示，CD3 CD56 pNK 亚群中 NKp30/CD158a、NKp46/CD158a 比值的降低与 uRM 显著相关。
我们的结果表明，由抑制性信号介导的低 pNK 细胞毒性可能与 uRM 有关。
