Cell Therapy, Stem Cells and Tissues Group, Basque Centre for Blood Transfusion and Human Tissues, 48960, Galdakao, Spain.
Cell Therapy, Stem Cells and Tissues Group, Biocruces Bizkaia Health Research Institute, 48903, Barakaldo, Spain.
J Assist Reprod Genet. 2023 Sep;40(9):2241-2250. doi: 10.1007/s10815-023-02862-4. Epub 2023 Jul 12.
To investigate if there are natural killer (NK) cells in endometrial fluid (EF) and their relationship with the endometrial cycle and reproductive parameters.
The population under study consisted of 43 women aged 18-40 undergoing infertility workup at our University Hospital in 2021-2022. The EF samples were obtained at the first visit to our unit, on occasion of the mock embryo transfer. The day of the cycle was considered only in cycles of 27-29 days. An immunophenotype study of NK in EF was performed by flow cytometry analysis. In a subgroup of women, on the same day, NK was studied in EF and peripheral blood.
Our study is the first to evidence NK cells in EF. None of the NK cells observed corresponded to a mature peripheral blood NK cell population (stages 4-5), and neither endometrial nor decidual uNK cells were detected. Nevertheless, we found 2 patient groups with an NK cell subset with a higher expression of CD16+, which could belong to an intermediate or transient stage between the uNK and pbNK NK cell population in the EF. We found that CD16 was significantly increased in the mid-late luteal phase and its correlation with the day of the cycle. The NK immunophenotype was different in EF and peripheral blood.
We described a new component of the EF, the NK cells, whose CD16 activity is closely correlated with the day of the cycle. These cells could play a role in implantation/implantation failure.
研究子宫内膜液（EF）中是否存在自然杀伤（NK）细胞及其与子宫内膜周期和生殖参数的关系。
本研究纳入了 2021 年至 2022 年在我院就诊的 43 名年龄在 18-40 岁之间的不孕患者。EF 样本是在我们单位首次就诊时获得的，即模拟胚胎移植时。仅在 27-29 天的周期中考虑周期日。通过流式细胞术分析对 EF 中的 NK 进行免疫表型研究。在一部分女性中，在同一天，还研究了 EF 和外周血中的 NK。
我们的研究首次证明了 EF 中的 NK 细胞。观察到的 NK 细胞均不属于成熟外周血 NK 细胞群体（阶段 4-5），也未检测到子宫内膜或蜕膜 uNK 细胞。然而，我们发现了 2 组患者的 NK 细胞亚群 CD16+表达较高，这可能属于 EF 中 uNK 和 pbNK NK 细胞群体之间的中间或短暂阶段。我们发现 CD16 在黄体中期和晚期显著增加，与周期日相关。EF 和外周血中的 NK 免疫表型不同。
我们描述了 EF 中的一种新成分，即 NK 细胞，其 CD16 活性与周期日密切相关。这些细胞可能在着床/着床失败中发挥作用。
