Xiaoyan Chen1, Najat Mariee2, Lingming Jiang3, Yingyu Liu1, Chi Chiu Wang4, Tin Chiu Li5, Susan Laird2. 1. Department of Obstetrics and Gynecology, Chinese University of Hong Kong, Shatin, Hong Kong. 2. Biomolecular Sciences Research Center, Sheffield Hallam University, Sheffield, United Kingdom. 3. Department of Obstetrics and Gynecology, Shenzhen People's Hospital, Second Affiliated Hospital of Jinan University, Shenzhen, China. 4. Department of Obstetrics and Gynecology, Chinese University of Hong Kong, Shatin, Hong Kong; Li Ka Shing Institute of Health Science, Chinese University of Hong Kong, Shatin, Hong Kong; School of Biomedical Science, Chinese University of Hong Kong, Shatin, Hong Kong. 5. Department of Obstetrics and Gynecology, Chinese University of Hong Kong, Shatin, Hong Kong. Electronic address: tinchiu.li@gmail.com.
Abstract
BACKGROUND: Uterine natural killer cells are the major leukocytes present in the periimplantation endometrium. Previous studies have found controversial differences in uterine natural killer cell percentage in women with recurrent reproductive failure compared with fertile controls. OBJECTIVE: We sought to compare the uterine natural killer cell percentage in women with recurrent reproductive failure and fertile controls. STUDY DESIGN: This was a retrospective study carried out in university hospitals. A total of 215 women from 3 university centers participated in the study, including 97 women with recurrent miscarriage, 34 women with recurrent implantation failure, and 84 fertile controls. Endometrial biopsy samples were obtained precisely 7 days after luteinization hormone surge in a natural cycle. Endometrial sections were immunostained for CD56 and cell counting was performed by a standardized protocol. Results were expressed as percentage of positive uterine natural killer cell/total stromal cells. RESULTS: The median uterine natural killer cell percentage in Chinese ovulatory fertile controls in natural cycles was 2.5% (range 0.9-5.3%). Using 5th and 95th percentile to define the lower and upper limits of uterine natural killer cell percentage, the reference range was 1.2-4.5%. Overall, the groups with recurrent reproductive failure had significantly higher uterine natural killer cell percentage than the controls (recurrent miscarriage: median 3.2%, range 0.6-8.8%; recurrent implantation failure: median 3.1%, range 0.8-8.3%). However, there was a subset of both groups (recurrent miscarriage: 16/97; recurrent implantation failure: 6/34) that had lower uterine natural killer cell percentage compared to fertile controls. CONCLUSION: A reference range for uterine natural killer cell percentage in fertile women was established. Women with recurrent reproductive failure had uterine natural killer cell percentages both above and below the reference range.
BACKGROUND: Uterine natural killer cells are the major leukocytes present in the periimplantation endometrium. Previous studies have found controversial differences in uterine natural killer cell percentage in women with recurrent reproductive failure compared with fertile controls. OBJECTIVE: We sought to compare the uterine natural killer cell percentage in women with recurrent reproductive failure and fertile controls. STUDY DESIGN: This was a retrospective study carried out in university hospitals. A total of 215 women from 3 university centers participated in the study, including 97 women with recurrent miscarriage, 34 women with recurrent implantation failure, and 84 fertile controls. Endometrial biopsy samples were obtained precisely 7 days after luteinization hormone surge in a natural cycle. Endometrial sections were immunostained for CD56 and cell counting was performed by a standardized protocol. Results were expressed as percentage of positive uterine natural killer cell/total stromal cells. RESULTS: The median uterine natural killer cell percentage in Chinese ovulatory fertile controls in natural cycles was 2.5% (range 0.9-5.3%). Using 5th and 95th percentile to define the lower and upper limits of uterine natural killer cell percentage, the reference range was 1.2-4.5%. Overall, the groups with recurrent reproductive failure had significantly higher uterine natural killer cell percentage than the controls (recurrent miscarriage: median 3.2%, range 0.6-8.8%; recurrent implantation failure: median 3.1%, range 0.8-8.3%). However, there was a subset of both groups (recurrent miscarriage: 16/97; recurrent implantation failure: 6/34) that had lower uterine natural killer cell percentage compared to fertile controls. CONCLUSION: A reference range for uterine natural killer cell percentage in fertile women was established. Women with recurrent reproductive failure had uterine natural killer cell percentages both above and below the reference range.
Authors: Ee Von Woon; Orene Greer; Nishel Shah; Dimitrios Nikolaou; Mark Johnson; Victoria Male Journal: Hum Reprod Update Date: 2022-06-30 Impact factor: 17.179