Early transient suppression of immune checkpoint proteins T-cell immunoglobulin mucin-3 and programmed cell death-1 in peripheral blood lymphocytes after blastocyst transfer is associated with successful implantation
Article In Press
Tao Zhang, Ph.D., Wenyue Zhu, M.Phil., Yiwei Zhao, M.B.B.S., Wing Ching Cheung, Ph.D., Yingyu Liu, Ph.D., Xiaoyan Chen, Ph.D., Yan Du, Dr.P.H., Kam Tong Leung, Ph.D., Yiu Leung Chan, Ph.D., Chi Chiu Wang, Ph.D., Susan Laird, Ph.D., Tin Chiu Li, Ph.D.
To compare the changing peripheral levels of immune checkpoint proteins T-cell immunoglobulin mucin-3 (Tim-3)/galectin-9 (Gal-9), and programmed cell death-1 (PD-1)/programmed death-ligand 1 (PD-L1) over a 9-day period after blastocyst transfer between women who did and did not conceive.
Prospective observational study.
University teaching hospital.
Fifty-one infertile women undergoing day-5 blastocyst transfer.
Serial blood samples obtained on the day of embryo transfer (ET), and 3, 6, and 9 days afterward for measurement of membranous Tim-3 and PD-1 expression on various peripheral lymphocytes by flow cytometry, and serum concentrations of ligands Gal-9 and PD-L1 by ELISA.
Main Outcome Measure(s)
Membranous Tim-3 and PD-1 expression on lymphocytes and serum Gal-9 and PD-L1 concentrations and comparison of results between pregnant and nonpregnant women.
In women who conceived, the measurements exhibited three different types of response:  a transient and statistically significant reduction of Tim-3+NK-like T cells, Tim-3+/PD-1+CD8+ T cells, and Tim-3+/PD-1+CD4+ T cells that returned back to baseline level 9 days after ET;  a reduction followed by steady increase to above baseline level on day 9 (Tim-3+CD56dimNK cells);  a steady increase in expression after ET to reach a level statistically significantly higher than that of the baseline by day 9 (Tim-3+CD56brightNK cells). Women who did not conceive showed no statistically significant fluctuation in any of the parameters measured across the four time pointswith exception of increased Tim-3 expression on NK cells on day 9.
Successful blastocyst implantation is associated with a reduction of Tim-3 and PD-1 expression in peripheral lymphocytes on days 3 and 6 that is no longer apparent on day 9.