CD8A and cholesteryl ester measurement: We found that the proportions of endometrial CD56+ NK cells (3.5 ± 1.6% vs. 5.1 ± 3.4%, P < 0.001) (Figure 3B), CD8+ T cells (1.6 ± 1.0% vs. 2.0 ± 1.3%, P = 0.019) (Figure 3C), Foxp3+ Treg cells (0.1 ± 0.1% vs. 0.2 ± 0.1%, P = 0.006) (Figure 3F), and T-bet+ Th1 cells (1.1 ± 0.8% vs. 1.5 ± 1.2%, P = 0.015) (Figure 3G) were significantly decreased in patients with persistent CE after PRP treatment.