Abstract
OBJECTIVE: This study aimed to assess associations between the peripheral natural killer (pNK) cell percentage and women's age, body mass index (BMI), serum anti-Müllerian hormone (AMH), autoantibodies, and thrombophilia-related markers among infertile women undergoing in vitro fertilization (IVF). METHODS: We enrolled 91 infertile Korean women (mean age 37.7 years [range, 26 to 48]) whose pNK cell percentage was measured either before IVF (22 women) or after ≥1 failed embryo transfer (ET) (69 women) between May 2017 and November 2022 at a single university hospital. Levels of antiphospholipid antibodies, thyroid-stimulating hormone (TSH), anti-thyroglobulin, anti-microsome, anti-nuclear antibodies, antithrombin III, protein C, and protein S were measured. Serum AMH was tested within 1 year of the pNK cell measurement. RESULTS: The mean pNK cell percentage was 16.69%±7.60%, and 68 women (74.7%) had pNK ≥12%. Univariate analysis of five continuous variables (age, BMI, AMH, TSH, and number of failed ETs) showed that the pNK percentage was negatively associated with BMI (r=-0.213, p=0.043) and AMH (r=-0.213, p=0.049). Among 11 autoantibodies/markers, only β2-glycoprotein 1 immunoglobulin G (IgG) antibody was associated with a difference in pNK percentage (9.75%±4.72% in 4 positive vs. 17.63%±7.77% in 76 negative women, p=0.022). In a multivariate analysis of BMI, AMH, and β2-glycoprotein 1 IgG positivity, AMH (B=-0.249, p=0.028) was significantly negatively associated with the pNK percentage. CONCLUSION: The percentage of pNK cells is closely associated with serum AMH levels.