In‐vitro Fertilization and Embryo Transfer and Cellular Immunity: Study on Cytokines and T Lymphocyte subpopulations in IVF‐ET Cycles

Objectives: To determine whether peripheral T lymphocyte subpopulations and cytokines change during in‐vitro fertilization and embryo transfer (IVF‐ET) cycles and to evaluate them with regard to pregnancy status and types of infertility. Methods: Peripheral T lymphocyte subpopulations and cytokines in 33 consecutive cycles of IVF‐ET were examined. All the women were stimulated with purified FSH and hCG after pituitary suppression with GnRH agonist. Peripheral blood samples were collected before FSH administration, on the day of hCG administration, the day of ET (day 2), day 6 and day 15. We measured plasma estradiol and progesterone levels and plasma interferon‐γ, interleukin‐4 (IL‐4), IL‐10 and IL‐12 levels. Peripheral T lymphocyte subpopulations, T helper type 1 and 2 cells (Th1 and Th2) and T cytotoxic type 1 and 2 cells (Tc1 and Tc2), were analyzed with three‐color flowcytometry. Results: There were no changes in the plasma levels of the cytokines or in the proportions of Th1 and Th2 and the proportions of Tc1 and Tc2 in peripheral blood lymphocytes during the IVF‐ET cycles. In women with endometriosis, the ratios of Tc1 to CD8 + lymphocytes and the Tc1 to Tc2 ratios before FSH administration were much higher than in women without endometriosis. The ratios of Tc1 to CD8 + lymphocytes were significantly lower in the patients with endometriosis who became pregnant. Conclusions: Peripheral cellular immunity does not change during IVF‐ET cycles. In women with endometriosis, the peripheral Tc1 subpopulation is more predominant before ovarian stimulation, suggest‐ ing that the ratio of Tc1 before ovarian stimulation could be an indicator of fecundity for women with endometriosis.