Stronger T-Cell Alloreactivity and Diminished Suppressive Capacity of Peripheral Regulatory T Cells in Infertile Women Undergoing In Vitro Fertilization.

Problem: Increasing evidence suggests modulation of the maternal immune response to be essential for successful pregnancy. We studied the immunophenotypic profile and function of peripheral blood T lymphocytes in infertile women undergoing in vitro fertilization (IVF) and fertile control population.

Method: We collected peripheral blood mononuclear cells (PBMC) from infertile patients with recurrent implantation failure (RIF), infertile patients with successful IVF (IVFs), and normal fertile women. Cells were phenotypically analyzed, and the proliferative response and cytokine production were studied in mixed lymphocyte cultures (MLC), using lymphocytes of the own partner, or a third-party male as stimulators cells. To examine the suppressive capacity of regulatory regulatory T cells (Tregs), we performed MLC studies with a CD45(+) fraction depleted for CD4(+) CD25(bright) T cells.

Results: No significant differences in proportions of subsets of circulating T lymphocytes were observed. The proliferative allo-immune response of PBMC of IVF women (RIF and IVFs) was significantly higher, with higher production of T-helper cells (Th1) and Th2 cytokines, compared to the fertile women. This difference in proliferation and cytokine production was associated with a diminished suppressive capacity of Tregs in these women.

Conclusion: The higher allo-immune response of the IVF women compared to fertile women might be the result of a diminished suppressive capacity of Tregs and emphasizes the important role of Tregs during conception.