Increasing circulating T-cell activation markers are linked to subsequent implantation failure after transfer of in vitro fertilized embryos

PROBLEM: Implantation determines success of in vitro fertilization (IVF) and embryo transfer (ET) cycles. Data are accumulating to support a role of the immune system in implantation. Most of the literature addresses the importance of natural killer (NK) cells in this process. The purpose of the current study is to examine the role of circulating T cells in implantation failure. METHOD OF STUDY: Blood from 22 women undergoing IVF/ET during November, 2001, was drawn on cycle day 9 and analyzed for the percentage of circulating T cells expressing the activation markers CD69+ and human leukocyte antigen (HLA)-DR and the suppressor marker CD11b using immunofluorescence and flow cytometry. These results were compared with total percentage circulating CD3, CD4 and CD8 cells as well as NK cells and pregnancy outcome that cycle. RESULTS: Infertile women had significantly greater expression of the activation marker of CD69+ among CD8+ and CD4+ T cells and HLA-DR among CD4 cells than fertile women. No difference in expression of T cell suppressor marker of CD11b was noted when infertile and fertile women were compared. No correlations were observed when activated T cells were compared with circulating CD3+, CD4+, CD8 +, activated NK cells and NK cytotoxicity. CD3 + 4 + HLA-DR + was expressed significantly less among successfully pregnant compared with unsuccessfully pregnant women. CONCLUSION: T-cell activation markers CD 69 + and HLA-DR + are associated with increased implantation failure after IVF/ET.