Embryo Implantation 6 Female 6 Humans 6 Pregnancy 6 Recurrent spontaneous abortions female 6 human 6 Abortion, Habitual 4 CD4+ T lymphocyte 4 Chemokines 4 Endometrium 4 Immune Tolerance 4 Leukocytes, Mononuclear 4 T lymphocyte 4 Trophoblasts 4 Vasoactive Intestinal Peptide 4 article 4 nidation 4 peripheral blood mononuclear cell 4 priority journal 4 recurrent abortion 4 spontaneous abortion 4 trophoblast 4 vasoactive intestinal polypeptide 4 Adult 2 Antigens 2 CD4-Positive T-Lymphocytes 2 Cell Communication 2 Cells, Cultured 2 Chemokine CCL5 2