Galectin-1 reduction and changes in T regulatory cells may play crucial roles in patients with unexplained recurrent spontaneous abortion.

To investigate the changes of Galectin-1 and T-lymphocyte phenotypes in unexplained recurrent spontaneous abortion (URSA). Totally 60 participants were recruited and divided into 3 groups in average: pregnant patients with URSA (URSA group), normal early pregnant women with induced abortion (IA group) and normal non-pregnant women (control group). After the tissue and blood sample were collected, Galectin-1 was measured using enzyme-linked immunosorbent assay. Then the proportion of T regulatory cells was determined by flow cytometry. The expression levels of Galectin-1 in IA group and URSA group was significantly higher than that in the control group (24.30 ± 3.06 and 6.23 ± 2.41 vs. 1.30 ± 0.66, P < 0.05). Besides, the expression level of Galectin-1 in URSA group was lower than that in IA group (P < 0.05). The percentage of CD4(+)CD25(+)Foxp3(+) Tregs was lower in URSA group than IA group (0.77 ± 0.31 vs. 1.00 ± 0.35, P < 0.05) and the ratio of CD4(+)CD25(+)Foxp3(+)/CD4(+) in URSA group was also obviously lower than that in IA and control group (P < 0.05). Galectin-1 and CD4(+)CD25(+)Foxp3(+) may play essential roles in maintaining a normal pregnancy and their reduction may involve in the pathogenesis of URSA.