[The measurement of proportion and function of regulatory T cells in unexplained recurrent spontaneous abortion]

To investigate the proportion and function of CD(4)(+)CD(25)(+) regulatory T cells (CD(4)(+)CD(25)(+) Tr) in unexplained recurrent spontaneous abortion (URSA).

(1) Proportion measurement: the proportion of CD(4)(+)CD(25)(+) Tr cells in peripheral blood was measured by double-label flow cytometric analysis. The samples were taken from 15 URSA women, 15 normal non-pregnancy women and 13 normal pregnancy women. (2) Function measurement: CD(4)(+)CD(25)(+) Tr cells and CD(4)(+)CD(25)(-) T cells were extracted from peripheral blood lymphocytes by the microbeads separation. The purity of CD(4)(+)CD(25)(+) Tr cells and CD(4)(+)CD(25)(-) T cells was measured by flow cytometry. The growth inhibitory effect of CD(4)(+)CD(25)(+) Tr cells on CD(4)(+)CD(25)(-) T cells was assessed in vitro.

The proportion of CD(4)(+)CD(25)(+) Tr cells was decreased significantly in URSA women (6.9 +/- 1.8)% than that in normal non-pregnancy women [(10.8 +/- 1.1)%] (P<0.05) and normal pregnancy women [(11.2 +/- 1.4)%] (P<0.01). Moreover, the suppressive rate of CD(4)(+)CD(25)(+) Tr cells was decreased significantly in URSA women (75 +/- 6)% than that in normal non-pregnancy women [(89 +/- 4)%] (P<0.05) and normal pregnancy women [(90 +/- 4)%] (P<0.01). However, with respect to the proportion and function of CD(4)(+)CD(25)(+) Tr cells, there was no significant difference between normal non-pregnancy women and normal pregnancy women (P > 0.05).

The results suggest that decrease in proportion and function of CD(4)(+)CD(25)(+) Tr cells may be associated with URSA.