DIFFERENTIAL EXPRESSION OF T REGULATORY CELLS IS CONTROLLED BY HORMONAL FACTORS: ITS ROLE IN THE REPRODUCTIVE FAILURE.

L.ARRUVITO; L.BOERO; A.NOVOA; L.FAINBOIM

Córdoba, Argentina

Congreso; VII Congreso Latinoamericano de Inmunología. ALAI. Argentina, Córdoba, Octubre 2005; 2005

The CD4+CD25+ T regulatory cells (Treg) are known to play an important role in the semi-allogeneic response along normal pregnancy. Hormonal changes provide one explanation for the enhanced maternal Treg development during fetal gestation. In particular, estradiol and progesterone have been implicated in promoting immunosuppression. We analyzed in peripheral blood, the phenotype, functional characteristics and the effect of the menstrual cycle on Treg. The frequency of CD4+CD25+ detected by flow cytometry during the luteal phase of 46 healthy women was significantly higher than the observed in 120 patients with recurrent spontaneous abortion (RSA), 19.70 ± 0.598 vs. 16.29 ± 0.326, *p < 0.0001. The analysis in the late follicular phase vs. luteal phase showed a higher percentage of Treg in the follicular phase (21.82 ± 1. 41 vs. 16.13 ± 0.90,    *p < 0.01; n=16 cycles). To confirm the suppressor activity, CD4+CD25- and CD4+CD25+ were purified by magnetic beads and assayed in a mixed lymphocyte reaction with autologous APC and allogeneic PBMCs. A dose dependent suppression was observed with different amount of CD4+CD25+ (70%, 72%, 61% and 48% with ratios of 1:1, 1:0.5, 1:0.25 and 1:0.12 respectively). We concluded that Treg cells seem to be regulated by hormonal factors. In addition their down modulation observed in RSA patients might contribute to the reproductive failure.