Evaluation of 1,25(OH)2D3 Effects on FOXP3, ROR-γt, GITR, and CTLA-4 Gene Expression in the PBMCs of Vitamin D-Deficient Women with Unexplained Recurrent Pregnancy Loss (URPL)

Background: Vitamin D insufficiency and deficiency can be associated with adverse effects on fetus and pregnancy outcomes. This study aimed at evaluating the effect of 1,25VitD3 on specific transcription factor and markers of Tregs and Th17 cells in the PBMCs of women with URPL as a case group and the PBMCs of healthy women as a control group. Methods: Samples from 20 non-pregnant patients with a history of URPL were compared to 20 normal non-pregnant women. PBMCs were divided into three wells for each subject in the presence of 1,25VitD3 (50 nM, for 16 hours), PHA (10 µM; positive control) and without any treatment (negative control). By Real-time PCR (Taqman assay), specific transcription factors of Tregs and Th17 cells, FOXP3, ROR-γt, GITR, and CTLA-4 mRNA expressions in two groups were measured. Results: FOXP3/ROR-γt mRNA expression in PBMCs decreased significantly in women experiencing URPL compared to the control group (p = 0.0001). Although 1,25VitD3 (50 nM) increased FOXP3 gene expression (p = 0.0001), it did not significantly affect ROR-γt gene expression. 1,25VitD3 treatment significantly increased FOXP3/ROR-γt mRNA expression from baseline in the PBMCs of the fetal loss group compared to that of the control group (p = 0.01). The 1,25VitD3 also increased GITR gene expression (p = 0.017) in the PBMCs of URPL women compared to the controls. Conclusion: Vitamin D deficiency may be a contributor to recurrent pregnancy loss and suggests that the supplementation of women with Vitamin D pre-pregnancy may be protective against URPL via affecting Tregs signature genes, FOXP3 and GITR.