Analysis of the Mediating Effect of Vitamin D via the TGF-β1/Treg Pathway in the Pathogenesis of Childhood Primary Immune Thrombocytopenia.

OBJECTIVE

To investigate the role of vitamin D (VitD), transforming growth factor-β1 (TGF-β1), and regulatory T cells (Treg) in the pathogenesis of primary immune thrombocytopenia (ITP) in children.

METHODS

From February 2023 to September 2024, 51 children with ITP and 44 healthy children from the First Affiliated Hospital of Xinxiang Medical College were enrolled. The serum levels of VitD and TGF-β1 and the percentage of Treg cells in peripheral blood were measured.

RESULTS

There was no significant difference in age and sex between the two groups (p  > 0.05). ITP group VitD, TGF-β1, and the level of Treg cells were significantly lower than those of the control group (p  < 0.05). In the ITP group, VitD and TGF-β1 (r = 0.421), Treg cells (r = 0.516), TGF-β1 and Treg cells (r = 0.563), and platelet count (r = 0.399, 0.305, 0.361, respectively, p  < 0.05). The median model analysis showed that VitD had a significant negative overall effect on ITP risk (regression coefficient = -0.014, p = 0.004), but its direct effect was no longer significant after the introduction of TGF-β1 and Treg, suggesting a complete mediation effect, where the path of VitD affecting ITP via TGF-β1 is significant (effect value = -0.015, p  < 0.001), but the mediated pathway involving Treg was not statistically significant.

CONCLUSION

There is dysregulation of VitD, TGF-β1, and Treg cells in newly diagnosed children with ITP. TGF-β1 may be a key mediator of the regulation of ITP by VitD, suggesting the potential value of TGF- β1 as an intervening target.