Influences of High-Dose Dexamethasone on Regulatory T Cells, Transforming Growth Factor-β1 and Interleukin-10 of Patients with Chronic ITP.

Immune thrombocytopenic purpura (ITP) is an autoimmune disorder and high-dose dexamethasone (HD-DXM) has been used as a first-line therapy for patients with ITP. However, little is known about the role of CD4 + CD25 + regulatory T (Treg) cells, interleukin-10 (IL-10) and transforming growth factor-β1 (TGF-β1) in the pathogenesis of chronic ITP and the effects of HD-DXM on them contained Treg cells, IL-10 and TGF-β1. In this study, we investigated the expressions of Treg cells, IL-10 and TGF-β1 in 26 untreated adult patients with chronic ITP. All patients had thrombocytopenia (platelet count 9 /L) for more than 6 months. We also observed short time changes of Treg cells, IL-10 and TGF-β1 after treatment with HD-DXM in these patients. The results showed that a good initial response to HD-DXM occurred in 24 of the 26 patients with chronic ITP (92.3%): the mean platelet count was (84.9±30.4)×10 9 /L [range, (20∼150) ×10 9 /L] one week after the initiation of treatment. The proportion of CD4 + CD25 + T cells in the peripheral blood of patients with chronic ITP was significantly higher than that in normal controls( P + CD25 high T cells between patients and controls ( P =0.317); but the number of CD 4 + F OXP 3 + T cells in patients was significantly lower than that in controls ( P 4 + CD25 + T cells ( P 4 + CD 25 high T cells ( P + F OXP 3 + T cells ( P P P >0.05) and there was no remarkable change of IL-10 in patients after HD-DXM treatment ( P >0.05). The mRNA levels of Foxp3 and TGF-β1 gene in patients were lower than those of controls ( P P P P P P r =0.403, P =0.041). These results suggest that Foxp3 and TGF-β1 gene are deficient in chronic ITP and the immunosuppressive therapy of glucocorticoids could improve the expression levels of these genes.