OBJECTIVE

To detect the expression levels of CD4(+) CD25(+) CDl27(low) Treg cells, TGF-β and Notch1 mRNA in peripheral blood of the patients with idiopathic thrombocytopenic purpura (IPT) before and after treatment, and to investigate their significance in the pathogenesis of ITP.

METHODS

Peripheral blood was collected from 30 newly diagnosed patients with ITP and 20 normal controls, then the number of CD4(+) CD25(+) Treg and CD4(+) CD25(+) CDl27(low) Treg were detected by the flow cytometry. Plasma TGF-β level was determined by ELISA. Total RNA was extracted and the expression level of Notch1 mRNA was measured by real-time Q-PCR.

RESULTS

The expression levels of CD4(+) CD25(+) CDl27(low) Treg and CD4(+) CD25(+) Treg in newly diagnosed ITP group were significantly lower than those in normal controls. After treatment, the proportion of Tregs increased to (5.17% ± 0.74%) and (4.16% ± 0.68%), and was higher than that in newly diagnosed patients. The TGF-β level in peripheral blood of newly-diagnosed patients was obviously lower than that in normal controls, and was (961.53 ± 60.10) ng/L after treatment and was significantly higher than that in newly diagnosed patients; the expression level of Notch1 mRNA in peripheral blood of patients in newly-diagnosed group was obviously lower than that in control, and was (1.35 ± 0.10) after treatment that was higher than that in newly-diagnosed group. After treatment, the proportion of Treg cells, level of TGF-β and erpression level of Notch1 mRNA in effective group were higher than those in effective group, improved group and ineffective group, and there was significant difference (P <0.01). The expression level of TGF-β and Notch1 mRNA in ITP patients possitively correlated to CD4(+) CD25(+) CDl27(low) (P <0.01).

CONCLUSIONS

The levels of CD4(+) CD25(+) CDl27(low) Treg, TGF-βand Notch1 mRNA in peripheral blood of the patients with ITP are significantly lower than those of normal control, suggesting that there is significant abnormal immunoregulation in ITP patients. In the ITP patients the levels of CD4(+) CD25(+) CDl27(low) Treg postively correlated with Notch1 mRNA expression, indicating that Notch signal may be revalent to Treg's immunosuppression function.