Aberrant Phosphorylation of STAT3 Protein of the CD4+ T Cells in Patients with Primary Immune Thrombocytopenia

Background: Primary immune thrombocytopenia (ITP) is an autoimmune mediated bleeding disorder characterized by decreased platelet count. Dysfunctional cellular immunity is considered important in the pathogenesis of ITP. Signal transducer and activators of transcription 3 (STAT3) is critical for the differentiation of T cells, abnormal activation of STAT3 pathway has been confirmed in a variety of autoimmune diseases. However little is known in its role in ITP. The present studiesaimed to analyze the STAT3 protein phosphorylation of CD4⁺ T cells before / after therapy, response group versus no response group, in newly diagnosed ITP patients.

Methods:Twenty-nine adult patients with newly diagnosed ITP and sixteen healthy controls enrolled in this study. The IL-6 level was measured by ELISA; the phosphorylation STAT3 protein and the percentage of Th17 cells of the CD4⁺ T cells were analyzed by flow cytometry; the STAT3 mRNA expression was analyzed by Real-time PCR.

Results: The levels of IL-6 in the response group were higher than that in the controls. The basal level of pSTAT3 in the response group was higher than that in the no response group. The basal level of pSTAT3 correlated with the response. There was no statistical difference between the three groups both in the STAT3 mRNA expression and the percentage of Th17 cells of the CD4⁺ T cells.

Conclusion: The higher basal level of pSTAT3 might have good response with the corticosteroids therapy. This suggested the level of pSTAT3 might has prognostic role in ITP patients.