The Ratio of Treg/Th17 Cells Correlates with the Disease Activity of Primary Immune Thrombocytopenia

BACKGROUND Primary immune thrombocytopenia (ITP) is an autoimmune heterogeneous disorder that is characterized by decreased platelet count. Regulatory T (Treg) cells and T helper type 17 (Th17) cells are two subtypes of CD4(+) T helper (Th) cells. They play opposite roles in immune tolerance and autoimmune diseases, while they share a common differentiation pathway. The imbalance of Treg/Th17 has been demonstrated in several autoimmune diseases. In this study, we aimed to investigate the ratio of the number of Treg cells to the number of Th17 cells in ITP patients and evaluate the clinical implications of the alterations in this ratio. METHODS Thirty adult patients with newly diagnosed ITP enrolled in this study. Twelve patients had been clinically followed up for 12 months. The percentages of CD4(+)CD25(hi)Foxp3(+) Treg cells and CD3(+)CD4(+)IL-17-producing Th17 cells in these patients and healthy controls (n = 17) were longitudinally analyzed by flow cytometry. RESULTS The percentage of Treg cells in ITP patients was significantly lower than that of healthy controls, and the percentage of Th17 cells increased significantly at disease onset. The ratio of Treg/Th17 correlated with the disease activity. CONCLUSION The ratio of Treg/Th17 might be relevant to the clinical diversity of ITP patients, and this Treg/Th17 ratio might have prognostic role in ITP patients.