Imbalance of T Lymphocyte Subsets in Adult Immune Thrombocytopenia

Primary immune thrombocytopenia (ITP) is defined as an acquired autoimmune disease characterized by isolated thrombocytopenia. This work is to further clarify the relationship between T cell immune dysfunction and the pathogenesis of ITP. 37 adult patients with ITP were selected and were classified into newly diagnosed ITP (nITP, n = 13), persistent ITP (pITP, n = 6) and chronic ITP (cITP n = 18). The frequency of cytotoxic T lymphocytes (Tc1, Tc2, and Tc17) and helper T cells (Th1, Th2, and Th17), Tregs, and the expression of chemokine receptors and PD-1 on CD4 T cells were investigated by flow cytometry. Plasma levels of T cell-related cytokines (IL-2, IL-4, IL-6, IL-10, TNF-α, IFN-γ, IL-17) were measured by cytometric beads array (CBA). The percentage of Tc1 in cITP was greatly higher than nITP and healthy controls ( < 0.05, < 0.01). The percentage of Treg in nITP and cITP groups was remarkably lower than those in healthy control group ( < 0.05, < 0.001); and according to platelet count analysis (PLT50x10 /L), Treg cells in ITP group were significantly lower than those in healthy control group ( < 0.001, < 0.05). The percentage of CD4 CXCR3 of cITP was significantly higher than healthy controls and nITP ( < 0.01, < 0.05). The percentage of CD4 CCR6 in cITP was significantly higher than healthy controls and nITP ( < 0.001, < 0.05). The expression of PD-1 in cITP patients was higher than healthy control ( < 0.05), but there was no significant difference among nITP, pITP and cITP ( = 0.25). The levels of IL-2, IFN-γ and TNFα in nITP group and cITP group were significantly higher than those in healthy control group ( < 0.01, < 0.05; < 0.01, < 0.05; < 0.05, < 0.05), and the level of IL-10 in nITP group was significantly higher than that in pITP group ( < 0.05). Our results suggest that T lymphocyte immune dysfunction does exist in adult ITP patients and plays an important role in the pathogenesis of ITP.