Imbalance of T Lymphocyte Subsets in Adult Immune Thrombocytopenia
Xiuxiu Lin, Anhui Xu, Li Zhou, Na Zhao, Xinhui Zhang, Jin Xu, Shanglong Feng, Changcheng Zheng
Abstract
Background: 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. Methods: 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). Results: The percentage of Tc1 in cITP was greatly higher than nITP and healthy controls ( p < 0.05, p < 0.01). The percentage of Treg in nITP and cITP groups was remarkably lower than those in healthy control group ( p < 0.05, p < 0.001); and according to platelet count analysis (PLT< 50x10 9 /L or PLT> 50x10 9 /L), Treg cells in ITP group were significantly lower than those in healthy control group ( p < 0.001, p < 0.05). The percentage of CD4 + CXCR3 + of cITP was significantly higher than healthy controls and nITP ( p < 0.01, p < 0.05). The percentage of CD4 + CCR6 + in cITP was significantly higher than healthy controls and nITP ( p < 0.001, p < 0.05). The expression of PD-1 in cITP patients was higher than healthy control ( p < 0.05), but there was no significant difference among nITP, pITP and cITP ( p = 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 ( p < 0.01, p < 0.05; p < 0.01, p < 0.05; p < 0.05, p < 0.05), and the level of IL-10 in nITP group was significantly higher than that in pITP group ( p < 0.05). Conclusion: Our results suggest that T lymphocyte immune dysfunction does exist in adult ITP patients and plays an important role in the pathogenesis of ITP. Keywords: primary immune thrombocytopenia, T helper cells, cytotoxic T lymphocyte, regulatory T cells