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Primary immune thrombocytopenia (ITP) is a disease of autoimmunity in which there are Th1/Th2 imbalance and disordered cytokine profiles. CXC chemokine ligand 16 (CXCL16) was proved to implicate in some autoimmune diseases. Our research aimed to determine plasma soluble CXCL16 (sCXCL16) levels and its effects in ITP. We used ELISA to measure plasma sCXCL16, IFN–γ and IL-4 and flow cytometry to determine expression of CXCR6 on lymphocyte subsets. We used real-time PCR to detect the CXCL16 and CXCR6 mRNA expression. Additionally, plasma sCXCL16, CXCL16 and CXCR6 mRNA levels of 8 patients were monitored before and after treatment. We found that patients with active ITP had higher circulating sCXCL16 in plasma than healthy controls and patients in remission. Meanwhile, negative relationships between sCXCL16 and platelet count, IL-4 and positive relationships between sCXCL16 and IFN-γ, IFN-γ/IL-4 ratio were observed. Besides, expression of CXCR6 on lymphocyte subsets and mRNA levels of CXCL16 and CXCR6 were all increased in active ITP. Additionally, plasma sCXCL16 and IFN-γ levels and CXCR6 mRNA expression were down-regulated after effective treatment compared with those before treatment. Thus, increased plasma sCXCL16 might be implicated in the pathogenesis of ITP and have a relationship with Th1/Th2 imbalance. [ABSTRACT FROM AUTHOR]

Primary immune thrombocytopenia (ITP) is an autoimmune disease with many immune dysfunctions including T helper type 1 cell (Th1) polarization and regulatory T cells (Tregs) deficiency. This study aimed to determine the effects of TLR4 on Treg differentiation and the cytokine production of peripheral blood mononuclear cells (PBMCs) from patients with ITP. We found that expression of TLR4 on monocytes was significantly decreased in patients with active ITP than that in healthy controls and it had positive correlation with platelet count. However, there was no expression of TLR4 on CD4+ T cells. The result of further experimentsin vitroshowed that lipopolysaccharide (LPS) stimulation could enhance TLR4 expression on monocytes. Additionally, activation of TLR4 with LPS could promote differentiation of Treg cells and anti-TLR4 attenuated this effect. There was no significant difference about Th17 cells among three subgroups. However, the Th17/Treg cell ratio was decreased after stimulation with LPS and increased with anti-TLR4. Moreover, activation of TLR4 with LPS could significantly promote the secretion of interleukin-10 (IL-10) and transforming growth factor-β1 (TGFB1), while anti-TLR4 significantly suppressed the secretion of them. Nevertheless, the secretion of IL-17A did not reach the statistical difference among three subgroups. In summary, decreased TLR4 appears to cause Tregs abnormality in ITP by modulating Tregs differentiation and immunoregulatory cytokines. [ABSTRACT FROM AUTHOR]

Primary immune thrombocytopenia ( ITP) is an acquired autoimmune disorder, and loss of immune tolerance has been implicated in ITP pathogenesis. CD8+CD28− suppressor (Ts) cells have an immunosuppression function and are involved in several autoimmune disorders. However, the role of Ts cells in ITP is currently not clear. Here, flow cytometry was used to detect the CD8+CD28−CD127− proportion, which was decreased in active ITP patients compared with that of controls. Function analysis showed that immunosuppression of CD8+CD28− Ts cells in ITP patients was impaired. Mechanistic studies have shown that CD8+CD28− Ts cells from controls can downregulate CD80 and upregulate LILRB4 (ITL3) and LILRB2 (ILT4) expression on CD14+ monocytes, whereas these abilities were not found in Ts cells from ITP patients. Furthermore, Inducible T-cell costimulatory ( ICOS) expression on the Ts cell surface after activation was decreased whereas programmed death 1 and interleukin 10 expression was not changed in ITP patients compared with those of controls. In summary, the down-regulated quantity and function of Ts cells in active patients indicated that a Ts defect was involved in ITP. Moreover, decreased ICOS expression and the loss of the ability to regulate co-stimulator expression on antigen-presenting cells partly explained the defective Ts-mediated suppression. [ABSTRACT FROM AUTHOR]

TMEVPG1 is a long noncoding RNA, which can promote Interferon gamma (IFNG) transcript as an enhancer. It has been reported that plasma IFNG concentration was elevated and partly due to dysregulation of micro RNAs in patients with primary immune thrombocytopenia (ITP). However, the effect of long noncoding RNA on IFNG expression in ITP is currently not well understood. To explore whether TMEVPG1 is involved in ITP, this study examined the TMEVPG1 expression and analyzed the association between TMEVPG1 transcript and IFNG expression in patients with ITP and healthy controls. The result showed that TMEVPG1 expression in peripheral blood mononuclear cells (PBMCs) from active ITP patients were lower than in that of healthy controls. Further activation for 24 hin vitroresulted in decreased TMEVPG1 while elevated IFNG mRNA and protein expressions in activated PBMCs compared with un-activated PBMCs both in ITP patients and healthy controls. However, TMEVPG1 and IFNG mRNA had same up-regulated tendency after short-time activation (1, 2 and 4 h) in healthy controls. In addition, we detected T helper 1 (Th1) cell associated transcription factors T-bet, STAT1 and STAT4 mRNA levels, and found T-bet mRNA expression was lower in PBMCs from ITP patient in remission compared with healthy controls. In conclusion, we speculated that TMEVPG1 could promote IFNG transcription, and IFNG over-expression negative feedback regulated on TMEVPG1 expression, which resulted in decreased TMEVPG1 in ITP patients. [ABSTRACT FROM PUBLISHER]

Primary immune thrombocytopenia (ITP) is an acquired autoimmune disease. 1α, 25-dihydroxyvitamin D 3 [1,25(OH) 2 D 3 ] and vitamin D receptor (VDR) play important immune-suppressive roles in immune system. It has been reported that serum 1,25(OH) 2 D 3 were lower in ITP patients. In this study, we evaluated local 1,25(OH) 2 D 3 level and VDR mRNA expression further, and determined whether 1,25(OH) 2 D 3 /VDR were correlated with T cell dysfunction in ITP patients. We found that 1,25(OH) 2 D 3 /VDR levels were decreased in active ITP patients, and 1,25(OH) 2 D 3 had significant anti-inflammatory effects on ITP patients, including both anti-proliferation of peripheral blood mononuclear cells (PBMCs) and reversing the abnormal T cells polarization. 1,25(OH) 2 D 3 inhibited the differentiation of T helper (Th)1 and Tc1 cells but induced the differentiation of Th2, Tc2 and T regulatory (Treg) cells in ITP patients. However, the percentage of Th17 cells were not affected obviously with 1,25(OH) 2 D 3 . In addition, 1,25(OH) 2 D 3 also suppressed pro-inflammatory cytokines (INF-γ and IL-17A) but promoted anti-inflammatory cytokine (IL-10) secretion in ITP patients. In conclusion, decreased 1,25(OH) 2 D 3 /VDR might participate in the pathogenesis of ITP, and appropriate supplement of 1,25(OH) 2 D 3 may be a promising treatment. [ABSTRACT FROM AUTHOR]

Phosphatase and tensin homolog (PTEN) is thought to mediate B cell activation by negatively regulating the phosphoinositide 3-kinase (PI3 K) signaling pathway. This pathway is important for activation, growth, and proliferation. Although enhanced B cell receptor (BCR) signaling contributes to increased B cell activity in immune thrombocytopenia (ITP), the role of PTEN is unclear. In this study, we analyzed B cells of ITP patients using flow cytometry and found that all B cell subsets, excluding memory B cells, showed lower PTEN expression than cells from healthy controls (HCs). PTEN expression was also positively-correlated with blood platelet count, although levels were lower in patients who were platelet autoantibody-positive compared with those who were negative. We next evaluated the effects of IL-21, anti-IgM, and CD40L on PTEN expression, demonstrating that they were potent inducers of PTEN expression in normal B cells. Induction of PTEN expression was lower in B cells of ITP patients. We also found that IL-21 increased the proportion of plasma cells in peripheral blood mononuclear cells (PBMCs) of ITP patients, independent of BCR signaling. This effect was reproducible using PTEN inhibitors with cells from HCs. In summary, defective PTEN expression, regulation, and function all contribute to the B cell hyper-responsiveness that associates with ITP. [ABSTRACT FROM AUTHOR]