Identification of ORM1, vWF, SPARC, and PPBP as immune-related proteins involved in immune thrombocytopenia by quantitative LC-MS/MS.

BACKGROUND: Immune thrombocytopenia (ITP) is a common autoimmune disease characterized by loss of immune tolerance to platelet autoantigens leading to excessive destruction and insufficient production of platelets. METHOD: Quantitative liquid chromatography tandem mass spectrometry (LC-MS/MS) was performed to detect the differentially expressed proteins in bone marrow samples from active ITP patients and normal controls. RESULT: Our bioinformatic analysis identified two upregulated proteins (ORM1 and vWF) and two downregulated proteins (PPBP and SPARC) related to immune function. The four proteins were all found to be related to the tumor necrosis factor (TNF) -α signalling pathway and involved in the pathogenesis of ITP in KEGG pathway analysis. CONCLUSION: Bioinformatics analysis identified differentially expressed proteins in bone marrow that are involved in the TNF-α signalling pathway and are related to the activation of immune function in ITP patients. These findings could provide new ideas for research on the loss of immune tolerance in ITP patients.

Blockade of T-cell immunoglobulin and mucin domain-containing molecule 3 aggravates T-helper cell 1 polarization in immune thrombocytopenia.

: An increased T-helper cell (Th) 1/Th2 ratio in the peripheral blood has been proposed to correlate with the disease activity of immune thrombocytopenia (ITP). T-cell immunoglobulin and mucin domain-containing molecule 3 (TIM-3) is a Th1-associated cell surface molecule that regulates Th1 responses and promotes tolerance. Consequently, we aimed to determine whether the regulation of TIM-3 expression is likely to be a promising therapeutic approach for ITP. In the present study, we investigated the immunomodulatory activities of TIM-3 in human peripheral blood mononuclear cell (PBMC) cultures. Levels of interferon-gamma (IFN-γ), tumor necrosis factor alpha (TNF-α), interleukin (IL)-4, IL-5, IL-2, and IL-10 were determined in PBMCs from 11 ITP patients and 10 healthy patients after TIM-3 antibody administration for 48 h. The proliferation of PBMCs was examined by cell counting kit-8 assay. Flow cytometry was used to observe apoptosis by staining cells with annexin V-fluorescein isothiocyanate/propidine iodide. PBMCs from ITP patients secreted higher amounts of IFN-γ than those from control patients but paradoxically expressed lower levels of TIM-3. Depletion of TIM-3 in PBMCs in vitro using a TIM-3 antibody enhanced IFN-γ secretion, directly demonstrating that TIM-3 expression on human T cells regulates proliferation and IFN-γ secretion. Failure to upregulate the T-cell expression of TIM-3 may represent a novel intrinsic defect that contributes to the pathogenesis of ITP.