Project description:Immune thrombocytopenia (ITP) is an autoimmune disease where platelets are destroyed prematurely. In the majority of children the disease resolves but in some it becomes chronic. To investigate whether the two forms of the disease are similar or separate entities we performed DNA microarray analysis of T-cells from newly diagnosed children and children with chronic ITP. We found complete separation of the expression files between the two forms of the disease. Furthermore, the gene expression of several cytokines differed between the two forms of the disease. This was also reflected in plasma with increased levels of IL-16 and TWEAK and lower levels of IL-4 in newly diagnosed compared with chronic ITP. Thus, our data indicate that the two forms of the disease may be separate entities. Microarray expression analysis of mRNA in peripheral blood T-cell of Newly diagnosed ITP vs Chronic ITP
Project description:Immune thrombocytopenia (ITP) is an autoimmune disease where platelets are destroyed prematurely. In the majority of children the disease resolves but in some it becomes chronic. To investigate whether the two forms of the disease are similar or separate entities we performed DNA microarray analysis of T-cells from newly diagnosed children and children with chronic ITP. We found complete separation of the expression files between the two forms of the disease. Furthermore, the gene expression of several cytokines differed between the two forms of the disease. This was also reflected in plasma with increased levels of IL-16 and TWEAK and lower levels of IL-4 in newly diagnosed compared with chronic ITP. Thus, our data indicate that the two forms of the disease may be separate entities.
Project description:Immune thrombocytopenia (ITP) is a common platelet disorder in pediatric patients. Pediatric and adult ITP have been associated with sialic acid alterations, but the pathophysiology of ITP remains elusive, and ITP is often a diagnosis of exclusion. Our analysis of pediatric ITP plasma samples showed increased anti-Thomsen-Friedenreich antigen (TF-antigen) antibody representation, suggesting increased exposure of the typically sialylated and cryptic TF-antigen in these patients. The O-glycan sialyltransferase St3gal1 add sialic acid specifically on the TF-antigen. To understand if TF-antigen exposure associates with thrombocytopenia, we generated a mouse model with targeted deletion of St3gal1 in megakaryocytes (MK) (St3gal1MK-/-). TF-antigen exposure was restricted to MKs and resulted in thrombocytopenia. Deletion of Jak3 in St3gal1MK-/- mice normalized platelet counts implicating involvement of immune cells. Interferon-producing Siglec H-positive bone marrow (BM) immune cells engaged with O-glycan sialic acid moieties to regulate type I interferon (IFN-I) secretion and platelet release (thrombopoiesis), as evidenced by partially normalized platelet count following and inhibition of interferon and Siglec H receptors. Single cell RNAseq determined that TF-antigen exposure by MKs primed St3gal1MK-/- BM immune cells to release IFN-I. Single cell RNAseq further revealed a new population of immune cells with a plasmacytoid dendritic cell (pDC)-like signature and concomitant upregulation of immunoglobulin re-arrangement gene transcripts Igkc and Ighm, suggesting additional immune regulatory mechanisms. Thus, aberrant TF-antigen moieties, often found in pathological conditions, regulate immune cells and thrombopoiesis in the BM, leading to reduced platelet count.
Project description:Immune thrombocytopenia (ITP) is an acquired autoimmune disease triggered by abnormal T cell immunity, especially the impairment of regulatory T (Treg) cells and helper T (Th) cell subsets. Decitabine, a hypomethylating agent promoting cell differentiation at low dose, has been demonstrated the function of increasing the number of mature polyploidy megakaryocytes in ITP as well as Treg cells in allogeneic transplantation. Recently, our clinical study proved that decitabine was effective and safe in the management of adult ITP patients, and nearly half showed sustained responses. However, whether low-dose decitabine has the potential in restoring immune tolerance in ITP is unknown. In our in vitro studies, we identified that low-dose decitabine could promote the generation and differentiation and enhance the immunosuppressive function of Treg cells. Furthermore, low-dose decitabine alleviated thrombocytopenia and regained the balance of Treg/Th cell subsets in active murine models of ITP. For patients who received low-dose decitabine therapy and showed responses, the quantity and function of Treg cells were substantially improved, whereas Th1 and Th17 cells were depressed compared with the pretreatment levels. Finally, immunophenotyping and next-generation RNA sequencing analysis showed that low-dose decitabine restored T cell homeostasis and decreased the level of proinflammatory cytokines along with the downregulation of STAT3 and Akt in refractory ITP patients. Therefore, our data reveal the immunomodulatory effect of decitabine and provide unique insights into the sustained response achieved by decitabine in the management of ITP patients.
Project description:Children with newly diagnosed ITP that after 12 month enter remission, shows molecular separate entities. The molecular basis for remission and tolerance induction is characterized by gene transcriptional profiling Global gene expression profile in isolated T-cells from 6 children with newly diagnosed ITP and after 12 month when they enter remission
Project description:Whole blood transcriptional profiling of pediatric idiopathic thrombocytopenic purpura (ITP) patients comparing self-limited acute ITP patients with chronic ITP patients or progression-to-chronic ITP patients. Patient samples were collected during 3 different disease states: 8 samples from acute ITP pts (within 6 months of dx, during active disease), 4 samples from progression-to-chronic ITP pts (within 6 months of dx), and 14 samples from chronic ITP (after 6 months of dx).
Project description:We investigated the expression profiles of plasma miRNAs in immune thrombocytopenia (ITP) patients. Peripheral blood plasma was used for Agilent miRNA expression microarray analysis to define miRNA profiles and to identify miRNAs with discriminatory levels for ITP and healthy controls. Results were further validated using quantitative realtime PCR on a larger cohort, enabling relative quantification of plasma miRNAs and defining miRNAs with diagnostic value for the disease.
Project description:Rituximab (RTX) is widely used as a first-line therapeutic strategy for patients affected by immune thrombocytopenia (ITP). However, a large proportion of patients relapse after successful treatment. The present NGS assay was done to help find the cause for this relapse on the immune repertoire level. Therefore, we performed antibody repertoire sequencing for three RTX relapse patients with subsequent mutation and clonal analysis, as well as for two patients with ongoing ITP and two healthy donors (HD) with subsequent mutation analysis.
Project description:Children with newly diagnosed ITP that after 12 month enter remission, shows molecular separate entities. The molecular basis for remission and tolerance induction is characterized by gene transcriptional profiling