Immune thrombocytopenia (ITP) is a hemorrhagic autoimmune disease characterized by antibody-mediated platelet injury. ITP has complicated immunopathological mechanisms that need further elucidation. It is well known that the costimulatory molecules OX40 ligand (OX40L) and OX40 play essential roles in the immunological mechanisms of autoimmune diseases. Previously, we discovered that the expression of OX40L and OX40 is significantly increased in the peripheral blood mononuclear cells (PBMCs) of ITP patients. In our present study, OX40L-induced follicular helper T (Tfh) cells exhibited an activated phenotype with elevated expression of inducible T-cell costimulator (ICOS), programmed cell death protein-1 (PD-1), and cluster of differentiation 40 ligand (CD40L) in vitro. Moreover, aberrant OX40L‒OX40 expression might promote the Tfh1-to-Tfh2 shift in vivo, inducing the generation of autoantibodies by enhancing the helper function of Tfh cells for B lymphocytes in a mouse model, which might accelerate the progression of ITP. Additionally, signal transduction through the OX40L‒OX40 axis might be related to the activation of tumor necrosis factor receptor-associated factor (TRAF)‒nuclear factor-κB (NF-κB) and Janus kinase (JAK)‒signal transducer and activator of transcription (STAT) signaling pathways. Overall, OX40L‒OX40 signaling is proposed as a potential novel therapeutic target for ITP.
Animals ; OX40 Ligand/physiology* ; Purpura, Thrombocytopenic, Idiopathic/immunology* ; Cell Differentiation ; Mice ; T-Lymphocytes, Helper-Inducer/cytology* ; T Follicular Helper Cells/cytology* ; Signal Transduction ; Receptors, OX40 ; Mice, Inbred C57BL ; Humans ; Female

INTRODUCTION: Immune thrombocytopenia (ITP) is the most common cause of acquired bleeding in childhood, but little is known about the clinical course and outcomes in infants with ITP. METHODS: This is a retrospective study of all infants (1-12 months of age) and toddlers (13-47 months of age) diagnosed with ITP from a single centre during a 13-year period. The following data were compared between the two patients groups: demographics, severity of bleeding, platelet counts, duration of illness, development of chronic ITP, treatment and association with recent vaccination. RESULTS: Twenty-two infants and 30 toddlers were diagnosed and followed up for ITP during the study period. Infants with ITP generally had minor or mild bleeding (19, 86.4%) and seldom required treatment (7, 31.8%), and their thrombocytopenia resolved at a mean of 1.90 months after diagnosis. Besides age, the sex ratio, severity of bleeding, platelet counts and proportion that required treatment were comparable between infants and toddlers. Fewer infants developed chronic ITP (1/22 vs. 9/30, P = 0.032), but more infants had a history of vaccination in the preceding 6 weeks prior to diagnosis of ITP (13/22 vs. 1/30, P < 0.001). CONCLUSION ITP in infants is almost always a self-limiting and transient illness, and the majority of cases do not require treatment.
Humans ; Retrospective Studies ; Infant ; Male ; Purpura, Thrombocytopenic, Idiopathic/complications* ; Female ; Child, Preschool ; Platelet Count ; Hemorrhage

BACKGROUND: Macrophage polarization anomalies and dysfunction play a crucial role in the pathogenesis of immune thrombocytopenia (ITP). Itaconate is a Krebs cycle-derived immunometabolite synthesized by myeloid cells to modulate cellular metabolism and inflammatory responses. This study aimed to evaluate the immunoregulatory effects of an itaconate derivative on macrophages in patients with ITP. METHODS: Peripheral blood-derived macrophages from patients with ITP and healthy controls were treated with 4-octyl itaconate (4-OI), a derivative of itaconate that can penetrate the cell membrane. Macrophage polarization, antigen-presenting functions, and phagocytic capability were measured via flow cytometry and enzyme-linked immunosorbent assay (ELISA). Macrophage glycolysis in patients with ITP and the metabolic regulatory effect of 4-OI were detected using a Seahorse XFe96 Analyzer. An active murine model of ITP was used to evaluate the therapeutic effects of 4-OI in vivo . RESULTS: 4-OI reduced the levels of CD80 and CD86 in M1 macrophages and suppressed the release of tumor necrosis factor-α (TNF-α) and interleukin (IL)-6 pro-inflammatory cytokines, suggesting that 4-OI could hinder the polarization of macrophages toward an M1 phenotype. We found that 4-OI pretreated M1 macrophages reduced the proliferation of CD4 + T cells and promoted the differentiation of regulatory T cells. In addition, after 4-OI treatment, the phagocytic capacity of M1 macrophages toward antibody-coated platelets decreased significantly in patients with ITP. In addition, the glycolytic function of M1 macrophages was elevated in individuals with ITP compared to those in healthy controls. 4-OI treatment downregulated glycolysis in M1 macrophages. The glycolysis inhibitor 2-deoxy-d-glucose (2-DG) also inhibited the polarization of M1 macrophages and restored their functions. In vivo , 4-OI treatment significantly increased platelet counts in the active ITP murine model. CONCLUSIONS Itaconate derivative 4-OI inhibited M1 macrophage polarization and restored impaired functions through metabolic reprogramming. This study provides a novel therapeutic option for ITP.
Macrophages/metabolism* ; Humans ; Animals ; Succinates/pharmacology* ; Mice ; Male ; Female ; Adult ; Middle Aged ; Flow Cytometry ; Tumor Necrosis Factor-alpha/metabolism* ; Enzyme-Linked Immunosorbent Assay ; Purpura, Thrombocytopenic, Idiopathic/metabolism* ; Glycolysis/drug effects* ; Metabolic Reprogramming

Objective This study investigated the regulatory effect of high mobility group protein B1 (HMGB1) in the peripheral blood of patients with primary immune thrombocytopenia (ITP) on myeloid dendritic cells (mDC) and Th17/regulatory T cells (Treg) balance. Methods The study enrolled 30 newly diagnosed ITP patients and 30 healthy controls.Flow cytometry was used to measure the proportion of mDC, Th17, and Treg cells in the peripheral blood of ITP patients and healthy controls. ELISA was conducted to quantify the serum levels of HMGB1, interleukin 6 (IL-6), IL-23, IL-17, and transforming growth factor β(TGF-β). The mRNA levels of retinoic acid-related orphan receptor γt(RORγt) and forehead box P3(FOXP3) were detected by real-time PCR. The correlation between the abovementioned cells, cytokines, and platelet count was assessed using Pearson linear correlation analysis. Results The proportion of Th17 cells and the expression levels of HMGB1, IL-6, IL-23, IL-17 and the level of RORγt mRNA in the peripheral blood of ITP patients were higher than those in healthy controls. However, the Treg cell proportion and TGF-β level were lower in ITP patients than those in healthy controls. In patients with ITP, the proportion of mDC and the level of FOXP3 mRNA did not show significant changes. The proportion of mDC cells was significantly correlated with the expression of IL-6 and IL-23. Moreover, the expression of HMGB1 showed a significant correlation with the expression of mDC, IL-6, IL-23, RORγt mRNA, and IL-17. Notably, both the proportion of mDC cells and the expression of HMGB1 were negatively correlated with platelet count. Conclusion The high expression of HMGB1 in peripheral blood of ITP patients may induce Th17/Treg imbalance by promoting the maturation of mDC and affecting the secretion of cytokines, thereby potentially playing a role in the immunological mechanism of ITP.
Humans ; Th17 Cells/cytology* ; HMGB1 Protein/genetics* ; T-Lymphocytes, Regulatory/cytology* ; Female ; Male ; Dendritic Cells/metabolism* ; Adult ; Middle Aged ; Purpura, Thrombocytopenic, Idiopathic/genetics* ; Nuclear Receptor Subfamily 1, Group F, Member 3/genetics* ; Young Adult ; Interleukin-23/blood* ; Interleukin-17/blood* ; Interleukin-6/blood* ; Forkhead Transcription Factors/genetics* ; Myeloid Cells/cytology* ; Aged

OBJECTIVES: To investigate the clinical and immunological features of children with primary immune thrombocytopenia (pITP) or connective tissue disease (CTD) with thrombocytopenia as the initial manifestation at initial diagnosis, and to provide a basis for early differentiation. METHODS: A retrospective study was performed on 236 children with pITP (pITP group) or CTD with thrombocytopenia as the initial manifestation (CTD-TP group) who were admitted from January 2019 to August 2024. Clinical and immunological indicators were compared between the two groups to identify potential influencing factors for early differentiation and their discriminative validity. RESULTS: Compared with the pITP group, the CTD-TP group had a significantly older age of onset and significantly lower leukocyte count, eosinophil count, lymphocyte count, and complement C4 level (P<0.05), as well as significantly higher levels of C-reactive protein, IgE, and IgM (P<0.05). The logistic regression analysis showed that age, IgE, IgM, total B cells, and complement C4 were predictive factors for early differentiation between pITP and CTD-TP (P<0.05). The receiver operating characteristic curve analysis showed that a combination of these five factors had a good discriminative validity, with an area under the curve of 0.944. The correlation analysis showed a negative correlation between IgG and platelet count in the pITP group (r_s=-0.363, P<0.05) and a positive correlation between NK cells and platelet count in the CTD-TP group (r_s=0.713, P<0.05). CONCLUSIONS There is heterogeneity in the clinical and immunological indicators between children with pITP and CTD-TP at initial diagnosis, and these research findings can help with the early differentiation between the two diseases.
Purpura, Thrombocytopenic, Idiopathic/immunology* ; Diagnosis, Differential ; Connective Tissue Diseases/immunology* ; Retrospective Studies ; Early Diagnosis ; Age of Onset ; Leukocyte Count ; Complement C4/immunology* ; C-Reactive Protein/immunology* ; Immunoglobulin E/immunology* ; Immunoglobulin M/immunology* ; Humans ; Male ; Female ; Infant ; Child, Preschool ; Child ; Adolescent ; Biomarkers/blood*

OBJECTIVES: To investigate the causal relationship between Helicobacter pylori (Hp) infection and immune thrombocytopenia (ITP) using Mendelian randomization (MR), as well as the association between Hp infection and chronic ITP (cITP) through a clinical study. METHODS: The datasets from genome-wide association studies were used to select the single nucleotide polymorphism loci significantly associated with Hp infection as genetic instrumental variables. The MR analysis model was used to investigate the causal relationship between ITP and Hp infection. A retrospective analysis was conducted on the medical data of 316 children with newly diagnosed ITP at the First Affiliated Hospital of Xinjiang Medical University from January 2020 to December 2023. The children were followed up for 1 year, and a multivariate logistic regression analysis was used to investigate the risk factors for cITP. RESULTS: The inverse variance weighted analysis revealed that Hp infection was significantly associated with an increased risk of ITP (OR=1.280, 95%CI: 1.098-1.492, P=0.002). There was no heterogeneity or pleiotropy in this MR study (P>0.05), and the model was stable. The "leave-one-out" sensitivity analysis verified the reliability of the results. The multivariate logistic regression analysis demonstrated that Hp infection was an independent risk factor for progression to cITP (OR=7.916, 95%CI: 3.327-18.832, P<0.001). CONCLUSIONS Hp infection is a risk factor for the onset of ITP and is an independent risk factor for cITP in children.
Humans ; Helicobacter Infections/complications* ; Purpura, Thrombocytopenic, Idiopathic/etiology* ; Child ; Male ; Female ; Helicobacter pylori ; Prognosis ; Child, Preschool ; Logistic Models ; Retrospective Studies ; Risk Factors ; Polymorphism, Single Nucleotide ; Adolescent ; Infant

This report describes two cases of severe immune-mediated thrombocytopenia after allogeneic hematopoietic stem cell transplantation (HSCT) who were treated with umbilical cord mesenchymal stem cells (UC-MSCs). Case 1 was a child with severe aplastic anemia who underwent haploidentical bone marrow and peripheral blood HSCT, with a chimerism rate of 99.8% on day +25 and severe immune-mediated thrombocytopenia on day +60. After intravenous immunoglobulin (IVIG) pulse therapy, platelet count increased temporarily but then decreased, while cyclosporine, methylprednisolone, and rituximab had a poor therapeutic effect. Case 2 was a child with Gaucher's disease who underwent unrelated umbilical cord blood HSCT, with a chimerism rate of 96.35% on day +41 and severe immune-mediated thrombocytopenia on day +153. After three sessions of IVIG pulse therapy, the platelet count increased initially but subsequently decreased. Therapies with dexamethasone, prednisone, cyclosporine, and recombinant human thrombopoietin also yielded a poor response. Both children received three sessions of UC-MSCs infusion, and platelet counts increased and were subsequently maintained within the normal range. Case 1 has been followed up for 10 years and remains in disease-free survival. UC-MSCs infusion may be effective for severe immune-mediated thrombocytopenia that is unresponsive to first- and second-line therapies after HSCT and could potentially improve the quality of life and disease-free survival rate.
Child ; Humans ; Hematopoietic Stem Cell Transplantation/adverse effects* ; Mesenchymal Stem Cell Transplantation ; Purpura, Thrombocytopenic, Idiopathic/etiology* ; Thrombocytopenia/therapy* ; Transplantation, Homologous ; Umbilical Cord/cytology*

OBJECTIVES: To investigate the expression of interleukin-37 (IL-37), vascular endothelial growth factor A (VEGFA), and transforming growth factor-β1 (TGF-β1) in children with primary immune thrombocytopenia (ITP) and their correlation with T cells. METHODS: A retrospective analysis was conducted on 45 children with ITP (ITP group) who were admitted to Handan Central Hospital from January 2020 to April 2022, and 30 healthy children who underwent physical examination during the same period were included as the healthy control group. The mRNA expression levels of IL-37, VEGFA, and TGF-β1 and the levels of regulatory T cells (Treg) and helper T cells 17 (Th17) were measured before and after treatment, and the correlation between the mRNA expression levels of IL-37, VEGFA, and TGF-β1 and the levels of Treg, Th17, and Treg/Th17 ratio were analyzed. RESULTS: Compared with the healthy control group, the ITP group had a significantly higher mRNA expression level of IL-37 and a significantly higher level of Th17 before and after treatment, as well as significantly lower mRNA expression levels of VEGFA and TGF-β1 and significantly lower levels of Treg and Treg/Th17 ratio (P<0.05). After treatment, the ITP group had significant reductions in the mRNA expression level of IL-37 and the level of Th17 and significant increases in the mRNA expression levels of VEGFA and TGF-β1 and the levels of Treg and Treg/Th17 ratio (P<0.05). Correlation analysis showed that in the ITP group, the mRNA expression levels of IL-37 and TGF-β1 were negatively correlated with the levels of Treg and Treg/Th17 ratio (P<0.05) and were positively correlated with the level of Th17 (P<0.05) before and after treatment; the mRNA expression level of VEGFA was positively correlated with the levels of Treg and Treg/Th17 ratio (P<0.05) and was negatively correlated with the Th17 level (P<0.05) before and after treatment. CONCLUSIONS Abnormal expression levels of IL-37, VEGFA, and TGF-β1 may be observed in children with ITP, which is significantly associated with the imbalance of Treg/Th17 ratio. It is speculated that the cytokines such as IL-37, VEGFA, and TGF-β1 may be involved in the development and progression of ITP or may become important potential targets for the treatment of children with ITP. Citation:Chinese Journal of Contemporary Pediatrics, 2023, 25(11): 1131-1136.
Child ; Humans ; Interleukins ; Purpura, Thrombocytopenic, Idiopathic ; Retrospective Studies ; RNA, Messenger/metabolism* ; T-Lymphocytes, Regulatory ; Th17 Cells/metabolism* ; Transforming Growth Factor beta1/genetics* ; Vascular Endothelial Growth Factor A/genetics*

Immune checkpoint inhibitors (ICIs) show unique advantages in the treatment of lung cancer, making the treatment of lung cancer enter the era of immunotherapy, but ICIs will also have adverse reactions, and the incidence of immune-induced hematological toxicity is not very high. Immunotherapy-induced thrombocytopenia is a rare adverse event.We report one case of thrombocytopenia induced by ICIs and review the literature on thrombocytopenia associated with ICIs and discuss the clinical features, possible mechanisms, and optimal treatment. 
.
Humans ; Purpura, Thrombocytopenic, Idiopathic/drug therapy* ; Lung Neoplasms/drug therapy* ; Thrombocytopenia/chemically induced* ; Antibodies, Monoclonal, Humanized/adverse effects*

Thrombotic microangiopathy (TMA) is a group of highly heterogeneous, acute and severe clinicopathological syndromes, characterized by microangiopathic hemolytic anemia (MAHA), thrombocytopenia and ischemic injury of end organs. TMA has the characteristics of dangerous condition, multiple organ involvement and high mortality. Patients with severe TMA need to be admitted to intensive care unit (ICU) for organ function support therapy. Early and rapid evaluation, differential diagnosis, and timely and effective treatment are the key to improve the prognosis of TMA patients. Here, we review the pathophysiological changes, diagnosis differential diagnosis, and treatment of the severe TMA in adult.
Adult ; Humans ; Thrombotic Microangiopathies/therapy* ; Purpura, Thrombotic Thrombocytopenic/therapy* ; Anemia, Hemolytic/therapy* ; Treatment Outcome ; Diagnosis, Differential