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

Critical care emphasizes critical thinking, focuses on the triggers that lead to disease progression, and attaches great importance to early diagnosis of diseases and assessment of the compensatory capacity of vital organs. Pregnancy-associated atypical hemolytic uremic syndrome (P-aHUS) is relatively rare in the intensive care unit (ICU). Most cases occur within 10 weeks after delivery. Severe cases can be life-threatening. It characterized by microangiopathic hemolytic anemia, decreased platelet count (PLT), and acute kidney injury (AKI). Early clinical diagnosis is difficult due to its similarity to various disease manifestations. On January 28, 2024, a 26-year-old pregnant woman at 26⁺³ weeks gestation was transferred to the ICU 19 hours post-vaginal delivery due to abdominal pain, reduced urine output, decreased PLT, elevated D-dimer, tachycardia, increased respiratory rate and declined oxygenation. On the day of ICU admission, the critical care physician identified the causes that triggered the acute respiratory and circulatory events based on the "holistic and local" critical care thinking. The condition was stabilized rapidly by improving the capacity overload. In terms of etiological diagnosis, under the guidance of the "point and face" critical care thinking, starting from abnormality indicators including a decrease in hemoglobin (Hb) and PLT and elevated D-dimer and fibrin degradation product (FDP) without other abnormal coagulation indicators, the critical care physician ultimately determined the diagnosis direction of thrombotic microangiopathy (TMA) by delving deeply into the essence of the disease and formulating a laboratory examination plan in a reasonable and orderly manner. In terms of in-depth diagnosis, combining the disease development process, family history, and past history, applying the two-way falsification thinking of "forward and reverse" as well as "questioning and hypothesis", the diagnosis possibilities of preeclampsia, HELLP syndrome [including hemolysis (H), elevated liver function (EL) and low platelet count (LP)], thrombotic thrombocytopenic purpura (TTP), typical hemolytic uremic syndrome (HUS), and autoimmune inflammatory diseases inducing the condition was ruled out. The diagnosis of complement activation-induced P-aHUS was finally established for the patient, according to the positive result of the complement factor H (CFH). Active decision was made in the initial treatment. The plasma exchange was initiated early. "Small goals" were formulated in stages. The "small endpoints" were dynamically controlled in a goal-oriented manner to achieve continuous realization of the overall treatment effect through phased "small goals". On the 5th day of ICU treatment, the trend of microthrombosis in the patient was controlled, organ function damage was improved, and the patient was transferred out of the ICU. It is possible to reach a favorable clinical outcome for critically ill patients by applying a critical care mindset to quickly integrate diagnostic and therapeutic strategies, accurately identifying the triggers and causes that led to the progression of the disease, and using critical care medical techniques for early and effective intervention.
Humans ; Female ; Pregnancy ; Adult ; Atypical Hemolytic Uremic Syndrome/therapy* ; Intensive Care Units ; Pregnancy Complications, Hematologic/therapy* ; Critical Care

Atypical hemolytic uremic syndrome (aHUS) is a thrombotic microangiopathy characterized by microangiopathic hemolytic anemia, thrombocytopenia, and multi-organ damage, with the kidneys being predominantly affected. aHUS results from dysregulation of the complement alternative pathway, triggered by factors including infection, pregnancy, and surgery, among others. Therefore, complement inhibitors play a crucial role in the treatment of aHUS by blocking abnormal activation of the complement system and improving patients' prognosis. This consensus, developed by the Multidisciplinary Consensus Working Group on Atypical Hemolytic Uremic Syndrome Diagnosis and Treatment, is based on the latest literature and guidelines, discusses the pathogenesis, diagnosis and differential diagnosis, and treatment strategies for aHUS, and provides a guide and reference for the standardized diagnosis and management of aHUS in China.
Humans ; Atypical Hemolytic Uremic Syndrome/therapy* ; Consensus ; Diagnosis, Differential ; Prognosis

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*

The patient was a girl aged 10 years and 10 months, with weakness, pale complexion, and rash as the initial presentation. She had the manifestations of anemia, thrombocytopenia, hematuria-proteinuria with renal insufficiency, hypocomplementemia, polyserositis, and positive anti-nuclear antibody and anti-dsDNA antibody. The girl was initially diagnosed with systemic lupus erythematosus and lupus nephritis. She demonstrated a suboptimal response to methylprednisolone pulse therapy, intravenous immunoglobulin administration, and therapeutic plasma exchange. She had persistent anemia, thrombocytopenia, abnormal renal function, elevated lactate dehydrogenase, decreased complement factors H and I, increased antibodies to C3 converting enzyme, and normal ADAMTS13 activity. She was diagnosed with complement-mediated hemolytic thrombotic microangiopathy secondary to systemic lupus erythematosus. The patient's condition improved after treatment with two doses of eculizumab (600 mg per dose). Patients with systemic lupus erythematosus complicated by thrombotic microangiopathy often have a severe disease course and poor prognosis; therefore, early recognition and aggressive intervention are crucial for improving outcomes.
Humans ; Female ; Lupus Erythematosus, Systemic/drug therapy* ; Thrombotic Microangiopathies/etiology* ; Antibodies, Monoclonal, Humanized/therapeutic use* ; Child