Emerging Concepts in Immune Thrombocytopenia

Nipocalimab, an immunoselective FcRn blocker that lowers IgG and has unique molecular properties

Nipocalimab is a human immunoglobulin G (IgG)1 monoclonal antibody that binds to the neonatal Fc receptor (FcRn) with high specificity and high affinity at both neutral (extracellular) and acidic (intracellular) pH, resulting in the reduction of circulating IgG levels, including those of pathogenic IgG antibodies. Here, we present the molecular, cellular, and nonclinical characteristics of nipocalimab that support the reported clinical pharmacology and potential clinical application in IgG-driven, autoantibody- and alloantibody-mediated diseases. The crystal structure of the nipocalimab antigen binding fragment (Fab)/FcRn complex reveals its binding to a unique epitope on the IgG binding site of FcRn that supports the observed pH-independent high-binding affinity to FcRn. Cell-based and in vivo studies demonstrate concentration/dose- and time-dependent FcRn occupancy and IgG reduction. Nipocalimab selectively reduces circulating IgG levels without detectable effects on other adaptive and innate immune functions. In vitro experiments and in vivo studies in mice and cynomolgus monkeys generated data that align with observations from clinical studies of nipocalimab in IgG autoantibody- and alloantibody-mediated diseases.

Diagnostic Implications of CD63 and CD64 Expression Levels and FcγRIIIA 158 V/F Gene Polymorphism in Primary Immune Thrombocytopenia Adult Patients

OBJECTIVE

Immune thrombocytopenic purpura (ITP) is an acquired autoimmune disease characterized by reduced platelet counts due to immune system dysregulation caused by many factors, including genetics, autoimmune diseases, infections, and inflammations. Therefore, the current study aimed to evaluate immunological markers such as the expression level of lysosomal associated membrane protein 3 (LAMP-3), also known as CD63, and the expression level of Fc-gamma receptor I (FcγRI), also known as CD64 and also investigate the association of Fc-gamma receptor IIIA (FcγRIIIA) 158 V/F polymorphism to the risk of ITP.

METHODS

A total of 180 subjects; 60 ITP patients, 60 patients with thrombocytopenia of other causes and 60 controls were enrolled into our study. The expression level of CD63 was done using reverse transcription quantitative PCR (RTqPCR), while CD64 expression level was done by flow cytometry. The polymorphism of FcγRIIIA 158 V/F gene was analyzed by polymerase chain reaction followed by restriction fragment length polymorphism (PCR-RFLP) analysis. Finally, CD63 and CD64 protein-protein interactions were done by using the STRING online database.

RESULTS

The expression of CD63 was significantly elevated in ITP patients than thrombocytopenia patients and healthy control. Also there was high expression level of CD64 on granulocytes and monocytes from ITP patients than other groups. Receiver operating characteristic curve (ROC curve) analysis of CD63 showed an area under the curve (AUC) revealed of 1.00, sensitivity of 100% and specificity of 100%; while for CD64 on granulocytes, AUC of 0.998 as well as a sensitivity of 96.66% and specificity of 93.33%. Regarding FcγRIIIa 158 V/F polymorphism, all patients and healthy volunteers included in this study showed the wild FF genotype.

CONCLUSIONS

The expression of both CD63 and CD64 were significantly increased in ITP patients and could be good biomarkers to diagnose ITP. Additionally, there is no association between FcγRIIIa 158 V/F polymorphism and the risk of ITP disease.

Interplay of leucocyte-platelet complexes and clinical response to eltrombopag in immune thrombocytopenia patients

Eltrombopag (ELT) is a thrombopoietin-receptor agonist that stimulates platelet (PLT) production in patients with primary immune thrombocytopenia (ITP). One potential mechanism of ELT is modulating the inflammatory response by increasing PLTs binding to leucocytes. This study examined the effect of ELT on leucocyte-PLTs complexes in 38 ITP patients. Patients, predominantly females with a mean age of 59 years, underwent treatments like corticosteroids, intravenous immunoglobulin and splenectomy. Compared to healthy donors, ITP patients exhibited lower percentages of lymphocyte with bound PLTs, but similar monocyte- or neutrophil with bound PLTs. ELT treatment increased PLTs counts and all types of leucocyte with bound PLTs. Network analysis showed dynamic changes in leucocyte with bound PLTs relationships due to ELT. Machine learning indicated that higher percentages of monocytes with bound PLTs were linked to a better clinical response to ELT. A possible mechanism was an increased IL-10 production in monocytes with bound PLTs from responder patients. This study provides insights into the immunological changes in ITP patients undergoing ELT and suggests potential predictive biomarkers for treatment response and disease monitoring.

A 10-year retrospective study of antibacterial-induced thrombocytopenia in a women and children hospital using China Hospital Pharmacovigilance System and Visual Basic for Applications

AIMS

We aimed to investigate antibacterial-induced thrombocytopenia using the China Hospital Pharmacovigilance System (CHPS) in conjunction with Visual Basic for Applications (VBA).

METHODS

Between September 2011 and December 2022, a 2-phase workflow was employed to identify antibacterial-induced thrombocytopenia, including preliminary screening in phase (I) conducted by CHPS algorithms and causality assessment by trained pharmacists in phase (II) using VBA. The incidence of thrombocytopenia in each antibacterial was calculated, and comparisons were performed between paediatric and adult patients.

RESULTS

CHPS algorithms identified 4080 cases from 485 238 admissions (including 223 735 admissions receiving at least 1 antibacterial treatment). After ruling out cases with chemotherapy and abnormal platelet count at admission, 3832 cases were available. Using VBA, pharmacists identified 1039 cases (1246 antibacterial treatments, 28 agents) as potential thrombocytopenia instances (κ = 0.89), with an incidence of 0.46%. All antibacterial treatments correlated temporally with thrombocytopenia. Carbapenems (meropenem 1.77%), glycopeptides (vancomycin 1.55%) and lincosamides (clindamycin 0.44%) were prominent causal groups. The highest incidences of thrombocytopenia in the cephalosporins and penicillins groups were ceftazidime (2.04%) and piperacillin/tazobactam (1.24%), respectively. Among all antibacterial treatments, clindamycin showed the shortest time to onset (TTO), and erythromycin showed the longest TTO. Paediatric patients exhibited a longer TTO (61 vs. 29 h), extended time to nadir (83 vs. 37 h), lower platelet nadir count values (110 vs. 92 × 109/L), and a higher severe case proportion (12.37 vs. 3.86%) when compared with adults.

CONCLUSION

Different antibacterial agents exhibit varying incidences of thrombocytopenia, with notable disparities between adults and children in the characteristics of thrombocytopenia.

Therapeutic potential of roxadustat in immune thrombocytopenia: a Mendelian randomization analysis

BACKGROUND

Immune thrombocytopenia (ITP) is characterized by immune-mediated platelet destruction and impaired megakaryocyte maturation. Hypoxia-inducible factor-1α (HIF-1α), pivotal in the development of megakaryocytes and immune regulation, is downregulated in ITP. Roxadustat, which stabilizes HIF-1α, has emerged as a potential therapeutic drug for ITP that acts by enhancing HIF-1α-mediated megakaryocyte development and modulating immune responses.

OBJECTIVES

This study evaluates the safety profile of roxadustat and its therapeutic efficacy for ITP treatment using Mendelian randomization (MR) analysis.

METHODS

We used expression quantitative trait loci data for roxadustat's target genes (EGLN1, EGLN2, and EGLN3) and genetic associations with ITP and adverse outcomes from the Open Genome-Wide Association Study project. MR analysis included inverse-variance weighted, MR-Egger regression, weighted median, and MR pleiotropy residual sum and outlier methods to evaluate pleiotropy. Heterogeneity was assessed using Cochran's Q statistic and I2 measure with sensitivity analyses. A meta-analysis was performed to integrate effect sizes from multiple literature sources.

RESULTS

MR analysis revealed a significant association between roxadustat and reduced ITP risk (odds ratio, 0.79; 95% CI, 0.66-0.95; P = .01) with no evidence of horizontal pleiotropy. Meta-analysis confirmed the protective effect of roxadustat on ITP. Utilizing the expression quantitative trait loci of roxadustat's target gene EGLN1 as instrumental variables, an MR analysis of 39 potential adverse reactions revealed no significant increase, suggesting a favorable safety profile for roxadustat.

CONCLUSION

Roxadustat demonstrates a potential protective effect against ITP without increasing the risk of adverse outcomes, suggesting its promise as a therapeutic option for ITP and warranting further investigation.

Inhibition of FcRn with rozanolixizumab in adults with immune thrombocytopenia: Two randomised, double-blind, placebo-controlled phase 3 studies and their open-label extension

Primary immune thrombocytopenia (ITP) is an antiplatelet-antibody-mediated disorder with accelerated platelet clearance and decreased platelet production. Rozanolixizumab, a monoclonal IgG4 anti-FcRn antibody, blocks IgG recycling and decreases IgG levels. We report efficacy and safety of rozanolixizumab in adults with persistent/chronic ITP in 24-week phase 3 studies (TP0003; TP0006), and their 52-week open-label extension (OLE). Primary end-point was durable clinically meaningful platelet response (DCMPR) of ≥50 × 109/L for 8/12 weeks during Weeks 13-25 in the double-blind studies. Operational delays and evolving ITP treatment landscape led the sponsor to terminate these studies early; thus, only 21 and 12 (TP0003) and 20 and 10 (TP0006) patients were randomised to rozanolixizumab or placebo. Forty-three patients enrolled in the OLE: 42 started on every 2-week dosing; 21 later switched to weekly dosing. More rozanolixizumab-treated than placebo-treated patients achieved DCMPR: 4/21 versus 0 (TP0003) and 1/20 versus 0 (TP0006). Platelet increases to ≥50 × 109/L were observed on Day 8 in 52.4% (TP0003; 2/12 placebo) and 45.0% (TP0006; 1/10 placebo) of rozanolixizumab-treated patients. OLE platelet increases were maintained while on weekly dosing. The most frequent treatment-emergent adverse events overall were headache, pyrexia and nausea, as seen previously. Weekly dosing appears more efficacious than every 2-week dosing.

Pediatric Immune Thrombocytopenia: The Impact of Antithyroid Antibodies on the Treatment Outcomes

Immune thrombocytopenic purpura (ITP) is an acquired immune-mediated bleeding disorder characterized by isolated low platelet (PLT) counts. Immune thrombocytopenic purpura pathogenesis involves multiple immune mechanisms causing PLT destruction and inadequate production. Owing to impaired immune homeostasis, ITP patients can develop other than anti-PLT autoantibodies even in the absence of clinical signs of autoimmune disease, such as anti-thyroglobulin (TG) and anti-thyroperoxidase (TPO) antibodies. Our objective is to determine the prevalence of antithyroid antibodies (ATAs) in the population of pediatric ITP patients, and the differences in ATA positivity prevalence in newly diagnosed/persistent ITP, and chronic ITP patient subgroups, as well as to establish the impact of ATA positivity on the treatment outcomes. A cross-sectional observational study was conducted involving 75 pediatric patients diagnosed with ITP and 60 healthy controls, carried out over a period of 11 years. The prevalence of ATA was significantly higher in ITP patients compared with controls (28% vs 5%, P < .05). Initial PLT count was significantly lower in ATA-positive patients, but the treatment response did not differ between ATA-positive and ATA-negative patients. To conclude, our study confirmed that ITP patients have a higher prevalence of ATA compared with the healthy pediatric population; however, no association was found between ATA positivity and disease duration or treatment outcomes. Our findings suggest that ATA screening may not be prognostic for ITP in pediatric population, but further research with larger cohorts may be beneficial to elucidate the role of ATA in ITP pathogenesis and management.

Antigen B from Echinococcus granulosus regulates macrophage phagocytosis by controlling TLR4 endocytosis in immune thrombocytopenia

Immune thrombocytopenia (ITP) is characterized by a reduction in platelet counts, stemming from an autoimmune-mediated process where platelets are excessively cleared by macrophages. This enhanced phagocytosis is a cardinal pathogenic mechanism in ITP. Antigen B (AgB), a principal component of the Echinococcus granulosus cyst fluid, plays a pivotal role in safeguarding the parasite from host immune defenses by modulating macrophage activation. In this study, we explored the potential of AgB to regulate macrophage activation in the context of ITP. Our observations indicated a diminished presence of M1 macrophages and a reduced phagocytic capacity in patients infected with E. granulosus sensu stricto. We isolated AgB from E. granulosus cyst fluid (EgCF) and discovered that it could suppress the polarization of M1 macrophages and weaken their phagocytic activity via Fcγ receptors, consequently alleviating thrombocytopenia in an ITP mouse model. At the molecular level, AgB was found to suppress the activation of nuclear factor kappa B (NF-κB) and interferon regulatory factor 3 (IRF3) by impeding their nuclear translocation, leading to a reduction in the generation of inflammatory cytokines. Furthermore, AgB was shown to inhibit Toll-like receptor 4 (TLR4) endocytosis and the recycling of CD14. In aggregate, our findings uncover a novel immunomodulatory mechanism of AgB, which suppresses macrophage phagocytosis by regulating TLR4 endocytosis and the subsequent activation of NF-κB and IRF3 signaling pathways. These insights shed new light on the molecular intricacies of E. granulosus-induced immune evasion and suggest that AgB may serve as a promising therapeutic agent for ITP.

CD8+CD25+ Tregs as a predictor of glucocorticoid sensitivity in patients with immune thrombocytopenia

BACKGROUND

ITP is an immune-mediated disorder showing increased platelet destruction and reduced platelet production. Glucocorticoids are the first-line treatment, but 10-20% of patients are insensitive to them. We should avoid the irrational use of steroids for treating ITP. No markers exist to predict treatment responses in ITP. Recently, a few studies showed abnormal ratio and function of Tregs in ITP patients and that the levels of Tregs change after glucocorticoid treatment. We aimed to study the value of CD8+ CD25+ Tregs in predicting glucocorticoid sensitivity in newly diagnosed ITP patients.

RESEARCH DESIGN AND METHODS

This cohort (longitudinal) study included 60 ITP patients. The baseline platelet counts and levels of CD8+ CD25+ Tregs were measured at diagnosis. The response to steroids was evaluated after 2 weeks of treatment, then after 3 months and 6 months.

RESULTS

The ROC curve was plotted, and the p value was not significant; therefore, the optimal critical value, specificity and sensitivity could not be determined.

CONCLUSIONS

This study couldn't confirm the value of CD8+CD25+ Tregs in predicting glucocorticoid sensitivity in ITP, but there was a significant positive correlation between the CD8+CD25+ Tregs percentage and the steroids' response after 2 weeks. Therefore, further studies are recommended.

Mycobacterium immunogenum-Induced Thrombocytopenia

Mycobacterium immunogenum is a fast-growing non-tuberculous mycobacterium often found in soil, water, and aerosols. It primarily affects immunocompromised individuals. One common area of infection is the pulmonary system, but lymph nodes, bones, and joints are also commonly involved. We report a case of a young female with a two-year history of lymphadenopathy who developed thrombocytopenia with petechiae, bruising, and mucosal bleeding. Initially, she had a positron emission tomography/computed tomography (PET/CT) scan showing elevated standardized uptake value concerning for malignancy, but a biopsy shortly after revealed more of a reactive follicular hyperplastic etiology. Her platelet count was severely low (3 K/uL) and a diagnosis of immune (idiopathic) thrombocytopenic purpura (ITP) was made. After numerous negative tests, a Karius test was performed for possible infectious etiology, which revealed Mycobacterium immunogenum. The patient responded well to intravenous immunoglobulin and was managed outpatient without complications.  This case highlights the rare association of Mycobacterium immunogenum with ITP. There are studies that relate the occurrence of ITP in patients with Mycobacterium tuberculosis, another bacterium of similar taxonomy to Mycobacterium immunogenum. This case report is significant because there is limited research on the complications of Mycobacterium immunogenum, particularly its relationship to ITP. Given the lack of information regarding this association, this report serves as a catalyst for further research into identifying potential rare causes of ITP.

Autoimmune effector mechanisms associated with a defective immunosuppressive axis in immune thrombocytopenia (ITP)

Immune thrombocytopenia (ITP) is an autoimmune disease characterized by an isolated thrombocytopenia and variable phenotype as some patients suffer no bleeding whilst others have bleeding from mild to severe, which may be fatal. This variability probably reflects the disease's complex pathophysiology; a dysregulated hyperreactive immune effector cell response involving the entire adaptive immune system (e.g. B and T cell subsets) that leads to platelet and megakaryocyte (MK) destruction. It appears that these effector responses are due to a breakdown in immune tolerance, and this is characterized by defects in several immunosuppressive cell types. These include defective T regulatory cells (Tregs), B regulatory cells (Bregs) and Myeloid-derived suppressor cells (MDSC), all of which are all intimately associated with antigen presenting cells (APC) such as dendritic cells (DC). The loss of this immunosuppressive axis allows for the activation of unchecked autoreactive T cells and B cells, leading to the development of autoantibodies and cytotoxic T cells (CTL), which can directly destroy platelets in the periphery and inhibit MK platelet production in the bone marrow (BM). This review will focus on the effector cell mechanisms in ITP and highlight the defective immunosuppressive axis that appears responsible for this platelet-specific immune hyperreactivity.

Autoantibodies immuno-mechanically modulate platelet contractile force and bleeding risk

Altered mechanotransduction has been proposed as a putative mechanism for disease pathophysiology, yet evidence remains scarce. Here we introduce a concept we call single cell immuno-mechanical modulation, which links immunology, integrin biology, cellular mechanics, and disease pathophysiology and symptomology. Using a micropatterned hydrogel-laden coverslip compatible with standard fluorescence microscopy, we conduct a clinical mechanobiology study, specifically focusing on immune thrombocytopenia (ITP), an autoantibody-mediated platelet disorder that currently lacks a reliable biomarker for bleeding risk. We discover that in pediatric ITP patients (n = 53), low single platelet contraction force alone is a "physics-based" biomarker of bleeding (92.3% sensitivity, 90% specificity). Mechanistically, autoantibodies and monoclonal antibodies drive increases and decreases of cell force by stabilizing integrins in different conformations depending on the targeted epitope. Hence, immuno-mechanical modulation demonstrates how antibodies may pathologically alter mechanotransduction to cause clinical symptoms and this phenomenon can be leveraged to control cellular mechanics for research, diagnostic, and therapeutic purposes.

Romiplostim, low-dose rituximab and high-dose dexamethasone for newly diagnosed immune thrombocytopenia: A pilot study

Therapies such as corticosteroids, thrombopoietin receptor agonists and immunomodulators have been consistently under the spotlight in the search for a better treatment for immune thrombocytopenia (ITP). However, none of them has been widely embraced as a new standard. In this pilot study, we investigated feasibility, safety and preliminary efficacy of romiplostim, low-dose rituximab and high-dose dexamethasone for newly diagnosed ITP. We conducted a single-centre single-arm pilot. One-month treatment adherence was 100%. The 1-month overall response rate was 92.3%. Complete response occurred in 11 (84.6%) patients. Median duration of response was 4.13 monts (range 0.2-25). No serious adverse events presented.

The potential impact of COVID-19 vaccination on patients with immune thrombocytopenic purpura: A protocol for systematic review and meta-analysis

BACKGROUND

Immune thrombocytopenic purpura (ITP) is a disease characterized by a decrease in platelet count, which can be triggered by various factors, including viral infections and vaccination. With the widespread vaccination against COVID-19, concerns have arisen regarding a possible link between the vaccine and the exacerbation of ITP. This study aims to comprehensively evaluate the impact of COVID-19 vaccination on ITP patients, including associated risks and outcomes.

METHODS

A comprehensive search will be conducted in multiple electronic databases (including PubMed, Web of Science, EMBASE, Cochrane Library, CNKI, Wan Fang, VIP, and CBM) to identify relevant studies. This study will include randomized controlled trials, cohort studies, case-control studies, and case series evaluating the impact of COVID-19 vaccination on ITP patients. The primary outcome measure is the change in platelet count, while secondary outcome measures include the occurrence of thromboembolic events, bleeding complications, ITP recurrence rate, impact of ITP exacerbation, and adverse events. Data will be summarized and analyzed using Review Manager Software (RevMan) V.5.4. In addition, subgroup analyses will be performed to explore potential sources of heterogeneity.

RESULTS

It is anticipated that different types of COVID-19 vaccines may have varying impacts on ITP patients, leading to potential differences in outcomes. This study aims to comprehensively evaluate the potential impact of COVID-19 vaccination on ITP patients and provide reference for clinical decision-making.

CONCLUSIONS

The results of this systematic review and meta-analysis will provide crucial information on COVID-19 vaccination for ITP patients and clinicians, contributing to guiding vaccination decisions and monitoring potential impacts after vaccination.

The Many Faces of Immune Thrombocytopenia: Mechanisms, Therapies, and Clinical Challenges in Oncological Patients

The pathogenesis of immune thrombocytopenia (ITP) is complex and involves the dysregulation of immune cells, such as T and B lymphocytes, and several cytokines that promote the production of autoantibodies. In the context of cancer patients, ITP can occur in both primary and secondary forms related to anticancer therapies or the disease itself.

OBJECTIVE

In light of these data, we decided to prepare a literature review that will explain the classification and immunological determinants of the pathogenesis of ITP and present the clinical implications of this condition, especially in patients with cancer.

MATERIALS AND METHODS

We reviewed the literature on immunological mechanisms, therapies, and challenges in treating ITP, particularly on cancer patients.

RESULTS

The results of the literature review show that ITP in cancer patients can be both primary and secondary, with secondary ITP being more often associated with anticancer therapies such as chemotherapy and immunotherapy. Innovative therapies such as TPO-RA, rituximab, Bruton's kinase inhibitors, and FcRn receptor inhibitors have shown promising results in treating refractory ITP, especially in patients with chronic disease.

CONCLUSIONS

ITP is a significant clinical challenge, especially in the context of oncology patients, where both the disease and treatment can worsen thrombocytopenia and increase the risk of bleeding complications. Treatment of oncology patients with ITP requires an individualized approach, and new therapies offer effective tools for managing this condition. Future research into immunological mechanisms may bring further advances in treating ITP and improve outcomes in cancer patients.

Anti-synthetase and myelodysplastic syndromes with deep morphea: an example of shared immunopathogenesis? A case-based review

Anti-synthetase syndrome (AS) is a subset of idiopathic inflammatory myopathy (IIM) characterized by the presence of anti-aminoacyl-transfer RNA synthetase accompanied by myositis, interstitial lung disease and other clinical features. According to a recent multicentric study, 31% of AS patients present skin lesions compatible with dermatomyositis, but sclerodermiform features are rare. Therefore, we aimed to report the case of a patient with simultaneous diagnosis of AS, deep morphea, vasculitic neuropathy, and myelodysplastic syndrome and review the current literature regarding these uncommon associations. A 57 year old man with axial and symmetrical proximal muscle weakness, skin thickening and B symptoms, later diagnosed with PL7 + AS, deep morphea, myelodysplastic syndrome (MDS) and vasculitic neuropathy documented by histopathologic studies and immunologic assessments. Since both AS and deep morphea share the vasculopathic changes and type II interferon-induced inflammation, we hypothesize that they may share pathogenic mechanisms. The muscle biopsy of the patient was consistent with AS and showed focal neutrophil infiltration. The patient received intensive immunosuppressive therapy for AS and vasculitic neuropathy, with high dose steroids, intravenous immunoglobulin (IVIg) and rituximab. Nonetheless, he suffered an unfavorable evolution with a fatal outcome due to septic shock. Albeit sclerodermiform features are rare in patients with AS, we propose a pathogenic link among AS, deep morphea and the autoimmune/autoinflammatory signs of MDS. The vasculopathic changes along with the activation of the innate and adaptive immune system leading to the production of proinflammatory cytokines may have been one of the contributing factors for the coexisting diagnosis of the patient.

Thrombocytosis and Thrombocytopenia in Treatment-Naïve Rheumatoid Arthritis Patients: A Single-Centre Retrospective Data-Based Study From Pakistan

Background and objective This study aims to investigate thrombocytosis and thrombocytopenia in treatment-naïve rheumatoid arthritis (RA) patients, addressing the lack of data on their prevalence and clinical significance. By focusing on untreated patients, this study seeks to clarify the disease's natural course without confounding factors from prior therapies. The research is particularly important in the Pakistani context, where regional variations in RA presentation are underexplored. Findings are expected to enhance understanding of these hematological changes, ultimately guiding improved clinical management strategies for RA. Methods The present retrospective data-based study was conducted at the Department of Medicine & Allied Health Sciences, Azra Naheed Medical College, Superior University, Lahore, Pakistan. The 2010 American College of Rheumatology (ACR) diagnostic criteria were used to define RA. Thrombocytosis was defined as a platelet count greater than 400×109/L. Thrombocytopenia was defined as a platelet count less than 150×109/L. The Disease Activity Score in 28 joints (DAS-28 score) was used to categorize the disease severity of RA. Retrospective data were collected from the medical records of 165 patients with RA. Records from January 2023 to December 2023 were included. The assessment included demographic information, rheumatoid factor status, anti-CCP antibody status, disease severity measured by the DAS-28 score, and complete blood count (CBC) results, such as hemoglobin, white blood cell (WBC) count, and platelet count. Data entry and analysis were conducted using IBM SPSS Statistics software, version 23 (IBM Corp., Armonk, NY). Results The mean age of the patients was 42.5±13.6 years, with 25 (15.2%) male and 140 (84.8%) female patients. The RA factor (RAF) was positive in 128 (77.6%) and the anti-CCP antibody in 102 (61.8%). The mean DAS-28 score was 4.5±1.4, with 113 (68.5%) patients having mild-to-moderate disease and 52 (31.5%) patients having severe disease. Mean hemoglobin, WBC, and platelet counts were 12.0±1.4 g/dl, 9.0±2.7 ×109/L, and 352.6±110.4 ×109/L, respectively. Thrombocytosis was seen in 52 (31.5%) patients, while thrombocytopenia was seen in 11 (6.7%). Conclusion Thrombocytosis was seen in almost one-third of RA patients, having a significant association with age, the RAF factor positivity, and anti-CCP antibody negativity but not with gender and disease severity. Thrombocytopenia was relatively uncommon.

Possible immune mechanisms of gut microbiota and its metabolites in the occurrence and development of immune thrombocytopenia

Immune thrombocytopenia (ITP) is an autoimmune disease characterized by increased platelet destruction and impaired production, leading to an elevated bleeding tendency. Recent studies have demonstrated an important link between the gut microbiota and the onset and progression of several immune diseases in humans, emphasizing that gut microbiota-derived metabolites play a non-negligible role in autoimmune diseases. The gut microbiota and its metabolites, such as short-chain fatty acids, oxidized trimethylamine, tryptophan metabolites, secondary bile acids and lipopolysaccharides, can alter intestinal barrier permeability by modulating immune cell differentiation and cytokine secretion, which in turn affects the systemic immune function of the host. It is therefore reasonable to hypothesize that ecological dysregulation of the gut microbiota may be an entirely new factor in the triggering of ITP. This article reviews the potential immune-related mechanisms of the gut microbiota and representative metabolites in ITP, as well as the important influence of leaky gut on the development of ITP, with a view to enriching the theoretical system of ITP-related gut microecology and providing new ideas for the study of ITP.

Navigating Primary Immune Thrombocytopenia During Pregnancy With Management Strategies and Considerations: A Comprehensive Review

Primary immune thrombocytopenia (ITP) is an autoimmune disorder characterized by a reduction in platelet count due to autoantibody-mediated platelet destruction. ITP presents unique challenges during pregnancy, affecting both maternal and fetal health. This comprehensive review explores the pathophysiology, diagnosis, and management strategies of ITP in pregnant women, emphasizing the importance of individualized care. The incidence of ITP in pregnancy is significant, with potential complications including maternal hemorrhage and neonatal thrombocytopenia. Effective management is crucial to minimize these risks and ensure optimal outcomes. First-line treatments typically include corticosteroids and intravenous immunoglobulin (IVIG), with second-line options such as immunosuppressive agents and thrombopoietin receptor agonists. This review highlights the significance of multidisciplinary care and the need for careful monitoring and adjustment of treatment plans based on the severity of thrombocytopenia and the pregnancy stage. This review aims to enhance clinical decision-making and improve maternal and fetal outcomes in pregnancies complicated by ITP by providing a detailed analysis of current practices and emerging therapies.

Efficacy and safety of sovleplenib (HMPL-523) in adult patients with chronic primary immune thrombocytopenia in China (ESLIM-01): a randomised, double-blind, placebo-controlled, phase 3 study

BACKGROUND

Sovleplenib, a novel spleen tyrosine kinase (SYK) inhibitor, showed promising safety and activity in patients with primary immune thrombocytopenia in a phase 1b/2 trial. We aimed to evaluate the efficacy and safety of sovleplenib in patients with chronic primary immune thrombocytopenia.

METHODS

This randomised, double-blind, placebo-controlled, phase 3 trial (ESLIM-01) was done in 34 clinical centres in China. Eligible patients, aged 18-75 years, had chronic primary immune thrombocytopenia, an Eastern Cooperative Oncology Group (ECOG) performance status of 0-1, and received one or more previous treatments. Patients were randomly assigned (2:1) to receive oral sovleplenib or placebo, 300 mg once daily, for 24 weeks. Randomisation was stratified by baseline platelet counts, previous splenectomy, and concomitant treatment for anti-immune thrombocytopenia at baseline. The primary endpoint was durable response rate (proportion of patients with a platelet count of ≥50 × 109/L on at least four of six scheduled visits between weeks 14 and 24, not affected by rescue treatment) assessed by intention-to-treat. The trial is registered with ClinicalTrials.gov, NCT05029635, and the extension, open-label phase is ongoing.

FINDINGS

Between Sept 29, 2021, and Dec 31, 2022, 188 patients were randomly assigned to receive sovleplenib (n=126) or placebo (n=62). 124 (66%) were female, 64 (34%) were male, and all were of Asian ethnicity. Median previous lines of immune thrombocytopenia therapy were 4·0, and 134 (71%) of 188 patients had received previous thrombopoietin or thrombopoietin receptor agonist. The primary endpoint was met; durable response rate was 48% (61/126) with sovleplenib compared with zero with placebo (difference 48% [95% CI 40-57]; p<0·0001). The median time to response was 8 days with sovleplenib compared with 30 days with placebo. 125 (99%) of 126 patients in the sovleplenib group and 53 (85%) of 62 in the placebo group reported treatment-emergent adverse events (TEAEs), and most events were mild or moderate. Frequent TEAEs of grade 3 or higher for sovleplenib versus placebo were platelet count decreased (7% [9/126] vs 10% [6/62]), neutrophil count decreased (3% [4/126] vs 0% [0/62]), and hypertension (3% [4/126] vs 0% [0/62]). Incidences of serious TEAEs were 21% (26/126) in the sovleplenib group and 18% (11/62) in the placebo group. There were no deaths in the study.

INTERPRETATION

Sovleplenib showed a clinically meaningful sustained platelet response in patients with chronic primary immune thrombocytopenia, with a tolerable safety profile and improvement in quality of life. Sovleplenib could be a potential treatment option for patients with immune thrombocytopenia who received one or more previous therapy.

FUNDING

HUTCHMED and Science and Technology Commission of Shanghai Municipality.

Detection and characterization of autoreactive memory stem T-cells in children with acute immune thrombocytopenia

Primary immune thrombocytopenia (ITP) is an acquired autoimmune disorder characterized by an isolated decrease in platelets below 100 × 109/l after the exclusion of other conditions associated with thrombocytopenia. We investigated the role of different memory T-cell subsets, including T stem cell memory (TSCM), in children diagnosed with primary ITP and its association with therapeutic duration. This case-control study included 39 pediatric patients with acute ITP admitted to the Children's Hospital at Assiut University. Using a FACSCanto flow cytometer, CD8 + and CD4 + T-lymphocytes were gated. Five different subsets were characterized in each of these cells according to CD45RO and CD45RA expression. Afterward, gating was performed based on CCR7, CD95, and CD27. Examination of the CD8 + T cells subpopulation showed that Central memory T (TCM) and CD8+ Naïve T (TN) cells were significantly lower in ITP patients than in healthy children (p < 0.0001) and (p = 0.01), respectively. In addition, CD8 + TEMRA was significantly higher in ITP children than in controls (p = 0.001). CD4 + TCM cells were significantly lower in the ITP patient group (p = 0.04). However, CD4 + TEM was significantly higher in patients than controls (p = 0.04). Our research found that ITP patients had an imbalance in the ratio of CD4+ to CD8+ T cells in the peripheral blood and that TCM cells may be involved in the pathogenetic mechanism of ITP. TCMs could help in prediction of patients with higher risk of developing ITP.

ACVIM consensus statement on the diagnosis of immune thrombocytopenia in dogs and cats

Immune thrombocytopenia (ITP) is the most common acquired primary hemostatic disorder in dogs. Immune thrombocytopenia less commonly affects cats but is an important cause of mortality and treatment-associated morbidity in both species. Immune thrombocytopenia remains a diagnosis of exclusion for which diagnostic guidelines are lacking. Primary, or non-associative, ITP refers to autoimmune platelet destruction. Secondary, or associative, ITP arises in response to an underlying disease trigger. However, evidence for which comorbidities serve as ITP triggers has not been systematically evaluated. To identify key diagnostic steps for ITP and important comorbidities associated with secondary ITP, we developed 12 Population Evaluation/Exposure Comparison Outcome (PECO) format questions. These questions were addressed by evidence evaluators utilizing a literature pool of 287 articles identified by the panelists using a structured search strategy. Evidence evaluators, using panel-designed templates and data extraction tools, summarized evidence and created guideline recommendations that then were integrated by diagnosis and comorbidity domain chairs. The revised PECO responses underwent a Delphi survey process to reach consensus on final guidelines. A combination of panel expertise and PECO responses were employed to develop algorithms for diagnosis of ITP in dogs and cats, which also underwent 4 iterations of Delphi review. Comorbidity evidence evaluators employed an integrated measure of evidence (IME) tool to determine evidence quality for each comorbidity; IME values combined with evidence summaries for each comorbidity were integrated to develop ITP screening recommendations, which also were subjected to Delphi review. Commentary was solicited from multiple relevant professional organizations before finalizing the consensus. The final consensus statement provides clinical guidelines for the diagnosis of, and underlying disease screening for, ITP in dogs and cats. The systematic consensus process identified numerous knowledge gaps that should guide future studies. This statement is a companion manuscript to the ACVIM Consensus Statement on the Treatment of Immune Thrombocytopenia.

FOXO1 Single-Nucleotide Polymorphisms Are Associated with Bleeding Severity and Sensitivity of Glucocorticoid Treatment of Pediatric Immune Thrombocytopenia

Immune thrombocytopenia (ITP) is an autoimmune-mediated hemorrhagic disease. Emerging evidence indicates that FOXO1 SNPs are related to the immune dysregulation of several autoimmune diseases suggesting that FOXO1 may be involved in inflammation and pathologic activities in patients with ITP. This study aimed to evaluate whether FOXO1 gene single-nucleotide polymorphisms (SNPs) are associated with susceptibility to ITP and clinical priorities of concern include bleeding severity and sensitivity of glucocorticoid treatment. This study recruited 327 newly diagnosed ITP and 220 healthy controls. Four SNPs (rs17446593, rs17446614, rs2721068, and rs2721068) of the FOXO1 gene were detected using the Sequenom MassArray system. Bleeding severity were classified into the mild and severe groups based on the bleeding scores. ITP patients were classified as sensitive and insensitive to glucocorticoid treatment according to the practice guideline for ITP (2019 version). The frequencies of the four SNPs did not show any significant differences between the ITP and healthy control groups. Patients with AA genotype at rs17446593 (p = 0.009) and GG genotype at rs17446614 (p = 0.009) suffered more severe bleeding than patients without them. Carriers of haplotype Grs17446593Ars17446614Crs2721068Trs2755213 were protective to severe bleeding (p = 0.002). The AA genotype at rs17446593 was significantly higher in ITP patients sensitive to glucocorticoid treatment than in those insensitive to glucocorticoid treatment (p = 0.03). Haplotype Grs17446593Grs17446614Trs2721068Trs2755213 increases the risk of glucocorticoid resistance (p = 0.007). Although FOXO1 gene polymorphisms were not associated with susceptibility to ITP, the AA genotype at rs17446593 and GG genotype at rs17446614 were associated with bleeding severity. Haplotype GACT have a protective effect against severe bleeding. Patients with AA genotype at rs17446593 may tend to have good responds to glucocorticoid treatment. However, the FOXO1 gene haplotype GGTT increases the risk of glucocorticoid-resistant. Trial registration: ChiCTR1900022419.

HLA-DRB5 promotes immune thrombocytopenia via activating CD8+ T cells

Immune thrombocytopenia (ITP) is an autoimmune disease characterized by a low platelet (PLT) count and a high risk of bleeding, the clinical treatment for which still needs to be upgraded. Based on the critical role of human leukocyte antigen class II heterodimer β5 (HLA-DRB5) in immune system, we herein investigated its effect on ITP. ITP murine models were established by the injection of guinea pig anti-mouse platelet serum (GP-APS), and the PLT of mouse peripheral blood was counted during the modeling. Quantitative real-time reverse transcription polymerase chain reaction, western blot and immunofluorescence assay was performed to quantify expressions of HLA-DRB5, major histocompatibility complex II (MHC-II) and co-stimulatory molecules (CD80, CD86). Flow cytometry was conducted to analyze the percentage of CD8+ T cells. As a result, the PLT count was decreased in mouse peripheral blood. Expressions of HLA-DRB5, MHC-II and co-stimulatory molecules, as well as the percentage of CD8+ T cells were elevated in peripheral blood of ITP mice. HLA-DRB5 knockdown mitigated ITP by increasing peripheral PLT level, downregulating expressions of MHC-II and co-stimulatory molecules and inactivating CD8+ T cells. Collectively, the downregulation of HLA-DRB5 restores the peripheral PLT count in ITP mice by reducing MHC-II-mediated antigen presentation of macrophages to inhibit the activation of CD8+ T cells.

HLA-DRB5 Overexpression Promotes Platelet Reduction in Immune Thrombocytopenia Mice Model by Facilitating MHC-II-Mediated Antigen Presentation

INTRODUCTION

Major histocompatibility complex II (MHC-II)-mediated antigen presentation contributes to the pathogenesis of immune thrombocytopenia (ITP). Human leukocyte antigen (HLA)-DRB5 is an MHC-II molecule and this study aims to investigate its role and mechanisms in ITP development.

METHODS

Guinea pig anti-mouse platelet (PLT) serum-induced ITP mice received tail vein injection of HLA-DRB5 overexpressing adenoviral vector/immune receptor expressed on myeloid cells-1 (IREM-1) monoclonal antibody (mAb). PLT count changes in mice blood were assessed by a hematology analyzer. MHC-II/CD80/CD86 expression in mice blood was measured by quantitative real-time-PCR and immunofluorescence assay. CD8+ T-cell proportion in mice blood was detected by flow cytometry.

RESULTS

HLA-DRB5 overexpression exacerbated PLT reduction since the 5th day of the establishment of ITP mice model and enhanced MHC-II/CD80/CD86 expression upregulation as well as CD8+ T-cell ratio elevation in the blood of ITP mice, while its effects were reversed by IREM-1 mAb.

CONCLUSION

HLA-DRB5 overexpression upregulates MHC-II-mediated antigen presentation to CD8+ T cells, thus lowering PLT count in the ITP mice model.

Platelet Membrane-Derived Nanodiscs for Neutralization of Endogenous Autoantibodies and Exogenous Virulence Factors

The multifaceted functions of platelets in various physiological processes have long inspired the development of therapeutic nanoparticles that mimic specific platelet features for disease treatment. Here, the development and characterization of platelet membrane-derived nanodiscs (PLT-NDs) as platelet decoys for biological neutralization is reported. In one application, PLT-NDs effectively bind with anti-platelet autoantibodies, thus blocking them from interacting with platelets. In a mouse model of thrombocytopenia, PLT-NDs successfully neutralize pathological anti-platelet antibodies, preventing platelet depletion and maintaining hemostasis. In another application, PLT-NDs effectively neutralize the cytotoxicity of bacterial virulence factors secreted by methicillin-resistant Staphylococcus aureus (MRSA). In a mouse model of MRSA infection, treatment with PLT-NDs leads to significant survival benefits for the infected mice. Additionally, PLT-NDs show good biocompatibility and biosafety, as demonstrated in acute toxicity studies conducted in mice. These findings underscore the potential of PLT-NDs as a promising platelet mimicry for neutralizing various biological agents that target platelets. Overall, this work expands the repertoire of platelet-mimicking nanomedicine by creating a unique disc-like nanostructure made of natural platelet membranes.

A 11-year-old boy with Blastocystis hominis infection, presents as immune thrombocytopenia

BACKGROUND

Some causes of first-line treatment failure for ITP are often closely related to infections. But parasitic infections are rarely mentioned and easily overlooked. The case is the first to describe a boy with immune thrombocytopenia associated with blastocystis hominis.

CASE PRESENTATION

The case involved a boy presenting with bleeding skin spots and ecchymosis and accompanied by intermittent epigastric pain and constipation. After a series of complete examinations, the platelet count was found to be decreased to 13 × 109/L and immune thrombocytopenia was diagnosed. After first-line treatment with gamma globulin and prednisolone, the thrombocytopenia remained unchanged. Blastocystis hominis was subsequently found in the patient's stool and then the treatment of metronidazole was provided. One week later, the patient's thrombocytopenia was completely relieved. He was followed up for six months and was found to have recovered well.

CONCLUSIONS

The screening for potential predisposing factors is very important for immune thrombocytopenia patients with poor response to first-line treatment, and the best treatment strategy should include the management of potential diseases.

Pathophysiology, Clinical Manifestations and Diagnosis of Immune Thrombocytopenia: Contextualization from a Historical Perspective

Immune thrombocytopenia (ITP) is an autoimmune disease characterized by an isolated decrease in the platelet count and an increased risk of bleeding. The pathogenesis is complex, affecting multiple components of the immune system and causing both peripheral destruction of platelets and impaired central megakaryopoiesis and platelet production in the bone marrow. Here, we intend to contextualize the current knowledge on the pathophysiology, terminology, epidemiology, clinical manifestations, diagnosis, and prognosis of ITP from a historical perspective and the first references to the never-stopping garnering of knowledge about this entity. We highlight the necessity to better understand ITP in order to be able to provide ITP patients with personalized treatment options, improving disease prognosis and reducing the incidence or frequency of refractoriness.

Machine learning models developed and internally validated for predicting chronicity in pediatric immune thrombocytopenia

BACKGROUND

Primary immune thrombocytopenia (ITP) in children is typically self-limiting; however, 20% to 30% of patients may experience prolonged thrombocytopenia lasting over a year. The challenge is predicting chronicity to ensure personalized treatment approaches.

OBJECTIVES

To address this issue, we developed and internally validated 4 machine learning (ML) models using demographic and immunologic characteristics to predict the likelihood of chronicity.

METHODS

The present study was conducted at Beijing Children's Hospital from June 2018 to December 2021, aiming to develop predictive models for determining the chronicity of pediatric ITP. Four ML models, based on a logistic regression classifier, random forest classifier, eXtreme Gradient Boosting (XGBoost), and support vector machine, were employed. These models used a set of 16 variables, including 14 immunologic and 2 demographic predictors. The performance evaluation criteria included prediction accuracy, precision, recall, F1 score, and area under the receiver operating characteristic curve (AUROC).

RESULTS

Data were collected from 662 patients who were randomly assigned to either a training dataset or a testing dataset using a random number generator. Among them, 26.5% had chronic disease. All models performed well, with AUROC values ranging from 0.81 to 0.84, and XGBoost was selected for its highest AUROC score and interpretability in constructing the predictive model. Age, T helper 17, T helper 17-to-regulatory T cell ratio, T helper 1, and double-negative T cells were identified as significant predictors by the XGBoost algorithm.

CONCLUSION

We developed a precise predictive model for chronicity in pediatric ITP using ML during the initial phase. The XGBoost model achieved high predictive accuracy by using individual patient clinical parameters and demonstrated commendable interpretability.

Risk Factors for Pulmonary Embolism in Individuals Infected with SARS-CoV2-A Single-Centre Retrospective Study

The emergence of SARS-CoV2 has presented itself as a significant global health crisis. The prevalence of thrombotic events is known to be high in these patients, affecting various organ systems, sometimes leading to cutaneous thrombosis, pulmonary embolism (PE), stroke, or coronary thrombosis. The available evidence suggests that thromboembolism, hypercoagulability, and the excessive production of proinflammatory cytokines play a significant role in the development of multiorgan failure. Methodology: This retrospective single-centre study was conducted at "Victor Babes" University of Medicine and Pharmacy from Timisoara, Romania, involving a total of 420 patients diagnosed with COVID-19. We separated them into a CONTROL group that included 319 patients, and an intervention group (PE) with 101 patients that, subsequent to infection with the virus, developed pulmonary embolism. The study included the reporting of demographic data, laboratory findings, and comorbidities. Results: Out of a total of 420 patients, 24% experienced pulmonary embolism, while 21.42% died. Arterial thrombotic events were found to be associated with factors such as age, cardiovascular disease, levels of white blood cells, D-dimers, and albumin in the blood. The findings of the study indicate that there is an independent association between pulmonary thrombosis and hypertension (odds ratio (OR): 1.1; 95% confidence interval (CI): 0.7 to 1.7; p = 0.6463), cancer (OR: 1.1; 95% CI: 0.6 to 2.3; p = 0.6014), and COPD (OR: 1.2; 95% CI: 0.6 to 2.3; p = 0.4927). On the other hand, there is a stronger correlation between PE and obesity (OR: 2.8; 95% CI: 1.7 to 4.6; p < 0.0001), diabetes (OR: 3.3; 95% CI: 2 to 5.3; p < 0.0001), and dyslipidemia (OR: 3.6; 95% CI: 2.3 to 5.8; p < 0.0001) in a multivariable regression logistic model. Conclusions: Patients diagnosed with severe forms of COVID-19 display a comparable incidence of arterial thrombotic events, which have been linked to poor survival rates.

Viruses and thrombocytopenia

Thrombocytopenia, characterized by a decrease in platelet count, is a multifaceted clinical manifestation that can arise from various underlying causes. This review delves into the intriguing nexus between viruses and thrombocytopenia, shedding light on intricate pathophysiological mechanisms and highlighting the pivotal role of platelets in viral infections. The review further navigates the landscape of thrombocytopenia in relation to specific viruses, and sheds light on the diverse mechanisms through which hepatitis C virus (HCV), measles virus, parvovirus B19, and other viral agents contribute to platelet depletion. As we gain deeper insights into these interactions, we move closer to elucidating potential therapeutic avenues and preventive strategies for managing thrombocytopenia in the context of viral infections.

Immune Thrombocytopenic Purpura Associated With Systemic Lupus Erythematosus, Helicobacter pylori, and Hepatitis B

Immune thrombocytopenic purpura (ITP) is a hematologic condition characterized by decreased circulating platelets, resulting in bruising, bleeding gums, and internal bleeding. This disorder can be categorized into two primary forms based on the duration of symptoms and underlying causes. Acute ITP primarily affects young children, typically between the ages of two and six, but it can also impact older children and adults. Viral infections like chickenpox, respiratory infections, or gastroenteritis often precede it. Acute ITP manifests suddenly and lasts for a short period, typically less than six months and sometimes only a few weeks. On the other hand, chronic ITP primarily affects adults but can occur at any age, including childhood and adolescence. The main characteristic of chronic ITP is the persistence of symptoms for more than six months. It can be either idiopathic (primary), with no discernible etiologic cause, or secondary to various conditions such as autoimmune diseases (e.g., systemic lupus erythematosus), viral infections (e.g., human immunodeficiency virus (HIV), hepatitis C virus (HCV)), certain malignancies (e.g., chronic lymphocytic leukemia), or drug reactions. This case report presents the management of a 36-year-old African American female diagnosed with ITP associated with systemic lupus erythematosus, Helicobacter (H.) pylori, and hepatitis B infection.

Effects of canine influenza infection and DA2PP vaccination on the development of platelet-associated immunoglobulins and platelet counts in dogs

BACKGROUND

Immune thrombocytopenia (ITP) is commonly associated with platelet-associated immunoglobulins (PAIg). Demonstration of PAIg can help determine etiologies for thrombocytopenia. In humans, ITP and thrombocytopenia have been associated with various vaccinations and influenza infections, respectively.

OBJECTIVES

We aimed to evaluate platelet counts and PAIg in research dogs with H3N2 and in research and client-owned dogs routinely vaccinated for distemper, adenovirus-2, parainfluenza, and parvovirus (DA2PP). The hypotheses were that H3N2 infection but not DA2PP vaccination would decrease platelet counts, and neither would result in the detection of PAIg.

METHODS

Three pilot studies. Platelet counts and PAIg, measured by direct flow cytometry as %IgG, were evaluated in eight research Beagles following experimental infection with H3N2 (experiment 1), nine research Beagles vaccinated for DA2PP (experiment 2), and thirty client-owned dogs vaccinated for DA2PP (experiment 3). All animals were considered healthy at the start of the experiments.

RESULTS

Transient, self-resolving decreases in platelet counts and increases in %IgG occurred following H3N2 infection, and one dog became thrombocytopenic and positive for PAIg. Following DA2PP vaccination, %IgG increased in research and client-owned dogs, but only one dog was considered positive for PAIg with a concurrent increase in platelet count. Mean PAIg increased from baseline in client-owned dogs following vaccination.

CONCLUSIONS

Transient PAIg and thrombocytopenia can occur following H3N2 infection, while routine vaccination for DA2PP in this group of dogs was not associated with the development of thrombocytopenia or clinically relevant formation of PAIg.

Current Understanding of Immune Thrombocytopenia: A Review of Pathogenesis and Treatment Options

The management of immune thrombocytopenia (ITP) and the prediction of patient response to therapy still represent a significant and constant challenge in hematology. ITP is a heterogeneous disease with an unpredictable evolution. Although the pathogenesis of ITP is currently better known and its etiology has been extensively studied, up to 75% of adult patients with ITP may develop chronicity, which represents a significant burden on patients' quality of life. A major risk of ITP is bleeding, but knowledge on the exact relationship between the degree of thrombocytopenia and bleeding symptoms, especially at a lower platelet count, is lacking. The actual management of ITP is based on immune suppression (corticosteroids and intravenous immunoglobulins), or the use of thrombopoietin receptor agonists (TPO-RAs), rituximab, or spleen tyrosine kinase (Syk) inhibitors. A better understanding of the underlying pathology has facilitated the development of a number of new targeted therapies (Bruton's tyrosine kinase inhibitors, neonatal Fc receptors, strategies targeting B and plasma cells, strategies targeting T cells, complement inhibitors, and newer TPO-RAs for improving megakaryopoiesis), which seem to be highly effective and well tolerated and result in a significant improvement in patients' quality of life. The disadvantage is that there is a lack of knowledge of the predictive factors of response to treatments, which would help in the development of an optimized treatment algorithm for selected patients.

Efficacy and safety of mycophenolate mofetil in patients with immune thrombocytopenic purpura: a systematic review and meta-analysis

BACKGROUND

Immune thrombocytopenic purpura (ITP) is a challenging disease in its presentation and management as it may cause life-threatening hemorrhaging in vital organs and may resist several lines of treatment. This systematic review and meta-analysis aimed to evaluate the safety and efficacy of mycophenolate mofetil (MMF) in treating patients with ITP.

METHODS

We systematically searched four electronic databases (PubMed, Scopus, Web of Science, and Cochrane Central Register of Controlled Trials) from inception until 10 October 2022. We included all clinical trials, either controlled or single arm, and prospective and retrospective observational studies that evaluate the efficacy and safety of MMF in patients with ITP. We assessed the risk of bias using three tools (ROBINS-I, Cochrane ROB-2, and NIH), each for eligible study design.

RESULTS

Nine studies were included in this meta-analysis, with a total of 411 patients with ITP. We found that MMF demonstrated an overall response rate of (62.09%; 95% CI = [43.29 to 77.84]) and the complete response rate was (46.75%; 95% CI = [24.84 to 69.99]). The overall proportion of adverse events was (12%; 95% CI = [6 to 24]). After the sensitivity analysis, the overall response rate became 50%; 95% CI = [38 to 63]) and the complete response rate became (32%; 95% CI = [24 to 42]). However, MMF did not appear to affect white blood cell counts or hemoglobin levels significantly.

CONCLUSION

This systematic review and meta-analysis demonstrate that MMF appears to be an effective and relatively safe treatment option for patients with ITP when combined with steroids and even in those who have not responded to standard therapies (steroid-resistant cases). Further research with well-designed studies is warranted to better understand the factors influencing treatment response and to refine the use of MMF in the management of ITP. An interactive version of our analysis can be accessed from here: https://databoard.shinyapps.io/mycophenolate_meta/.

Recent advances in the management of immune thrombocytopenic purpura (ITP): A comprehensive review

Autoimmune disorders place a substantial burden on the healthcare system all over the world affecting almost 3% to 8% of the population. Immune thrombocytopenic purpura (ITP), also known as idiopathic thrombocytopenic purpura, is a blood disorder in which the body immune system destroys platelets, leading to low platelet counts in the blood (peripheral blood platelet count < 150 × 109/L). Although the pathophysiology of ITP is not fully understood, it is believed to result from a complex interplay between hereditary and environmental variables. Certain factors, such as a low platelet count, history of bleeding, and certain comorbidities can increase the risk of severe bleeding in patients with ITP. Corticosteroids, intravenous immunoglobulin (IVIG), immunosuppressants, rituximab, and thrombopoietin receptor agonists (TPO-RAs) are some of the advanced treatments for ITP. Although these therapies may be successful, they also carry the risk of negative effects. Recently, significant advancements have been made in the understanding and treatment of ITP. There is still much to learn about the disease, and new, more effective treatments are needed. This comprehensive review offers a comprehensive assessment of recent advancements in ITP management, with a focus on active research projects, novel therapeutic targets, new treatment modalities, and areas of uncertainty and unmet needs. According to research, it is crucial to develop individualized treatment plans for ITP patients based on their age, platelet count, risk of bleeding, and comorbidities. The article also looks at how future developments in gene editing, bispecific antibody therapies, and cellular therapy may completely change the treatment of ITP.

Trimethylamine-N-oxide (TMAO) and basic fibroblast growth factor (bFGF) are possibly involved in corticosteroid resistance in adult patients with immune thrombocytopenia

PURPOSE

Immune thrombocytopenia (ITP) is an autoimmune disease characterized by accelerated platelet clearance. Gut dysbiosis was associated with its pathogenesis, but the underlying mechanisms have not been fully elucidated. Patients with ITP exhibit varying degrees of responsiveness to corticosteroid treatment. Therefore, prognostic indexes for corticosteroid responsiveness in ITP could offer valuable guidance for clinical practices.

METHODS

The present study examined the signature of six types of gut-microbiota metabolites and forty-eight types of cytokines, chemokines, and growth factors and their clinical significance in patients with ITP.

RESULTS

Both patients with good and poor corticosteroid responsiveness exhibited significantly elevated/suppressed secretion of twenty-two cyto(chemo)kins/growth factors in comparison to healthy controls. Additionally, patients with ITP demonstrated a significant decrease in plasma levels of trimethylamine-N-oxide (TMAO), which was found to be negatively correlated to circulating platelet counts, and positively correlated with Interleukin (IL)-1β and IL-18. Notably, patients who exhibited poor response to corticosteroid treatment displayed elevated levels of TMAO and basic fibroblast growth factor (bFGF) in comparison to responders. Additionally, we found that the amalgamation of TMAO, bFGF and interleukin (IL)-13 could serve as a valuable prognostic tool for predicting CS responsiveness.

CONCLUSION

Patients with ITP were characterized overall by an imbalanced secretion of cyto(cheo)kins/growth factors and inadequate levels of TMAO. The varying degrees of responsiveness to corticosteroid treatment can be attributed to different profiles of basic FGF and TMAO that might be related to overburdened oxidative stress and inflammasome overactivation, and ultimately mediate corticosteroid resistance.

Regulatory role of ceRNA network in B lymphocytes of patients with immune thrombocytopenia

OBJECTIVE

High-throughput sequencing was used to screen expressing differences of miRNA, lncRNA, and mRNA in CD19+ B peripheral blood samples of newly diagnosed immune thrombocytopenia (ITP) patients and healthy controls. The study aimed to explore the regulatory role of ceRNA network in the pathogenesis of dysfunctional CD19 + B lymphocytes of ITP patients.

METHODS

CD19+ B lymphocytes were isolated from peripheral blood samples of ITP patients and their healthy counterparts. High-throughput sequencing was used to screen for the expression of miRNA, lncRNA, and mRNA of ITP patients and healthy controls, which were analysed by the ceRNA network. Moreover, qPCR was used to verify the differential expression of miRNA, lncRNA, and mRNA in ITP patients and healthy controls. The correlation between differentially expressed miRNA, lncRNA, mRNA, and B lymphocyte subsets was also analysed.

RESULTS

The CD19+ B lymphocytes of 4 newly diagnosed ITP patients and 4 healthy controls were sequenced and analysed. There were 65 differentially expressed lncRNA and 149 mRNA forming a ceRNA network showed that 12 lncRNA and 136 differentially expressed mRNA were closely associated. Similarly, miR-144-3p, miR-374c-3p, and miR-451a were highly expressed in ITP patients, as confirmed by qPCR, which was consistent with the high-throughput sequence results. LOC102724852 and CCL20 were highly expressed in ITP patients, while LOC105378901, LOC112268311, ALAS2, and TBC1D3F were not as compared to healthy controls, which was consistent with the high-throughput sequence results. In addition, the expression of miR-374c-3p, LOC112268311, LOC105378901, and CXCL3 were correlated with the percentage of B lymphocyte subsets.

CONCLUSIONS

The ceRNA network of miRNA, lncRNA, and mRNA in peripheral CD19 + B lymphocytes plays an essential role in the pathogenesis of ITP.

Platelet dropping, bleeding and new treatment requirements in ITP patients after inactivated COVID-19 vaccination

Significant decreases in platelet counts and ITP relapses have been documented in ITP patients receiving COVID-19 mRNA vaccines; however, the effect of the inactivated COVID-19 vaccine on ITP patients remains unclear. The present study aimed to investigate the impact of inactivated COVID-19 vaccines on ITP patients, with a focus on platelet dropping events, bleeding events/scores, and the requirement of a new round of treatment. A total of 118 ITP patients, with 97 chronic ITP and 21 persistent ITP, who received inactivated COVID-19 immunization were investigated retrospectively. Following vaccination (within 1 month), ITP patients reported platelet dropping (31.36 %), new bleeding events (22.88 %), increases in bleeding scores (23.73 %), and new treatment requirements (22.03 %). Among them, persistent ITP patients with disease duration of 3-12 months had higher ratios of the above adverse events (71.43 %, 57.14 %, 61.90 % and 71.43 %, respectively) than chronic ITP patients with duration > 1 year (22.68 %, 15.46 %, 15.46 % and 11.34 %, respectively); patients' disease duration was negatively correlated with platelet dropping events and new treatment requirements. Furthermore, logistic regression analysis also supported the above findings, revealing that persistent ITP patients had 9.40-9.70, 7.24-10.08, and 27.17-28.51 times incidence of having platelet dropping events, new bleeding events, and new treatment requirements after vaccination, respectively, when compared to chronic ITP patients. In conclusion, the present study demonstrates that after receiving inactivated COVID-19 vaccines, ITP patients may experience platelet dropping, which may lead to new bleeding events and the requirement of a new round of treatment for ITP recurrence. As a result, platelet level monitoring is crucial for ITP patients during the vaccination, especially those with persistent ITP.

A Successfully Treated COVID-19 Vaccine Induced Immune Thrombocytopenic Purpura

Immune Thrombocytopenic Purpura (ITP) is a life-threatening condition where an accurate initial assessment is essential to be able to offer the proper therapy in a timely matter to improve the outcome of the patient. Here, we present a case of ITP secondary to the coronavirus disease 2019 (COVID-19) vaccine (BioNTech, Pfizer vaccine). A 61-year-old obese African American female presented to the emergency room (ER) from a clinic with a platelet count of 11k/ul 21 days after she received the second dose of the BioNTech, Pfizer vaccine. The patient was immediately started on intravenous immunoglobulin (IVIG) 1g/kg twice daily (bid) and dexamethasone 20 mg IV every 12 hrs (q12h). The next day, the platelet count increased to 63 k/ul, and after the second dose of IVIG, the platelet count improved to 122 k/ul and trended up. The early detection of ITP induced by the mRNA COVID-19 vaccine is determinant to guide the early and proper therapy with immunoglobulins and steroids to improve the outcome of our patients.

The diagnostic accuracy of mean platelet volume in differentiating immune thrombocytopenic purpura from hypo-productive thrombocytopenia: A systematic review and meta-analysis

BACKGROUND

Thrombocytopenia is defined as a decreased number of platelets in the circulating blood as a result of hypo-proliferation in marrow or peripheral destruction of platelets. Several diagnostic methods have been proposed to discriminate the underline cause of thrombocytopenia. Recent studies showed that mean platelet volume (MPV) could be used for differential diagnosis of immune thrombocytopenic purpura (ITP). Thus, we aimed to investigate the diagnostic accuracy of MPV for differential diagnosis of ITP from hypo-productive thrombocytopenia.

METHODS

This study was conducted in accordance with the Preferred Reporting Items for Systematic Review and Meta-Analysis guidelines (PRISMA). The study protocol was registered on PROSPERO with the reference number CRD42023447789. Relevant published studies that were published up to April 10, 2023, in peer-reviewed journals were searched on electronic different databases. The methodological quality of the included studies was appraised using the quality assessment of diagnostic accuracy studies 2 (QADAS-2) tool. The pooled weight mean difference (WMD) of MPV between the ITP group and hypo-productive group was analyzed using a random-effects model meta-analysis. Relevant data were extracted using a Microsoft Excel spreadsheet and analyzed using STATA 11.0 and Meta-disc 1.4 software. Publication bias was evaluated using Deek's funnel plot asymmetry test.

RESULTS

A total of 14 articles were included in this systematic review and meta-analysis. The comparison of MPV between groups revealed that the pooled mean value of MPV increased significantly in ITP patients compared to patients with hypo-productive thrombocytopenia (WMD = 2.03; 95% CI, 1.38-2.69). The pooled sensitivity and specificity of MPV in differentiating ITP from hypo-productive thrombocytopenia were 76.0% (95% CI: 71.0%, 80.0%) and 79.0% (95% CI: 75.0%, 83.0%), respectively. The summary positive likelihood ratio (PLR) and negative likelihood ratio (NLR)using the random effects model were 3.89 (95% CI: 2.49, 6.10) and 0.29 (95% CI: 0.18, 0.46), respectively.

CONCLUSION

MPV can be used to discriminate ITP from hypo-productive thrombocytopenia. It can possess large advantages as it is noninvasive, simple, quick, inexpensive, easy to perform, reliable, and routinely generated by automated cell counters.

Causal relationship between gut microbiota and immune thrombocytopenia: a Mendelian randomization study of two samples

Background

Some observational studies have shown that immune thrombocytopenia (ITP) is highly associated with the alteration-composition of gut microbiota. However, the causality of gut microbiota on ITP has not yet been determined.

Methods

Based on accessible summary statistics of the genome-wide union, the latent connection between ITP and gut microbiota was estimated using bi-directional Mendelian randomization (MR) and multivariable MR (MVMR) analyses. Inverse variance weighted (IVW), weighted median analyses, and MR-Egger regression methods were performed to examine the causal correlation between ITP and the gut microbiota. Several sensitivity analyses verified the MR results. The strength of causal relationships was evaluated using the MR-Steiger test. MVMR analysis was undertaken to test the independent causal effect. MR analyses of reverse direction were made to exclude the potential of reverse correlations. Finally, GO enrichment analyses were carried out to explore the biological functions.

Results

After FDR adjustment, two microbial taxa were identified to be causally associated with ITP (PFDR < 0.10), namely Alcaligenaceae (PFDR = 7.31 × 10-2) and Methanobacteriaceae (PFDR = 7.31 × 10-2). In addition, eight microbial taxa were considered as potentially causal features under the nominal significance (P < 0.05): Actinobacteria, Lachnospiraceae, Methanobacteria, Bacillales, Methanobacteriales, Coprococcus2, Gordonibacter, and Veillonella. According to the reverse-direction MR study findings, the gut microbiota was not significantly affected by ITP. There was no discernible horizontal pleiotropy or instrument heterogeneity. Finally, GO enrichment analyses showed how the identified microbial taxa participate in ITP through their underlying biological mechanisms.

Conclusion

Several microbial taxa were discovered to be causally linked to ITP in this MR investigation. The findings improve our understanding of the gut microbiome in the risk of ITP.

Frequency of toll-like receptor 4 variants and association with treatment response in children with primary immune thrombocytopenia

OBJECTIVES

To investigate the frequency of toll-like receptor 4 (TLR4) variants c.896A>G (p.Asp299Gly) and c.1196C>T (p.Thr399Ile) among Egyptian children with primary immune thrombocytopenia (pITP), and their association with disease course and response to treatment.

METHODS

A case-control study that included 80 children with pITP and 50 age- and sex-matched healthy controls. TLR4 c.896A>G and c.1196C>T variants were genotyped using polymerase chain reaction-restriction fragment length polymorphism. Patients were classified according to their response to treatment after 3 months as responders and nonresponders.

RESULTS

Compared with controls, children with pITP had significantly higher minor allele frequencies of TLR4 p.Asp299Gly (16.25% vs. 6%, odds ratio [OR] 3.04, 95% confidence interval [CI]: 1.16-9.36, p = .014) and p.Thr399Ile (20% vs. 4%, OR 6, 95% CI: 2.02-24.01, p < .001). The presence of p.Asp299Gly variant was significantly associated with chronic ITP (OR 7.78, 95% CI: 2.04-35.69, p < .001) and non-response to therapy with steroid (OR 11.67, 95% CI: 1.32-104.08, p = .012), but not thrombopoietin-receptor agonist (OR 1.67, 95% CI: 0.35-8.19, p = .464). Likewise, having p.Thr399Ile variant was significantly associated with chronic ITP (OR 5.14, 95% CI: 1.6-17.4, p = .002) and non-response to therapy with steroid (OR 6.1, 95% CI: 1.01-49.06, p = .046) but not thrombopoietin-receptor agonist (OR 1.57, 95% CI: 0.33-7.58, p = .515).

CONCLUSION

The presence of TLR4 p.Asp299Gly or p.Thr399Ile variant may be associated with ITP predisposition, chronicity, and non-response to upfront steroid therapy. These findings enhance our understanding of the complex pathophysiology of pITP with potentially important clinical implications.

Early immunomodulation in immune thrombocytopenia-A report of the ICIS meeting in Lenzerheide, Switzerland 2022

The only way to prevent immune thrombocytopenia (ITP) from becoming refractory would be to restore tolerance to platelets at an early phase of the disease. Numerous immune alterations probably accumulate in chronic ITP; thus, the chances of cure decrease significantly with time. Currently, sustained remission off treatment (SROT) is a clinical definition describing patients who can discontinue their ITP treatment without risk and maintain a state of remission. Different treatment strategies are presently being evaluated with the goal of attaining SROT, mostly combining drugs targeting the innate and/or the adaptive immune system, the inflammation state, so as increasing the platelet load. In this sense, thrombopoietin receptor agonists (TPO-RAs) have shown promising results if used as upfront treatment. TPO-RAs seem to exhibit immunomodulation and immune tolerance properties, increasing not only the platelet antigen mass but also increasing the transforming growth factor-β concentration, and stimulating regulatory T and B lymphocytes. However, more immunological studies are needed to establish accurate molecular alterations in ITP that are potentially reversed with treatments.

The mTORC1 pathway participate in hyper-function of B cells in immune thrombocytopenia

B cell hyper-function plays an important role in the pathogenesis of immune thrombocytopenia (ITP), but the molecular mechanisms underlying such changes remain unclear. We sought to identify regulators of B cell dysfunction in ITP patients through transcriptome sequencing and the use of inhibitors. B cells were isolated from PBMC of 25 ITP patients for B cell function test and transcriptome sequencing. For the potential regulatory factors identified by transcriptome sequencing, the corresponding protein inhibitors were used to explore the regulatory effect of the regulatory factors on B cell dysfunction in vitro. In this study, increased antibody production, enhanced terminal differentiation and highly expressed costimulatory molecules CD80 and CD86 were found in B cells of patients with ITP. In addition, RNA sequencing revealed highly activated mTOR pathway in these pathogenic B cells, indicating that the mTOR pathway may be involved in B cell hyper-function. Furthermore, mTOR inhibitors rapamycin or Torin1 effectively blocked the activation of mTORC1 in B cells, resulting in reduce antibody secretion, impaired differentiation of B cells into plasmablasts and downregulation of costimulatory molecules. Interestingly, as an unspecific inhibitor of mTORC2 besides mTORC1, Torin1 did not show a stronger capacity to modulate B cell function than rapamycin, suggesting that the regulation of B cells by Torin1 may depend on blockade of mTORC1 rather than mTORC2 pathway. These results indicated that the activation of mTORC1 pathway is involved in B cell dysfunction in patients with ITP, and inhibition of mTORC1 pathway might be a potential therapeutic approach for ITP.

Restraint Stress-Induced Immunosuppression Is Associated with Concurrent Macrophage Pyroptosis Cell Death in Mice

Psychological stress is widely acknowledged as a major contributor to immunosuppression, rendering individuals more susceptible to various diseases. The complex interplay between the nervous, endocrine, and immune systems underlies stress-induced immunosuppression. However, the underlying mechanisms of psychological-stress-induced immunosuppression remain unclear. In this study, we utilized a restraint stress mouse model known for its suitability in investigating physiological regulations during psychological stress. Comparing it with cold exposure, we observed markedly elevated levels of stress hormones corticosterone and cortisol in the plasma of mice subjected to restraint stress. Furthermore, restraint-stress-induced immunosuppression differed from the intravenous immunoglobulin-like immunosuppression observed in cold exposure, with restraint stress leading to increased macrophage cell death in the spleen. Suppression of pyroptosis through treatments of inflammasome inhibitors markedly ameliorated restraint-stress-induced spleen infiltration and pyroptosis cell death of macrophages in mice. These findings suggest that the macrophage pyroptosis associated with restraint stress may contribute to its immunosuppressive effects. These insights have implications for the development of treatments targeting stress-induced immunosuppression, emphasizing the need for further investigation into the underlying mechanisms.

Children with Chronic Immune Thrombocytopenia Exhibit High Expression of Human Endogenous Retroviruses TRIM28 and SETDB1

Chronic immune thrombocytopenia (CITP) is an autoimmune disease whose underlying biologic mechanisms remain elusive. Human endogenous retroviruses (HERVs) derive from ancestral infections and constitute about 8% of our genome. A wealth of clinical and experimental studies highlights their pivotal pathogenetic role in autoimmune diseases. Epigenetic mechanisms, such as those modulated by TRIM28 and SETDB1, are involved in HERV activation and regulation of immune response. We assessed, through a polymerase chain reaction real-time Taqman amplification assay, the transcription levels of pol genes of HERV-H, HERV-K, and HERV-W; env genes of Syncytin (SYN)1, SYN2, and HERV-W; as well as TRIM28 and SETDB1 in whole blood from 34 children with CITP and age-matched healthy controls (HC). The transcriptional levels of all HERV sequences, with the exception of HERV-W-env, were significantly enhanced in children with CITP as compared to HC. Patients on eltrombopag treatment exhibited lower expression of SYN1, SYN2, and HERV-W-env as compared to untreated patients. The mRNA concentrations of TRIM28 and SETDB1 were significantly higher and were positively correlated with those of HERVs in CITP patients. The over-expressions of HERVs and TRIM28/SETDB1 and their positive correlations in patients with CITP are suggestive clues of their contribution to the pathogenesis of the disease and support innovative interventions to inhibit HERV and TRIM28/SETDB1 expressions in patients unresponsive to standard therapies.

T memory stem cell characteristics in autoimmune diseases and their promising therapeutic values

Memory T cells are conventionally subdivided into T central memory (TCM) and T effector memory (TEM) cells. However, a new subset of memory T cells named T memory stem cell (TSCM) cells has been recognized that possesses capabilities of both TCM and TEM cells including lymphoid homing and performing effector roles through secretion of cytokines such as interleukin-2 (IL-2) and interferon-gamma (IFN-γ). The TSCM subset has some biological properties including stemness, antigen independency, high proliferative potential, signaling pathway and lipid metabolism. On the other hand, memory T cells are considered one of the principal culprits in the pathogenesis of autoimmune diseases. TSCM cells are responsible for developing long-term defensive immunity against different foreign antigens, alongside tumor-associated antigens, which mainly derive from self-antigens. Hence, antigen-specific TSCM cells can produce antitumor responses that are potentially able to trigger autoimmune activities. Therefore, we reviewed recent evidence on TSCM cell functions in autoimmune disorders including type 1 diabetes, systemic lupus erythematosus, rheumatoid arthritis, acquired aplastic anemia, immune thrombocytopenia, and autoimmune uveitis. We also introduced TSCM cell lineage as an innovative prognostic biomarker and a promising therapeutic target in autoimmune settings.

Immune thrombocytopenia: a review on the pathogenetic role of immune cells

INTRODUCTION

Immune thrombocytopenia [ITP] is a common bleeding disorder with an isolated platelet count of less than 100 × 109/L.

AREAS COVERED

Relevant literature from 2003 to 2022 was retrieved and reviewed from the Google Scholar search engine and PubMed database. Antibodies produced by autoreactive B lymphocytes and the phagocytic function of macrophages are considered the most critical factors in platelet destruction. Also, macrophages present the antigen to T lymphocytes and activate them. Follicular helper T-cells [TFH] play a role in stimulating, differentiating, and activating autoreactive B cells, while cluster of differentiation [CD]-8+ T plays a role in platelet destruction through apoptosis. The classical pathway of the complement system also causes platelet destruction. By inhibiting platelet production, low levels of thrombopoietin and an immune response against megakaryocytes in the bone marrow worsen thrombocytopenia.

EXPERT OPINION

T-cell subset changes and an increase in activated autoreactive B cells, in addition to the function of components of the innate immune system [the complement system, dendritic cells, and natural killer cells], play a critical role in the pathogenesis of the ITP. Accurate detection of these changes may lead to developing new therapeutic strategies and identifying better prognostic/diagnostic factors.