Updated international consensus report on the investigation and management of primary immune thrombocytopenia

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.

Platelets mediate the clearance of senescent red blood cells by forming prophagocytic platelet-cell complexes

ABSTRACT

In humans, ∼0.1% to 0.3% of circulating red blood cells (RBCs) are present as platelet-RBC (P-RBC) complexes, and it is 1% to 2% in mice. Excessive P-RBC complexes are found in diseases that compromise RBC health (eg, sickle cell disease and malaria) and contribute to pathogenesis. However, the physiological role of P-RBC complexes in healthy blood is unknown. As a result of damage accumulated over their lifetime, RBCs nearing senescence exhibit physiological and molecular changes akin to those in platelet-binding RBCs in sickle cell disease and malaria. Therefore, we hypothesized that RBCs nearing senescence are targets for platelet binding and P-RBC formation. Confirming this hypothesis, pulse-chase labeling studies in mice revealed an approximately tenfold increase in P-RBC complexes in the most chronologically aged RBC population compared with younger cells. When reintroduced into mice, these complexes were selectively cleared from the bloodstream (in preference to platelet-free RBC) through the reticuloendothelial system and erythrophagocytes in the spleen. As a corollary, patients without a spleen had higher levels of complexes in their bloodstream. When the platelet supply was artificially reduced in mice, fewer RBC complexes were formed, fewer erythrophagocytes were generated, and more senescent RBCs remained in circulation. Similar imbalances in complex levels and senescent RBC burden were observed in humans with immune thrombocytopenia (ITP). These findings indicate that platelets are important for binding and clearing senescent RBCs, and disruptions in platelet count or complex formation and clearance may negatively affect RBC homeostasis and may contribute to the known risk of thrombosis in ITP and after splenectomy.

Splenectomy outcomes in immune cytopenias: Treatment outcomes and determinants of response

BACKGROUND

Splenectomy is commonly used to treat refractory immune-mediated cytopenia, but there are no established factors that are associated with response to the procedure.

OBJECTIVES

A cohort study was conducted to evaluate the hematologic and surgical outcomes of splenectomy in adult patients with immune cytopenias and identify preoperative factors associated with response.

METHODS

Data from the Cleveland Clinic Foundation for 1824 patients aged over 18 who underwent splenectomy from 2002 to 2020 were analyzed.

RESULTS

The study found that the most common indications for splenectomy were immune thrombocytopenic purpura (ITP) and autoimmune hemolytic anemia, with a median age of 55 years and median time from diagnosis to splenectomy of 11 months. Hematologic response rates were 74% overall, with relapse in 12% of cases. Postsplenectomy discordant diagnoses were present in 13% of patients, associated with higher relapse rates. Surgery-related complications occurred in 12% of cases, whereas only 3% of patients died from disease complications. On univariate analysis, preoperative factors associated with splenectomy treatment failure were ≥3 lines of pharmacologic treatment, whereas isolated thrombocytopenia, primary ITP, and age ≤40 years had a strong association with response. The multivariable regression confirmed that treatment failure with multiple lines of medical therapy was associated with the failure to respond to splenectomy.

CONCLUSION

Overall, the study demonstrates that splenectomy is an effective treatment option for immune-mediated cytopenias with a low complication rate.

Avatrombopag for the Treatment of Immune Thrombocytopenia and Periprocedural Thrombocytopenia Associated With Chronic Liver Disease

Objective: To review the pharmacology, pharmacokinetics, clinical efficacy, safety, dosing and administration, and place in therapy of avatrombopag for the treatment of immune thrombocytopenia and chronic liver disease-associated thrombocytopenia. Summary: Avatrombopag is an orally administered thrombopoietin receptor agonist approved for the treatment of immune thrombocytopenia and is the first oral thrombopoietin receptor agonist approved for the treatment of perioperative thrombocytopenia associated with chronic liver disease in adults. The efficacy and safety of avatrombopag has been demonstrated in a multicenter, randomized, double blind, placebo-controlled phase III study in the setting of immune thrombocytopenia and in 2 identically designed, multicenter, randomized, double blind, placebo-controlled phase III trials in the setting of thrombocytopenia associated with chronic liver disease. The most common adverse events reported in the clinical trials were headache, fatigue, and gastrointestinal toxicities. The incidence of bleeding events was comparable between the avatrombopag and placebo treatment groups in each study. Avatrombopag has not been shown to be associated with hepatoxicity and does not require food restriction like the other oral thrombopoietin receptor agonist for immune thrombocytopenia, eltrombopag. Also, unlike eltrombopag for immune thrombocytopenia, it can be dosed less frequently than once daily. Conclusion: Avatrombopag offers another safe and effective oral option for the treatment of immune thrombocytopenia without food restrictions and an alternative, transfusion-sparing option for thrombocytopenia associated with chronic liver disease patients undergoing surgery.

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/.

Assessing uptake of the core outcome set in clinical trials for immune thrombocytopenia: A cross-sectional analysis

INTRODUCTION

Clinical trials (CTs) guide clinical practice, but inconsistent outcome reporting presents challenges. To increase comparability, a core outcome set (COS) was created for primary Immune thrombocytopenia (ITP) in 2009 to standardize outcome measurements. We aimed to evaluate uptake of the primary ITP COS in CT registries.

MATERIALS & METHODS

Our cross-sectional analysis employed a search string on ClinicalTrials.gov and ICTRP for phase III/IV CTs in June 2023. Inclusion criteria consisted of subjects with primary ITP, study was registered five years before COS publication to June 26, 2023, and assessed effectiveness of interventions. Two investigators extracted data in a masked, duplicate manner. Interrupted time series analysis, ANOVAs, and correlation analyses were conducted to assess the main outcome of COS uptake pre/post COS publication.

RESULTS

The search identified 131 eligible trials for data extraction. Altogether, 38.2 % (50/131) followed IWG platelet response guidelines. An alternative platelet count measurement was 50,000 × 109 L, with 46.56 % (61/131) of trials reporting it. The most measured outcome was adverse events (106/131, 80.9 %). Remaining secondary outcomes were measured in <50 % of studies. After COS publication, there was a statistically non-significant 0.03 % (p = 0.50, CI 95 % = [-0.06, 0.13]) 0.03 % (p = 0.50, CI 95 % = [-0.06, 0.13]) increase in the monthly trend of COS-defined outcomes.

CONCLUSION

We found a non-significant increase in uptake of the ITP COS since its publication and highlighted the lack of standardization among endpoints within ITP clinical trials. Our analysis highlights the need for heightened awareness and a COS update that acknowledges the variability in clinical trials.

Systemic immunosuppression depletes peripheral blood regulatory B cells in patients with immune thrombocytopenia

Regulatory B (Breg) cells are potentially implicated in the pathogenesis of immune thrombocytopenia (ITP). We analysed a prospective cohort of newly diagnosed steroid naïve ITP patients enrolled in the multicentre FLIGHT trial and found that the numbers of Bregs in their peripheral blood were similar to healthy controls. In contrast, Breg numbers were significantly reduced in ITP patients treated with systemic immunosuppression (glucocorticoids or mycophenolate mofetil). We also demonstrate that glucocorticoid treatment impairs Breg interleukin-10 production via an indirect T-cell-mediated mechanism.

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.

How I diagnose and treat thrombocytopenia in geriatric patients

ABSTRACT

Thrombocytopenia in older individuals is a common but diagnostically challenging condition that has variable clinical impact to those who are affected. Diagnostic approach requires evaluation of the preexisting clinical conditions, detailed review of medications, and assessment for disorders that warrant urgent treatment. In this article, we describe a systematic approach to diagnosis of thrombocytopenia and present a schematic review for management strategies. Three clinical scenarios are presented that are relevant for their prevalence and management challenges in an older adult population. The first scenario addresses primary immune thrombocytopenia (ITP) and reviews different treatment options. The second one addresses complications of thrombocytopenia in management of the myelodysplastic syndrome. The last one reviews diagnostic challenges of drug-induced ITP.

Safety of Immunization for Children with Immune Thrombocytopenia

Vaccine hesitancy is a common issue for children with immune thrombocytopenia (ITP) in China. The objective of this paper is to assess the immunization statuses of children with ITP, analyze the possible relationship between immunization and thrombocytopenia, and evaluate the safety of immunization after ITP remission. We included 186 children with an ITP history and followed up with them for two years after receiving re-immunization recommendations. The participants had an overall age-appropriate vaccine coverage of 57.9%. Vaccine-associated thrombocytopenia occurred in 99 (53.2%, 95% CI = 46.06-60.26) children ranging from 0 to 34 days following immunization, with 14 vaccines involved. One hundred and fifty-four (82.3%, 95% CI = 76.72-87.54) children were advised to restart immunization, whereas 32 (17.2%, 95% CI = 12.46-23.28) were advised to postpone partial or full vaccination. Following the follow-up, 150 (80.6%, 95% CI = 74.37-85.68) children completed the catch-up immunization, whereas 27 (14.5%, 95% CI = 10.17-20.30) partially completed it. Four patients with thrombocytopenia relapsed following the re-immunization. Incomplete catch-up immunization was related to the factors of chronic thrombocytopenia, vaccine-associated thrombocytopenia, and the relapse of ITP following re-immunization. ITP may occur after immunization with vaccines other than measles-containing vaccines. Re-immunization in children with ITP generally does not result in a relapse, regardless of whether the previous thrombocytopenia was vaccine-associated.

Sirolimus for the treatment of patients with refractory connective tissue disease-related thrombocytopenia: a pilot study

OBJECTIVE

CTD-related immune thrombocytopenia (CTD-ITP) represents an unmet medical need because the drugs that are available are only partly effective and have considerable side-effects. The aim of this study was to assess the efficacy and safety of sirolimus in refractory CTD-ITP patients.

METHODS

We did a single-arm, open-label, pilot study of sirolimus in patients with CTD-ITP unresponsive to, or intolerant of, conventional medications. Patients received oral sirolimus for 6 months at a starting dose of 0.5-1 mg per day, with dose adjusted according to tolerance and to maintain a therapeutic range of 6-15 ng/ml. The primary efficacy end point was changes in platelet count, and overall response assessed according to the ITP International Working Group Criteria. Safety outcomes included tolerance as assessed by the occurrence of common side-effects.

RESULTS

Between November 2020 and February 2022, 12 consecutively hospitalized patients with refractory CTD-ITP were enrolled and prospectively followed. Of these, six patients (50%) achieved complete response, two (16.7%) achieved partial response, and four (33.3%) were no response under therapy. Three of four patients with primary Sjögren's syndrome and two of three patients with systemic lupus erythematosus achieved overall response. One of two patients with overlapping Sjögren's syndrome and systemic lupus erythematosus achieved complete response at 6 months. No severe drug-related toxicities were observed.

CONCLUSION

Our results do support sirolimus as an alternative regimen for refractory CTD-ITP patients, including systemic lupus erythematosus and primary SS.

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.

Reference guide for the diagnosis of adult primary immune thrombocytopenia, 2023 edition

Primary immune thrombocytopenia (ITP) is an autoimmune disorder characterized by isolated thrombocytopenia due to accelerated platelet destruction and impaired platelet production. Diagnosis of ITP is still challenging because ITP has been diagnosed by exclusion. Exclusion of thrombocytopenia due to bone marrow failure is especially important in Japan because of high prevalence of aplastic anemia compared to Western countries. Hence, we propose a new diagnostic criteria involving the measurement of plasma thrombopoietin (TPO) levels and percentage of immature platelet fraction (RP% or IPF%); 1) isolated thrombocytopenia with no morphological evidence of dysplasia in any blood cell type in a blood smear, 2) normal or slightly increased plasma TPO level (< cutoff), 3) elevated RP% or IPF% (> upper limit of normal), and 4) absence of other conditions that potentially cause thrombocytopenia including secondary ITP. A diagnosis of ITP is made if conditions 1-4 are all met. Cases in which criterion 2 or 3 is not met or unavailable are defined as "possible ITP," and diagnosis of ITP can be made mainly by typical clinical course. These new criteria enable us to clearly differentiate ITP from aplastic anemia and other forms of hypoplastic thrombocytopenia and can be highly useful in clinical practice for avoiding unnecessary bone marrow examination as well as for appropriate selection of treatments.

Sustained response off-treatment in eltrombopag-treated adult patients with ITP who are refractory or relapsed after first-line steroids: Primary, final, and ad-hoc analyses of the Phase II TAPER trial

Immune thrombocytopenia (ITP) is characterized by reduced platelet count due to increased destruction and is categorized according to the time following diagnosis (newly diagnosed, persistent, chronic). First-line corticosteroid therapy is associated with transient response, high relapse rates, and considerable toxicity. TAPER (NCT03524612) is a Phase II, prospective, single-arm trial investigating whether eltrombopag can induce a sustained response off-treatment (SRoT) in adult patients with ITP after first-line corticosteroid failure. This study defines SRoT as an off-treatment period wherein platelet count remains above 30 × 109 /L in the absence of bleeding or rescue therapy. The primary endpoint was the proportion of patients who achieved SRoT until Month 12, which was 30.5% (n = 32/105; p < .0001 testing hypothesis H1: proportion >15%) following eltrombopag tapering and discontinuation, and median SRoT duration was ~8 months until Month 12. Median platelet count increased within 1 month of treatment and remained elevated until Month 12. Quality of life improved within 3 months and was maintained. Headache (21%) was the most common adverse event. None of the 4 deaths reported were considered treatment-related. In summary, ~one-third of patients achieved SRoT until Month 12 following eltrombopag tapering and discontinuation. An ad-hoc early-use analysis, stratified by ITP duration at baseline, assessed initial hematologic responses and safety. Results suggest that eltrombopag has similar efficacy in newly diagnosed and later stages of ITP. In follow-up until Month 24, a median SRoT duration of ~22 months was observed (n = 20). The safety profile was comparable across analyses and ITP duration groups and aligned with its well-established safety profile.

Study of platelet kinetics in immune thrombocytopenia to predict splenectomy response

Despite the efficacy of splenectomy for chronic immune thrombocytopenia (ITP), its considerable failure rate and its possible related complications prove the need for further research into potential predictors of response. The platelet sequestration site determined by 111 In-labelled autologous platelet scintigraphy has been proposed to predict splenectomy outcome, but without standardisation in clinical practice. Here, we conducted a single-centre study by analysing a cohort of splenectomised patients with ITP in whom 111 In-scintigraphy was performed at La Paz University Hospital in Madrid to evaluate the predictive value of the platelet kinetic studies. We also studied other factors that could impact the splenectomy outcome, such as patient and platelet characteristics. A total of 51 patients were splenectomised, and 82.3% responded. The splenic sequestration pattern predicted a higher rate of complete response up to 12 months after splenectomy (p = 0.005), with 90% sensitivity and 77% specificity. Neither age, comorbidities, therapy lines nor previous response to them showed any association with response. Results from the platelet characteristics analysis revealed a significant loss of sialic acid in platelets from the non-responding patients compared with those who maintained a response (p = 0.0017). Our findings highlight the value of splenic sequestration as an independent predictor of splenectomy response.

Addressing thrombosis concerns in immune thrombocytopenia: the role of fostamatinib in immune thrombocytopenia management

INTRODUCTION

Immune thrombocytopenia (ITP), a disease that commonly presents with an increased risk of bleeding, can also paradoxically produce an increased risk of thromboembolic events. The risk of thromboembolism can be associated with patient-related factors (e.g. co-morbidities, age and history of thrombosis), disease-related factors (e.g. a greater proportion of younger, more reactive platelets, and the presence of microparticles and pro-inflammatory cytokines) and treatment-related factors (e.g. splenectomy, thrombopoietin receptor agonists, and IVIg).

AREAS COVERED

Aspects of the pathophysiology of ITP and the effects of treatment are discussed with emphasis on individualizing treatment based on the patient's thromboembolic risk, treatment options and preferences.

EXPERT OPINION

An increased understanding of the pathophysiology of ITP has led to the development of new agents such as fostamatinib, a spleen tyrosine kinase inhibitor. Further research into the factors contributing to the risks for bleeding and thromboembolic events can contribute to the development of more specific therapies for ITP and allow greater individualization of therapy based on each patient's medical history and clinical status.

Immune attack on megakaryocytes in immune thrombocytopenia

A State of the Art lecture titled "Immune Attack on Megakaryocytes in ITP: The Role of Megakaryocyte Impairment" was presented at the International Society on Thrombosis and Haemostasis Congress in 2023. Immune thrombocytopenia (ITP) is an acquired autoimmune disorder caused by autoantibodies against platelet surface glycoproteins that provoke increased clearance of circulating platelets, leading to reduced platelet number. However, there is also evidence of a direct effect of antiplatelet autoantibodies on bone marrow megakaryocytes. Indeed, immunologic cells responsible for autoantibody production reside in the bone marrow; megakaryocytes progressively express during their maturation the same glycoproteins against which ITP autoantibodies are directed, and platelet autoantibodies have been detected in the bone marrow of patients with ITP. In vitro studies using ITP sera or monoclonal antibodies against platelet and megakaryocyte surface glycoproteins have shown an impairment of many steps of megakaryopoiesis and thrombopoiesis, such as megakaryocyte differentiation and maturation, migration from the osteoblastic to the vascular niche, adhesion to extracellular matrix proteins, and proplatelet formation, resulting in impaired and ectopic platelet production in the bone marrow and diminished platelet release in the bloodstream. Moreover, cytotoxic T cells may target bone marrow megakaryocytes, resulting in megakaryocyte destruction. Altogether, these findings suggest that antiplatelet autoantibodies and cellular immunity against bone marrow megakaryocytes may significantly contribute to thrombocytopenia in some patients with ITP. Finally, we summarize relevant new data on this topic presented during the 2023 International Society on Thrombosis and Haemostasis Congress. The complete unraveling of the mechanisms of immune attack-induced impairment of megakaryopoiesis and thrombopoiesis may open the way to new therapeutic approaches.

Predicting the efficacy of glucocorticoids in pediatric primary immune thrombocytopenia using plasma proteomics

Objective

Primary immune thrombocytopenia (ITP) is the most common acquired autoimmune bleeding disorder among children. While glucocorticoids are the primary first-line treatment for ITP treatment, they prove ineffective in certain patients. The challenge of identifying biomarkers capable of early prediction regarding the response to glucocorticoid therapy in ITP persists. This study aimed to identify ideal biomarkers for predicting glucocorticoid efficacy in patients with ITP using plasma proteomics.

Methods

A four-dimensional data-independent acquisition approach was performed to determine the differentially expressed proteins in plasma samples collected from glucocorticoid-sensitive (GCS) (n=18) and glucocorticoid-resistant (GCR) (n=17) children with ITP treated with prednisone. The significantly differentially expressed proteins were selected for enzyme-linked immunosorbent assay validation in a cohort conprising 65 samples(30 healthy controls, 18 GCS and 17 GCR children with ITP). Receiver operating characteristics curves, calibration curves, and clinical decision curve analysis were used to determine the diagnostic efficacy of this method.

Results

47 differentially expressed proteins (36 up-regulated and 11 down-regulated) were identified in the GCR group compared with the GCS group. The significantly differentially expressed proteins myosin heavy chain 9 (MYH9) and fetuin B (FETUB) were selected for enzyme-linked immunosorbent assay validation. The validation results were consistent with the proteomics analyses. Compared with the GCS group, the GCR group exhibited a significantly reduced the plasma concentration of MYH9 and elevated the plasma concentration of FETUB. Furthermore, the receiver operating characteristics curves, calibration curves, and clinical decision curve analysis demonstrated good diagnostic efficacy of these validated biomarkers.

Conclusion

This study contributes to the establishment of objective biological indicators for precision therapy in children with ITP. More importantly, the proteins MYH9 and FETUB hold potential as a foundation for making informed decisions regarding alternative treatments for drugresistant patients, thereby preventing treatment delays.

Thrombopoietin-receptor agonists for adult patients with immune thrombocytopenia: a narrative review and an approach for managing patients fasting intermittently

Introduction

Thrombopoietin-receptor agonist (TPO-RAs) currently represent the state of art for treating immune thrombocytopenia. Their different molecular structures contribute to the difference in their pharmacodynamics and pharmacokinetics. This narrative review aims to provide an overview of the current TPO-RAs approved for primary immune thrombocytopenia (romiplostim, eltrombopag, avatrombopag) and the effect of intermittent fasting in adult patients receiving TPO-RAs.

Areas covered

Literature was searched with no limits on date or language, using various combinations of keywords. Data on the pharmacokinetics, pharmacodynamics, efficacy, and safety of TPO-RAs and the effect of intermittent fasting were summarized.

Expert opinion

Switching between TPO-RAs is a useful strategy to tackle some associated limitations. Romiplostim and avatrombopag have an advantage over eltrombopag as they do not require any dietary restrictions. In cases where romiplostim and avatrombopag are unavailable, patients should be educated on the appropriate administration, possible interactions, and dietary restrictions before initiating eltrombopag.

Evaluating the prevalence of inborn errors of immunity in adults with chronic immune thrombocytopenia or Evans syndrome

Inborn errors of immunity (IEIs) are monogenic disorders that predispose patients to immune dysregulation, autoimmunity, and infection. Autoimmune cytopenias, such as immune thrombocytopenia (ITP) and Evans syndrome (a combination of ITP and autoimmune hemolytic anemia), are increasingly recognized phenotypes of IEI. Although recent findings suggest that IEIs may commonly underlie pediatric ITP and Evans syndrome, its prevalence in adult patients with these disorders remains undefined. This study sought to estimate the prevalence of underlying IEIs among adults with persistent or chronic ITP or Evans syndrome using a next-generation sequencing panel encompassing >370 genes implicated in IEIs. Forty-four subjects were enrolled from an outpatient adult hematology clinic at a tertiary referral center in the United States, with a median age of 49 years (range, 20-83). Fourteen subjects (31.8%) had secondary ITP, including 8 (18.2%) with Evans syndrome. No cases of IEI were identified despite a high representation of subjects with a personal history of autoimmunity (45.5%) and early onset of disease (median age at diagnosis of 40 years [range, 2-77]), including 20.5% who were initially diagnosed as children. Eight subjects (18.2%) were found to be carriers of pathogenic IEI variants, which, in their heterozygous state, are not disease-causing. One case of TUBB1-related congenital thrombocytopenia was identified. Although systematic screening for IEI has been proposed for pediatric patients with Evans syndrome, findings from this real-world study suggest that inclusion of genetic testing for IEI in the routine work-up of adults with ITP and Evans syndrome has a low diagnostic yield.

Efficacy and safety of QL0911 in adult patients with chronic primary immune thrombocytopenia: A multicenter, randomized, double-blind, placebo-controlled, phase III trial

Objective

QL0911, a recombinant human thrombopoietin mimetic peptide-Fc fusion protein, is a romiplostim (Nplate®) biosimilar used to treat primary immune thrombocytopenia (ITP). This phase III study aimed to assess the efficacy and safety of QL0911 in adult patients with chronic primary ITP over a 24-week treatment period.

Methods

We conducted a double-blind, placebo-controlled, phase III study in patients diagnosed with primary ITP for at least 12 months who had received at least one first-line ITP treatment with no response or recurrence after treatment, or who relapsed after splenectomy at 44 sites in China. Patients were randomly allocated (2:1 ratio) to QL0911 or placebo injection subcutaneously once weekly at an initial dose of 1 μg/kg for 24 weeks. The doses were adjusted to maintain the target platelet counts from 50 × 109/L to 200 × 109/L. Patients and investigators were blinded to the assignment. The primary endpoints were the proportion of patients who achieved a durable platelet response at week 24 (platelet count, ≥ 50 × 109/L during 6 of the last 8 weeks of treatment) and safety. The study was registered at ClinicalTrials.gov (NCT05621330).

Results

Between October 2019 and December 2021, 216 patients were randomly assigned (QL0911,144; placebo,72). A durable platelet response was achieved by significantly more patients in the QL0911 group (61.8%, 95% CI: 53.3-69.8; P < 0.0001) than in the placebo group (0%). The mean duration of platelet responses was 15.9 (SE: 0.43) weeks with QL0911, and 1.9 (SE:0.26) week with placebo. Consistent results were achieved in subgroup analyses categorized by baseline splenectomy status (yes/no), concomitant ITP treatment (yes/no), and baseline platelet count (≤ 10 × 109/L, > 10 × 109/L, ≤ 20 × 109/L, > 20 × 109/L, and < 30 × 109/L). The incidence of TEAEs was comparable between the QL0911 and the placebo groups (91.7% and 88.9%, respectively). The most common adverse events overall were ecchymosis (28.5% for QL0911 vs. 37.5% for placebo), upper respiratory tract infections respiratory tract infections (31.9% for QL0911 vs. 27.8% for placebo), and gingival bleeding (17.4% for QL0911 vs. 26.4% for placebo).

Conclusion

QL0911 was well-tolerated and increased and maintained platelet counts in adults with ITP. QL0911, a biosimilar to romiplostim (Nplate®), may be a novel treatment option for patients with ITP who have failed or relapsed from first-line treatment in China. Ongoing studies will provide further data on long-term efficacy and safety in such patient populations.

Recombinant human thrombopoietin (rhTPO) of different dosing regimens for refractory/relapsed primary immune thrombocytopenia: a multicenter, randomized controlled trial and pharmacokinetics study

Recombinant human TPO (rhTPO) is effective for refractory/relapsed primary immune thrombocytopenia (ITP), but optimal dosing regimen remains elusive. In this multicenter, randomized, controlled trial, a total of 282 adult ITP patients (mean age 47.3 years; 82 men) with a platelet count ≤30 × 10⁹/L or >30 × 10⁹/L with active bleeding randomly received a once daily (QD) subcutaneous injection of 7500 U (n = 64) or 15000 U rhTPO for 14 injections, or 15000 U or 30000 U rhTPO once every other day (QOD) for 7 injections. The primary outcomes included change from baseline in platelet count and total response rate (TRR) on day 14. On day 14, the median increase of platelet count from baseline was the highest in the 15000-U QD group (167.5 × 10⁹/L, interquartile range [IQR] 23.0-295.0 × 10⁹/L), followed by the 30000-U QOD group (57.5 × 10⁹/L, IQR 9.0-190.0 × 10⁹/L) (ANCOVA P < .001; P = .266 with baseline count as a covariate). The TRR on day 14 was also the highest in the 15000-U QD group (63.2%), followed by the 30000-U QOD group (59.7%). The rate of grade 3 and above adverse events did not differ among the four groups. There were no new safety concerns. All 4 regimens are safe and well-tolerated. The 30000-U QOD regimen is practically indistinguishable in efficacy to the 15000-U QD regimen.

Treatment preferences towards thrombopoietin-receptor agonists for immune thrombocytopenia and experience of disease (TRAPeze): Italy cohort

OBJECTIVE

Identify patient preference towards thrombopoietin-receptor agonists (TPO-RAs) and determine the clinical and social impact of immune thrombocytopenia (ITP) in Italy.

METHODS

The Thrombopoietin-Receptor Agonist Patient experience (TRAPeze) survey collected responses from Italian residents from 17th January to 28th February 2022. TRAPeze utilized a discrete choice experiment (DCE) to elicit patient preferences towards TPO-RA attributes and a patient burden survey (PBS) to determine ITP disease characteristics and social impact.

RESULTS

Seventy-six respondents completed the DCE, of which 69 completed both the DCE and PBS (mean [range] age 45 [18.0-73.0] years, 80% female). TPO-RA attributes with the greatest influence over respondent choice were method of administration (odds ratio [OR] 2.96; 95% confidence interval [CI] 2.16-4.06), drug-food interactions (OR 1.48; 95% CI 1.17-1.86) and frequency of dosing (OR 1.32; 95% CI 1.15-1.52). Respondents were more likely to prefer therapies administered orally over subcutaneous injection (OR 3.76; 95% CI 2.51-5.63), once weekly over once daily (OR 1.83; 95% CI 1.26-2.65), and therapies without food restrictions over with restrictions (OR 1.58; 95% CI 1.17-2.14).The most frequently reported symptoms were bruising (82%), petechiae (65%) and fatigue (64%). Most respondents (84%) felt ITP impacted familial relationships and 71% of employed respondents reported fatigue influencing their ability to work, with 31% reducing working hours.

CONCLUSION

Although responses indicated a moderate perception of general health, ITP clearly impacted respondent work and social life. Our findings demonstrate respondents preferred TPO-RAs delivered orally, with less frequent dosing and without food restrictions.

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.

Patient preferences and experiences regarding thrombopoietin-receptor agonists for immune thrombocytopenia in The Netherlands (TRAPeze Netherlands study)

OBJECTIVE

Identify patient experience and preference towards thrombopoietin-receptor agonists (TPO-RAs) in treatment of immune thrombocytopenia (ITP) in the Netherlands.

METHODS

The Thrombopoietin-Receptor Agonist Patient experience (TRAPeze) survey used a discrete choice experiment (DCE) to elicit patient preferences and a patient burden survey (PBS) to evaluate the clinical and social impact of ITP. TRAPeze collected responses from 6th October to 19th November 2021.

RESULTS

Seventy-six respondents completed the DCE: treatment preference appeared to be driven by method of administration (odds ratio [OR] 4.33; 95% confidence interval [CI] 2.88-6.52), frequency of dosing (OR 2.33; 95% CI 1.86-2.92) and drug-food interactions (OR 1.91; 95% CI 1.54-2.37). Respondents preferred therapies delivered orally over subcutaneous injection (OR 4.22; 95% CI 2.76-6.46), dosed once weekly over once daily (OR 2.37; 95% CI 1.58-3.54) and without food restrictions over with restrictions (OR 1.90; 95% CI 1.52-2.38). Sixty-nine respondents completed the DCE and PBS (mean [range] age 53 [19-83] years, 65% female). Seven incomplete PBS responses were excluded from analysis. Respondents were currently, or most recently, receiving eltrombopag (n = 43) or romiplostim (n = 26), of which 30% (n = 21/69) had previously received another TPO-RA. Loss (29%, n = 6/21) and lack (29%, n = 6/21) of response were the most common reasons for switching TPO-RA. Only 28% (n = 18/65) of respondents felt their TPO-RA increased energy levels.

CONCLUSION

Patients preferred therapies delivered orally, dosed less frequently and without food restrictions. QoL of ITP patients on TPO-RAs can be improved; the burden analyses presented can inform future efforts towards this.

European Delphi panel to build consensus on tapering and discontinuing thrombopoietin receptor agonists in immune thrombocytopenia

To establish pan-European consensus on tapering and discontinuing thrombopoietin receptor agonists (TPO-RAs) in patients with immune thrombocytopenia (ITP), we applied a three-step Delphi technique consisting of a one-to-one interview round and two online survey rounds. Three healthcare professionals (HCPs) from Italy, Spain, and the United Kingdom formed the Steering Committee (SC), which advised on study design, panelist selection, and survey development. A literature review also informed the development of the consensus statements. Likert scales were used to collect quantitative data on panelists' level of agreement. Twelve hematologists representing nine European countries assessed 121 statements spanning three categories: (1) patient selection; (2) tapering and discontinuation strategies; (3) post-discontinuation management. Consensus was reached on approximately half of the statements in each category (32.2%; 44.6%; 66%). Panelists agreed on patients' main selection criteria, patients' involvement in decision-making, tapering strategies, and follow-up criteria. Areas not reaching consensus were risk factors and predictors of successful discontinuation, monitoring intervals, and rates of successful discontinuation or relapse. This lack of consensus signals knowledge and practice gaps among European countries and suggests the need for the development of clinical practice guidelines that outline a pan-European, evidence-based approach to tapering and discontinuing TPO-RAs.

Treatment of immune thrombocytopenia during pregnancy with thrombopoietin receptor agonists

The introduction of thrombopoietin receptor agonists (TPO-RAs) led to a paradigm shift in the management of immune thrombocytopenia (ITP). However, TPO-RAs are not approved for use during pregnancy due to the absence of evidence and concerns for possible effects on the fetus due to their expected transplacental transfer. This comprehensive review examines the safety and efficacy of TPO-RA in 45 pregnancies of women with ITP (romiplostim n = 22; eltrombopag n = 21; both in the same pregnancy n = 2). Mothers experienced failure of the median of three treatment lines during pregnancy prior to TPO-RA administration. A platelet response (>30 × 109 /L) was seen in 86.7% of cases (including a complete response >100 × 109 /L in 66.7%) and was similar between eltrombopag and romiplostim (87.0% and 83.3%, p = 0.99). The maternal safety profile was favourable, with no thromboembolic events encountered. Neonatal thrombocytopenia was noted in one third of cases, with one case of ICH grade 3, and neonatal thrombocytosis was observed in three cases. No other neonatal adverse events attributable to TPO-RAs were seen. This review suggests that the use of TPO-RA during pregnancy is associated with a high response rate and appears safe. Nevertheless, TPO-RA should not be routinely used in pregnancy and should be avoided in the first trimester until further evidence is accumulated.

Clinical and immunological characterisation of patients with common variable immunodeficiency related immune thrombocytopenia

Primary Immune thrombocytopenia (ITP) is an autoimmune disease. Secondary ITP occurs in patients with underlying diseases such as common variable immunodeficiency (CVID). CVID is one of the most common symptomatic primary immunodeficiencies in adults, characterised by infectious and non-infectious symptoms. Amongst CVID patients, ITP is the most frequent autoimmune manifestation. In this single-centre study, we performed a clinical and immunological characterisation of 20 patients with CVID-related ITP and 20 ITP patients without CVID to compare severity and remission rates. We found that patients with CVID-related ITP had a higher WHO Bleeding Scale at initial diagnosis yet showed higher remission rates and required less treatment. Patients with ITP needed up to seven therapy options and were often treated with second-line drug therapy, whilst only one CVID-related ITP patient required second-line drug therapy. Therefore, we show that the course of thrombocytopenia in patients with CVID-related ITP is milder. Furthermore, we show that soluble interleukin-2 receptor (sIL-2R, CD25) was higher in CVID-related ITP compared to ITP patients and could accurately classify patient cohorts with an Area Under the Receiver Operating Characteristic of 0.92. Whilst none of the ITP patients had a history of immunodeficiency, we found immunological abnormalities in 12 out of 18 patients. Therefore, we recommend screening ITP patients for CVID and other immunodeficiencies to detect immune abnormalities early, as we found patients with reduced immunoglobulin levels as well as severe lymphocytopenia in our ITP cohort.

Relationships of platelet glycoprotein specific antibody with therapeutic efficacy of short-term high-dose dexamethasone and bleeding score in the newly diagnosed adult patients with primary immune thrombocytopenia

Objectives: We aimed to investigate relationships of platelet glycoprotein (GP) specific antibody with therapeutic efficacy of high-dose dexamethasone (HD-DXM) and bleeding score in primary immune thrombocytopenia (ITP) adults. Methods: A retrospective study was carried out to analyze relationships of polymorphism of GP specific antibody with initial therapeutic efficacy of HD-DXM and bleeding score of newly diagnosed ITP adults between 1 June, 2016 and 31 January, 2020. Results: 59 patients were involved in the study, with 33 cases of responders and 26 cases of non-responders between June 2016 and January 2020. At admission, there were 31 (52.5%) GP antibody-positive patients. Initial therapy of HD-DXM was effective for 78.6% GP antibody-negative patients and 35.5% GP antibody-positive patients, with a better therapeutic efficacy in patients with anti-GP Ib/IX antibody or anti-GP IIb/IIIa antibody but not in those with anti-GP Ib/IX antibody plus anti-GP IIb/IIIa antibody. Notably, therapeutic efficacy is much worse for minority (Uyghur) patients compared with corresponding Han patients. Similarly, it was much lower in GP antibody-positive patients compared with corresponding negative ones at low and medium bleeding score, with no response in GP antibody-positive patients at high bleeding score. Furthermore, there was a moderate negative correlation between therapeutic efficacy and GP-specific antibody (p < 0.05), but no obvious linear relationship between clinical bleeding degree and GP-specific antibody (p > 0.05). Conclusion: Collectively, the newly diagnosed ITP adults with GP-specific antibody have a poor response to short-term HD-DXM, especially in minority (Uyghur) patients with GP-specific antibody in China.

Recombinant human thrombopoietin therapy for primary immune thrombocytopenia in pregnancy: a retrospective comparative cohort study

BACKGROUND

Treatment options for pregnant women with immune thrombocytopenia (ITP) who do not respond to first-line treatment are limited. Few studies have reported the use of recombinant human thrombopoietin (rhTPO) for this subset of patients.

AIMS

To investigate the efficacy and safety of rhTPO in ITP during pregnancy and determine obstetric outcomes and predictors of treatment response.

METHODS

From July 2013 to October 2022, the data of 81 pregnant women with ITP and a platelet count < 30 × 109/L who did not respond to steroids and/or intravenous immunoglobulin were retrospectively analysed. Of these patients, 33 received rhTPO treatment (rhTPO group) while 48 did not (control group). Baseline characteristics, haematological disease outcomes before delivery, obstetric outcomes, and adverse events were compared between groups. In the rhTPO group, a generalised estimating equation (GEE) was used to investigate the factors influencing the response to rhTPO treatment.

RESULTS

The baseline characteristics were comparable between both groups (P > 0.05, both). Compared with controls, rhTPO patients had higher platelet counts (median [interquartile range]: 42 [21.5-67.5] vs. 25 [19-29] × 109/L, P = 0.002), lower bleeding rate (6.1% vs. 25%, P = 0.027), and lower platelet transfusion rate before delivery (57.6% vs. 97.9%, P < 0.001). Gestational weeks of delivery (37.6 [37-38.4] vs 37.1 [37-37.2] weeks, P = 0.001) were longer in the rhTPO group than in the control group. The rates of caesarean section, postpartum haemorrhage, foetal or neonatal complications, and complication types in both groups were similar (all P > 0.05). No liver or renal function impairment or thrombosis cases were observed in the rhTPO group. GEE analysis revealed that the baseline mean platelet volume (MPV) (odds ratio [OR]: 0.522, P = 0.002) and platelet-to-lymphocyte ratio (PLR) (OR: 1.214, P = 0.025) were predictors of response to rhTPO treatment.

CONCLUSION

rhTPO may be an effective and safe treatment option for pregnancies with ITP that do not respond to first-line treatment; it may have slightly prolonged the gestational age of delivery. Patients with a low baseline MPV and high baseline PLR may be more responsive to rhTPO treatment. The present study serves as a foundation for future research.

Study on the Treatment of ITP Mice with IVIG Sourced from Distinct Sex-Special Plasma (DSP-IVIG)

Intravenous immunoglobulin (IVIG) is a first-line drug prepared from human plasma for the treatment of autoimmune diseases (AIDs), especially immune thrombocytopenia (ITP). Significant differences exist in protein types and expression levels between male and female plasma, and the prevalence of autoimmune diseases varies between sexes. The present study seeks to explore potential variations in IVIG sourced from distinct sex-specific plasma (DSP-IVIG), including IVIG sourced from female plasma (F-IVIG), IVIG sourced from male plasma (M-IVIG), and IVIG sourced from a blend of male and female plasma (Mix-IVIG). To address this question, we used an ITP mouse model and a monocyte-macrophage inflammation model treated with DSP IVIG. The analysis of proteomics in mice suggested that the pathogenesis and treatment of ITP may involve FcγRs mediated phagocytosis, apoptosis, Th17, cytokines, chemokines, and more. Key indicators, including the mouse spleen index, CD16+ macrophages, M1, M2, IL-6, IL-27, and IL-13, all indicated that the efficacy in improving ITP was highest for M-IVIG. Subsequent cell experiments revealed that M-IVIG exhibited a more potent ability to inhibit monocyte phagocytosis. It induced more necrotic M2 cells and fewer viable M2, resulting in weaker M2 phagocytosis. M-IVIG also demonstrated superiority in the downregulation of surface makers CD36, CD68, and CD16 on M1 macrophages, a weaker capacity to activate complement, and a stronger binding ability to FcγRs on the THP-1 surface. In summary, DSP-IVIG effectively mitigated inflammation in ITP mice and monocytes and macrophages. However, M-IVIG exhibited advantages in improving the spleen index, regulating the number and typing of M1 and M2 macrophages, and inhibiting macrophage-mediated inflammation compared to F-IVIG and Mix-IVIG.

Efficacy and safety of the neonatal Fc receptor inhibitor efgartigimod in adults with primary immune thrombocytopenia (ADVANCE IV): a multicentre, randomised, placebo-controlled, phase 3 trial

BACKGROUND

Primary immune thrombocytopenia is an autoimmune disorder mediated partly by platelet autoantibodies, resulting in thrombocytopenia, bleeding, and constitutional symptoms. Efgartigimod, a first-in-class novel human IgG1 Fc fragment, binds the neonatal Fc receptor with high affinity and thus reduces serum IgG concentrations, including autoantibodies. The objective of this study was to evaluate the efficacy and safety of efgartigimod in adults with persistent and chronic primary immune thrombocytopenia.

METHODS

This phase 3, multicentre, randomised, double-blinded, placebo-controlled, 24-week study evaluated the efficacy and safety of intravenous efgartigimod in adults aged 18 years or older with chronic or persistent primary immune thrombocytopenia who had an average platelet count of less than 30 000, had responded to at least one previous immune thrombocytopenia therapy, and were on a concurrent therapy at baseline or had received at least a second previous immune thrombocytopenia therapy. The study took place in 71 participating sites from Asia, Europe, and North America. Patients were randomly assigned 2:1 to receive either efgartigimod (10 mg/kg) or placebo intravenously for the first 4 weeks, after which the dosing schedule could be altered to once per week or every other week depending on the patients' platelet count. The primary endpoint, evaluated in the chronic population, was sustained platelet count response (≥50 × 109 for at least 4 of the last 6 weeks). This study is registered with ClinicalTrials.gov (NCT04188379) and is completed.

FINDINGS

A total of 205 patients were screened from Dec 9, 2019, to Feb 3, 2022, and 131 (86 in the efgartigimod group; 45 in the placebo group) were randomly assigned. These patients represented a population with long-term disease who had a mean time since diagnosis of 10·6 years and 67% (88/131) of whom had received at least three previous immune thrombocytopenia treatments. 22% (17/78) of patients with chronic immune thrombocytopenia receiving efgartigimod reached the primary endpoint compared with 5% (2/40) of those receiving placebo (p=0·032; adjusted difference in response, 16% [95% CI 2·6-26·4]). The median number of weeks of disease control in patients with chronic immune thrombocytopenia was 2·0 (IQR 0·0-11·0) for efgartigimod versus 0·0 (0·0-1·0) for placebo (p=0·0009). Efgartigimod was well tolerated; most adverse events were mild to moderate in severity. The most common adverse events of interest in both groups were headache (16% in efgartigimod and 13% in placebo), haematuria (16% in efgartigimod and 16% in placebo), and petechiae (15% in efgartigimod and 27% in placebo).

INTERPRETATION

Efgartigimod significantly increased sustained platelet count responses compared with placebo in patients with chronic immune thrombocytopenia, including those who had received multiple previous immune thrombocytopenia therapies. Upon completion of the ADVANCE IV study, patients could enroll in the ongoing open-label extension. Subcutaneous efgartigimod is currently being evaluated in patients with immune thrombocytopenia in the ADVANCE SC+ trial.

FUNDING

argenx.

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.

Watchful Waiting Phase As Window of Opportunities for Non-pharmaceutical and Non-surgical Management of a Small Splenic Cyst Complicated With Thrombocytopenia

An asymptomatic splenic cyst smaller than 50 mm was detected incidentally at a routine health checkup. Management of the cyst, affected and determined by multiple factors, including force majeure, became difficult and thrombocytopenia developed during watchful waiting. Spontaneous recovery of the spleen did not occur with continued watchful waiting, and thrombocytopenia worsened. However, when a three-month dietary intervention was subsequently implemented, the initiation of recovery was observed. The diet modification was adding to regular meals a daily serving of vegetables prepared following traditional Chinese culinary style. A second course of dietary intervention was undertaken, and accelerated recovery was detected thereafter, with eventual complete resolution of the splenic cyst and thrombocytopenia. This case demonstrates the feasibility and potential benefits of lifestyle intervention for the management of small splenic cysts, including those complicated with thrombocytopenia. Lifestyle intervention, such as dietary intervention, is particularly suitable for the watchful waiting phase since disease management during this time is non-pharmaceutical and non-surgical by nature.

Bleeding risk assessment in immune thrombocytopenia

The bleeding risk in immune thrombocytopenia (ITP) is related not only to low platelet count but also to the presence of platelet dysfunction. However, diagnosing a concomitant platelet dysfunction is challenging as most of the available platelet function assays (PFAs) require a platelet count of greater than 100,000/μL. Sonoclot coagulation and platelet function analyzer works on the principle of viscoelastometry, and results remain unaffected by the platelet counts. To assess the platelet function in adult acute ITP patients with the help of sonoclot coagulation and platelet function analyzer and correlate it with the risk of bleeding. Newly diagnosed acute ITP patients with a platelet count less than 20,000/μL were divided into two groups based on WHO bleeding grade: ITP non-bleeder (ITP-NB) group (WHO bleeding grade ≤1) and ITP bleeder (ITP-B) group (WHO bleeding grade ≥2). Platelet function was assessed by sonoclot in both groups. The patients without significant bleeding (ITP-NB) were followed up monthly for six months with the assessment of platelet function during each contact. Eighty patients (30 ITP-B and 50 ITP-NB) were prospectively included in this study. The median age of patients in the two groups was 37 years and 30 years, respectively. The female-to-male ratio was 4:1 and 1:1 in ITP-B and ITP-NB groups. The median platelet count in ITP-B and ITP-NB was 12000/μL (range 1000-19000/μL) and 8000/μL (range 1000-19000/μL), respectively. Mean platelet functions by sonoclot in both groups were lower than the normal cut-off (>1.6). However, the mean platelet function in the ITP-B group (0.2 + 0.17) was significantly lower than the ITP-NB group (1.2 ± 0.52) (p = 0.01). During the follow-up period of 6 months, patients in ITP-NB with a normal platelet function (>1.6) on sonoclot had lesser episodes (one episode) of clinically significant bleeding than patients with a low platelet function (4 episodes). Patients with acute severe thrombocytopenia and bleeding phenotype have a greater abnormality on platelet function by sonoclot than patients with non-bleeding phenotype. This information may help in taking therapeutic decisions in patients with acute ITP.

Is Childhood Immune Thrombocytopenia Associated With Acquired Toxoplasmosis? An Unusual Case of Infection That Led to Acute ITP in a Greek Male Toddler and Implications for Guidelines

INTRODUCTION

Childhood immune thrombocytopenic purpura (ITP) is a heterogeneous immune-mediated process triggered by infections, vaccines, allergies and parasites. Currently, there is little evidence in the literature beyond case reports of an association with Toxoplasma gondii (T. gondii).

METHODS

The authors describe the unusual case of an earlier healthy 2.5-year-old Greek boy who developed acute ITP with a life-threatening platelet count a few days after a T. gondii infection. Evidence for the infection onset was found incidentally 3 months after the initial admission to the hospital and only after any other plausible cause of thrombocytopenia was excluded, according to diagnosis guidelines.

RESULTS

The boy underwent 3 intravenous immunoglobulin treatments within a trimester, a period during which his alarming platelets count levels led to housebound activities. A quite slow recovery was only ignited after the third treatment, which was administered in conjunction with a mild antibiotic medication for the T. gondii infection. Full recovery was obtained 9 months after the initial admission, although the boy's potential scored high in clinical prediction models for developing transient ITP.

CONCLUSION

There is a need for more research on ITPs with no obvious cause to investigate a causal association with toxoplasmosis. Currently, testing for diseases of greater rarity and of higher diagnostic cost than T. gondii is included in the ITP guidelines. Hence, routinely testing for toxoplasmosis when considering potential childhood ITP triggers and infection treatment complementary to treating the ITP might be the key to accelerating the healing process and improving the quality of life of otherwise confined children.

Glucocorticoids regulate thrombopoiesis by remodeling the megakaryocyte transcriptome

BACKGROUND

Glucocorticoids are widely known for their immunomodulatory action. Their synthetic analogs are used to treat several autoimmune diseases, including immune thrombocytopenia. However, their efficacy and mechanisms of action in immune thrombocytopenia are not fully understood.

OBJECTIVES

To investigate the mechanism of glucocorticoid actions on platelet production.

METHODS

The actions of glucocorticoids on platelet production were studied combining in vivo, ex vivo and in vitro approaches.

RESULTS

Dexamethasone reduced bleeding in mice and rapidly increased circulating young platelet counts. In vitro glucocorticoid treatment stimulated proplatelet formation by megakaryocytes and platelet-like particle release. This effect was blocked by glucocorticoid receptor antagonist RU486, indicating a glucocorticoid receptor-dependent mechanism. Genome-wide analysis revealed that dexamethasone regulates the expression of >1000 genes related to numerous cellular functions, including predominant cytoplasm and cytoskeleton reorganization. Dexamethasone and other glucocorticoids induced the expression of Gda (the gene encoding guanine deaminase), which has been reported to have a role in dendrite development. Inhibition of guanine deaminase enzymatic activity blocked dexamethasone stimulation of proplatelet formation, implicating a critical role for this enzyme in glucocorticoid-mediated platelet production.

CONCLUSION

Our findings identify glucocorticoids as new regulators of thrombopoiesis.

Management of Recurrent Venous Thromboembolism in Severe Immune Thrombocytopenia: A Case Report and a Review of the Literature

We report a case of a 58-year-old man with recurrent unprovoked deep vein thrombosis (DVT) and severe immune thrombocytopenia (ITP) with a platelet count of 19 × 109/L. We further review studies reporting venous thromboembolism (VTE) in patients with severe ITP (≤ 35 × 109/L) and identified 14 patients highlighting VTE risk factors and management of these patients. The present case had several risk factors for VTE (previous DVT, obesity, heterozygosity for factor V Leiden mutation, and previous splenectomy). The patient was initially treated with low-molecular-weight heparin followed by long-term apixaban treatment. The literature review together with our case demonstrates that VTE in severe ITP (≤ 35 × 109/L) can occur in patients with VTE risk factors and antithrombotic management of these patients can be achieved without bleeding depending on severity of thrombocytopenia either by full or reduced dose of anticoagulation together with ITP therapy.

Simultaneous analysis of avatrombopag, eltrombopag, and hetrombopag in human plasma by UPLC-MS/MS for therapeutic drug monitoring

Avatrombopag, eltrombopag, and hetrombopag are three oral thrombopoietin receptor agonists used to treat thrombocytopenia. To investigate the pharmacokinetic properties, a fast and robust UPLC-MS/MS method was developed and validated for simultaneous determination of avatrombopag, eltrombopag, and hetrombopag in human plasma. Chromatographically separation was achieved on an Acquity BEH C18 column using a gradient elution of methanol-water (20:80, v/v) and acetonitrile containing 0.1% formic acid at a flow rate of 0.4 mL/min within 4.5 min. The linearity was assessed over the range of 7.5-1500 ng/mL for avatrombopag, 50-10,000 ng/mL for eltrombopag, and 5-1000 ng/mL for hetrombopag. This method was validated with adequate results in terms of selectivity, precision (intra- and inter-day CV from 4.2% to 12.2%), accuracy (RE from -6.6% to 7.5%), dilution integrity, carryover, recovery, matrix effects, as well as stability of the analytes under various conditions. The developed approach has been successfully applied to the therapeutic drug monitoring of avatrombopag, eltrombopag, and hetrombopag in patients with immune thrombocytopenia.

Rilzabrutinib versus placebo in adults and adolescents with persistent or chronic immune thrombocytopenia: LUNA 3 phase III study

Background

Immune thrombocytopenia (ITP) is characterized by primarily autoantibody-mediated platelet destruction and impaired platelet production resulting in thrombocytopenia and an increased risk of bleeding. Other manifestations include increased risk of thrombosis and diminished quality of life. Current treatment approaches are directed toward lowering the rate of platelet destruction or stimulating platelet production to prevent bleeding. Rilzabrutinib is an oral, reversible, potent Bruton tyrosine kinase inhibitor that was specifically designed to treat immune-mediated diseases and mediates its therapeutic effect through a dual mechanism of action: (1) inhibiting B-cell activation and (2) interrupting antibody-coated cell phagocytosis by Fc gamma receptor in spleen and liver. A 24-week dose-finding phase I/II study of rilzabrutinib in patients with ITP showed a 40% platelet response (⩾2 consecutive platelet counts of ⩾50 × 109/L and increase from baseline ⩾20 × 109/L without rescue medication use) and a well-tolerated safety profile with only grade 1/2 transient adverse events across dose levels.

Objectives

Assess the efficacy and safety of oral rilzabrutinib in adult and adolescent patients with persistent or chronic ITP.

Design

Rilzabrutinib 400 mg BID is being evaluated in the ongoing LUNA 3 multicenter, double-blind, placebo-controlled phase III study.

Methods and analysis

The primary endpoint is durable platelet response, defined as achieving platelet counts of ⩾50 × 109/L for at least two-thirds of ⩾8 available weekly scheduled platelet measurements during the last 12 weeks (including ⩾2 available measurements within the last 6 weeks) of the 24-week blinded treatment period in the absence of rescue therapy.

Ethics

Ethical guidelines and informed consent are followed.

Discussion

The LUNA 3 trial will further investigate rilzabrutinib's safety and efficacy in adult and adolescent patients, with the primary goal of addressing a major objective in treating patients with ITP: durability of platelet response.

Trail Registration

ClinicalTrials.gov NCT04562766: https://clinicaltrials.gov/ct2/show/NCT04562766; EU Clinical Trials Register EudraCT 2020-002063-60: https://www.clinicaltrialsregister.eu/ctr-search/search?query=2020-002063-60.

Mycophenolate mofetil for autoimmune cytopenias in children: high rates of response in inborn errors of immunity

Second-line treatments of autoimmune cytopenias (AC) are not well-defined in children. Mycophenolate mofetil (MMF) is an immunosuppressant agent that has been demonstrated to be safe and effective in this setting. A retrospective observational study was conducted in 18 children with prolonged AC who received MMF, in order to describe clinical and biological markers of response. The overall response rate of MMF at 20-30 mg/kg per day was 73.3%. All patients with Evans syndrome (n = 9) achieved complete response. Among the patients with monolineage AC (n = 9), those with an underlying inborn errors of immunity (IEI), tended to respond better to MMF. No biological markers related to treatment response were found. Rather, lymphocyte subpopulations proved useful for patient selection as a marker suggestive of IEI along with immunoglobulin-level determination.

The serum lipid profiles in immune thrombocytopenia: Mendelian randomization analysis and a retrospective study

BACKGROUND

Immune thrombocytopenia (ITP) is an autoimmune hemorrhagic disease characterized by increased platelet destruction and impaired thrombopoiesis. The changes in platelet indices depend on the morphology and volume of platelets. Serum lipids have been found to affect platelet formation and activity in certain diseases, thus inducing the corresponding variation of platelet indices.

METHODS

Mendelian randomization (MR) analysis was performed based on databases. The clinical data from 457 ITP patients were retrospectively collected and analyzed, including platelet indices, serum lipids, hemorrhages and therapeutic responses.

RESULTS

MR analysis showed low high-density-lipoprotein-cholesterol (HDL-C), low apolipoprotein A-1, high triglyceride (TG) and high apolipoprotein B (ApoB) caused high platelet distribution width (PDW); high low-density-lipoprotein-cholesterol (LDL-C) increased mean platelet volume (MPV). In ITP, there were positive correlations between platelet count with TG, PDW with HDL-C and ApoB, and plateletcrit with TG and non-esterified fatty acid, and the correlation had gender differences. Bleeding scores were negatively correlated with cholesterol and LDL-C. LDL-C and homocysteine were risk factors for therapeutic responses.

CONCLUSIONS

Serum lipids, especially cholesterol were tightly correlated with platelet indices, hemorrhage and therapeutic effects in ITP patients. These results provide clinical references for the management of serum lipids, and highlight the necessity to further explore the relationship between lipids and pathogenesis of ITP.

TRIAL REGISTRATION

No: NCT05095896, October 14, 2021, retrospectively registered.

Impact of Helicobacter pylori Infection upon the Evolution and Outcome of Pediatric Immune Thrombocytopenic Purpura: A Comprehensive Review

In adults with immune thrombocytopenic purpura (ITP), the identification of H. pylori infection and its subsequent eradication proved to aid platelet recovery. Similar findings, at a smaller scale, were allegedly reported by some pediatric studies. This review's objective was to establish the influence of H. pylori infection and its eradication upon platelet count and recovery in pediatric ITP. Three databases, namely Pubmed, Scopus and Web of Science, were searched for pediatric studies which investigated a link between H. pylori infection and thrombocytopenia. The search results retrieved a number of 21 articles which complied to the inclusion and exclusion criteria. Some studies report lower platelet values among children with ITP and documented H. pylori infection, as well as an improve in platelet numbers after H. pylori treatment. However, results are controversial, as multiple authors failed to identify a higher prevalence of H. pylori among children with ITP or a lack of significant change in therapeutic outcome with the addition of an eradication regimen to standard treatment. The main limitations of current pediatric studies remain the small study samples and the short follow-up periods of the included subjects. Hence, the long-term impact of H. pylori in children with ITP is still uncertain.

Recommendations for the Clinical Approach to Immune Thrombocytopenia: Spanish ITP Working Group (GEPTI)

Primary immune thrombocytopenia (ITP) is a complex autoimmune disease whose hallmark is a deregulation of cellular and humoral immunity leading to increased destruction and reduced production of platelets. The heterogeneity of presentation and clinical course hampers personalized approaches for diagnosis and management. In 2021, the Spanish ITP Group (GEPTI) of the Spanish Society of Hematology and Hemotherapy (SEHH) updated a consensus document that had been launched in 2011. The updated guidelines have been the reference for the diagnosis and management of primary ITP in Spain ever since. Nevertheless, the emergence of new tools and strategies makes it advisable to review them again. For this reason, we have updated the main recommendations appropriately. Our aim is to provide a practical tool to facilitate the integral management of all aspects of primary ITP management.

Anti-Inflammatory and Immunomodulatory Effect of High-Dose Immunoglobulins in Children: From Approved Indications to Off-Label Use

BACKGROUND

The large-scale utilization of immunoglobulins in patients with inborn errors of immunity (IEIs) since 1952 prompted the discovery of their key role at high doses as immunomodulatory and anti-inflammatory therapy, in the treatment of IEI-related immune dysregulation disorders, according to labelled and off-label indications. Recent years have been dominated by a progressive imbalance between the gradual but constant increase in the use of immunoglobulins and their availability, exacerbated by the SARS-CoV-2 pandemic.

OBJECTIVES

To provide pragmatic indications for a need-based application of high-dose immunoglobulins in the pediatric context.

SOURCES

A literature search was performed using PubMed, from inception until 1st August 2023, including the following keywords: anti-inflammatory; children; high dose gammaglobulin; high dose immunoglobulin; immune dysregulation; immunomodulation; immunomodulatory; inflammation; intravenous gammaglobulin; intravenous immunoglobulin; off-label; pediatric; subcutaneous gammaglobulin; subcutaneous immunoglobulin. All article types were considered.

IMPLICATIONS

In the light of the current imbalance between gammaglobulins' demand and availability, this review advocates the urgency of a more conscious utilization of this medical product, giving indications about benefits, risks, cost-effectiveness, and administration routes of high-dose immunoglobulins in children with hematologic, neurologic, and inflammatory immune dysregulation disorders, prompting further research towards a responsible employment of gammaglobulins and improving the therapeutical decisional process.

Efficacy and safety of caffeic acid tablets in the treatment of thrombocytopenia: A systematic review and meta-analysis

BACKGROUND

Caffeic acid tablets (CFA) are a proprietary Chinese medicine in treating thrombocytopenia. The efficacy and safety of CFA compared with other platelet-raising drugs for the treatment of thrombocytopenia have been widely reported in the literature, but there is no systematic evaluation. Therefore, we designed this meta-analysis to further establish the efficacy and safety of CFA in treating thrombocytopenia.

METHODS

A computerized search was conducted in the Chinese biomedical database (CBM), Chinese National Knowledge Infrastructure (CNKI), Wanfang database, Chinese Scientific Journal Database (VIP), PubMed, and Web of Science databases using the keywords "caffeic acid tablets" and "thrombocytopenia." All randomized controlled trials were selected for the timeframe of build to 02/2023 and then screened and analyzed using RevMan 5.4 and stata17.0 software.

RESULTS

A total of 35 publications with an overall 2533 patients were included in the study. The results of the meta-analysis showed that CFA were effective in the treatment of thrombocytopenia with a statistically significant difference [relative risk ratio (RR) = 1.24, 95% CI (1.17, 1.31), P < .00001] and in increasing platelet counts [standardized mean difference (SMD) = 1.50, 95% CI (1.09, 1.91), P < .00001], white blood cell count [SMD = 1.08, 95% CI (0.77, 1.39), P < .00001], and neutrophil count [SMD = 0.73, 95% CI (0.19, 1.28), P = .009], and CFA reduced myelosuppression [RR = 0.19, 95% CI (0.1, 0.37), P < .00001] and adverse effects [RR = 0.75, 95% CI (0.58, 0.96), P = .02].

CONCLUSION

CFA can effectively improve the clinical outcome of patients with thrombocytopenia with a good safety profile and are worth promoting. However, due to the low quality and small sample size of the included literature, a larger sample size and more standardized, high-quality studies are needed to validate these results.

Real-world use of avatrombopag in patients with chronic liver disease and thrombocytopenia undergoing a procedure

The phase 4 observational cohort study assessed the effectiveness and safety of the thrombopoietin receptor agonist avatrombopag in patients with chronic liver disease (CLD) and thrombocytopenia undergoing a procedure. Patients with CLD may have thrombocytopenia, increasing the risk of periprocedural bleeding. Prophylactic platelet transfusions used to reduce this risk have limitations including lack of efficacy and transfusion-associated reactions. Prophylactic thrombopoietin receptor agonists have been shown to increase platelet counts and decrease platelet transfusions. Effectiveness was assessed by change from baseline in platelet count and proportion of patients needing a platelet transfusion. Safety was assessed by monitoring adverse events (AEs). Of 50 patients enrolled, 48 were unique patients and 2 patients were enrolled twice for separate procedures. The mean (standard deviation) change in platelet count from baseline to procedure day was 41.1 × 109/L (33.29 × 109/L, n = 38), returning to near baseline at the post-procedure visit (change from baseline -1.9 × 109/L [15.03 × 109/L], n = 11). The proportion of patients not requiring a platelet transfusion after baseline and up to 7 days following the procedure was 98% (n = 49). Serious AEs were infrequent (n = 2 [4%]). No treatment-emergent AEs were considered related to avatrombopag. There were 2 mild bleeding events, no thromboembolic events or deaths, and no patients received rescue procedures (excluding transfusions). This study found that in a real-world setting, treatment with avatrombopag was well tolerated, increased the mean platelet count by procedure day, and reduced the need for intraoperative platelet transfusions in patients with CLD and thrombocytopenia.

Desialylated Platelet Clearance in the Liver is a Novel Mechanism of Systemic Immunosuppression

Platelets are small, versatile blood cells that are critical for hemostasis/thrombosis. Local platelet accumulation is a known contributor to proinflammation in various disease states. However, the anti-inflammatory/immunosuppressive potential of platelets has been poorly explored. Here, we uncovered, unexpectedly, desialylated platelets (dPLTs) down-regulated immune responses against both platelet-associated and -independent antigen challenges. Utilizing multispectral photoacoustic tomography, we tracked dPLT trafficking to gut vasculature and an exclusive Kupffer cell-mediated dPLT clearance in the liver, a process that we identified to be synergistically dependent on platelet glycoprotein Ibα and hepatic Ashwell-Morell receptor. Mechanistically, Kupffer cell clearance of dPLT potentiated a systemic immunosuppressive state with increased anti-inflammatory cytokines and circulating CD4+ regulatory T cells, abolishable by Kupffer cell depletion. Last, in a clinically relevant model of hemophilia A, presensitization with dPLT attenuated anti-factor VIII antibody production after factor VIII ( infusion. As platelet desialylation commonly occurs in daily-aged and activated platelets, these findings open new avenues toward understanding immune homeostasis and potentiate the therapeutic potential of dPLT and engineered dPLT transfusions in controlling autoimmune and alloimmune diseases.