Knowledge mapping of immune thrombocytopenia: a bibliometric study.

Background: Immune thrombocytopenia (ITP) is an autoimmune disease characterized by isolated thrombocytopenia. Recently, the pathophysiology and novel drugs of ITP have been the focus of researchers with plenty of publications emerging. Bibliometrics is the process of extracting measurable data through statistical analysis of published research studies to provide an insight into the trends and hotspots. Objective: This study aimed to provide an insight into developing trends and hotspots in the field of ITP by bibliometric analysis. Methods: By using three bibliometric mapping tools (bibliometrix R package, VOSviewer, CiteSpace), we summarized the overview information of retrieved publications, as well as the analysis of keyword co-occurrence and reference co-citation. Results: A total of 3299 publications with 78066 citations on ITP research were included in the analysis. The keyword co-occurrence network identified 4 clusters relating to the diagnosis, pathophysiology, and treatment of ITP respectively. Then the reference co-citation analysis produced 12 clusters with a well-structured and highly credible clustering model, and they can be divided into 5 trends: second-line treatment, chronic ITP, novel therapy and pathogenesis, COVID-19 vaccine. Treg cells, spleen tyrosine kinase, and mesenchymal stem cells were the latest hotspots with strong burstness. Conclusion: This bibliometric analysis provided a comprehensive insight into research hotspots and trends on ITP, which would enrich the review of the ITP research.

Current Concepts in the Diagnosis and Management of Adult Primary Immune Thrombocytopenia: Our Personal View.

Primary immune thrombocytopenia (ITP) is an acquired blood disorder that causes a reduction in circulating platelets with the potential for bleeding. The incidence of ITP is slightly higher in adults and affects more women than men until 60 years, when males are more affected. Despite advances in basic science, primary ITP remains a diagnosis of exclusion. The disease is heterogeneous in its clinical behavior and response to treatment. This reflects the complex underlying pathophysiology, which remains ill-understood. Platelet destruction plays a role in thrombocytopenia, but underproduction is also a major contributing factor. Active ITP is a proinflammatory autoimmune disease involving abnormalities within the T and B regulatory cell compartments, along with several other immunological abnormalities. Over the last several years, there has been a shift from using immunosuppressive therapies for ITP towards approved treatments, such as thrombopoietin receptor agonists. The recent COVID-19 pandemic has hastened this management shift, with thrombopoietin receptor agonists becoming the predominant second-line treatment. A greater understanding of the underlying mechanisms has led to the development of several targeted therapies, some of which have been approved, with others still undergoing clinical development. Here we outline our view of the disease, including our opinion about the major diagnostic and therapeutic challenges. We also discuss our management of adult ITP and our placement of the various available therapies.

Vaccine-induced immune thrombotic thrombocytopenia.

Within the first months of the COVID-19 vaccination campaign, previously healthy recipients who developed severe thrombosis (often cerebral and/or splanchnic vasculature) and thrombocytopenia typically after adenoviral vector-based vaccination were identified. Similarities between this syndrome, vaccine-induced immune thrombotic thrombocytopenia (VITT), and heparin-induced thrombocytopenia prompted recognition of the role of antiplatelet factor 4 (PF4) antibodies and management strategies based on IV immunoglobulin and nonheparin anticoagulants, which improved outcome. We update current understanding of VITT and potential involvement of anti-PF4 antibodies in thrombotic disorders.

COVID-19: Vaccine-induced immune thrombotic thrombocytopenia.

In late February 2021, a prothrombotic syndrome was encountered for the first time in some of the recipients of ChAdOx1 CoV-19 vaccine (AstraZeneca, University of Oxford, and Serum Institute of India). Since the hallmark of this syndrome is the development of thrombocytopenia and/or thrombosis between 4 and 42 days after receiving a COVID-19 vaccine, it was named vaccine-induced immune thrombotic thrombocytopenia (VITT). Other names include "vaccine-induced prothrombotic immune thrombocytopenia" and "thrombosis with thrombocytopenia syndrome" by the Centers for Disease Control and the Food and Drug Administration (FDA). VITT appears similar to heparin-induced thrombocytopenia in that "platelet activating" autoantibodies are produced in both these conditions due to prior exposure of COVID-19 vaccine and heparin respectively, in turn causing thrombotic complications and consumptive thrombocytopenia. In this article, recent advances in the understanding of pathobiology, clinical features, investigative work-up, and management of VITT are reviewed.

Diagnosis of immune thrombocytopenia, including secondary forms, and selection of second-line treatment.

This article summarizes our approach to the diagnosis of immune thrombocytopenia (ITP), its secondary forms, and choice of second-line treatment options. We very briefly summarize first-line treatment and then utilize a case-based approach. We first explore persistent, chronic ITP in a younger female. We consider many possibilities beyond primary ITP e.g., hypogammaglobulinemia, chronic infection, and anemia, and how to approach their diagnosis and management. The journey continues throughout pregnancy and the post-partum period and eventually includes fourth-line treatment after a late relapse. We then consider an older male, emphasizing differences in diagnostic considerations and management. The focus is on initiation and continuation of second-line treatment, the pros and cons of each option, and briefly the impact of treatment choices related to the endemic presence of severe acute respiratory syndrome coronavirus 2. During the review of potential second-line treatment options, we also briefly touch upon novel treatments. Finally, there is a short section on refractory disease drawn from our previous extensive review published in February 2020.1 The clinical nature of the discussions, replete with figures and tables and with the interspersion of pearls regarding efficacy and toxicity at different ages and genders, will serve the reader in the management of "typical" adult patients who develop persistent and chronic ITP.

Relapse of immune thrombotic thrombocytopenic purpura (iTTP) possibly triggered by COVID-19 vaccination and/or concurrent COVID-19 infection.

Thrombotic thrombocytopenic purpura (TTP) is a life-threatening disease that may be triggered by inflammation, including infection or vaccination. Since the start of the COVID-19 pandemic, several case reports were published on de novo or relapsed immune TTP (iTTP) in COVID-19-infected patients. Case reports of iTTP episodes following vaccination against COVID-19 are also emerging. We report a case of relapsed iTTP in a patient who received Moderna mRNA-1273 SARS-CoV-2 vaccine and developed concurrent severe COVID-19 infection. The patient's iTTP was successfully managed with caplacizumab, therapeutic plasma exchange and high-dose steroids. We summarise published cases of iTTP associated with COVID-19 infection or vaccination.

Alternatives for managing patients with newly diagnosed immune thrombocytopenia: a narrative review.

INTRODUCTION: Primary immune thrombocytopenia (ITP) is an acquired bleeding disorder. Conventionally, first-line ITP therapy aims to obtain a rapid response and stop or decrease the risk of bleeding by increasing the platelet count. At this point, the duration of the response, the tolerability, and the long-term safety of pharmacologic interventions are considered less of a priority. Combination treatments that simultaneously address multiple disease mechanisms are an attractive strategy to increase efficacy in acute ITP therapy. In this review, we discuss the treatment of newly diagnosed ITP patients, emphasizing the use of new combinations to benefit from their synergy. AREAS COVERED: This article summarizes conventional treatment, recent and novel combinations, and COVID-19 management recommendations of newly diagnosed ITP patients. EXPERT OPINION: The key areas for improvement consider the long-term effects of conventional first-line therapy, reducing relapse rates, and extending responses to achieve long-term remission. Although corticosteroids remain a first-line therapy, restricting their use to avoid toxicity and the increasing use of rituximab and TPO-RAs in the first three months after diagnosis open the landscape for future interventions in frontline therapy for ITP. First-line therapy intensification or synergistic drug combination offers a potential and realistic shift in future treatment guidelines.

Bioinformatic Analysis Underpinning the Frequent Occurrence of Immune Thrombocytopenic Purpura in COVID-19 Patients.

BACKGROUND: Secondary immune thrombocytopenic purpura (ITP) associated with coronavirus disease 2019 (COVID-19) is a rare but serious complication of the pandemic. Diagnostic criteria include clinical and laboratory findings. Early treatment is often effective, but rare severe bleeding and death can occur. An autoimmune mechanism is likely. OBJECTIVES: To determine a role for molecular mimicry in producing disease. METHODS: Hexapeptide and heptapeptide matches between severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and platelet N-glycosylated proteins and other human proteins were assessed. RESULTS: Shared viral and platelet glycoprotein peptides were found. Copy frequency of these peptides in the human proteome was low for many of the candidate molecular mimics. CONCLUSIONS: The data support a contribution of molecular mimicry in COVID-19 ITP autoimmunity and offer avenues for in vitro diagnostic assay development. The continuation of the pandemic necessitates additional understanding of COVID-19 ITP as well as studies on diagnosis and mitigation.

COVID-19 Vaccine-Induced Pro-thrombotic Immune Thrombocytopenia (VIPIT): State of the Art.

In 2020, as the severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) pandemic spread rapidly throughout the world, scientists worked relentlessly to develop and test the safety and effectiveness of potential vaccines. Usually, the vaccine development process involves years of investigation and testing prior to gaining approval for use in practice. A pathogenic PF4-dependent syndrome, unrelated to the use of heparin therapy, may be manifested following the administration of viral vector vaccines. It leads to severe clot formation at unusual sites approximately in 1 out of 110.000 vaccinated persons. This side effect, although rare, represents a newly devastating clotting phenomenon manifested in otherwise healthy young adults, who are often female. An in-depth description of the specific biological mechanisms implicated in the syndrome is here summarized.

COVID-19-associated Evans syndrome: A case report and review of the literature.

Evans syndrome is a rare condition characterized by simultaneous or sequential development of autoimmune hemolytic anemia and immune thrombocytopenia (and/or immune neutropenia). Coronavirus disease 2019 (COVID-19) may cause various hematologic conditions, such as coagulation abnormalities (e.g., bleeding or thrombosis) or cell count alterations (e.g., lymphopenia and neutrophilia). COVID-19 may also induce Evans syndrome via immune mechanisms. Here, we describe the case of a patient developing Evans syndrome shortly after COVID-19 infection. Immune thrombocytopenia and warm-type autoimmune hemolytic anemia developed simultaneously, and intravenous immunoglobulin and methylprednisolone were initially administered. Additionally, we intend to review all COVID-19-induced Evans syndrome cases currently present in the literature and emphasize the differences as well as the similarities regarding patient characteristics, relationship to COVID-19 infection, and treatment approach. Since autoimmune cytopenias are frequent in COVID-19 patients, clinicians should pay particular attention to profound and abrupt-onset cytopenias. In these circumstances, hemolysis markers such as lactate dehydrogenase, haptoglobulin, Coombs tests, etc. should be investigated, and the possibility of Evans syndrome should always be considered to ensure prompt and appropriate treatment. These factors are essential to ensure hematologic recovery and prevent complications such as thrombosis.

Refractory vaccine-induced immune thrombotic thrombocytopenia (VITT) managed with delayed therapeutic plasma exchange (TPE).

Vaccine-induced immune thrombotic thrombocytopenia (VITT) is a newly described hematologic disorder, which presents as acute thrombocytopenia and thrombosis after administration of the ChAdOx1 nCov-19 (AstraZeneca) and Ad26.COV2.S (Johnson & Johnson) adenovirus-based vaccines against COVID-19. Due to positive assays for antibodies against platelet factor 4 (PF4), VITT is managed similarly to autoimmune heparin-induced thrombocytopenia (HIT) with intravenous immunoglobulin (IVIG) and non-heparin anticoagulation. We describe a case of VITT in a 50-year-old man with antecedent alcoholic cirrhosis who presented with platelets of 7 × 103 /µL and portal vein thrombosis 21 days following administration of the Ad26.COV2.S COVID-19 vaccine. The patient developed progressive thrombosis and persistent severe thrombocytopenia despite IVIG, rituximab and high-dose steroids and had persistent anti-PF4 antibodies over 30 days after his initial presentation. As such, delayed therapeutic plasma exchange (TPE) was pursued on day 32 of admission as salvage therapy, with a sustained improvement in his platelet count. Our case serves as proof-of-concept of the efficacy of TPE in VITT.

Treatment of ChAdOx1 nCoV-19 Vaccine-Induced Immune Thrombotic Thrombocytopenia Related Acute Ischemic Stroke.

Recently cases of vaccine-induced immune thrombotic thrombocytopenia (VITT) and thrombosis following the adenoviral vector vaccine against the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) were reported. A mechanism similar to heparin-induced thrombocytopenia was proposed with antibodies to platelet factor 4 (PF4). Vaccine related arterial thrombosis in the brain is rare but life-threatening and optimal treatment is not established. We report clinical, laboratory, imaging findings and treatment in a 51-year-old female presenting with acute left middle cerebral artery (MCA) occlusion 7 days after the first dose of ChAdOx1 nCoV-19 vaccine. Due to low platelet count and suspicion of VITT she was not eligible for intravenous thrombolysis (IVT) and proceeded to mechanical thrombectomy (MER) with successful recanalization four hours after onset of symptoms. Treatment with intravenous immunoglobulin (IVIG) and heparin pentasaccharide fondaparinux was initiated. Presence of anti-PF4 antibodies was confirmed. The patient improved clinically with normalization of platelet count. Clinicians should be alert of VITT in patients with acute ischemic stroke after ChAdOx1 nCov-19 vaccination and low platelet counts. MER showed to be feasible and effective. We propose considering MER in patients with VITT and large vessel occlusion despite thrombocytopenia. High-dose IVIG should be started immediately. Alternative anticoagulation to heparin should be started 24 hours after stroke onset unless significant hemorrhagic transformation occurred. Platelet transfusion is contraindicated and should be considered only in severe hemorrhagic complications. Restenosis or reocclusion of the revascularized artery is possible due to the hypercoagulable state in VITT and angiographic surveillance after the procedure is reasonable.

A real-world study of immune thrombocytopenia management during the COVID-19 pandemic in the UK.

The COVID-19 pandemic has created many challenges in the management of immune thrombocytopenic purpura (ITP). The recommendation for avoidance of steroids by WHO led to the off-licence use, supported by NHS England, of thrombopoietin mimetics (TPO-RA) for newly diagnosed or relapsed ITP. This is a real-world prospective study which investigated the treatment patterns and outcomes in this setting. Twenty-four hospitals across the UK submitted 343 cases. Corticosteroids remain the mainstay of ITP treatment, but TPO-RAs were more effective. Incidental COVID-19 infection was identified in a significant number of patients (9·5%), while 14 cases were thought to be secondary to COVID-19 vaccination.

Clinical Features of Vaccine-Induced Immune Thrombocytopenia and Thrombosis.

BACKGROUND: Vaccine-induced immune thrombocytopenia and thrombosis (VITT) is a new syndrome associated with the ChAdOx1 nCoV-19 adenoviral vector vaccine against severe acute respiratory syndrome coronavirus 2. Data are lacking on the clinical features of and the prognostic criteria for this disorder. METHODS: We conducted a prospective cohort study involving patients with suspected VITT who presented to hospitals in the United Kingdom between March 22 and June 6, 2021. Data were collected with the use of an anonymized electronic form, and cases were identified as definite or probable VITT according to prespecified criteria. Baseline characteristics and clinicopathological features of the patients, risk factors, treatment, and markers of poor prognosis were determined. RESULTS: Among 294 patients who were evaluated, we identified 170 definite and 50 probable cases of VITT. All the patients had received the first dose of ChAdOx1 nCoV-19 vaccine and presented 5 to 48 days (median, 14) after vaccination. The age range was 18 to 79 years (median, 48), with no sex preponderance and no identifiable medical risk factors. Overall mortality was 22%. The odds of death increased by a factor of 2.7 (95% confidence interval [CI], 1.4 to 5.2) among patients with cerebral venous sinus thrombosis, by a factor of 1.7 (95% CI, 1.3 to 2.3) for every 50% decrease in the baseline platelet count, by a factor of 1.2 (95% CI, 1.0 to 1.3) for every increase of 10,000 fibrinogen-equivalent units in the baseline d-dimer level, and by a factor of 1.7 (95% CI, 1.1 to 2.5) for every 50% decrease in the baseline fibrinogen level. Multivariate analysis identified the baseline platelet count and the presence of intracranial hemorrhage as being independently associated with death; the observed mortality was 73% among patients with platelet counts below 30,000 per cubic millimeter and intracranial hemorrhage. CONCLUSIONS: The high mortality associated with VITT was highest among patients with a low platelet count and intracranial hemorrhage. Treatment remains uncertain, but identification of prognostic markers may help guide effective management. (Funded by the Oxford University Hospitals NHS Foundation Trust.).