The role of platelet desialylation as a biomarker in primary immune thrombocytopenia: mechanisms and therapeutic perspectives.

Primary immune thrombocytopenia (ITP) is an acquired autoimmune disorder characterized by the destruction of platelets. Although it was long believed that the critical role of autoantibodies in platelet destruction, primarily through the Fc-dependent platelet clearance pathway, recent findings indicate that the significance of the Fc-independent platelet clearance pathway mediated by hepatocytes, thus shedding light on a previously obscure aspect of ITP pathogenesis. Within this context, the desialylation of platelets has emerged as a pivotal biochemical marker. Consequently, targeting platelet desialylation emerges as a novel therapeutic strategy in the pathogenesis of ITP. Notably, prevailing research has largely focused on antiplatelet antibodies and the glycosylation-associated mechanisms of platelet clearance, while comprehensive analysis of platelet desialylation remains scant. In response, we retrospectively discuss the historical progression, inducing factors, generation process, and molecular regulatory mechanisms underlying platelet desialylation in ITP pathogenesis. By systematically evaluating the most recent research findings, we contribute to a comprehensive understanding of the intricate processes involved. Moreover, our manuscript delves into the potential application of desialylation regulatory strategies in ITP therapy, heralding novel therapeutic avenues. In conclusion, this manuscript not only fills a critical void in existing literature but also paves the way for future research by establishing a systematic theoretical framework. By inspiring new research ideas and offering insights into the development of new therapeutic strategies and targeted drugs, our study is poised to significantly advance the clinical management of ITP.

Patient-centric care in primary immune thrombocytopenia (ITP): shared decision-making and assessment of health-related quality of life.

ABSTRACTImmune thrombocytopenia (ITP), an autoimmune disease characterized by low platelet counts and increased bleeding risk, can impair health-related quality of life (HRQoL), impacting patients' daily lives and mental health. A number of patient-reported outcome (PRO) measures (both generic and specific to ITP) can be used to understand the impact of ITP on HRQoL and generate evidence to guide disease management. As well-developed PRO tools could help in HRQoL assessment, their optimization could help to solidify a patient-centric approach to ITP management. Shared decision-making is a collaborative process between a patient and their healthcare professional in making decisions about care. Treatment decisions based on this shared process between physician and patient are recommended by clinical guidelines. The goal of this narrative review is to discuss treatment decisions with regards to patient-centric ITP management, with a focus on the impact of PRO measures and the process of shared decision-making in practice.

Hematological manifestation of Pediatric Systemic Lupus Erythematosus (SLE) - A single centered cross-sectional study.

Introduction: Systemic lupus erythematosus (SLE), the commonest type of lupus, is an autoimmune multisystemic disorder that can affect any organ system of the body, especially blood vessels and connective tissues, causing widespread inflammation. Pediatric onset of SLE is a rare condition with more hematological involvement. Aim: This study was undertaken to observe various hematological abnormalities and their association with various autoantibodies present in pediatric SLE in Eastern India. Methodology: It was a single-centered, cross-sectional, observational, hospital-based study conducted in the Department of Pediatric Medicine in collaboration with the Department of Rheumatology in IPGME and R and SSKM Hospital, Kolkata. The duration of the study was 1.5 years, and a total of 30 children up to 12 years of age of either gender were enrolled. Study participants were evaluated for various parameters like demographic, hematological (anemia, neutropenia, leucopenia, lymphopenia, and thrombocytopenia), biochemical (CRP, Lactate dehydrogenase (LDH), and bilirubin), autoantibodies (anti-dsDNA, anti-Ro 52, and anti-Ribonucleoprotein [RNP]), and SLE related pathologies (Cutaneous, nephritis, serositis). Results: In the present study, most of the participants had arthritis, muscle pain (86.66%), and hematological involvement (80%). Among cytopenias, anemia was the commonest. dsDNA autoantibody was positive in most of the patients (83%), and about one-third suffered from autoimmune hemolytic anemia (AIHA). No association was observed between autoantibodies and various hematological manifestations. Conclusion: It can be concluded from the present study that anemia is the most common cytopenia in pediatric SLE, but there is no association between autoantibodies and these cytopenias. However, study on larger population may give better results.

Epidemiology, Treatment Patterns, and Cost Analysis of Immune Thrombocytopenia in Spain between 2014 and 2020: A Population-based Study.

Background Immune thrombocytopenia (ITP) is characterised by low platelet counts and often leads to bleeding, fatigue, and reduced health-related quality of life. Methods This observational, retrospective, population-based study using BIG-PAC® database included Spanish paediatric and adult patients with primary ITP diagnosed in primary care and hospitals between 2014 and 2020 (median follow-up: 4 years). Epidemiology, baseline/clinical characteristics, treatment trends, healthcare resources and costs were analysed. Results The BIG-PAC® database contains records of 1,818,588 patients; 170 adults and 27 children with ITP were included in our analysis. ITP prevalence and annual incidence per 100,000 were estimated in 10.8 (2.8 in chronic ITP [cITP] patients) and 1.5 (0.3 in cITP patients), respectively. Epistaxis was the most common bleeding event, followed by genitourinary and gastrointestinal bleeding; >50%/> 75% of ITP/cITP patients reported fatigue. Chronic patients had lower platelet counts at baseline and required more transfusions. Corticosteroids, immunosuppressants, and thrombopoietin receptor agonists were the most used agents in first-, second- and third-line treatment, respectively. Thirty-five patients, all of them in chronic phase, underwent splenectomy. Patients had on average 13.9, 6.6, and 1.2 visits/year to primary care, haematology/internal medicine, and emergency departments, respectively. More than one-fourth of adult patients took on average 16.3 days of sick leave annually. Mean annual total health care costs were €10,741 (ITP patients) and €19,809 (cITP patients). Conclusion This is the first study to provide an overall perspective on the situation of the Spanish ITP population in terms of epidemiology, treatment trends, health care resources and costs, highlighting unmet patient needs, and direct and indirect costs/resource use between 2014 and 2020.

Real-world experience of thrombopoietin receptor agonists in pediatric immune thrombocytopenia: a report from a Chinese tertiary children's hospital.

Background: Primary immune thrombocytopenia (ITP) is the most common bleeding disorder in children. There are approximately 20% pediatric ITP patients respond poor to corticosteroids as first-line treatment. Recently thrombopoietin receptor agonists (TPO-RAs) have been used to treat refractory ITP and have achieved certain therapeutic effects. To investigate the efficacy and safety of TPO-RAs in the treatment of pediatric ITP, we conducted this real-world study. Methods: Fifty-three pediatric patients with ITP who did not respond well to corticosteroids were treated with TPO-RAs. Clinical data, including therapeutic response rate, changes in platelet (PLT) count, and adverse events (AEs) were collected. Results: Of the 51 evaluable patients, 37 (72.5%) responded to TPO-RAs. Patients aged >4 years had a higher response rate than those aged ≤4 years (81.1% vs. 50.0%, P=0.04). There was no effect of sex, duration of disease, prior therapy, Mycoplasma pneumoniae (MP) immunoglobulin M (IgM) positivity, antinuclear antibody (ANA) positivity, CD4/CD8 ratio or baseline PLT count on the response rate (P>0.05). Other than 10 patients with PLT counts that exceeded the upper limit of normal, AEs were sporadic, including increased aminotransferase levels, cough, headache, and vomiting. Conclusions: TPO-RAs exhibited good clinical efficacy in pediatric ITP patients who failed to respond to first-line treatment, especially patients aged >4 years, and the side effects were minor.

Flow cytometry vs conventional methods for the evaluation of anti-PF4/heparin antibodies: a single center study.

Aim: Heparin-induced thrombocytopenia (HIT) is a rare, life-threatening, immune-mediated adverse effect of heparin administration. This study compares frequently used laboratory assays in terms of their effectiveness in HIT diagnosis. Materials & methods: Fifty patients with suspected HIT were tested by gel immunoassay and solid phase PF4/heparin antibody ELISA. On positive results, platelet activation markers P-selectin and Annexin V were assayed using flow cytometry. Results: Thirty/50 patients were negative for both immunoassays. Flow cytometry was performed in the 20 immunoassay positive patients. Platelet activation was observed in 7/20 in the presence of low heparin concentration (0.2 IU/ml). Conclusion: The results are in accordance with the currently available literature and flow cytometry seems a promising alternative in HIT laboratory investigation.

[Box: see text].

Therapeutic effects of Medicago sativa against cyclophosphamide-induced toxicity in rats.

Objective: Medicago sativa (M. sativa) has been traditionally used for treating anemia; therefore, M. sativa hydro-ethanolic extract therapeutic effects against cyclophosphamide (CP) -induced hematologic and liver toxicity were examined. Materials and Methods: Thirty male Wistar rats were randomly divided to control (saline); CP (100 mg/kg, day 1-3, subcutaneously); CP+ M. sativa 200 mg/kg (MS 200); CP+ M. sativa 400 mg/kg (MS 400); CP+ dexamethasone (0.1 mg/kg), (all groups n=6). Treated animals received M. sativa or dexamethasone by gavage from days 7-14. On days 0, 7, and 14, hematologic parameters, and on the 14th day, serum and liver tissue oxidative stress markers including nitric oxide, malondialdehyde (MDA) and total thiol levels, superoxide dismutase (SOD) and catalase (CAT) activities, serum lipids, and liver enzymes were measured. Results: Animal weight, platelet, white blood cells, and red blood cells counts, hemoglobin and hematocrit as well as thiol, SOD, and CAT activities in serum and liver tissue were significantly reduced, but serum nitric oxide, MDA, total cholesterol, triglycerides, low-density lipoproteins levels, and liver enzymes were increased in the CP group compared to the control group (p<0.05 to p<0.001). Administering M. sativa extract (400 mg/kg) significantly enhanced platelet count, and SOD and CAT activities and inhibited all of the CP toxic effects, while dexamethasone improved platelet count and oxidative stress markers compared to the CP group (p<0.05 to p<0.001). Conclusion: The extract of M. sativa (400 mg/kg) showed therapeutic effects against the CP-induced myelosuppression and thrombocytopenia and improved oxidative stress markers which were comparable to the effect of dexamethasone.

Thrombocytopenia is Associated with Higher Fontan Pressure and Increased Morbidity in Patients with Fontan Circulation.

After the Fontan procedure, patients require lifelong follow-up due to significant late morbidity and mortality. Thrombocytopenia is seen frequently post-Fontan, likely due to secondary hypersplenism from elevated Fontan pressure. We investigated platelet counts in patients with a Fontan circulation and assessed associations with catheterization data and clinical outcomes. This retrospective study included 92 patients (33% female) post-Fontan who had a complete blood count performed between January 2011 and July 2023. The age at evaluation was 24.0 ± 8.9 years. Outcomes measured included elevated Fontan pressure (≥ 15 mmHg), Fontan-associated liver disease (FALD), unscheduled admissions, transplant, and death. Participants with thrombocytopenia (≤ 150,000/µL) had significantly higher rates of elevated Fontan pressure (OR 8.1, 95% CI 1.3-52.7, p = 0.03), FALD (OR 4.1, 95% CI 1.6-10.6, p = 0.004), and unscheduled admissions (362 ± 577 versus 115 ± 185 admissions per 1000 patient-years, p = 0.02). Thrombocytopenia post-Fontan is associated with elevated Fontan pressure, FALD, and increased morbidity. Platelet count could serve as a non-invasive factor in identifying patients at risk of decompensation.

[Clinical management of thrombocytopenia in cirrhosis].

Thrombocytopenia is one of the common complications of cirrhotic patients, which can induce an increasing bleeding risk and closely correlate with bleeding following invasive procedures. Consequently, how to respond to thrombocytopenia is crucial for improving the prognosis of patients with cirrhosis. This article reviews the main mechanisms of cirrhosis concurrent with thrombocytopenia, as well as the corresponding clinical management strategies.

[Pay attention to the diagnosis and treatment of "easily neglected" complications in liver cirrhosis].

Managing cirrhosis complications is an important measure for improving patients' clinical outcomes. Therefore, in order to provide a complete disease assessment and comprehensive treatment, improve quality of life, and improve the prognosis for patients with cirrhosis, it is necessary to pay attention to complications such as thrombocytopenia and portal vein thrombosis in addition to common or severe complications such as ascites, esophagogastric variceal bleeding, hepatic encephalopathy, and hepatorenal syndrome. The relevant concept that an effective albumin concentration is more helpful in predicting the cirrhosis outcome is gradually being accepted; however, the detection method still needs further standardization and commercialization.

[An analysis of related factors in thrombocytopenia combined with cirrhosis: a cross-sectional study of 2 517 cases].

Objective: To explore the related factors of thrombocytopenia (TCP) occurrence in patients with cirrhosis. Methods: A cross-sectional study was conducted. Inpatients with an initial diagnosis of cirrhosis at Peking University First Hospital from January 1, 2010 to December 31, 2020 were included. Clinical data such as demographic characteristics, etiology of cirrhosis, complications of cirrhosis, laboratory indicators, Child-Pugh grade, invasive procedures, and mortality during hospitalization were collected. A logistic regression model was used to explore the related factors of TCP occurrence in patients with cirrhosis. Categorical variables were compared by the χ(2) test. The inter-group comparison was performed using continuous variables, a t-test, one-way analysis of variance (ANOVA), or a nonparametric test. Results: There were a total of 2 592 cases of cirrhosis. 75 cases with incomplete clinical data were excluded. 2 517 cases were included for analysis. The median age was 58 (50, 67) years. Males accounted for 64%. 1 435 cases (57.0%) developed TCP, and 434 cases (17.2%) had grade 3-4 TCP. Gender, primary biliary cholangitis (PBC), primary sclerosing cholangitis (PSC), and concomitant esophagogastric varices (EGV) were the major factors associated with TCP. Females were more prone to combine with TCP (OR=1.32, 95%CI: 1.12-1.56, P=0.001). Patients combined with EGV (OR=3.09, 95%CI: 2.63-3.65, P<0.001) were more prone to develop TCP, which was associated with the increased incidence of hypersplenism (P<0.001). Patients with PBC (OR=0.64, 95%CI: 0.50-0.82, P<0.001) and PSC (OR=0.23, 95%CI: 0.06-0.65, P=0.010) were less prone to develop TCP, which was due to the shorter prothrombin time and better coagulation function of PBC patients (P<0.001), and the lower proportion of hypersplenism in combined PSC patients (P=0.004). Patients with TCP and grade 3-4 TCP had a higher rate of hemostatic procedures (P<0.05), but a lower rate of liver biopsy (P<0.05). Patients with grade 3-4 TCP had a higher nosocomial mortality rate compared to those without (P=0.004). Conclusion: TCP is common in patients with cirrhosis. However, TCP occurrence is higher in female patients with EGV and lower in patients combined with PBC and PSC. TCP affects invasive procedures and is associated with adverse outcomes.

Validation of the newly proposed Brighton Collaboration case definition for vaccine-induced immune thrombocytopenia and thrombosis.

Vaccine-induced immune thrombocytopenia and thrombosis (VITT) is a newly recognized syndrome mediated by anti-platelet factor 4 antibodies induced by Covid-19 adenovirus-vectored vaccines including ChAdOx1 nCoV-19 and Ad26.COV2.S. This study validated a proposed Brighton Collaboration case definition for VITT. A data collection form was developed and used to capture the variations in VITT criteria and assess their level of diagnostic certainty from adjudicated positive VITT case datasheets in Germany (n = 71), UK (n = 220), Australia (n = 203), and Taiwan (n = 56). We observed high prevalence of each component of the proposed VITT definition in positive cases (84%-100%), except for the occurrence of thrombosis or thromboembolism criterion in only 34% of VITT cases in Taiwan. The sensitivity of this proposed definition was 100% for Germany and UK, 92% for Australia, and 89% for Taiwan cases. These findings support the validity of this case definition for VITT.

The CARMEN-France registry of adult patients with immune thrombocytopenia and autoimmune hemolytic anemia in France.

The CARMEN-France registry is a prospective, multicenter registry in France including adult patients with a new diagnosis of immune thrombocytopenia or of autoimmune immune hemolytic anemia (2402 patients included in December 31, 2023). The recording of clinical, biological and treatment data allows detailed epidemiological and pharmacoepidemiological real-world studies. This review summarizes the CARMEN-France registry protocol, gives examples of studies conducted in the registry, and indicates future directions such as inclusion of patient reported outcomes, linkage with the French national health insurance database and linkage with other registries in Europe.

Acquired immune thrombotic thrombocytopenic purpura (TTP) associated with inactivated COVID-19 vaccine CoronaVac.

Corona virus disease 2019 (COVID-19) due to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection has affected the whole world. Acquired thrombotic thrombocytopenic purpura (TTP) has been reported after administration of mRNA- or adenoviral vector-based COVID-19 vaccines, including Ad26.COV2-S, BNT162b2, mRNA-1273, and ChAdOx1 nCov-19. However, whether inactivated vaccines, such as CoronaVac, could cause TTP and whether the symptoms in TTPs caused by inactivated vaccines are different from previously reported cases are unknown. In this study, two cases were reported. Both cases developed TTP after the second CoronaVac vaccination shot, but not the first. They demonstrated symptoms of fever, neurological abnormalities, renal dysfunction, thrombocytopenia, and hemolysis. Both patients achieved complete remission through several sessions of plasma exchanges and immune suppression. The incidence of TTP in Nanjing area was analyzed. The number of patients with TTP was 12 in 2019, 6 in 2020, 16 in 2021, and 19 in 2022. To the authors' knowledge, this report is the first report of TTP associated with inactivated COVID-19 vaccine (CoronaVac). The rarity and delayed onset may be due to the relatively milder immune response caused by the inactivated vaccines than mRNA-based ones. Timely plasma exchange is a vital treatment for CoronaVac-related TTP, similar to activated vaccine-related TTP.

Electronic alerts to improve management of heparin-induced thrombocytopenia.

Background: Heparin-induced thrombocytopenia (HIT) is a difficult clinicopathologic diagnosis to make and to treat. Delays in identification and appropriate treatment can lead to increased morbidity and mortality. Objectives: To use electronic health alert interventions to improve provider diagnosis and management of heparin-induced thrombocytopenia through guideline-based, accurate care delivery. Methods: This quality improvement initiative developed 3 electronic health record-based interventions at our 750-bed academic medical center to improve the initial management of suspected HIT between 2018 and 2021: 1. an interruptive alert to recommend discontinuation of active heparin products when signing a heparin-platelet factor 4 test (PF4) order, 2. integrated 4T score calculation in the heparin-PF4 test order, and 3. interruptive alert suggesting not to order heparin-PF4 tests when the 4T score is <4. Changes in practice were assessed over defined time periods pre and post each intervention. Results: Intervention 1 resulted in heparin discontinuation in more patients, with 65% (191 heparin orders/293 heparin-PF4 enzyme-linked immunosorbent assay tests) of cases continuing heparin prealert and only 54% (127 heparin orders/235 heparin-PF4 enzyme-linked immunosorbent assay tests) postinterruptive alert (95% CI 2.3-19.9; P = .015). Intervention 2 increased appropriate heparin-PF4 test ordering from 40.4% (110/272) preintervention to 79.1% (246/311) (95% CI 30.9-46.4; P < .00001) postintervention, with inappropriate PF4 ordering defined as testing when 4T score was <4. Intervention 3 did not lead to reduction in heparin-PF4 testing in the control group (96 inappropriate orders/402 total orders, 24%) compared to the randomized alert group (56 inappropriate orders/298 total orders; 19%) (95% CI -1.2 to 11.5; P = .13). Conclusion: Implementation of unique electronic health record interventions, including both diagnostic and management interventions, led to improved guideline-based, accurate care delivery with 4T score calculation and cessation of heparin for patients with suspected HIT.

Association of thrombocytopenia with immune checkpoint inhibitors: a large-scale pharmacovigilance analysis based on the data from FDA adverse event reporting system database.

Introduction: An increasing number of immune-related adverse events (irAEs) induced by immune checkpoint inhibitors (ICIs) have been reported during clinical treatment. We aimed to explore the clinical characteristics of patients with ICIs-induced ITP under different therapeutic strategies based on the FAERS database and explore the potential biological mechanisms in combination with TCGA pan-cancer data. Methods: Data from FAERS were collected for ICIs adverse reactions between January 2012 and December 2022. Disproportionality analysis identified ICIs-induced ITP in the FAERS database using the reporting odds ratio (ROR), proportional reporting ratio (PRP), Bayesian confidence propagation neural network (BCPNN), and multi-item gamma Poisson shrinker algorithms (MGPS). The potential biological mechanisms underlying ITP induced by ICIs were examined using TCGA transcriptome data on cancers. Results: In the FAERS, 345 ICIs-induced ITP reports were retrieved, wherein 290 (84.06%) and 55 (15.94%) were reported as monotherapy and combination therapy, respectively. The median age of the reported patients with ICIs-induced ITP was 69 years (IQR 60-76), of which 62 (18%) died and 47 (13.6%) had a life-threatening outcome. The majority of reported indications were lung, skin, and bladder cancers, and the median time to ITP after dosing was 42 days (IQR 17-135), with 64 patients (43.5%) experiencing ITP within 30 days of dosing and 88 patients experiencing ITP in less than 2 months (59.9%). The occurrence of ICIs-induced ITP may be associated with ICIs-induced dysregulation of the mTORC1 signaling pathway and megakaryocyte dysfunction. Conclusion: There were significant reporting signals for ITP with nivolumab, pembrolizumab, cemiplimab, atezolizumab, avelumab, durvalumab, ipilimumab, nivolumab/ipilimumab, and pembrolizumab/ipilimumab. Patients treated with anti-PD-1 in combination with anti-CTLA-4 are more likely to have an increased risk of ICIs-induced ITP. Patients with melanoma are at a higher risk of developing ITP when treated with ICI and should be closely monitored for this risk within 60 days of treatment. The potential biological mechanism of ICIs-induced ITP may be related to the dysfunction of megakaryocyte autophagy through the overactivation of the mTOR-related signaling pathway. This study provides a comprehensive understanding of ICIs-induced ITP. Clinicians should pay attention to this potentially fatal adverse reaction.

Macrothrombocytopenia with leukocyte inclusions in a patient with Wilson disease: a case report and literature review.

BACKGROUND: Wilson disease (WD) is an autosomal recessive disorder caused by homozygous or compound heterozygous mutations in ATP7B. Clinical manifestations primarily involve liver and nervous system lesions, with rarely observed hematologic manifestations. CASE PRESENTATION: In the present case, a patient with WD presented with thrombocytopenia, giant platelets, and Döhle-like cytoplasmic inclusions in the leukocytes. Initially, the May-Hegglin anomaly was considered; however, whole-exome sequencing did not reveal any mutation in the MYH9 gene but a heterozygous mutation was found in (C.2804 C > T, p.T935M) in the ATP7B gene. After two years, the patient developed tremors in his hands, lower limb stiffness, and foreign body sensation in the eyes. Additionally, Kayser-Fleischer rings in the corneal limbus were detected by slit-lamp examination. Copper metabolism test indicated a slight decrease in serum ceruloplasmin. Transmission electron microscopy revealed that the inclusion bodies of leukocytes were swollen mitochondria. Mass spectrometry analysis showed that the copper levels were almost 20-fold higher in the leukocytes of the patient than in those of the control group. Based on the Leipzig scoring system, a diagnosis of WD was confirmed. Zinc sulfate treatment ameliorated the patient's symptoms and enhanced platelet, serum ceruloplasmin, and albumin levels. CONCLUSIONS: In conclusion, this case represents the first documented instance of WD presenting as thrombocytopenia, giant platelets, and Döhle-like cytoplasmic inclusions in the leukocytes. Excessive cellular copper accumulation likely underlies these findings; however, understanding precise mechanisms warrants further investigation.

Association of Metal Cations with the Anti-PF4/Heparin Antibody Response in Heparin-Induced Thrombocytopenia.

Heparin-induced thrombocytopenia (HIT) is an antibody-mediated immune response against complexes of heparin and platelet factor 4 (PF4). The electrostatic interaction between heparin and PF4 is critical for the anti-PF4/heparin antibody response seen in HIT. The binding of metal cations to heparin induces conformational changes and charge neutralization of the heparin molecule, and cation-heparin binding can modulate the specificity and affinity for heparin-binding partners. However, the effects of metal cation binding to heparin in the context of anti-PF4/heparin antibody response have not been determined. Here, we utilized inductively coupled plasma mass spectrometry (ICP-MS) to quantify 16 metal cations in patient plasma and tested for correlation with anti-PF4/heparin IgG levels and platelet count after clinical suspicion of HIT in a cohort of heparin-treated patients. The average age of the cohort (n = 32) was 60.53 (SD = 14.31) years old, had a mean anti-PF4/heparin antibody optical density [OD405] of 0.93 (SD = 1.21) units, and was primarily female (n = 23). Patients with positive anti-PF4/heparin antibody test results (OD405 ≥ 0.5 units) were younger, had increased weight and BMI, and were more likely to have a positive serotonin release assay (SRA) result compared to antibody-negative patients. We observed statistical differences between antibody-positive and -negative groups for sodium and aluminum and significant correlations of anti-PF4/heparin antibody levels with sodium and silver. While differences in sodium concentrations were associated with antibody-positive status and correlated with antibody levels, no replication was performed. Additional studies are warranted to confirm our observed association, including in vitro binding studies and larger observational cohorts.

GATA1 in Normal and Pathologic Megakaryopoiesis and Platelet Development.

GATA1 is a highly conserved hematopoietic transcription factor (TF), essential for normal erythropoiesis and megakaryopoiesis, that encodes a full-length, predominant isoform and an amino (N) terminus-truncated isoform GATA1s. It is consistently expressed throughout megakaryocyte development and interacts with its target genes either independently or in association with binding partners such as FOG1 (friend of GATA1). While the N-terminus and zinc finger have classically been demonstrated to be necessary for the normal regulation of platelet-specific genes, murine models, cell-line studies, and human case reports indicate that the carboxy-terminal activation domain and zinc finger also play key roles in precisely controlling megakaryocyte growth, proliferation, and maturation. Murine models have shown that disruptions to GATA1 increase the proliferation of immature megakaryocytes with abnormal architecture and impaired terminal differentiation into platelets. In humans, germline GATA1 mutations result in variable cytopenias, including macrothrombocytopenia with abnormal platelet aggregation and excessive bleeding tendencies, while acquired GATA1s mutations in individuals with trisomy 21 (T21) result in transient abnormal myelopoiesis (TAM) and myeloid leukemia of Down syndrome (ML-DS) arising from a megakaryocyte-erythroid progenitor (MEP). Taken together, GATA1 plays a key role in regulating megakaryocyte differentiation, maturation, and proliferative capacity. As sequencing and proteomic technologies expand, additional GATA1 mutations and regulatory mechanisms contributing to human diseases of megakaryocytes and platelets are likely to be revealed.