Evaluation of a diagnostic platelet aggregation test strategy for platelet rich plasma samples with low platelet counts

INTRODUCTION

Light transmission aggregometry (LTA) is important for diagnosing platelet function disorders (PFD) and von Willebrand disease (VWD) affecting ristocetin-induced platelet aggregation (RIPA). Nonetheless, data is lacking on the utility of LTA for investigating thrombocytopenic patients and platelet rich plasma samples with low platelet counts (L-PRP). Previously, we developed a strategy for diagnostic LTA assessment of L-PRP that included: (1) acceptance of referrals/samples, regardless of thrombocytopenia severity, (2) tailored agonist selection, based on which are informative for L-PRP with mildly or severely low platelet counts, and (3) interpretation of maximal aggregation (MA) using regression-derived 95% confidence intervals, determined for diluted control L-PRP (C-L-PRP).

METHODS

To further evaluate the L-PRP LTA strategy, we evaluated findings for a subsequent patient cohort.

RESULTS

Between 2008 and 2021, the L-PRP strategy was applied to 211 samples (11.7% of all LTA samples) from 192 unique patients, whose platelet counts (median [range] × 109 /L) for blood and L-PRP were: 105 [13-282; 89% with thrombocytopenia] and 164 [17-249], respectively. Patient-L-PRP had more abnormal MA findings than simultaneously tested C-L-PRP (p-values <0.001). Among patients with accessible electronic medical records (n = 181), L-PRP LTA uncovered significant aggregation abnormalities in 45 (24.9%), including 18/30 (60%) with <80 × 109  platelets/L L-PRP, and ruled out PFD, and VWD affecting RIPA, in others. The L-PRP LTA strategy helped diagnose VWD affecting RIPA, Bernard Soulier syndrome, familial platelet disorder with myeloid malignancy, suspected ITGA2B/ITGB3-related thrombocytopenia, and acquired PFD.

CONCLUSION

Diagnostic LTA with L-PRP, using a strategy that considers thrombocytopenia severity, is feasible and informative.

Immune-mediated thrombocytopenia and IL-6-mediated thrombocytosis observed in idiopathic multicentric Castleman disease

Idiopathic multicentric Castleman disease (iMCD) is a rare haematological disorder characterized by generalized lymphadenopathy with atypical histopathological features and systemic inflammation caused by a cytokine storm involving interleukin-6 (IL-6). Three clinical subtypes are recognized: thrombocytopenia, anasarca, fever, renal dysfunction, organomegaly (iMCD-TAFRO); idiopathic plasmacytic lymphadenopathy (iMCD-IPL), involving thrombocytosis and hypergammaglobulinaemia; and iMCD-not otherwise specified (iMCD-NOS), which includes patients who do not meet criteria for the other subtypes. Disease pathogenesis is poorly understood, with potential involvement of infectious, clonal and/or autoimmune mechanisms. To better characterize iMCD clinicopathology and gain mechanistic insights into iMCD, we analysed complete blood counts, other clinical laboratory values and blood smear morphology among 63 iMCD patients grouped by clinical subtype. Patients with iMCD-TAFRO had large platelets, clinical severity associated with lower platelet counts and transfusion-resistant thrombocytopenia, similar to what is observed with immune-mediated destruction of platelets in immune thrombocytopenic purpura. Conversely, elevated platelet counts in iMCD-IPL were associated with elevated IL-6 and declined following anti-IL-6 therapy. Our data suggest that autoimmune mechanisms contribute to the thrombocytopenia in at least a portion of iMCD-TAFRO patients whereas IL-6 drives thrombocytosis in iMCD-IPL, and these mechanisms likely contribute to disease pathogenesis.

Detection of circulating normal and tumor plasma cells in newly diagnosed patients of multiple myeloma and their associations with clinical and laboratory parameters

INTRODUCTION

Circulating plasma cells (CPCs) are frequently noted in variable frequencies in the entire spectrum of plasma cells neoplasms. With advent of high sensitivity multi-parametric flow cytometry, it is not only possible to detect CPCs present in very low numbers, but also to categorise them into circulating tumor plasma cells (CTPCs) and circulating normal plasma cells (CNPCs), based on their marker-profile. This study used multi-colour flow cytometry to evaluate the load of both CTPCs & CNPCs at the time of diagnosis and at six months' time-point of therapy, and evaluated associations of both with clinical and laboratory parameters.

METHODS

Twenty one newly diagnosed MM patients were enrolled. Six to nine millilitres of EDTA-anticoagulated peripheral blood sample was used for flow cytometry. A ten colour antibody panel was used for analysis of CPCs, which were categorised further into CTPCs and CNPCs. Approximately 4.8 million events were acquired for the analysis. The percentage &absolute numbers of CTPCs and CNPCs were noted and the proportion of CTPCs out of all CPCs (CTPCs + CNPCs) were also calculated for evaluating their statistical associations.

RESULTS

All 21 patients of newly diagnosed MM showed presence of CPCs (CTPCs and/or CNPCs) at the time of diagnosis. The CTPCs were detected in 76 % of the study population. The median percentage and absolute counts of CTPCs were 0.52 % and 54.9 cells /µL, respectively. CNPCs were found in 95 % and the median percentage and absolute counts of CNPCs were 0.025 % and 2.66 cells/µL. After six months of therapy, CPCs (CTPCs and/or CNPCs) were found in all nine patients evaluated for this assay. CTPCs were found 33 %, with a median of 0.075 % and CNPCs were found in 89 % with a median of 0.01 %. Our study showed that the load of CTPCs was found to be higher in patients with presence of lytic bone lesions, plasmacytoma, presence of PCs on peripheral blood film by light microscopy, presence of Chr 1p32 deletion, expression of CD56 and CD81 on CTPCs, and in patients with absence of very good partial response (VGPR). Conversely, the load of CTPCs was significantly lower in patients with concomitant amyloidosis. Also, percentage of bone marrow plasma cells exhibited a significant positive correlation with the absolute count of CTPCs. We observed that the mean percentage of CNPCs was significantly higher in female patients. The load of CNPCs was lower in patients with thrombocytopenia and with hypoalbuminemia.

CONCLUSION

Increased burden of CTPCs was associated with presence of lytic lesions, plasmacytomas, Chr 1p32 deletion, expression of CD56 and CD81 on tumor cells and with failure to achieve very good partial response. The CNPCs were lower in patients with thrombocytopenia and with hypoalbuminemia. To best ot our knowledge, this is the first study from India on the relevance of circulating tumor plasma cells and the first study in the world to analyse the associations of circulating normal plasma cells in newly diagnosed patients of multiple myeloma. The study also highlights the utility of multi-parametric flow cytometry in identification and enumeration of circulating plasma cells.

MICRO ABSTRACT

Circulating plasma cells indicates poorer outcomes in patients of multiple myeloma. Twenty one newly diagnosed multiple myeloma patients were evaluated by flow cytometry to enumerate and characterise circulating tumor plasma cells (CTPCs) and circulating normal plasma cells (CNPCs). Higher load of CTPCs correlated with known poor prognostic markers and poor response to therapy.

A novel GATA1 variant p.G229D causing the defect of procoagulant platelet formation

INTRODUCTION

GATA1 is one of the master transcription factors in hematopoietic lineages development which is crucial for megakaryocytic differentiation and maturation. Previous studies have shown that distinct GATA1 variants are associated with varying severities of macrothrombocytopenia and platelet dysfunction.

OBJECTIVE

To determine the underlying pathological mechanisms of a novel GATA1 variant (c. 686G > A, p. G229D) in a patient with recurrent traumatic muscle hematomas.

METHODS

Comprehensive phenotypic analysis of the patient platelets was performed. Procoagulant platelet formation and function were detected using flow cytometry assay and thrombin generation test (TGT), respectively. The ANO6 expression was measured by qPCR and western blot. The intracellular supramaximal calcium flux was detected by Fluo-5N fluorescent assay.

RESULTS

The patient displayed mild macrothrombocytopenia with defects of platelet granules, aggregation, and integrin αIIbβ3 activation. The percentage of the procoagulant platelet formation of the patient upon the stimulation of thrombin plus collagen was lower than that of the healthy controls (40.9 % vs 49.0 % ± 5.1 %). The patient platelets exhibited a marked reduction of thrombin generation in platelet rich plasma TGT compared to the healthy controls (peak value: ∼70 % of the healthy controls; the endogenous thrombin potential: ∼40 % of the healthy controls). The expression of ANO6 and intracellular calcium flux were impaired, which together with abnormal granules of the patient platelets might contribute to defect of procoagulant platelet function.

CONCLUSIONS

The G229D variant could lead to a novel platelet phenotype characterized by defective procoagulant platelet formation and function, which extended the range of GATA1 variants associated platelet disorders.

Improving the chances of response to splenectomy in immune thrombocytopenia

Immune thrombocytopenia (ITP) is an autoimmune bleeding disorder characterized by isolated thrombocytopenia. Its pathogenesis is complex relying in large part on destruction of platelets recognized by autoantibodies within the spleen. However, other mechanisms, such as platelet desialylation, may play a role in platelet reduction by accelerating their clearance in the liver. In their study, Mendoza and colleagues reported on platelet scintigraphy performed in 51 ITP patients, showing a response in 87.5% when the sequestration occurred in the spleen versus 45% in case of non-splenic destruction. Platelet desialylation was also measured after splenectomy and found to be higher in non-responder patients. These latter results, while requiring confirmation prior to splenectomy, support platelet desialylation may also be a potential biomarker of non-response to splenectomy. Commentary on: Mendoza et al. Study of platelet kinetics in immune thrombocytopenia to predict splenectomy response. Br J Haematol 2024;204:315-323.

Bone marrow metastasis in nonhematological malignancies: A study from tertiary care center

Introduction

Metastatic cancer presents a treatment challenge to clinicians, particularly for patients with bone marrow infiltration. For tumor staging, therapy selection, and prognosis risk stratification, the status of the bone marrow should be known for the presence or absence of metastasis. The study aimed to evaluate the hematological findings and comprehensive analysis of bone marrow in cases of nonhematological malignancies with bone marrow metastasis.

Materials and Methods

This retrospective study comprised a record retrieval of the departmental archives for the past 6 years. A total of 331 patients with nonhematological malignancies were found, of whom 31.42% (104/331) showed bone marrow metastasis. An integrated clinical approach with bone marrow examination findings and immunohistochemistry whenever necessary was used to achieve a definitive diagnosis of bone marrow metastasis.

Results

Among the study population, 31.42% (104/331) of patients had nonhematological malignancies that metastasized to the bone marrow. Most of the patients with bone marrow metastasis had anemia, which was found in 77.88% (81/104) of the cases. Leukoerythroblastic reaction was noted in 31.73% (33/104) of the cases, and thrombocytopenia was found in 25% (26/104) of the cases. The most common malignancy with bone marrow metastasis in adults was prostatic adenocarcinoma (28.1%) (9/32) and in pediatric cases, neuroblastoma (53.9%) (52/98).

Conclusions

It is essential to diagnose nonhematological malignancies that have metastasized to the bone marrow since this necessitates tumor staging, therapy selection, and prognosis risk stratification. To conclude, not a single hematological parameter is predictive of bone marrow metastasis; however, unexplained anemia, a leukoerythroblastic blood picture, and thrombocytopenia in peripheral blood should raise suspicion for bone marrow metastasis in cases of nonhematological malignancies.

Anti-PF4 immunothrombosis without proximate heparin or adenovirus vector vaccine exposure

ABSTRACT

Platelet-activating anti-platelet factor 4 (PF4)/heparin antibodies and anti-PF4 antibodies cause heparin-induced thrombocytopenia (HIT) and vaccine-induced immune thrombocytopenia and thrombosis (VITT), respectively. Diagnostic and treatment considerations differ somewhat between HIT and VITT. We identified patients with thrombocytopenia and thrombosis without proximate heparin exposure or adenovirus-based vaccination who tested strongly positive by PF4/polyanion enzyme-immunoassays and negative/weakly positive by heparin-induced platelet activation (HIPA) test but strongly positive by PF4-induced platelet activation (PIPA) test (ie, VITT-like profile). We tested these patients by a standard chemiluminescence assay that detects anti-PF4/heparin antibodies found in HIT (HemosIL AcuStar HIT-IgG(PF4-H)) as well as a novel chemiluminescence assay for anti-PF4 antibodies found in VITT. Representative control sera included an exploratory anti-PF4 antibody-positive but HIPA-negative/weak cohort obtained before 2020 (n = 188). We identified 9 patients with a clinical-pathological profile of a VITT-like disorder in the absence of proximate heparin or vaccination, with a high frequency of stroke (arterial, n = 3; cerebral venous sinus thrombosis, n = 4), thrombocytopenia (median platelet count nadir, 49 × 109/L), and hypercoagulability (greatly elevated D-dimer levels). VITT-like serological features included strong reactivity by PIPA (aggregation <10 minutes in 9/9 sera) and positive testing in the novel anti-PF4 chemiluminescence assay (3/9 also tested positive in the anti-PF4/heparin chemiluminescence assay). Our exploratory cohort identified 13 additional patient sera obtained before 2020 with VITT-like anti-PF4 antibodies. Platelet-activating VITT-like anti-PF4 antibodies should be considered in patients with thrombocytopenia, thrombosis, and very high D-dimer levels, even without a proximate exposure to heparin or adenovirus vector vaccines.

The immunology of PF4 polyanion interactions

PURPOSE OF REVIEW

Platelet factor 4 (PF4, CXCL4), the most abundant α-granule platelet-specific chemokine, forms tetramers with an equatorial ring of high positive charge that bind to a wide range of polyanions, after which it changes conformation to expose antigenic epitopes. Antibodies directed against PF4 not only help to clear infection but can also lead to the development of thrombotic disorders such as heparin-induced thrombocytopenia (HIT) and vaccine-induced thrombocytopenia and thrombosis (VITT). This review will outline the different mechanisms through which PF4 engagement with polyanions combats infection but also contributes to the pathogenesis of inflammatory and thrombotic disease states.

RECENT FINDINGS

Recent work has shown that PF4 binding to microbial polyanions may improve outcomes in infection by enhancing leukocyte-bacterial binding, tethering pathogens to neutrophil extracellular traps (NETs), decreasing the thrombotic potential of NET DNA, and modulating viral infectivity. However, PF4 binding to nucleic acids may enhance their recognition by innate immune receptors, leading to autoinflammation. Lastly, while HIT is induced by platelet activating antibodies that bind to PF4/polyanion complexes, VITT, which occurs in a small subset of patients treated with COVID-19 adenovirus vector vaccines, is characterized by prothrombotic antibodies that bind to PF4 alone.

SUMMARY

Investigating the complex interplay of PF4 and polyanions may provide insights relevant to the treatment of infectious disease while also improving our understanding of the pathogenesis of thrombotic disorders driven by anti-PF4/polyanion and anti-PF4 antibodies.

Targeted therapy with nanatinostat and valganciclovir in recurrent EBV-positive lymphoid malignancies: a phase 1b/2 study

Lymphomas are not infrequently associated with the Epstein-Barr virus (EBV), and EBV positivity is linked to worse outcomes in several subtypes. Nanatinostat is a class-I selective oral histone deacetylase inhibitor that induces the expression of lytic EBV BGLF4 protein kinase in EBV+ tumor cells, activating ganciclovir via phosphorylation, resulting in tumor cell apoptosis. This phase 1b/2 study investigated the combination of nanatinostat with valganciclovir in patients aged ≥18 years with EBV+ lymphomas relapsed/refractory to ≥1 prior systemic therapy with no viable curative treatment options. In the phase 1b part, 25 patients were enrolled into 5 dose escalation cohorts to determine the recommended phase 2 dose (RP2D) for phase 2 expansion. Phase 2 patients (n = 30) received RP2D (nanatinostat 20 mg daily, 4 days per week with valganciclovir 900 mg orally daily) for 28-day cycles. The primary end points were safety, RP2D determination (phase 1b), and overall response rate (ORR; phase 2). Overall, 55 patients were enrolled (B-non-Hodgkin lymphoma [B-NHL], [n = 10]; angioimmunoblastic T-cell lymphoma-NHL, [n = 21]; classical Hodgkin lymphoma, [n = 11]; and immunodeficiency-associated lymphoproliferative disorders, [n = 13]). The ORR was 40% in 43 evaluable patients (complete response rate [CRR], 19% [n = 8]) with a median duration of response of 10.4 months. For angioimmunoblastic T-cell lymphoma-NHL (n = 15; all refractory to the last prior therapy), the ORR/CRR ratio was 60%/27%. The most common adverse events were nausea (38% any grade) and cytopenia (grade 3/4 neutropenia [29%], thrombocytopenia [20%], and anemia [20%]). This novel oral regimen provided encouraging efficacy across several EBV+ lymphoma subtypes and warrants further evaluation; a confirmatory phase 2 study (NCT05011058) is underway. This phase 1b/2 study is registered at www.clinicaltrials.gov as #NCT03397706.

[The 502nd case: thrombocytopenia, splenomegaly, disseminated intravascular coagulation, and spontaneous rupture of the spleen]

A young man with a history of thrombocytopenia for seven years presented with splenomegaly and fever and rapidly evolved to disseminated intravascular coagulation (DIC) and hemorrhagic shock. Spontaneous rupture of the spleen was diagnosed. The critical patient underwent an emergency splenectomy. Pathological examination revealed splenic peliosis, an extremely rare disease with unknown etiology and pathogenesis. Despite the high mortality rate due to spontaneous splenic rupture with DIC, the patient was successfully treated and the details of the case are presented in this report.

Ribosome dysfunction underlies SLFN14-related thrombocytopenia

Pathogenic missense variants in SLFN14, which encode an RNA endoribonuclease protein that regulates ribosomal RNA (rRNA) degradation, are known to cause inherited thrombocytopenia (TP) with impaired platelet aggregation and adenosine triphosphate secretion. Despite mild laboratory defects, the patients displayed an obvious bleeding phenotype. However, the function of SLFN14 in megakaryocyte (MK) and platelet biology remains unknown. This study aimed to model the disease in an immortalized MK cell line (imMKCL) and to characterize the platelet transcriptome in patients with the SLFN14 K219N variant. MK derived from heterozygous and homozygous SLFN14 K219N imMKCL and stem cells of blood from patients mainly presented with a defect in proplatelet formation and mitochondrial organization. SLFN14-defective platelets and mature MK showed signs of rRNA degradation; however, this was absent in undifferentiated imMKCL cells and granulocytes. Total platelet RNA was sequenced in 2 patients and 19 healthy controls. Differential gene expression analysis yielded 2999 and 2888 significantly (|log2 fold change| >1, false discovery rate <0.05) up- and downregulated genes, respectively. Remarkably, these downregulated genes were not enriched in any biological pathway, whereas upregulated genes were enriched in pathways involved in (mitochondrial) translation and transcription, with a significant upregulation of 134 ribosomal protein genes (RPGs). The upregulation of mitochondrial RPGs through increased mammalian target of rapamycin complex 1 (mTORC1) signaling in SLFN14 K219N MK seems to be a compensatory response to rRNA degradation. mTORC1 inhibition with rapamycin resulted in further enhanced rRNA degradation in SLFN14 K219N MK. Taken together, our study indicates dysregulation of mTORC1 coordinated ribosomal biogenesis is the disease mechanism for SLFN14-related TP.

The Role of Follicular Regulatory T Cells/Follicular Helper T Cells in Primary Immune Thrombocytopenia

INTRODUCTION

Immune thrombocytopenia (ITP) is an autoimmune disease characterized by thrombocytopenia. Herein, we sought to identify potential immune-related therapeutic targets in ITP.

METHODS

The differentially expressed genes (DEGs) between ITP patients and controls in GSE43177 and PRJNA299534 were analyzed. The intersections of the two DEG groups were screened as common genes, and enrichment analysis was performed. Additionally, differential analysis of immune cell levels between ITP and controls was performed. Changes in the proportions of T follicular helper (Tfh) and follicular regulatory T (Tfr) cells in peripheral blood samples from ITP patients, ITP patients responding to therapy, and healthy controls were identified. The expression changes in B-cell lymphoma (Bcl)-6 and interleukin (IL)-21 were further evaluated.

RESULTS

A total of 76 common genes were identified, and enrichment analysis found that these genes were mainly associated with neutrophil-mediated immunity, the MAPK signaling pathway, and the FOXO signaling pathway. Furthermore, we found different levels of Tfh cells in patients with ITP and controls. The level of Tfh cells in the peripheral blood is significantly increased in ITP patients and declines after responding to therapy. The Tfr/Tfh ratio was reduced in ITP patients and increased after responding to therapy. IL-21 and Bcl-6 were more highly expressed in ITP patients than in controls.

CONCLUSION

We identified abnormally expressed genes in ITP related to immune-related biological functions. We further identified the changes in Tfh and Tfr cells during ITP treatment. This provides a rationale for immunotherapy in ITP patients.

Successful Treatment With Everolimus for Multifocal Lymphangioendotheliomatosis With Thrombocytopenia in an Infant

Multifocal lymphangioendotheliomatosis with thrombocytopenia (MLT) is a rare disease characterized by the presence of multiple cutaneous lesions and bleeding from the gastrointestinal tract with thrombocytopenia. Because of the varied phenotypes and rarity of MLT, a treatment strategy has not been standardized thus far. We describe a case of infantile MLT that did not respond to treatment with propranolol, prednisolone, or vincristine. We successfully treated the patient with everolimus, an inhibitor of the mammalian target of rapamycin. Our case provides the first evidence of the effectiveness of everolimus for the treatment of MLT.

Benefit of prednisolone alone in nodal peripheral T-cell lymphoma with T follicular helper phenotype

A 71-year-old Japanese man presented with severe thrombocytopenia. A whole-body CT at presentation showed small cervical, axillary, and para-aortic lymphadenopathy, leading to suspicion of immune thrombocytopenia due to lymphoma. Biopsy was difficult to perform because of severe thrombocytopenia. Thus, he received prednisolone (PSL) therapy and his platelet count gradually recovered. Two and a half years after PSL therapy initiation, his cervical lymphadenopathy slightly progressed without other clinical symptoms. Hence, a biopsy from the left cervical lymph node was performed, and he was diagnosed with nodal peripheral T-cell lymphoma (PTCL) with T follicular helper (TFH) phenotype. Due to various complications, we continued treatment with prednisolone alone after the diagnosis of lymphoma; however, there was no further increase in lymph node enlargement and no other lymphoma-related symptoms for one and a half years after diagnosis. Although immunosuppressive therapy has been reported to produce a response in some patients with angioimmunoblastic T-cell lymphoma, our experience suggests that a similar subset may exist in patients with nodal PTCL with TFH phenotype, which has the same cellular origin. Immunosuppressive therapies may constitute an alternative treatment option even in the era of novel molecular-targeted therapies, especially for elderly patients who are ineligible for chemotherapy.

Laboratory Markers of Platelet Production and Turnover

Platelets are formed from bone marrow megakaryocytes, circulate in blood for 7-10 days, and then are destroyed in the spleen and/or liver. Platelet production depends on the megakaryocyte population state in the bone marrow: number and size of the cells. The platelet turnover, i.e., the number of platelets passing through the bloodstream in a certain time, is determined by both the rate of their production and the rate of their destruction. The review considers laboratory markers, which are used to assess platelet production and turnover in the patients with hematologic and cardiovascular pathologies. These markers include some characteristics of platelets themselves: (i) content of reticulated ("young") forms in the blood detected by their staining with RNA dyes; (ii) indicators of the platelet size determined in hematology analyzers (mean volume, percentage of large forms) and in flow cytometers (light scattering level). Alterations of platelet production and turnover lead to the changes in blood plasma concentrations of such molecules as thrombopoietin (TPO, main mediator of megakaryocyte maturation and platelet formation in the bone marrow) and glycocalicin (soluble fragment of the membrane glycoprotein Ib detached from the surface of platelets during their destruction). Specific changes in the markers of platelet production and turnover have been observed in: (i) hypoproductive thrombocytopenias caused by suppression of megakaryocytes in the bone marrow; (ii) immune thrombocytopenias caused by accelerated clearance of the autoantibody-sensitized platelets; and (iii) thrombocytosis (both primary and reactive). The paper presents the data indicating that in patients with cardiovascular diseases an increased platelet turnover and changes in the corresponding markers (platelet size indexes and content of reticulated forms) are associated with the decreased efficacy of antiplatelet drugs and increased risk of thrombotic events, myocardial infarction, and unstable angina (acute coronary syndrome).

Valproic Acid Induced Thrombocytopenia and Dysmegakaryopoiesis in a Pediatric Patient

OBJECTIVE

Valproic acid (VPA) is an effective first-line anticonvulsant that is associated with several side effects including bone marrow suppression and subsequent cytopenia. However, VPA associated myelodysplasia is not a well described entity that can be seen in patients on VPA treatment.

CASE REPORT

Herein, we describe a 9-year-old female patient with a past medical history of seizure disorder who presented with 3-week history of intermittent fevers, fatigue, weakness, and multiple unexplained bruises. Complete blood count (CBC) was remarkable for marked thrombocytopenia. Trephine biopsy showed a normocellular marrow with maturing trilineage hematopoiesis and scattered atypical megakaryocytes including numerous small hypolobated forms with frequent forms showing separated nuclei. Her CBC showed normalization 7 months after VPA was stopped.

CONCLUSIONS

The presence of bone marrow suppression and myelodysplasia in patients on VPA treatment should be taken into consideration as it can cause a diagnostic pitfall especially in pediatric and elderly populations. A careful review of past medical history and medications can help make the correct diagnosis.

A Prospective Multicenter Phase II Study on the Feasibility and Efficacy of S-1 and Oxaliplatin Neoadjuvant Chemotherapy for Locally Advanced Rectal Cancer

BACKGROUND

Neoadjuvant chemoradiotherapy and total mesorectal excision compose the standard of care for rectal cancer in multiple guidelines. However, neoadjuvant chemoradiotherapy has not exhibited clear survival benefits but rather has led to an increase in adverse events. Conversely, neoadjuvant chemotherapy is expected to prevent adverse events caused by radiation, yet this treatment is still controversial.

OBJECTIVE

The purpose of this study was to evaluate the feasibility and efficacy of S-1 and oxaliplatin neoadjuvant chemotherapy together with total mesorectal excision for resectable locally advanced rectal cancer.

DESIGN

The study was a prospective, single-arm phase II trial.

SETTINGS

The study was conducted at multiple institutions.

PATIENTS

Fifty-eight patients with resectable locally advanced rectal cancer were enrolled.

INTERVENTION

Three cycles of S-1 and oxaliplatin were administered before surgery. S-1 was administered orally at 80 mg/m2 per day for 14 consecutive days, followed by a 7-day resting period. Oxaliplatin was given intravenously on the first day at a dose of 130 mg/m2 per day. The duration of 1 cycle was considered to be 21 days. Total mesorectal excision with bilateral lymph node dissection was carried out after neoadjuvant chemotherapy.

MAIN OUTCOME MEASURES

The study was designed to detect the feasibility and efficacy of S-1 and oxaliplatin as neoadjuvant chemotherapy.

RESULTS

The completion rate of 3 courses of S-1 and oxaliplatin as neoadjuvant chemotherapy was 94.8% (55/58). The reasons for discontinuation were thrombocytopenia (3.4%) and liver injury (1.7%). The most common severe (grade ≥3) adverse effect of neoadjuvant chemotherapy was thrombocytopenia (3.4%). There were no severe adverse clinical symptoms. Consequently, R0 resection was achieved in 51 (98.1%) of 52 patients. Pathologic complete response occurred in 10 patients (19.2%).

LIMITATIONS

This was a single-arm, nonrandomized phase II study.

CONCLUSIONS

The combination of S-1 and oxaliplatin neoadjuvant chemotherapy and total mesorectal excision is a feasible and promising treatment option for resectable locally advanced rectal cancer. See Video Abstract at http://links.lww.com/DCR/B555.

UN ESTUDIO PROSPECTIVO MULTICNTRICO FASE II SOBRE LA FACTIBILIDAD Y EFICACIA DE LA QUIMIOTERAPIA NEOADYUVANTE SCON OXALIPLATINO PARA EL CNCER DE RECTO LOCALMENTE AVANZADO

ANTECEDENTES:La quimiorradioterapia neoadyuvante y la escisión mesorrectal total constituyen el estándar de atención para el cáncer de recto en varias guías. Sin embargo, la quimiorradioterapia neoadyuvante no ha mostrado beneficios claros en la sobrevida, pero si ha creado un aumento de eventos adversos. Por otro lado, se espera que la quimioterapia neoadyuvante prevenga los eventos adversos asociados a la radiación, aunque este tratamiento sigue siendo controvertido.OBJETIVO:Evaluar la factibilidad y eficacia de la quimioterapia neoadyuvante S-1 con oxaliplatino en conjunto con la escisión mesorrectal total para el cáncer de recto localmente avanzado resecable.DISEÑO:El estudio fue un ensayo prospectivo fase II de brazo único.AMBITO:Estudio realizado en múltiples instituciones.PACIENTES:Se incluyeron 58 pacientes con cáncer de recto localmente avanzado resecable.INTERVENCIÓN:Se administraron tres ciclos de S-1 con oxaliplatino antes de la cirugía. Se administró S-1 por vía oral a 80 mg / m2 / día durante 14 días consecutivos, seguido de un período de descanso de 7 días. El oxaliplatino se administró por vía intravenosa el primer día a una dosis de 130 mg / m2 / día. Se consideró la duración de un ciclo de 21 días. Posterior a la quimioterapia neoadyuvante se realizó la excisión total mesorrectal con disección ganglionar bilateral.PRINCIPALES VARIABLES EVALUDADAS:El estudio fue diseñado para conocer la factibilidad y eficacia de S-1 con oxaliplatino como quimioterapia neoadyuvante.RESULTADOS:La tasa de conclusión con tres ciclos de S-1 con oxaliplatino como quimioterapia neoadyuvante fue del 94,8% (55/58). Los motivos de interrupción fueron trombocitopenia (3,4%) y daño hepático (1,7%). El efecto adverso grave más común (grado ≥ 3) de la quimioterapia neoadyuvante fue la trombocitopenia (3,4%). No hubo síntomas clínicos adversos graves. Como resultado, la resección R0 se logró en 51 de 52 pacientes (98,1%). Una respuesta patológica completa se obtuvo en 10 pacientes (19,2%).LIMITACIONES:Fue un estudio de fase II no aleatorizado de un solo brazo.CONCLUSIONES:La combinación de S-1 con oxaliplatino como quimioterapia neoadyuvante y escisión mesorrectal total es factible y es una opción de tratamiento prometedora para el cáncer de recto localmente avanzado resecable. Consulte Video Resumen en http://links.lww.com/DCR/B555. (Traducción-Dr Juan Antonio Villanueva-Herrero).

[Functional deficiency of bone marrow mesenchymal stem cells in patients with immune thrombocytopenia: An update]

Immune thrombocytopenia (ITP) is an acquired autoimmune hemorrhagic disorder characterized by persistent thrombocytopenia. It may be induced by different pathogenesis due to its heterogeneity, and the therapeutic effects vary on different patients. Bone marrow derived mesenchymal stem cells (BMMSCs) can modulate innate and adaptive immunity, thus resulting in a tolerant microenvironment. Functional defects and immunomodulatory disorders of BMMSCs are significant causes of ITP. Functional effects associated with the activation of the P53 pathway include decreased activity of the phosphatidylinositol 3 kinase/AKT pathway and activation of the TNFAIP3/NF-κB/SMAD7 pathway. Immune dysfunction appears to be correlated with an impaired ability of BMMSCs to induce various types of immune cells in ITP. An in-depth investigation into the pathogenesis of ITP facilitates the treatment of ITP, but larger-scale clinical trials are needed to verify the efficacy of exogenous BMMSCs in the clinical treatment of ITP.

Baseline blood count levels increase odds of cytopenia among CML patients in Kenya: a case control study

BACKGROUND

Imatinib is the gold standard for the treatment of all phases of Philadelphia positive Chronic Myeloid Leukemia (CML). During treatment, patients may develop cytopenia. We aimed to study the baseline characteristics and factors associated with cytopenia at a Nairobi Hospital.

METHODS

This was a retrospective case-control study of patients aged ≥18 years on follow-up at the Glivec International Patient Access Program (GIPAP) clinic from 2007 to 2015. The cases consisted of CML patients on imatinib who developed cytopenia. The controls were CML patients on imatinib who did not develop cytopenia. Baseline socio - demographic, clinical, hematologic, and molecular data were retrieved from patients' files. Chi square or fishers' exact tests were used to analyze for differences between cytopenia and no cytopenia. Binary logistic regressions were employed to identify relationships. Univariate and multivariate analyses were done to identify independent predictors of cytopenia. Odds ratios (OR) were presented including the 95% confidence intervals and respective p values.

RESULTS

A total of 201 patients were studied consisting of ninety-four (94) patients with cytopenia and 107 with no cytopenia. Among the entire population, males were 52, and 42% were aged 36-50 years. Sex, age, marital status, occupation and education level were similar between the cytopenia and no cytopenia groups. Among the 201 patients, 70% had symptoms for > 12 months before diagnosis, 78.6% had B symptoms at baseline, 80% had a moderate splenomegaly at baseline. Among patients with cytopenia, 40 and 37.4% developed cytopenia within 3 months and 3-6 months respectively after imatinib initiation. Baseline neutrophilia, neutropenia, anaemia, thrombocytosis, thrombocytopenia was found in 68, 11, 11, 23.5 and 11% respectively. Baseline hemoglobin, neutrophil and platelet level were significantly different between the cytopenia and the no cytopenia group. On univariable analysis, baseline anemia with hb < 7.9 g/dL (p = 0.002), neutropenia (p = 0.001), neutrophilia > 100,000/mm3 (p = 0.002) and thrombocytopenia (p = 0.001) increased the odds of developing cytopenia. On multivariable analysis, baseline anaemia (p value < 0.002), neutropenia (p value < 0.001), thrombocytopenia (p value, < 0.001) and thrombocytosis (p value, 0.033) increased the odds of developing cytopenia.

CONCLUSION

Odds of cytopenia were higher in presence of baseline cytopenia and thrombocytosis. Clinicians should have a high index of suspicion for these patients.

T-follicular helper cell expansion and chronic T-cell activation are characteristic immune anomalies in Evans syndrome

Pediatric Evans syndrome (pES) is increasingly identified as the presenting manifestation of several inborn errors of immunity. Despite an improved understanding of genetic defects in pES, the underlying immunobiology of pES is poorly defined, and characteristic diagnostic immune parameters are lacking. We describe the immune characteristics of 24 patients with pES and compared them with 22 patients with chronic immune thrombocytopenia (cITP) and 24 healthy controls (HCs). Compared with patients with cITP and HC, patients with pES had increased circulating T-follicular helper cells (cTfh), increased T-cell activation, and decreased naïve CD4+ T cells for age. Despite normal or high immunoglobulin G (IgG) in most pES at presentation, class-switched memory B cells were decreased. Within the cTfh subset, we noted features of postactivation exhaustion with upregulation of several canonical checkpoint inhibitors. T-cell receptor β chain (TCR-β) repertoire analysis of cTfh cells revealed increased oligoclonality in patients with pES compared with HCs. Among patients with pES, those without a known gene defect had a similar characteristic immune abnormality as patients with defined genetic defects. Similarly, patients with pES with normal IgG had similar T-cell abnormalities as patients with low IgG. Because genetic defects have been identified in less than half of patients with pES, our findings of similar immune abnormalities across all patients with pES help establish a common characteristic immunopathology in pES, irrespective of the underlying genetic etiology.

Viper venoms drive the macrophages and hepatocytes to sequester and clear platelets: novel mechanism and therapeutic strategy for venom-induced thrombocytopenia

Venomous snakebites cause clinical manifestations that range from local to systemic and are considered a significant global health challenge. Persistent or refractory thrombocytopenia has been frequently reported in snakebite patients, especially in cases caused by viperidae snakes. Viper envenomation-induced thrombocytopenia may persist in the absence of significant consumption coagulopathy even after the antivenom treatment, yet the mechanism remains largely unknown. Our study aims to investigate the mechanism and discover novel therapeutic targets for coagulopathy-independent thrombocytopenia caused by viper envenomation. Here we found that patients bitten by Protobothrops mucrosquamatus and Trimeresurus stejnegeri, rather than Naja. atra may develop antivenom-resistant and coagulopathy-independent thrombocytopenia. Crude venoms and the derived C-type lectin-like proteins from these vipers significantly increased platelet surface expression of neuraminidase and platelet desialylation, therefore led to platelet ingestion by both macrophages and hepatocytes in vitro, and drastically decreased peripheral platelet counts in vivo. Our study is the first to demonstrate that desialylation-mediated platelet clearance is a novel mechanism of viper envenomation-induced refractory thrombocytopenia and C-type lectin-like proteins derived from the viper venoms contribute to snake venom-induced thrombocytopenia. The results of this study suggest the inhibition of platelet desialylation as a novel therapeutic strategy against viper venom-induced refractory thrombocytopenia.

Megakaryopoiesis and Platelet Biology: Roles of Transcription Factors and Emerging Clinical Implications

Platelets play a critical role in hemostasis and thrombus formation. Platelets are small, anucleate, and short-lived blood cells that are produced by the large, polyploid, and hematopoietic stem cell (HSC)-derived megakaryocytes in bone marrow. Approximately 3000 platelets are released from one megakaryocyte, and thus, it is important to understand the physiologically relevant mechanism of development of mature megakaryocytes. Many genes, including several key transcription factors, have been shown to be crucial for platelet biogenesis. Mutations in these genes can perturb megakaryopoiesis or thrombopoiesis, resulting in thrombocytopenia. Metabolic changes owing to inflammation, ageing, or diseases such as cancer, in which platelets play crucial roles in disease development, can also affect platelet biogenesis. In this review, I describe the characteristics of platelets and megakaryocytes in terms of their differentiation processes. The role of several critical transcription factors have been discussed to better understand the changes in platelet biogenesis that occur during disease or ageing.

Interactions of Spike-RBD of SARS-CoV-2 and Platelet Factor 4: New Insights in the Etiopathogenesis of Thrombosis

The rare but dangerous adverse events evidenced after massive vaccination against SARS-CoV-2 are represented by thrombosis and thrombocytopenia. The patients diagnosed with severe COVID-19 may develop a pro-thrombotic state with a much higher frequency, thus we decided to investigate the role of Spike protein (the only common product of the two conditions) or the anti-Spike antibodies in the etiopathogenesis of thrombosis. A pathogenic Platelet Factor 4 (PF4)-dependent syndrome, unrelated to the use of heparin therapy, has been reported after the administration of vaccines in the patients manifesting acute thrombocytopenia and thrombosis. Thus, we aimed at shedding light on the structural similarities of Spike of SARS-CoV-2 and PF4 on their eventual biochemical interactions and on the role of their specific antibodies. The similarities between PF4 and Spike-RBD proteins were evaluated by a comparison of the structures and by testing the cross-reactivity of their specific antibodies by ELISA assays. We found that the anti-Spike antibodies do not recognize PF4, on the contrary, the anti-PF4 antibodies show some cross-reactivity for Spike-RBD. More interestingly, we report for the first time that the PF4 and Spike-RBD proteins can bind each other. These data suggest that the interaction of the two proteins could be involved in the generation of anti-PF4 antibodies, their binding to Spike-RBD, which could lead to platelets aggregation due also to their high expression of ACE2.

Intracerebral Hemorrhage due to Thrombosis with Thrombocytopenia Syndrome after Vaccination against COVID-19: the First Fatal Case in Korea

Vaccination with an adenoviral vector vaccine against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can result in the rare development of thrombosis with thrombocytopenia mediated by platelet-activating antibodies against platelet factor 4 (PF4). This is a life-threating condition that may be accompanied by bleeding due to thrombocytopenia with thrombosis of the cerebral venous sinus or splanchnic vein. Herein, we describe the first fatal case of thrombosis with thrombocytopenia syndrome in Korea, presenting with intracranial hemorrhage caused by cerebral venous sinus thrombosis. A 33-year-old Korean man received the first dose of the ChAdOx1 nCoV-19 vaccination. He developed severe headache with vomiting 9 days after the vaccination. Twelve days after vaccination, he was admitted to the hospital with neurological symptoms and was diagnosed with cerebral venous sinus thrombosis, which was accompanied by intracranial hemorrhage. Thrombocytopenia and D-dimer elevation were observed, and the result of the PF4 enzyme-linked immunosorbent assay antibody test was reported to be strongly positive. Despite intensive treatment, including intravenous immunoglobulin injection and endovascular mechanical thrombectomy, the patient died 19 days after vaccination. Physicians need to be aware of thrombosis with thrombocytopenia syndrome (TTS) in adenoviral vector-vaccinated patients. Endovascular mechanical thrombectomy might be a useful therapeutic option for the treatment of TTS with cerebral venous sinus thrombosis.

A Novel Use of Romiplostim for SARS-CoV-2-induced Thrombocytopenia

The literature regarding coronavirus disease of 2019 (COVID-19) infection in pediatrics indicates that children have less severe clinical presentations and lower mortality rates. There remains limited data regarding hematologic sequelae in pediatric patients with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Romiplostim has shown a platelet response in pediatric patients with chronic immune thrombocytopenic purpura, and eltrombopag is proven to increase platelet counts in patients with inherited thrombocytopenia. We review SARS-CoV-2-associated thrombocytopenia and present a pediatric patient with acute on chronic thrombocytopenia in the setting of COVID-19 with subsequent platelet recovery using romiplostim.

Thrombocytopenia Is Associated with COVID-19 Severity and Outcome: An Updated Meta-Analysis of 5637 Patients with Multiple Outcomes

The COVID-19 pandemic is persistent worldwide. A prior meta-analysis suggested the association of thrombocytopenia (TCP) with more severe COVID-19 illness and high mortality. Considering newly published studies, we updated the previous meta-analysis to confirm and explain the association of TCP with COVID-19 severity and multiple outcomes. Twenty-four studies with 5637 patients with COVID-19 were included in this study. The weighted incidence of TCP in COVID-19 was 12.4% (95% confidence interval [CI], 7.9%-17.7%). Data synthesis showed that the platelet number was lower in patients with either more severe illness or poor outcomes and even lower in nonsurvivors, with weighted mean differences of -24.56 × 109/L, -22.48 × 109/L, and -49.02 × 109/L, respectively. The meta-analysis of binary outcomes (with and without TCP) indicated the association between TCP and 3-fold enhanced risk of a composite outcome of intensive care unit admission, progression to acute respiratory distress syndrome, and mortality (odds ratio [OR], 3.49; 95% CI, 1.57-7.78). Subgroup analysis by endpoint events suggested TCP to be significantly associated with mortality (OR, 7.37; 95% CI, 2.08-26.14). Overall, the present comprehensive meta-analysis indicated that approximately 12% of hospitalized patients with COVID-19 have TCP, which also represents a sign of more severe illness and poor outcomes.

Bortezomib treatment of steroid-refractory Evans syndrome in children

Treatment of refractory Evans syndrome (ES) remains a challenge in hematology practice. Due to rarity of this condition, evidence-based approaches are limited and often treatment choices stem from small case series or anecdotal experiences. There is mounting evidence that some patients have genetic defects that could be targeted with promising preliminary results. Here, we describe three very refractory pediatric ES cases treated on bortezomib without adverse effects. Two of the three patients had dramatic and long-lasting recovery that started following the initial doses of the drug. Clinical trials to assess the role of bortezomib in ES treatment are warranted.

Eltrombopag for the Treatment of Severe Inherited Thrombocytopenia

Inherited thrombocytopenias correspond to a group of hereditary disorders characterized by a reduced platelet count, platelet dysfunction, and a family history of thrombocytopenia. It is commonly associated with mucocutaneous bleeding. Thrombocytopenia results from mutations in genes involved in megakaryocyte differentiation, platelet formation, and clearance. Here we report on a patient presenting with severe syndromic inherited thrombocytopenia manifesting as spontaneous mucocutaneous bleeds, requiring frequent platelet transfusions. Thrombocytopenia was explained by the presence of 4 mutations in 3 hematopoietic transcription factor genes: FLI1, RUNX1, and ETV6. The patient was successfully treated with high-dose eltrombopag at 150 mg/day, an orally available non-peptide thrombopoietin receptor agonist. Since the start of treatment 23 months ago, the manifestations of bleeding have resolved, and no platelet transfusions or corticosteroids have been required. The patient has no clinical or laboratory evidence of myeloid malignancy so far.

ETV6 germline mutations cause HDAC3/NCOR2 mislocalization and upregulation of interferon response genes

ETV6 is an ETS family transcription factor that plays a key role in hematopoiesis and megakaryocyte development. Our group and others have identified germline mutations in ETV6 resulting in autosomal dominant thrombocytopenia and predisposition to malignancy; however, molecular mechanisms defining the role of ETV6 in megakaryocyte development have not been well established. Using a combination of molecular, biochemical, and sequencing approaches in patient-derived PBMCs, we demonstrate abnormal cytoplasmic localization of ETV6 and the HDAC3/NCOR2 repressor complex that led to overexpression of HDAC3-regulated interferon response genes. This transcriptional dysregulation was also reflected in patient-derived platelet transcripts and drove aberrant proplatelet formation in megakaryocytes. Our results suggest that aberrant transcription may predispose patients with ETV6 mutations to bone marrow inflammation, dysplasia, and megakaryocyte dysfunction.

Haematological characteristics and risk factors in the classification and prognosis evaluation of COVID-19: a retrospective cohort study

BACKGROUND

COVID-19 is an ongoing global pandemic. Changes in haematological characteristics in patients with COVID-19 are emerging as important features of the disease. We aimed to explore the haematological characteristics and related risk factors in patients with COVID-19.

METHODS

This retrospective cohort study included patients with COVID-19 admitted to three designated sites of Wuhan Union Hospital (Wuhan, China). Demographic, clinical, laboratory, treatment, and outcome data were extracted from electronic medical records and compared between patients with moderate, severe, and critical disease (defined according to the diagnosis and treatment protocol for novel coronavirus pneumonia, trial version 7, published by the National Health Commission of China). We assessed the risk factors associated with critical illness and poor prognosis. Dynamic haematological and coagulation parameters were investigated with a linear mixed model, and coagulopathy screening with sepsis-induced coagulopathy and International Society of Thrombosis and Hemostasis overt disseminated intravascular coagulation scoring systems was applied.

FINDINGS

Of 466 patients admitted to hospital from Jan 23 to Feb 23, 2020, 380 patients with COVID-19 were included in our study. The incidence of thrombocytopenia (platelet count <100 × 109 cells per L) in patients with critical disease (42 [49%] of 86) was significantly higher than in those with severe (20 [14%] of 145) or moderate (nine [6%] of 149) disease (p<0·0001). The numbers of lymphocytes and eosinophils were significantly lower in patients with critical disease than those with severe or moderate disease (p<0·0001), and prothrombin time, D-dimer, and fibrin degradation products significantly increased with increasing disease severity (p<0·0001). In multivariate analyses, death was associated with increased neutrophil to lymphocyte ratio (≥9·13; odds ratio [OR] 5·39 [95% CI 1·70-17·13], p=0·0042), thrombocytopenia (platelet count <100 × 109 per L; OR 8·33 [2·56-27·15], p=0·00045), prolonged prothrombin time (>16 s; OR 4·94 [1·50-16·25], p=0·0094), and increased D-dimer (>2 mg/L; OR 4·41 [1·06-18·30], p=0·041). Thrombotic and haemorrhagic events were common complications in patients who died (19 [35%] of 55). Sepsis-induced coagulopathy and International Society of Thrombosis and Hemostasis overt disseminated intravascular coagulation scores (assessed in 12 patients who survived and eight patients who died) increased over time in patients who died. The onset of sepsis-induced coagulopathy was typically before overt disseminated intravascular coagulation.

INTERPRETATION

Rapid blood tests, including platelet count, prothrombin time, D-dimer, and neutrophil to lymphocyte ratio can help clinicians to assess severity and prognosis of patients with COVID-19. The sepsis-induced coagulopathy scoring system can be used for early assessment and management of patients with critical disease.

FUNDING

National Key Research and Development Program of China.

Covid-19: The Rollercoaster of Fibrin(Ogen), D-Dimer, Von Willebrand Factor, P-Selectin and Their Interactions with Endothelial Cells, Platelets and Erythrocytes

Severe acute respiratory syndrome coronavirus 2 (SARS-Cov-2), also known as coronavirus disease 2019 (COVID-19)-induced infection, is strongly associated with various coagulopathies that may result in either bleeding and thrombocytopenia or hypercoagulation and thrombosis. Thrombotic and bleeding or thrombotic pathologies are significant accompaniments to acute respiratory syndrome and lung complications in COVID-19. Thrombotic events and bleeding often occur in subjects with weak constitutions, multiple risk factors and comorbidities. Of particular interest are the various circulating inflammatory coagulation biomarkers involved directly in clotting, with specific focus on fibrin(ogen), D-dimer, P-selectin and von Willebrand Factor (VWF). Central to the activity of these biomarkers are their receptors and signalling pathways on endothelial cells, platelets and erythrocytes. In this review, we discuss vascular implications of COVID-19 and relate this to circulating biomarker, endothelial, erythrocyte and platelet dysfunction. During the progression of the disease, these markers may either be within healthy levels, upregulated or eventually depleted. Most significant is that patients need to be treated early in the disease progression, when high levels of VWF, P-selectin and fibrinogen are present, with normal or slightly increased levels of D-dimer (however, D-dimer levels will rapidly increase as the disease progresses). Progression to VWF and fibrinogen depletion with high D-dimer levels and even higher P-selectin levels, followed by the cytokine storm, will be indicative of a poor prognosis. We conclude by looking at point-of-care devices and methodologies in COVID-19 management and suggest that a personalized medicine approach should be considered in the treatment of patients.

Novel phenotypes observed in patients with ETV6-linked leukaemia/familial thrombocytopenia syndrome and a biallelic ARID5B risk allele as leukaemogenic cofactor

Background. The phenotypes of patients with the recently discovered, dominant, ETV6-linked leukaemia predisposition and familial thrombocytopenia syndrome are variable, and the exact mechanism of leukaemogenesis remains unclear. Patients and Methods. Here, we present novel clinical and laboratory phenotypes of seven individuals from three families with ETV6 germline mutations and a refined genetic analysis of one child with additional high-hyperdiploid acute lymphoblastic leukaemia (HD-ALL), aiming to elucidate second oncogenic hits. Results. Four individuals from two pedigrees harboured one novel or one previously described variant in the central domain of ETV6 (c.592C>T, p.Gln198* or c.641C>T, p.Pro241Leu, respectively). Neutropenia was an accompanying feature in one of these families that also harboured a variant in RUNX1 (c.1098_1103dup, p.Ile366_Gly367dup), while in the other, an autism-spectrum disorder was observed. In the third family, the index patient suffered from HD-ALL and life-threatening pulmonary mucor mycosis, and had a positive family history of 'immune' thrombocytopenia. Genetic analyses revealed a novel heterozygous mutation in the ETS domain of ETV6 (c.1136T>C, p.Leu379Pro) along with absence of heterozygosity of chromosome (10)(q21.2q21.3), yielding a biallelic leukaemia risk allele in ARID5B (rs7090445-C). The neutrophil function was normal in all individuals tested, and the platelet immune histochemistry of all three pedigrees showed delta-storage-pool defect-like features and cytoskeletal defects. Conclusions. Our clinical observations and results of high-resolution genetic analyses extend the spectrum of possible phenotypes cosegregating with ETV6 germline mutations. Further, we propose ARID5B as potential leukaemogenic cofactor in patients with ETV6-linked leukaemia predisposition and familial thrombocytopenia syndrome.

Recognition of PF4-VWF complexes by heparin-induced thrombocytopenia antibodies contributes to thrombus propagation

Heparin-induced thrombocytopenia (HIT) is a prothrombotic disorder mediated by complexes between platelet factor 4 (PF4) and heparin or other polyanions, but the risk of thrombosis extends beyond exposure to heparin implicating other PF4 partners. We recently reported that peri-thrombus endothelium is targeted by HIT antibodies, but the binding site(s) has not been identified. We now show that PF4 binds at multiple discrete sites along the surface of extended strings of von Willebrand factor (VWF) released from the endothelium following photochemical injury in an endothelialized microfluidic system under flow. The HIT-like monoclonal antibody KKO and HIT patient antibodies recognize PF4-VWF complexes, promoting platelet adhesion and enlargement of thrombi within the microfluidic channels. Platelet adhesion to the PF4-VWF-HIT antibody complexes is inhibited by antibodies that block FcγRIIA or the glycoprotein Ib-IX complex on platelets. Disruption of PF4-VWF-HIT antibody complexes by drugs that prevent or block VWF oligomerization attenuate thrombus formation in a murine model of HIT. Together, these studies demonstrate assembly of HIT immune complexes along VWF strings released by injured endothelium that might propagate the risk of thrombosis in HIT. Disruption of PF4-VWF complex formation may provide a new therapeutic approach to HIT.

Fc-modified HIT-like monoclonal antibody as a novel treatment for sepsis

Sepsis is characterized by multiorgan system dysfunction that occurs because of infection. It is associated with high morbidity and mortality and is in need of improved therapeutic interventions. Neutrophils play a crucial role in sepsis, releasing neutrophil extracellular traps (NETs) composed of DNA complexed with histones and toxic antimicrobial proteins that ensnare pathogens, but also damage host tissues. At presentation, patients often have a significant NET burden contributing to the multiorgan damage. Therefore, interventions that inhibit NET release would likely be ineffective at preventing NET-based injury. Treatments that enhance NET degradation may liberate captured bacteria and toxic NET degradation products (NDPs) and likely be of limited therapeutic benefit as well. We propose that interventions that stabilize NETs and sequester NDPs may be protective in sepsis. We showed that platelet factor 4 (PF4), a platelet-associated chemokine, binds and compacts NETs, increasing their resistance to DNase I. We now show that PF4 increases NET-mediated bacterial capture, reduces the release of NDPs, and improves outcome in murine models of sepsis. A monoclonal antibody KKO which binds to PF4-NET complexes, further enhances DNase resistance. However, the Fc portion of this antibody activates the immune response and increases thrombotic risk, negating any protective effects in sepsis. Therefore, we developed an Fc-modified KKO that does not induce these negative outcomes. Treatment with this antibody augmented the effects of PF4, decreasing NDP release and bacterial dissemination and increasing survival in murine sepsis models, supporting a novel NET-targeting approach to improve outcomes in sepsis.

LncRNA GAS5 inhibits Th17 differentiation and alleviates immune thrombocytopenia via promoting the ubiquitination of STAT3

BACKGROUND

The increased differentiation of T helper 17 cells (Th17) accelerates the development of immune thrombocytopenia (ITP), which is a common autoimmune disease with limited therapeutic methods. Recent studies have revealed that long non-coding RNAs (lncRNAs) play a critical role in autoimmune diseases, thus this study aims to investigate the effect of lncRNA GAS5 on the differentiation of Th17 cells in ITP.

METHODS

The expression of GAS5 in peripheral blood mononuclear cells (PBMCs) of ITP patients and spleen tissues of ITP mice was measured by qRT-PCR. The percentage of Th17 cells in CD4⁺ cells was measured by flow cytometry. The combination between GAS5 and STAT3 was confirmed by RNA pull-down assay and RNA Binding Protein Immunoprecipitation (RIP). The ubiquitination of STAT3 was detected by ubiquitination assay and the interaction between STAT3 and TRAF6 was measured by Co-Immunoprecipitation (Co-IP). Finally, the effect of GAS5 on Th17 differentiation was investigated in vitro and in vivo using lentivirus (lenti)-GAS5.

RESULTS

GAS5 expression was downregulated both in PBMCs of ITP patients and spleen tissues of ITP mice. Overexpression of GAS5 suppressed Th17 differentiation while had no effect on Treg differentiation in naïve CD4⁺ cells. RNA pull-down and RNA immunoprecipitation assays confirmed the interaction between GAS5 and STAT3. Further studies showed GAS5 accelerated the degradation of STAT3 via promoting TRAF6-mediated ubiquitination. Overexpressing GAS5 suppressed Th17 differentiation in vitro and alleviated ITP in vivo via reducing STAT3.

CONCLUSION

LncRNA GAS5 inhibited Th17 differentiation through promoting the TRAF6-mediated ubiquitination of STAT3, thus relieving ITP.

Cirrhosis in Wilson Disease is characterized by Impaired Hepatic Synthesis, Leukopenia and Thrombocytopenia

Background: Patients with Wilson disease (WD) progress to cirrhosis at an early age but have good prognoses. This study aimed to delineate hepatic features in WD patients with or without cirrhosis. Methods: Medical data were retrospectively collected from 27 July 2015 to 27 June 2018. WD patients were divided into two groups based on whether or not they progressed to cirrhosis. Liver function, portal hypertension features and hematocytopenia rates were compared between groups. Results: The study enrolled 119 WD patients with cirrhosis and 53 WD patients without cirrhosis. There were no differences between groups for liver enzyme levels or incidence rates of Kayser-Fleischer ring (all P > 0.05). Ascites and hepatic encephalopathy were nearly absent in both groups, and almost all patients were Child-Pugh group A. However, WD-associated cirrhotic patients had a higher prothrombin time (beta = 0.908, P = 0.004) and international normalized ratio (beta = 0.089, P = 0.040), wider portal vein diameter (beta = 1.330, P < 0.001), and an increased risk of splenomegaly/splenectomy (odds ratio [OR] = 4.36, 95% confidence interval [CI]: 2.15-8.84, P < 0.001). Moreover, WD-associated cirrhotic patients have significantly increased risks of leukopenia (OR = 2.30, 95% CI: 1.00-5.25, P = 0.049) and thrombocytopenia (OR = 6.89, 95% CI: 2.01-23.59, P = 0.002). Conclusions: Despite presenting good outcomes, mild hepatocyte injury, and good hepatic metabolic function, WD-associated cirrhotic patients show more serious impairment of hepatic synthetic function, wider portal vein diameter, and higher risk of splenomegaly due to portal hypertension.

Lowering the boom on lower-risk myelodysplastic syndromes

Lower-risk myelodysplastic syndromes are defined using prognostic scoring systems that incorporate data on bone marrow blast percentage, degree and numbers of cytopenias, and cytogenetic abnormalities. Increasingly, these are incorporating molecular abnormalities to further refine risk. Therapy is geared toward predominating cytopenias, with erythropoiesis-stimulating agents luspatercept and lenalidomide used to ameliorate anemia, romiplostim and eltrombopag tackling thrombocytopenia, and hypomethylating agents and antithymocyte globulin palliating pancytopenia. Newer agents on the horizon are abrogating the downstream sequelae of specific molecular mutations. One challenge for the future is in further modifying response criteria to align with improvements that are clinically meaningful to patients.

Exposure-Toxicity Association of Cyclophosphamide and Its Metabolites in Infants and Young Children with Primary Brain Tumors: Implications for Dosing

PURPOSE

To characterize the population pharmacokinetics of cyclophosphamide, active 4-hydroxy-cyclophosphamide (4OH-CTX), and inactive carboxyethylphosphoramide mustard (CEPM), and their associations with hematologic toxicities in infants and young children with brain tumors. To use this information to provide cyclophosphamide dosing recommendations in this population.

PATIENTS AND METHODS

Patients received four cycles of a 1-hour infusion of 1.5 g/m² cyclophosphamide. Serial samples were collected to measure cyclophosphamide, 4OH-CTX, and CEPM plasma concentrations. Population pharmacokinetic modeling was performed to identify the patient characteristics influencing drug disposition. Associations between drug exposures and metrics reflecting drug-induced neutropenia, erythropenia, and thrombocytopenia were investigated. A Bayesian approach was developed to predict 4OH-CTX exposure using only cyclophosphamide and CEPM plasma concentrations.

RESULTS

Data from 171 patients (0.07-4.9 years) were adequately fitted by a two-compartment (cyclophosphamide) and one-compartment model (metabolites). Young infants (<6 months) exhibited higher mean 4OH-CTX exposure than did young children (138.4 vs. 107.2 μmol/L·h, P < 0.0001). No genotypes exhibited clinically significant influence on drug exposures. Worse toxicity metrics were significantly associated with higher 4OH-CTX exposures. Dosing simulations suggested decreased cyclophosphamide dosage to 1.2 g/m² for young infants versus 1.5 g/m² for children to attain similar 4OH-CTX exposure. Bayesian-modeled 4OH-CTX exposure predictions were precise (mean absolute prediction error 14.8% ± 4.2%) and had low bias (mean prediction error 4.9% ± 5.1%).

CONCLUSIONS

A 4OH-CTX exposure-toxicity association was established, and a decreased cyclophosphamide dosage for young infants was suggested to reduce toxicity in this population. Bayesian modeling to predict 4OH-CTX exposure may reduce clinical processing-related costs and provide insights into further exposure-response associations.

ETV6-related thrombocytopenia and leukemia predisposition

Germ line mutations in ETV6 are responsible for a familial thrombocytopenia and leukemia predisposition syndrome. Thrombocytopenia is almost completely penetrant and is usually mild. Leukemia is reported in ∼30% of carriers and is most often B-cell acute lymphoblastic leukemia. The mechanisms by which ETV6 dysfunction promotes thrombocytopenia and leukemia remain unclear. Care for individuals with ETV6-related thrombocytopenia and leukemia predisposition includes genetic counseling, treatment or prevention of excessive bleeding and surveillance for the development of hematologic malignancy.

Characterization of acute TLR-7 agonist-induced hemorrhagic myocarditis in mice by multiparametric quantitative cardiac magnetic resonance imaging

Hemorrhagic myocarditis is a potentially fatal complication of excessive levels of systemic inflammation. It has been reported in viral infection, but is also possible in systemic autoimmunity. Epicutaneous treatment of mice with the Toll-like receptor 7 (TLR-7) agonist Resiquimod induces auto-antibodies and systemic tissue damage, including in the heart, and is used as an inducible mouse model of systemic lupus erythematosus (SLE). Here, we show that overactivation of the TLR-7 pathway of viral recognition by Resiquimod treatment of CFN mice induces severe thrombocytopenia and internal bleeding, which manifests most prominently as hemorrhagic myocarditis. We optimized a cardiac magnetic resonance (CMR) tissue mapping approach for the in vivo detection of diffuse infiltration, fibrosis and hemorrhages using a combination of T1, T2 and T2* relaxation times, and compared results with ex vivo histopathology of cardiac sections corresponding to CMR tissue maps. This allowed detailed correlation between in vivo CMR parameters and ex vivo histopathology, and confirmed the need to include T2* measurements to detect tissue iron for accurate interpretation of pathology associated with CMR parameter changes. In summary, we provide detailed histological and in vivo imaging-based characterization of acute hemorrhagic myocarditis as an acute cardiac complication in the mouse model of Resiquimod-induced SLE, and a refined CMR protocol to allow non-invasive longitudinal in vivo studies of heart involvement in acute inflammation. We propose that adding T2* mapping to CMR protocols for myocarditis diagnosis improves diagnostic sensitivity and interpretation of disease mechanisms.This article has an associated First Person interview with the first author of the paper.

Concurrent manifestation of oligodontia and thrombocytopenia caused by a contiguous gene deletion in 12p13.2: A three-generation clinical report

BACKGROUND

Wnt and Wnt-associated pathways play an important role in the genetic etiology of oligodontia, a severe form of tooth agenesis. Loss-of-function mutations in LRP6 , encoding a transmembrane cell-surface protein that functions as a coreceptor in the canonical Wnt/b-catenin signaling cascade, also contribute to genetic oligodontia.

METHODS AND RESULTS

We describe a three-generation family with hereditary thrombocytopenia and oligodontia. Genome wide array analysis was performed. The array results from the index patient revealed an interstitial loss of 150 kb in 8p23.1 (chr8:6,270,299-6,422,558; hg19) encompassing MCPH1 and ANGPT2 and an interstitial loss of 290 kb in 12p13.2 (chr12:12,005,720-12,295,290; hg19) encompassing ETV6, BCL2L14 and LRP6.

CONCLUSION

This case report shows a three-generation family with hereditary thrombocytopenia and oligodontia with a heterozygous 290 kb novel contiguous gene deletion in band p13.2 of chromosome 12, encompassing LRP6 and ETV6. In this report we discuss the clinical relevance of the deletion of both genes and illustrate the importance of thorough examination of oligodontia patients. Comprising not only the oral status but also the medical history of the patients and their relatives.

Dengue virus nonstructural protein 1 activates platelets via Toll-like receptor 4, leading to thrombocytopenia and hemorrhage

Dengue virus (DENV) infection, the most common mosquito-transmitted viral infection, can cause a range of diseases from self-limiting dengue fever to life-threatening dengue hemorrhagic fever and shock syndrome. Thrombocytopenia is a major characteristic observed in both mild and severe dengue disease and is significantly correlated with the progression of dengue severity. Previous studies have shown that DENV nonstructural protein 1 (NS1), which can be secreted into patients’ blood, can stimulate immune cells via Toll-like receptor 4 (TLR4) and can cause endothelial leakage. However, it is unclear whether DENV NS1 can directly induce platelet activation or cause thrombocytopenia during DENV infection. In this study, we first demonstrated that DENV but not Zika virus cell culture supernatant could induce P-selectin expression and phosphatidylserine (PS) exposure in human platelets, both of which were abolished when NS1 was depleted from the DENV supernatant. Similar results were found using recombinant NS1 from all four serotypes of DENV, and those effects were blocked in the presence of anti-NS1 F(ab’)₂, anti-TLR4 antibody, a TLR4 antagonist (Rhodobacter sphaeroides lipopolysaccharide, LPS-Rs) and a TLR4 signaling inhibitor (TAK242), but not polymyxin B (an LPS inhibitor). Moreover, the activation of platelets by DENV NS1 promoted subthreshold concentrations of adenosine diphosphate (ADP)-induced platelet aggregation and enhanced platelet adhesion to endothelial cells and phagocytosis by macrophages. Finally, we demonstrated that DENV-induced thrombocytopenia and hemorrhage were attenuated in TLR4 knockout and wild-type mice when NS1 was depleted from DENV supernatant. Taken together, these results suggest that the binding of DENV NS1 to TLR4 on platelets can trigger its activation, which may contribute to thrombocytopenia and hemorrhage during dengue infection.

Over the past 50 years, dengue has been a continuing global threat, with no effective vaccine or specific antiviral drug. Dengue infection causes a wide range of outcomes, from fever-like symptoms to severe dengue hemorrhagic fever. Thrombocytopenia, a reduction in platelet count, is a common feature observed in both mild and severe dengue and is correlated with disease severity. In this study, we used dengue viral supernatant or DENV recombinant NS1 protein to stimulate human-isolated platelets. We found that DENV NS1 could directly activate platelets through TLR4 and could further enhance platelet aggregation, adhesion to endothelial cells and phagocytosis by macrophages, which could lead to thrombocytopenia. We also proved that both NS1 and TLR4 are critical for DENV-induced thrombocytopenia and hemorrhage using a DENV-induced hemorrhagic mouse model. Our study reveals a new pathogenic role of NS1 during dengue infection and highlights that NS1 should be a topic of attention in the development of therapeutic drugs and vaccines against dengue infection.

A phase I study of the HDM2 antagonist SAR405838 combined with the MEK inhibitor pimasertib in patients with advanced solid tumours

BACKGROUND

This phase I, open-label, dose-escalation study evaluated the safety, pharmacokinetics and pharmacodynamics of combination therapy with the HDM2 inhibitor SAR405838 and the MEK1/2 inhibitor pimasertib administered orally once daily (QD) or twice daily (BID) in locally advanced or metastatic solid tumours (NCT01985191).

METHODS

Patients with locally advanced or metastatic solid tumours with documented wild-type TP53 and RAS or RAF mutations were enroled. A 3 + 3 dose-escalation design was employed. The primary objective was to assess maximum tolerated dose (MTD).

RESULTS

Twenty-six patients were treated with SAR405838 200 or 300 mg QD plus pimasertib 60 mg QD or 45 mg BID. The MTD was SAR405838 200 mg QD plus pimasertib 45 mg BID. The most common dose-limiting toxicity was thrombocytopenia. The most frequently occurring treatment-related adverse events were diarrhoea (81%), increased blood creatine phosphokinase (77%), nausea (62%) and vomiting (62%). No significant drug-drug interactions were observed. The biomarkers MIC-1 and pERK were, respectively, upregulated and downregulated in response to study treatment. In 24 efficacy-evaluable patients, one patient (4%) had a partial response and 63% had stable disease.

CONCLUSIONS

The safety profile of SAR405838 and pimasertib combined was consistent with the safety profiles of both drugs. Preliminary antitumour activity was observed.

Clinical value of high expression level of CD71 in acute myeloid leukemia

CD71 (transferrin receptor 1, TfR-1) is a type II membrane glycoprotein and associated closely with tumors. It was recognized as an indication for diagnosing acute erythroid leukemia (AEL). High expression level of CD71 has been identified as a negative prognostic marker for many solid tumors. However, whether CD71 should be identified as an adverse marker in acute myeloid leukemia (AML) remained conflicting. We studied 214 AML patients for analysis of clinical and laboratory data. Taking the CD71 expression level of 60% as a standard, we divided our patients into two groups. We discovered that AML with high expression level of CD71 was prone to linked with severe anemia (P=0.004), thrombocytopenia (P<0.001) and complex karyotype (P=0.024) and had increasing expression level of CD117 (P=0.001). No statistically significant correlations in age, gender, WBC counting, molecular markers between the two groups. And moreover, high expression level of CD71 did not alter the pattern of survival time.

Anticoagulating patients with high-risk acquired thrombophilias

Antiphospholipid syndrome (APS), heparin-induced thrombocytopenia, and paroxysmal nocturnal hemoglobinuria are 3 acquired thrombophilias that carry a high risk of venous and arterial thromboembolism. Management of these conditions has largely included anticoagulation with a vitamin K antagonist after an initial period of a parenteral anticoagulant, for as long as the thrombotic risk is still present. The available evidence for the use of direct oral anticoagulants (DOACs) is limited and primarily consists of case series and cohort studies, which are summarized in this chapter. Randomized trials evaluating DOACs in patients with APS are reviewed. Further research is needed prior to widely adopting DOACs for use in these high-risk acquired thrombophilias; however, there may be selected low-risk subgroups where DOAC use is possible after careful consideration and patient discussion.

American Society of Hematology 2018 guidelines for management of venous thromboembolism: heparin-induced thrombocytopenia

BACKGROUND

Heparin-induced thrombocytopenia (HIT) is an adverse drug reaction mediated by platelet-activating antibodies that target complexes of platelet factor 4 and heparin. Patients are at markedly increased risk of thromboembolism.

OBJECTIVE

These evidence-based guidelines of the American Society of Hematology (ASH) are intended to support patients, clinicians, and other health care professionals in their decisions about diagnosis and management of HIT.

METHODS

ASH formed a multidisciplinary guideline panel balanced to minimize potential bias from conflicts of interest. The McMaster University GRADE Centre supported the guideline development process, including updating or performing systematic evidence reviews. The panel prioritized clinical questions and outcomes according to their importance for clinicians and patients. The Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach was used to assess evidence and make recommendations, which were subject to public comment.

RESULTS

The panel agreed on 33 recommendations. The recommendations address screening of asymptomatic patients for HIT, diagnosis and initial management of patients with suspected HIT, treatment of acute HIT, and special situations in patients with acute HIT or a history of HIT, including cardiovascular surgery, percutaneous cardiovascular intervention, renal replacement therapy, and venous thromboembolism prophylaxis.

CONCLUSIONS

Strong recommendations include use of the 4Ts score rather than a gestalt approach for estimating the pretest probability of HIT and avoidance of HIT laboratory testing and empiric treatment of HIT in patients with a low-probability 4Ts score. Conditional recommendations include the choice among non-heparin anticoagulants (argatroban, bivalirudin, danaparoid, fondaparinux, direct oral anticoagulants) for treatment of acute HIT.