Thrombocytosis in children and adolescents-classification, diagnostic approach, and clinical management

Successful treatment of a chronic myeloid leukemia patient with extreme thrombocytosis by a combination of imatinib and interferon‑α: A case report

Chronic myeloid leukemia with extreme thrombocytosis (CML-T), defined by a platelet count >1,000x109/l is a rare leukemia subtype. The present case report described a 66-year-old female CML-T patient presenting with a platelet count of 3,798x109/l, but a consistently normal spleen size. Following treatment with imatinib combined with interferon-α, the patient achieved hematological remission within 2 months, with a platelet count reduction to 311x109/l and complete cytogenetic remission after 10 months. The patient experienced myocardial infarction and liver injury during treatment, which was managed with supportive care. The present case suggested that imatinib combined with interferon-α may be a safe and effective treatment option for patients with CML-T and extreme thrombocytosis and suboptimal response to imatinib monotherapy.

[Advances in the diagnosis and treatment of thrombocytosis in children]

Thrombocytosis is a common condition in children, classified into primary and secondary types. Secondary thrombocytosis is mainly caused by factors such as infection, anemia, iron deficiency, trauma, or surgical intervention, and it typically occurs without severe thrombosis or bleeding events. Platelet counts can return to normal after control of the primary factors, with favorable clinical outcomes. Primary thrombocytosis is mainly caused by myeloproliferative neoplasms such as polycythemia vera, essential thrombocythemia, and myelofibrosis, often accompanied by gene mutations in hematopoietic cells. In children, clinical manifestations are atypical compared to adults, with few thromboembolic or bleeding events. No special treatment is required for patients who are asymptomatic or have mild symptoms, and it is recommended to regularly monitor platelet counts. Antiplatelet therapy with aspirin can be considered for patients at risk of thrombosis or those with extreme thrombocytosis, and cytoreductive therapy can be performed when necessary, but the toxicities and side effects of drugs should be closely monitored. At present, hydroxyurea, interferon-alpha, and anagrelide are commonly used for cytoreductive therapy. This article provides an overview of the etiology, classification, clinical manifestations, diagnosis, and treatment of childhood thrombocytosis to guide healthcare professionals in treatment decisions.

Childhood and adolescent essential thrombocythemia and prefibrotic primary myelofibrosis: insights into diagnosis, outcomes, and treatment from a large Chinese cohort

The paucity of essential thrombocythemia (ET) and prefibrotic primary myelofibrosis (pre-PMF) in individuals younger than 18 years highlights several unresolved issues in diagnosis, clinical outcomes, and treatment strategies. To address these knowledge gaps, we analyzed a large bidirectional cohort consisting of childhood and adolescent ET (CAA-ET, n = 156) and pre-PMF (CAA-preMF, n = 13), as well as adult ET (n = 349). We introduced immunophenotypic abnormalities as novel clonal markers in CAA-ET and CAA-preMF, establishing a comprehensive method for clonal marker detection that integrated driver and non-driver mutations, positive endogenous erythroid colony formation, immunophenotypic abnormalities, and chromosomal aberrations. Next-generation sequencing revealed distinct mutational profiles between CAA-ET and adult ET, along with different age-related trends in the distribution of driver mutations. Venous thrombosis was more prevalent in CAA-ET, with JAK2 V617F emerging as a potential risk factor (P = 0.018). Immunophenotypic abnormalities were identified as risk factors for disease progression (P = 0.027). Significant differences between expected and actual treatment practices were identified. Compared to CAA-ET, CAA-preMF demonstrated poorer progression-free survival (P < 0.001) and faster disease progression (P = 0.019). This study provides a critical foundation for refining diagnostic, prognostic, and therapeutic approaches for CAA-ET and CAA-preMF.

Etiology and clinical course of severe and extreme thrombocytosis in children: a retrospective single-center study

The aim of this study was to describe the etiology and clinical course in children with severe thrombocytosis (ST, platelet counts > 900 × 109/L) and extreme thrombocytosis (ET, platelet counts > 1000 × 109/L) in a tertiary pediatric hospital. Patients aged 0-18 years with platelet counts over 900 × 109/L who were admitted to our hospital were analyzed. Thrombocytosis was defined as a platelet count exceeding 450 × 109/L. Thrombosis was diagnosed based on computed tomography scans or ultrasound findings. Potential factors associated with the development of extreme thrombocytosis were identified using logistic regression models. Only one (0.8%) out of the 120 patients identified with ST (n = 61) and ET (n = 59) had primary thrombocytosis. The most common underlying condition was congenital heart disease (26.7%), followed by Kawasaki disease (16.7%). With the exception of the hemoglobin level, no major differences were found for the baseline characteristics between the ST and ET groups. A lower hemoglobin level (< 10.0 g/dL) at the onset of thrombocytosis was identified as a predictor for ET development (adjusted odds ratio 2.73, 95% confidence interval 1.18-6.28). Overall, 56 of 120 (46.7%) patients received aspirin therapy. Venous thrombosis occurred in one (0.8%) patient.

CONCLUSIONS

We found a low proportion of primary thrombocytosis and a low incidence of thrombosis in children with ST and ET. Our results suggest that pediatric ST and ET may share common characteristics and may have features that are distinct from those in adults.

WHAT IS KNOWN

• Secondary thrombocytosis is a frequent finding in children. • Adult extreme thrombocytosis has been found to be associated with primary thrombocytosis.

WHAT IS NEW

• There were no major differences in the baseline characteristics between children with severe and extreme thrombocytosis. • The incidence of thrombosis was markedly low in both severe and extreme thrombocytosis groups.

The relationship between severity of periapical periodontitis and next-generation systemic inflammatory biomarkers in children with early childhood caries

INTRODUCTION

Early childhood caries (ECC) is closely associated with poor oral hygiene and cariogenic diet. Untreated ECC results in recurrent odontogenic infections and local and systemic consequences. In this study, our goal is to assess the relationship between the intensity of odontogenic infection-associated periapical periodontitis and new generation of systemic inflammatory markers (SII, NLR, PLR) in ECC-affected children.

MATERIAL AND METHOD

95 healthy patients in early childhood and demonstrating periapical periodontitis who underwent dental treatment under general anesthesia (GA) in the last two years were included in the present study. Their periapical statuses were dichotomized as mild and severe. Periapical Index (PAI) scores of 2 and 3 were regarded as "mild" whereas 4 and 5 as "severe". Of the complete blood test (CBC) parameters, systemic inflammatory index (SII), neutrophil-to-lymphocyte ratio (NLR), platelet-lymphocyte ratio (PLR), neutrophilic granulocyte (NEUT), lymphocyte (LYMPH) and platelet (PLT) were recorded. The relationship between the degree of periapical pathology and the evaluated markers was assessed using Receiver Operating Characteristic (ROC) analysis.

RESULTS

Results of the present study revealed that mean NLR, SII and NEUT index scores of the patients having severe periapical periodontitis were statistically higher than those of the ones with mild pathology (p < 0.05). A positive, statistically significant interrelationship was found between the number of teeth demonstrating a PAI score of severe periapical periodontitis with the signs of exacerbation (PAI 5) and NLR and SII values (p < 0.05). Area under the ROC curve (AUC) values for NLR and SII were determined as 66.8% and 66.6% respectively, indicating that classification performance was sufficient and statistically significant (p < 0.05).

CONCLUSION

Postponing the management of odontogenic infections will induce some complications such as, infective endocarditis and cause the systemic inflammatory process to continue by aggravating the systemic effects of local lesions. Thus, underlying mechanism should be eliminated and oral hygiene should be maintained, also novel biomarkers may be recommended to be used for the decision-making process for the teeth with persistent periapical lesions unresponsive to treatment.

THROMKIDplus Patient Registry and Biomaterial Banking for Children with Inherited Platelet Disorders

Inherited platelet disorders (IPDs) represent a heterogeneous group of disorders that include both quantitative (thrombocytopenia or thrombocytosis) and qualitative (thrombocytopathy) defects. To gain better knowledge about the prevalence, pathogenesis, and clinical consequences of specific diseases, to improve diagnosis and treatment of patients with IPD, and to support translational research on a genetic, molecular, and physiological basis, the THROMKIDplus study group currently comprising 24 sites in Germany, Austria, and Switzerland decided to establish a patient registry with associated biomaterial banking for children. This registry is designed as a retrospective-prospective, multicenter observational study and supposed to launch in the second half of 2023. Blood smears, plasma, platelet pellets, and DNA of patients will be stored in certified biomaterial banks for future translational research projects. The main inclusion criteria are (1) diagnosis of or highly suspected IPD after assessment of a THROMKIDplus competence center and (2) patients aged 0 to 17 years. Initial and follow-up data on patient history, laboratory parameters, standardized documentation of bleeding tendency, and congenital defects are collected according to good clinical practice and current data protection acts by using the MARVIN platform, a broadly used data management system supported by the German Society for Pediatric Oncology Hematology (GPOH). The THROMKIDplus study group intends to enroll ∼200 patients retrospectively and an annual amount of ∼50 patients prospectively.

TNF-α is a predictive marker in distinguishing myeloproliferative neoplasm and idiopathic erythrocytosis/thrombocytosis: development and validation of a non-invasive diagnostic model

Purpose

Philadelphia-chromosome negative myeloproliferative neoplasms (MPN) exhibit phenotypic similarities with JAK/STAT-unmutated idiopathic erythrocytosis and thrombocytosis (IE/IT). We aimed to develop a clinical diagnostic model to discern MPN and IE/IT.

Methods

A retrospective study was performed on 77 MPN patients and 32 IE/IT patients in our center from January 2018 to December 2023. We investigated the role of hemogram, cytokine and spleen size in differentiating MPN and IE/IT among newly onset erythrocytosis and thrombocytosis patients. Independent influencing factors were integrated into a nomogram for individualized risk prediction. The calibration and discrimination ability of the model were evaluated by concordance index (C-index), calibration curve.

Results

MPN had significantly higher TNF-α level than IE/IT, and the TNF-α level is correlated with MF-grade. Multivariable analyses revealed that TNF-α, PLT count, age, size of spleen were independent diagnostic factors in differentiating MPN and IE/IT. Nomograms integrated the above 4 factors for differentiating MPN and IE/IT was internally validated and had good performance, the C-index of the model is 0.979.

Conclusion

The elevation of serum TNF-α in MPN patients is of diagnostic significance and is correlated with the severity of myelofibrosis. The nomogram incorporating TNF-α with age, PLT count and spleen size presents a noteworthy tool in the preliminary discrimination of MPN patients and those with idiopathic erythrocytosis or thrombocytosis. This highlights the potential of cytokines as biomarkers in hematologic disorders.

A novel germline hyperactivating JAK2 mutation L604F

Somatic JAK2 mutations are the main molecular cause of the vast majority of polycythemia vera (PV) cases. According to a recent structural model, the prevalent acquired V617F mutation improves the stability of the JAK2 dimer, thereby enhancing the constitutive JAK2 kinase activity. Germline JAK2 mutations usually do not largely alter JAK2 signaling, although they may modulate the impact of V617F. We found an unusual germline JAK2 mutation L604F in homozygous form in a young PV patient, along with a low allele burden JAK2 V617F mutation, and in her apparently healthy sister. Their father with a PV-like disease had L604F in a heterozygous state, without V617F. The functional consequences of JAK2 L604Fmutation were compared with those induced by V617F in two different in vitro model systems: (i) HEK293T cells were transfected with plasmids for exogenous JAK2-GFP expression, and (ii) endogenous JAK2 modifications were introduced into HeLa cells using CRISPR/Cas9. Both mutations significantly increased JAK2 constitutive activity in transfected HEK293T cells. In the second model, JAK2 modification resulted in reduced total JAK2 protein levels. An important difference was also detected: as described previously, the effect of V617F on JAK2 kinase activity was abrogated in the absence of the aromatic residue F595. In contrast, JAK2 hyperactivation by L604F was only partially inhibited by the F595 change to alanine. We propose that the L604F mutation increases the probability of spontaneous JAK2 dimer formation, which is physiologically mediated by F595. In addition, L604F may contribute to dimer stabilization similarly to V617F.

The predictive usefulness of the novel "combined hemoglobin-to-platelet ratio and maximum mouth opening index" on prevalence of radiation induced trismus in patients with nasopharyngeal cancer

OBJECTIVES

To explore how well a unique combination of hemoglobin-to-platelet ratio (HPR) and pretreatment maximum mouth opening (MMO) predicts the prevalence of radiation-induced trismus (RIT).

PATIENTS AND METHODS

HPR and MMO cutoff values (0.54 and 40.7 mm) divided patients into two groups. To develop the novel HPR-MMO index, four combinations of these factors were tested for predictive power: Group 1: HPR > 0.54 and MMO > 40.7 mm; Group 2: HPR ≤ 0.54 but MMO > 40.7 mm; Group 3: HPR > 0.54 but MMO ≤ 40.7 mm; Group 4: HPR ≤ 0.54 and MMO ≤ 40.7 mm.

RESULTS

Data of 198 patients with LA-NPC was analyzed retrospectively. RIT rates for Groups 1 to 4 were 10.2%, 15.2%, 25%, and 59.4%. Groups 2 and 3 were merged to generate HPR-MMO index because of statistically equivalent RIT rates: Low-risk: HPR > 0.54 and MMO > 40.7 mm; Intermediate-risk: HPR ≤ 0.54 but MMO > 40.7 mm or; HPR > 0.54 but MMO ≤ 40.7 mm; High-risk: HPR ≤ 0.54 and MMO ≤ 40.7 mm. It was revealed that the low-, high-, and intermediate-risk group's RIT rates; 10.2%, 59.4%, and 19.2%, respectively.

CONCLUSION

The novel HPR-MMO index may to classify LA-NPC patients into low, intermediate, and high-risk RIT groups.

EAHP 2020 workshop proceedings, pediatric myeloid neoplasms

The first section of the bone marrow workshop of the European Association of Haematopathology (EAHP) 2020 Virtual Meeting was dedicated to pediatric myeloid neoplasms. The section covered the whole spectrum of myeloid neoplasms, including myelodysplastic syndromes (MDS), myeloproliferative neoplasms (MPN), myelodysplastic/myeloproliferative neoplasms (MDS/MPN), and acute myeloid leukemia (AML). The workshop cases are hereby presented, preceded by an introduction on these overall rare diseases in this age group. Very rare entities such as primary myelofibrosis, pediatric MDS with fibrosis, and MDS/MPN with JMML-like features and t(4;17)(q12;q21); FIP1L1::RARA fusion, are described in more detail.

Thromboses and Hemostasis Disorders Associated with COVID-19: The Possible Causal Role of Cross-Reactivity and Immunological Imprinting

By examining the issue of the thromboses and hemostasis disorders associated with severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) through the lens of cross-reactivity, it was found that 60 pentapeptides are shared by SARS-CoV-2 spike glycoprotein (gp) and human proteins that— when altered, mutated, deficient or, however, improperly functioning— cause vascular diseases, thromboembolic complications, venous thrombosis, thrombocytopenia, coagulopathies, and bleeding, inter alia. The peptide commonality has a relevant immunological potential as almost all of the shared sequences are present in experimentally validated SARS-CoV-2 spike gp-derived epitopes, thus supporting the possibility of cross-reactions between the viral gp and the thromboses-related human proteins. Moreover, many of the shared peptide sequences are also present in pathogens to which individuals have previously been exposed following natural infection or vaccinal routes, and of which the immune system has stored imprint. Such an immunological memory might rapidly trigger anamnestic secondary cross-reactive responses of extreme affinity and avidity, in this way explaining the thromboembolic adverse events that can associate with SARS-CoV-2 infection or active immunization.

Essential Thrombocythemia in Children and Adolescents

Simple Summary

Among chronic Ph-negative myeloproliferative neoplasms, essential thrombocythemia is found in children with low but increasing incidence. The diagnostic and clinical features do not completely overlap with ET of adult age. A significant number of cases, in fact, do not meet the criteria of clonality, and many cases require extensive clinical evaluation to exclude secondary, reactive forms. Therefore, histological analysis of bone marrow biopsy is necessary, and its use should be enforced. The clinical course appears to be more benign, at least within the first decades of observation, with the incidence of thrombotic events being much lower than in adults (4 % vs. 30%). Hemorrhages are mostly irrelevant. Therefore, the management should be carefully adapted to the individual patient, balancing the risk of future complications with long-term collateral effects of any drug. This review analyzes the peculiarities of the disease facing similarities and differences with adult scenarios.

Abstract

This paper reviews the features of pediatric essential thrombocythemia (ET). ET is a rare disease in children, challenging pediatric and adult hematologists alike. The current WHO classification acknowledges classical Philadelphia-negative MPNs and defines diagnostic criteria, mainly encompassing adult cases. The presence of one of three driver mutations (JAK2V617F, CALR, and MPL mutations) represent the proof of clonality typical of ET. Pediatric ET cases are thus usually confronted by adult approaches. These can fit only some patients, because only 25–40% of cases present one of the driver mutations. The diagnosis of hereditary, familial thrombocytosis and the exclusion of reactive/secondary thrombocytosis must be part of the diagnostic process in children and can clarify most of the negative cases. Still, many children present a clinical, histological picture of ET, with a molecular triple wild-type status. Moreover, prognosis seems more benign, at least within the first few decades of follow-up. Thrombotic events are rare, and only minor hemorrhages are ordinarily observed. As per the management, the need to control symptoms must be balanced with the collateral effects of lifelong drug therapy. We conclude that these differences concert a compelling case for a very careful therapeutic approach and advocate for the importance of further cooperative studies.