Thrombosis in myeloproliferative neoplasms: update in pathophysiology

Thromboinflammation in ischemic cerebrovascular patients with the JAK2V617F mutation

BACKGROUND

The JAK2V617F mutation is a driver of Philadelphia chromosome-negative myeloproliferative neoplasms (MPN) and is also implicated in cardiovascular diseases. Thrombosis in MPN involves JAK2V617F-associated platelet activation and endothelial dysfunction, all potentially influenced by chronic inflammation. Whether the mutation affects thromboinflammatory markers similarly in non-MPN patients remains unclear.

METHOD

We conducted a study involving 63 ischemic cerebrovascular patients with the JAK2V617F mutation, matched with 63 patients without the mutation. Serum samples were analyzed for 12 thromboinflammatory markers during the acute phase and at three months follow-up.

RESULTS

Overall, there was no significant difference in thromboinflammatory markers between cases and controls. However, subgroup analysis of patients with a JAK2V617F allele burden ≥1 % (n = 15) showed higher levels of Vascular Cell Adhesion Molecule-1 (VCAM-1) at baseline (p = 0.018), and elevated Interleukin-10 (IL-10) (p = 0.004) and Tumor Necrosis Factor α (TNF-α) (p = 0.018) at follow-up compared to controls. Regression analysis revealed an association between higher JAK2V617F allele burden and increased VCAM-1 at baseline (p < 0.001), and higher VCAM-1 (p = 0.012), IL-10 (p = 0.003), and TNF-α (p = 0.034) at follow-up.

CONCLUSION

In ischemic cerebrovascular patients, the JAK2V617F mutation is associated with elevated markers of endothelial dysfunction and chronic inflammation. This underscores the role of inflammation in thrombosis driven by the JAK2V617F mutation.

Neutrophil-to-lymphocyte ratio (NLR) at diagnosis in essential thrombocythemia: A new promising predictor of thrombotic events

BACKGROUND

Myeloproliferative neoplasms represent a heterogeneous group of acquired hematopoietic stem cell diseases in which chronic inflammation is essential for both clonal evolution and thrombotic complications. The neutrophil-to-lymphocyte ratio (NLR), reflecting the imbalance between systemic inflammation and immunity, is emerging as a prognostic biomarker in several diseases, including hematological ones.

METHODS

A total of 473 patients with essential thrombocythemia (ET), the relationship between NLR value at diagnosis and the risk of thrombotic events in the follow-up, in addition to conventional clinical and biological variables, were retrospectively analyzed.

RESULTS

A total of 78 thrombotic events were reported for an incidence rate of 1.8 × 100 patients/year. In multivariate analysis, NLR value ≥4 at diagnosis was associated with higher cumulative thrombotic risk (hazard ratio [HR], 2.05; 95% CI, 1.29-2.28; p = .0001) as well International Prognostic Score for Thrombosis in Essential Thrombosis score intermediate-high (HR, 2.69; 95% CI, 1.27-5.72; p = .01) and diabetes (HR, 2.49; 95% CI, 1.23-3.05; p = .010). Concerning arterial thrombotic events, in multivariate analysis, NLR value at diagnosis ≥4 was predictive for thrombosis (HR, 2.13; 95% CI, 1.31-4.04; p = .001 as well diabetes (HR, 2.44; 95% CI, 1.05-5.68; p = .04) and hypertension (HR, 2.46; 95% CI, 1.05-5.68; p = .01). About venous thrombotic events, NLR value ≥5 was a marker predictive for venous thrombosis (HR, 2.99; 95% CI, 2.45-6.48; p = .01) as well age >60 years old (HR, 2.26; 95% CI, 1.0-5.10; p = .05).

CONCLUSION

NLR value is a simple, cost-effective, and easy-to-obtain inflammatory marker that can predict a diagnosis the risk of thrombosis in ET. Our results suggest that NLR value could be integrated into conventional cardiovascular risk scores, to better classify high-risk patients who are candidates for cytoreductive therapy. Further larger and prospective studies are warranted.

Cardiovascular risk in a contemporary cohort of patients with myeloproliferative neoplasms'

BACKGROUND

Myeloproliferative neoplasms (MPNs) are a group of disorders of clonal haemopoiesis associated with an inherent risk of arterial and venous thrombotic complications. The prevalence of thrombotic complications and the impact of cardiovascular risk factors (CVRFs) in contemporary patient cohorts within the current era of MPN treatments have not been completely defined.

OBJECTIVES

We aim to characterise the cardiovascular risk of patients with MPN by identifying the prevalence of CVRFs and describing the pattern of thrombotic events. We also aim to utilise the QRISK3 algorithm, which is a validated model used to estimate an individual's risk of developing cardiovascular disease, to further phenotype this cohort of patients.

METHODS

We perform a retrospective analysis on a single-centre cohort of 438 patients with MPN.

RESULTS

MPN patients continue to carry a high burden of vascular morbidity with a prevalence of arterial thrombotic events in 15.8 % (69/438) and venous thrombotic events in 13.2 % (58/438) of the cohort. The novel use of the QRISK3 algorithm, which showed a mean score of 13.7 % across the MPN population, provides further evidence to suggest an increased cardiovascular risk in MPN patients.

CONCLUSION

With an increased risk of cardiovascular disease in patients with MPN, we propose an integrated approach between primary and specialised healthcare services using risk stratification tools such as QRISK3, which will allow aggressive optimisation of CVRFs to prevent thrombosis and reduce the overall morbidity and mortality in patients with MPN.

Exploring the Molecular Aspects of Myeloproliferative Neoplasms Associated with Unusual Site Vein Thrombosis: Review of the Literature and Latest Insights

Myeloproliferative neoplasms (MPNs) are the leading causes of unusual site thrombosis, affecting nearly 40% of individuals with conditions like Budd-Chiari syndrome or portal vein thrombosis. Diagnosing MPNs in these cases is challenging because common indicators, such as spleen enlargement and elevated blood cell counts, can be obscured by portal hypertension or bleeding issues. Recent advancements in diagnostic tools have enhanced the accuracy of MPN diagnosis and classification. While bone marrow biopsies remain significant diagnostic criteria, molecular markers now play a pivotal role in both diagnosis and prognosis assessment. Hence, it is essential to initiate the diagnostic process for splanchnic vein thrombosis with a JAK2 V617F mutation screening, but a comprehensive approach is necessary. A multidisciplinary strategy is vital to accurately determine the specific subtype of MPNs, recommend additional tests, and propose the most effective treatment plan. Establishing specialized care pathways for patients with splanchnic vein thrombosis and underlying MPNs is crucial to tailor management approaches that reduce the risk of hematological outcomes and hepatic complications.

Abdominal aortic calcification in patients newly diagnosed with essential thrombocythemia

Background

Although atherosclerosis is likely to be involved in the development of arterial thrombotic events in patients with essential thrombocythemia (ET), abdominal aortic calcification (AAC) has rarely been investigated. We evaluated the prevalence and clinical relevance of AAC at the time of ET diagnosis.

Methods

This retrospective study included patients newly diagnosed with ET who underwent abdominal computed tomography (CT) at the time of diagnosis between January 2002 and December 2021 at Chungnam National University Hospital, Daejeon, Korea. CT images were reviewed and an aortic calcification score was assigned.

Results

Of the 94 patients (median age, 62 yr; range, 18‒90 yr), AAC was detected in 62 (66.0%). AAC was most commonly mild (33.0%), followed by moderate (22.7%) and severe (5.3%). Old age [odds ratio (OR), 34.37; 95% confidence interval (CI), 12.32‒95.91; P＜0.001] was an independent risk factor for AAC. The patients with AAC had a higher WBC count (11.8±4.7 vs. 9.7±2.9×109/L, P=0.017), higher neutrophil-to-lymphocyte ratio (4.3±2.7 vs. 3.1±1.5, P=0.039), and higher JAK2V617F positivity (81.5% vs. 58.8%, P=0.020) compared to those without AAC. AAC was an independent risk factor for arterial thrombotic vascular events that occurred before or at diagnosis of ET (OR, 4.12; 95% CI, 1.11‒15.85; P=0.034).

Conclusion

AAC is common in patients with ET and is associated with arterial thrombotic events.

Clinical features associated with thrombotic events in children with myeloproliferative neoplasms

In children with MPNs, clots are most common in those with JAK2 mutations and those with polycythemia vera.