{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,2,2]],"date-time":"2026-02-02T20:13:50Z","timestamp":1770063230222,"version":"3.49.0"},"reference-count":30,"publisher":"MDPI AG","issue":"3","license":[{"start":{"date-parts":[[2026,2,2]],"date-time":"2026-02-02T00:00:00Z","timestamp":1769990400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["JCM"],"abstract":"<jats:p>Background\/Objectives: Thrombotic events represent the leading cause of morbidity and mortality in patients with Philadelphia chromosome-negative myeloproliferative neoplasms (Ph\u2212 MPNs), particularly in those aged &gt; 60 years. The immature platelet fraction (IPF) reflects the proportion of newly released, reticulated, highly reactive platelets and has emerged as a marker of thrombopoietic activity in various prothrombotic conditions. Methods: We prospectively measured IPF in 45 patients with newly diagnosed Ph\u2212 MPNs (24 with essential thrombocythemia, 13 with polycythemia vera, 5 with MPN-unclassified, and 3 with primary myelofibrosis) and 27 controls without MPN. Results: IPF was significantly higher in patients with Ph\u2212 MPN than in controls (median 27 vs. 10.9, p &lt; 0.0001). Within the MPN cohort, IPF values differed significantly across subtypes (p = 0.027), being highest in essential thrombocythemia and primary myelofibrosis, intermediate in unclassified MPN, and lowest in polycythemia vera. Patients older than 60 years exhibited higher IPF independently of platelet count (p = 0.021). No significant difference was observed between JAK2V617F-positive and -negative cases. Conclusions: These results indicate that IPF captures accelerated and dysregulated thrombopoiesis characteristics of Ph\u2212 MPNs and may provide additional insight into subtype-specific biology and age-related prothrombotic risk beyond conventional complete blood count parameters.<\/jats:p>","DOI":"10.3390\/jcm15031140","type":"journal-article","created":{"date-parts":[[2026,2,2]],"date-time":"2026-02-02T09:00:33Z","timestamp":1770022833000},"page":"1140","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Immature Platelet Fraction as a Potential Biomarker of Dysregulated Thrombopoiesis in Philadelphia-Negative Myeloproliferative Neoplasms"],"prefix":"10.3390","volume":"15","author":[{"given":"Ivan","family":"Zekanovic","sequence":"first","affiliation":[{"name":"Department of Internal Medicine, General Hospital Zadar, 23000 Zadar, Croatia"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6008-5179","authenticated-orcid":false,"given":"Tina","family":"Marketin","sequence":"additional","affiliation":[{"name":"Department of Internal Medicine, General Hospital Zadar, 23000 Zadar, Croatia"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Martina","family":"Moric Peric","sequence":"additional","affiliation":[{"name":"Department of Internal Medicine, General Hospital Zadar, 23000 Zadar, Croatia"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Drazen","family":"Zekanovic","sequence":"additional","affiliation":[{"name":"Department of Internal Medicine, General Hospital Zadar, 23000 Zadar, Croatia"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3899-5819","authenticated-orcid":false,"given":"Ante","family":"Vulic","sequence":"additional","affiliation":[{"name":"Department of Hematology, University Hospital Centre Zagreb, 10000 Zagreb, Croatia"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-0248-4278","authenticated-orcid":false,"given":"Marija","family":"Milos","sequence":"additional","affiliation":[{"name":"Department of Laboratory Diagnostics, University Hospital Centre Zagreb, 10000 Zagreb, Croatia"},{"name":"Faculty of Pharmacy, University of Mostar, 88000 Mostar, Bosnia and Herzegovina"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Anamarija","family":"Bogic","sequence":"additional","affiliation":[{"name":"Department of Laboratory Diagnostics, University Hospital Centre Zagreb, 10000 Zagreb, Croatia"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Marta","family":"Marcinkovic","sequence":"additional","affiliation":[{"name":"Department of Internal Medicine, General Hospital Zadar, 23000 Zadar, Croatia"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Petra","family":"Grbic Pavlovic","sequence":"additional","affiliation":[{"name":"Department of Internal Medicine, General Hospital Zadar, 23000 Zadar, Croatia"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Margareta","family":"Radic Antolic","sequence":"additional","affiliation":[{"name":"Department of Laboratory Diagnostics, University Hospital Centre Zagreb, 10000 Zagreb, Croatia"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Josip","family":"Knezevic","sequence":"additional","affiliation":[{"name":"Department of Laboratory Diagnostics, University Hospital Centre Zagreb, 10000 Zagreb, Croatia"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Ljiljana","family":"Jurlina","sequence":"additional","affiliation":[{"name":"Department of Laboratory Diagnostics, General Hospital Zadar, 23000 Zadar, Croatia"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3532-2336","authenticated-orcid":false,"given":"Ana","family":"Boban","sequence":"additional","affiliation":[{"name":"Department of Hematology, University Hospital Centre Zagreb, 10000 Zagreb, Croatia"},{"name":"School of Medicine, University of Zagreb, 10000 Zagreb, Croatia"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2026,2,2]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"1200","DOI":"10.1182\/blood.2022015850","article-title":"International Consensus Classification of Myeloid Neoplasms and Acute Leukemias: Integrating morphologic, clinical, and genomic data","volume":"140","author":"Arber","year":"2022","journal-title":"Blood"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"4229","DOI":"10.1002\/cncr.35559","article-title":"New advances in the role of JAK2 V617F mutation in 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