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Brissot E, Troadec M, Loréal O, Brissot P. Iron and platelets: A subtle, under-recognized relationship. Am J Hematol 2021; 96:1008-1016. [PMID: 33844865 DOI: 10.1002/ajh.26189] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Revised: 03/16/2021] [Accepted: 04/08/2021] [Indexed: 12/16/2022]
Abstract
The role of iron in the formation and functioning of erythrocytes, and to a lesser degree of white blood cells, is well established, but the relationship between iron and platelets is less documented. Physiologically, iron plays an important role in hematopoiesis, including thrombopoiesis; iron levels direct, together with genetic factors, the lineage commitment of megakaryocytic/erythroid progenitors toward either megakaryocyte or erythroid progenitors. Megakaryocytic iron contributes to cellular machinery, especially energy production in platelet mitochondria. Thrombocytosis, possibly favoring vascular thrombosis, is a classical feature observed with abnormally low total body iron stores (mainly due to blood losses or decreased duodenal iron intake), but thrombocytopenia can also occur in severe iron deficiency anemia. Iron sequestration, as seen in inflammatory conditions, can be associated with early thrombocytopenia due to platelet consumption and followed by reactive replenishment of the platelet pool with possibility of thrombocytosis. Iron overload of genetic origin (hemochromatosis), despite expected mitochondrial damage related to ferroptosis, has not been reported to cause thrombocytopenia (except in case of high degree of hepatic fibrosis), and iron-related alteration of platelet function is still a matter of debate. In acquired iron overload (of transfusional and/or dyserythropoiesis origin), quantitative or qualitative platelet changes are difficult to attribute to iron alone due to the interference of the underlying hematological conditions; likewise, hematological improvement, including increased blood platelet counts, observed under iron oral chelation is likely to reflect mechanisms other than the sole beneficial impact of iron depletion.
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Affiliation(s)
- Eolia Brissot
- Service d'Hématologie Clinique et de Thérapie Cellulaire, Hôpital Saint Antoine APHP Paris France
- Sorbonne Universités, UPMC Univ. Paris 06, Centre de recherche Saint‐Antoine, UMR‐S938 Paris France
| | - Marie‐Bérengère Troadec
- Univ Brest, Inserm, EFS, UMR 1078, GGB Brest France
- Service de génétique, laboratoire de génétique chromosomique CHRU Brest Brest France
| | - Olivier Loréal
- Inserm, University of Rennes1, UMR 1241, Inrae, NuMeCan Institute Rennes France
| | - Pierre Brissot
- Inserm, University of Rennes1, UMR 1241, Inrae, NuMeCan Institute Rennes France
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Thom CS, Echevarria E, Osborne AD, Carr L, Rubey K, Salazar E, Callaway D, Pawlowski T, Devine M, Kleinman S, Witmer C, Flibotte J, Lambert MP. Extreme thrombocytosis is associated with critical illness and young age, but not increased thrombotic risk, in hospitalized pediatric patients. J Thromb Haemost 2020; 18:3352-3358. [PMID: 32979018 PMCID: PMC7855272 DOI: 10.1111/jth.15103] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Revised: 09/01/2020] [Accepted: 09/11/2020] [Indexed: 12/25/2022]
Abstract
BACKGROUND Extreme thrombocytosis (EXT, platelet count > 1000 × 103 /μL) is an uncommon but potentially clinically significant finding. Primary EXT in the setting of myeloproliferative disorders is linked to thrombotic and/or bleeding complications more frequently than secondary EXT, which typically occurs in reaction to infection, inflammation, or iron deficiency. However, comorbidities have been reported in adults with secondary EXT. Clinical implications of EXT in children are not well defined, as prior studies targeted small and/or specialized pediatric populations. OBJECTIVES Our objectives were to determine etiologies and sequelae of EXT in a hospitalized general pediatric patient population. PATIENTS AND METHODS We retrospectively analyzed EXT cases from a single-center pediatric cohort of ~80 000 patients over 8 years. RESULTS Virtually all cases (99.8%) were secondary in nature, and most were multifactorial. Many cases of EXT occurred in children under 2 years old (47%) and/or during critical illness (55%). No thrombotic or bleeding events directly resulted from EXT, confirming a paucity of clinical complications associated with EXT in pediatric patients. There were indications that neonatal hematopoiesis and individual genetic variation influenced some cases, in addition to certain diagnoses (eg, sickle cell anemia) and clinical contexts (eg, asplenia). CONCLUSION Our findings confirm that thrombotic events related to EXT are rare in pediatric patients, which can inform the use of empiric anti-platelet therapy.
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Affiliation(s)
- Christopher S Thom
- Department of Pediatrics, Children’s Hospital of
Philadelphia, Philadelphia, PA, USA
- Division of Neonatology, Children’s Hospital of
Philadelphia, Philadelphia, PA, USA
| | - Emily Echevarria
- Department of Pediatrics, Children’s Hospital of
Philadelphia, Philadelphia, PA, USA
- Division of Neonatology, Children’s Hospital of
Philadelphia, Philadelphia, PA, USA
| | - Ashley D Osborne
- Department of Pediatrics, Children’s Hospital of
Philadelphia, Philadelphia, PA, USA
| | - Leah Carr
- Department of Pediatrics, Children’s Hospital of
Philadelphia, Philadelphia, PA, USA
- Division of Neonatology, Children’s Hospital of
Philadelphia, Philadelphia, PA, USA
| | - Kathryn Rubey
- Department of Pediatrics, Children’s Hospital of
Philadelphia, Philadelphia, PA, USA
- Division of Neonatology, Children’s Hospital of
Philadelphia, Philadelphia, PA, USA
| | - Elizabeth Salazar
- Department of Pediatrics, Children’s Hospital of
Philadelphia, Philadelphia, PA, USA
- Division of Neonatology, Children’s Hospital of
Philadelphia, Philadelphia, PA, USA
| | - Danielle Callaway
- Department of Pediatrics, Children’s Hospital of
Philadelphia, Philadelphia, PA, USA
- Division of Neonatology, Children’s Hospital of
Philadelphia, Philadelphia, PA, USA
| | - Thomas Pawlowski
- Department of Pediatrics, Children’s Hospital of
Philadelphia, Philadelphia, PA, USA
- Division of Neonatology, Children’s Hospital of
Philadelphia, Philadelphia, PA, USA
| | - Matthew Devine
- Department of Pediatrics, Children’s Hospital of
Philadelphia, Philadelphia, PA, USA
- Division of Neonatology, Children’s Hospital of
Philadelphia, Philadelphia, PA, USA
| | - Stacey Kleinman
- Department of Pediatrics, Children’s Hospital of
Philadelphia, Philadelphia, PA, USA
| | - Char Witmer
- Department of Pediatrics, Children’s Hospital of
Philadelphia, Philadelphia, PA, USA
- Division of Hematology, Children’s Hospital of
Philadelphia, Philadelphia, PA, USA
| | - John Flibotte
- Department of Pediatrics, Children’s Hospital of
Philadelphia, Philadelphia, PA, USA
- Division of Neonatology, Children’s Hospital of
Philadelphia, Philadelphia, PA, USA
| | - Michele P Lambert
- Department of Pediatrics, Children’s Hospital of
Philadelphia, Philadelphia, PA, USA
- Division of Hematology, Children’s Hospital of
Philadelphia, Philadelphia, PA, USA
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