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Thrombocytopenia is a potential dialysis-related treatment complication. Developments in bio-compatible dialyser membranes have decreased the occurrence of thrombocytopenia. We investigated whether thrombopoiesis is impaired in haemodialysis patients by measuring the thrombopoietin level and absolute immature platelet number ( AIPN) in the blood of patients undergoing haemodialysis. Samples were collected from the dialysis tubing pre- and post- haemodialysis in a cohort of 45 well-characterized haemodialysis patients. Thrombopoietin levels and AIPN increased following haemodialysis, despite no change in platelet count. Observed increase in release of immature platelets from the bone marrow following haemodialysis indicates possible complement activation secondary to interaction between blood constituents and the dialysis membrane. [ABSTRACT FROM AUTHOR]

Background The ability to distinguish increased platelet ( PLT) destruction from PLT hypoproduction is important in the care of patients with marrow failure syndromes and patients receiving high-dose chemotherapy. The measurement of immature circulating PLTs based on RNA content using an automated counter is now feasible. This study evaluated the impact of recent PLT transfusion on measurement of immature PLT variables. Study Design and Methods The immature PLT fraction ( IPF) and absolute immature PLT number ( AIPN) were measured using a hematology analyzer before and after PLT transfusion in nine transfusion-dependent patients with marrow failure secondary to aplastic anemia, myelodysplasia, or transplantation conditioning. IPF and AIPN were also measured serially over 5 days of storage in three plateletpheresis components collected from normal donors. Results PLT transfusion did not significantly change the mean AIPN in transfused patients. In contrast, IPF decreased significantly from 6.6 ± 4.6% on Day −1 to 2.3 ± 1.4% on Day 0 before returning to 4.3 ± 2.3% on Day +1. In the PLT component, AIPN and IPF% increased significantly over 5 days of storage, most likely due to an artifact of the staining and detection process for stored PLTs, no longer detected in vivo once the PLTs were transfused. Conclusion PLT transfusion decreases the IPF due to the resultant increase in circulating PLT count. However, PLT transfusion does not change the circulating AIPN, validating this assay as a reflection of ongoing PLT production by the marrow in various clinical settings, regardless of proximity to PLT transfusion. [ABSTRACT FROM AUTHOR]

Summary: COVID‐19, caused by SARS‐CoV‐2, is a contagious life‐threatening viral disease that has killed more than three million people worldwide to date. Attempts have been made to identify biomarker(s) to stratify disease severity and improve treatment and resource allocation. Patients with SARS‐COV‐2 infection manifest with a higher inflammatory response and platelet hyperreactivity; this raises the question of the role of thrombopoiesis in COVID‐19 infection. Immature platelet fraction (IPF, %) and immature platelet counts (IPC, ×109/l) can be used to assess thrombopoiesis. This study investigates whether the level of thrombopoiesis correlates with COVID‐19 severity. A large cohort of 678 well‐characterized COVID‐19 patients was analyzed, including 658 (97%) hospitalized and 139 (21%) admitted to the intensive care unit (ICU). Elevated percentage IPF at presentation was predictive of length of hospitalization (P < 0·01) and ICU admission (P < 0·05). Additionally, percentage IPF at the peak was significantly higher among ICU patients than non‐ICU patients (6·9 ± 5·1 vs 5·3 ± 8·4, P < 0·01) and among deceased patients than recovered patients (7·9 ± 6·3 vs 5·4 ± 7·8, P < 0·01). Furthermore, IPC at the peak was significantly higher among ICU patients than non‐ICU patients (18·5 ± 16·2 vs. 13·2 ± 8·3, P < 0·05) and among patients on a ventilator than those not (22·1 ± 20·1 vs.13·4 ± 8·4, P < 0·05). Our study demonstrated that elevated initial and peak values of percentage IPF and IPC might serve as prognostic biomarkers for COVID‐19 progression to severe conditions. [ABSTRACT FROM AUTHOR]