Haemostatic function and biomarkers of endothelial damage before and after platelet transfusion in patients with acute myeloid leukaemia.

OBJECTIVES: The beneficial effect of platelet transfusion on haemostasis is well established, but there is emerging evidence that platelet transfusion induces an inflammatory response in vascular endothelial cells. BACKGROUND: We investigated haemostatic function and endothelial biomarkers before and after platelet transfusion in patients with acute myeloid leukaemia. MATERIALS AND METHODS: Blood was sampled before, 1 and 24 h after platelet transfusion. Primary and secondary haemostasis was evaluated by whole blood aggregometry (Multiplate) and thromboelastography (TEG). Endothelial biomarkers (sICAM-1, syndecan-1, sThrombomodulin, sVE-Cadherin) and platelet activation biomarkers (sCD40L, TGF-beta) were investigated along with haematology/biochemistry analyses. RESULTS: Twenty-two patients were included. Despite continued low platelet counts, platelet transfusion normalised the median values of most TEG parameters and slightly increased platelet aggregation (all P < 0·05). Endothelial biomarkers were not significantly affected by transfusion. The 1 h sCD40L level correlated positively with Syndecan-1 and soluble thrombomodulin delta values, biomarkers of endothelial damage (both P = 0·005). CONCLUSION: Platelet transfusion improved haemostasis, whereas post-transfusion increases in sCD40L were associated with endothelial damage, indicating that transfused platelets and platelet-derived pro-inflammatory mediators may have opposite effects on the endothelium.

Haemostatic function and biomarkers of endothelial damage before and after RBC transfusion in patients with haematologic disease.

BACKGROUND AND OBJECTIVES: Transfusion of red blood cells (RBC) is beneficial for the patient but can also be harmful, as randomized trials have demonstrated increased infection rates, bleeding and mortality. The study aim was to investigate the response of the vascular system (the haemostatic function and the endothelium) to RBC transfusion. MATERIALS AND METHODS: Blood was sampled from patients with various transfusion-dependent haematologic diseases before 1 and 24 h after RBC transfusion. Primary and secondary haemostasis was evaluated by whole-blood impedance aggregometry (Multiplate) and by thromboelastography (TEG). Samples were analysed by ELISA for biomarkers reflecting endothelial activation and damage (sICAM-1, syndecan-1, sThrombomodulin (sTM), sVE-Cadherin), platelet activation (sCD40L) and inflammation (hsCRP). RESULTS: A total of 58 patients were enrolled in the study. Median age was 71 years. Compared to before transfusion, patients had slightly reduced coagulability 1 h after RBC transfusion, assessed by TEG. However, transfusion of older RBC products (>14 days) was associated with increased coagulability (all P < 0·05). The level of syndecan-1 increased slightly 24 h after transfusion (median 12·4 (IQR 9-23) vs. 13·2 (9-25) ng/ml, P < 0·01), indicating increased glycocalyx degradation. CONCLUSION: Overall, RBC transfusion was associated with reduced coagulability and endothelial glycocalyx degradation. Transfusion of older RBCs was however associated with increased coagulability. The changes observed were small to moderate and the clinical relevance of these findings should be investigated in larger studies.

Measuring the impact of a restrictive transfusion guideline in patients with acute myeloid leukaemia.

Interventions to change physician transfusion behavior are often evaluated by examining the amount of red blood cell (RBC) units transfused or the proportion of patients transfused before and after the intervention. The pre-transfusion haemoglobin concentration is a sensitive measure of transfusion practice, but has not been used to evaluate behavioral interventions. We examined the effect of a Danish National Board of Health December 2007 transfusion guideline on the behavior of clinicians treating acute myeloid leukaemia (AML). We compared the effect of the guideline on pre-transfusion haemoglobin concentrations with other measures of transfusion behavior, including use of RBC units and proportion of patients transfused. No change in transfusion behavior could be demonstrated by examining amount of RBC units transfused and proportion of patients transfused. Conversely, the pre-transfusion haemoglobin concentration fell significantly. Pre-transfusion haemoglobin determination is a sensitive measure of the effect of an intervention to change physician transfusion behaviour.

Multiple platelet defects identified by flow cytometry at diagnosis in acute myeloid leukaemia.

Summary Previous findings of megakaryocytic hypogranulation and dysmegakaryocytopoietic features in acute myeloid leukaemia (AML) strongly indicate defects in platelet production. The bleeding tendency of these patients may result from dysregulated platelet production, resulting in thrombocytopenia as well as qualitative platelet defects. The present study examined platelet function at diagnosis in 50 AML patients by whole blood flow cytometry. Following in vitro platelet agonist stimulation, platelet activation markers were analysed and compared with 20 healthy individuals. To detect recent in vivo platelet activation, plasma soluble P-selectin (sP-selectin) was measured. Flow cytometric analysis of platelet activation markers demonstrated reduced CD62P [35.6 vs. 118.5 x 10(3) molecules of equivalent soluble fluorochrome (MESF); P < 0.0001], CD63 (11.3 vs. 50.7 x 10(3) MESF; P < 0.0001), and PAC-1 (41.5 vs. 90.5%; P = 0.0001) while reductions in CD42b were abnormal (45.6 vs. 70%; P < 0.0001). sP-selectin levels were similar in patients and healthy controls (0.04 vs. 0.27 fg/platelet; P = 0.84). The presented data indicate that AML pathogenesis may result in multiple platelet defects, involving adhesion, aggregation, and secretion and demonstrate that flow cytometry is a feasible method for platelet function analysis in patients with thrombocytopenia.

[Acquired factor VIII deficiency treated with cyclosporine]. / Erhvervet faktor VIII-mangel behandlet med ciclosporin.

The treatment of acquired factor VIII inhibitors remains controversial, and no standard therapy exists. We describe a case story of successful treatment with prednisolone and cyclosporine of an 83-year old female with severe bleeding disorder due to an acquired factor VIII inhibitor. The patient had complete remission, and no side effects were observed. We recommend that treatment of acquired factor VIII inhibitor with cyclosporine is further investigated.