Decreased generation of procoagulant platelets detected by flow cytometric analysis in patients with bleeding diathesis

Abstract

Background: A clinically relevant bleeding diathesis is a frequent diagnostic

Safety and efficacy of cryopreserved autologous platelet concentrates in HLA‐alloimmunized patients with hematologic malignancies

“…Compared to fresh control PLTs, thawed cryopreserved PLTs showed a tendency to a smaller size, with borderline cytoplasmic complexity and surface densities of the fibrinogen and von Willebrand factor receptors (Table ). Their dense granule content was significantly decreased compared to control PLTs (mean, 29%; 95% confidence interval [CI], 17.1%‐40.9%; n = 7; in‐house cutoff ≥ 70%) …”

“…Analysis of surface glycoproteins (GP) Ibα (by a monoclonal anti‐human CD42b antibody coupled with phycoerythrin [PE], Dako), GPIIb‐IIIa (anti‐hCD41‐fluorescein isothiocyanate [FITC] and anti‐hCD61‐FITC, Becton Dickinson), baseline expression P‐selectin expression (anti‐CD62P‐PE, Becton Dickinson), and PAC1 binding (PAC1‐FITC, Becton Dickinson) were performed in a 100‐µL volume containing cryopreserved PLTs at a final concentration of 5 × 10 9 /L and combinations of relevant antibodies at saturating concentrations. After a 15‐minute incubation at room temperature in the dark, 1000 µL of Tyrode's buffer was added and cryopreserved PLTs were immediately analyzed by flow cytometry (FACSCanto, Becton Dickinson) . Dose response of PLT reactivity was investigated with ADP (baseline and final ADP concentrations of 0.5, 5.0, and 50 µmol/L), convulxin (0.5, 5, and 50 ng/mL), or thrombin (0.005, 0.05, and 0.5 U/mL) in a 100‐µL volume containing cryopreserved PLTs at a concentration of 5× 10 9 /L, anti‐CD62P‐PE, and PAC1‐FITC.…”

“…Secretion of dense granule was assessed after an additional 10‐minute incubation at 37°C with buffer versus either 100 µmol/L ADP or 0.5 U/mL thrombin. Immediately before flow cytometric analysis cryopreserved PLTs were diluted with 1000 µL of Hank's buffer …”

Coated platelets and severe haemophilia A bleeding phenotype: Is there a connection?

“…In a single‐case series, mean coated platelet levels of 30% were reported in haemophilia A patients; and those with a severe bleeding phenotype had significantly less compared to a mild phenotype . Another study has suggested that a decreased ability to generate procoagulant coated platelets has been reported to be a cause for a bleeding diathesis .…”

Acute hemorrhagic complications are associated with lower coated‐platelet levels in non‐lacunar brain infarction

“…Impaired coated‐platelet potential has also been noted in studies examining disparate bleeding diatheses occurring in humans and animals. Specifically, a genetically‐determined deficiency of coated‐platelet production in German shepherd dogs results in a bleeding diathesis , while recently published data demonstrate impaired coated‐platelet generation in a significant proportion of individuals with platelet‐based bleeding diathesis of unknown etiology . In contrast, increased coated‐platelet levels are present in patients with non‐lacunar ischemic stroke or TIA when compared with controls .…”