Comprehensive investigation of platelet function in patients with cirrhosis.

Cirrhosis presents with thrombocytopenia and possibly thrombocytopathy. Previous studies exploring platelet function gave conflicting results and most controversies are explained by the variety of methods employed for investigation. We sought to assess in-vitro the overall platelet function in cirrhosis.

Evaluation of an automated platelet aggregation method for detection of congenital or acquired platelet function defects.

Background: Light transmission aggregometry (LTA) is the most widely used laboratory method for an initial screening of patients with a suspected platelet function defect (PFD), and its use has also been proposed for assessing the efficacy of antiplatelet treatment (APT). An automated LTA method has been developed by Sysmex (Kobe, Japan) on a routine coagulation analyzer (CS-2400), together with a new research parameter called PAL (platelet aggregation level) to evaluate patients on APT.

Materials And Methods: We evaluated the performance of CS-2400 compared to a stand-alone lumi-dual-aggregometer device in the diagnosis of PFD and in assessing the efficacy of APT.

Flow-chamber device (T-TAS) to diagnose patients suspected of platelet function defects.

Background: Patients suspected of platelet function defects represent a diagnostic challenge for the clinical laboratory, mainly due to the complexity and poor standardization of screening methods. We compared a new flow-based chip-equipped point-of-care (T-TAS) device with lumi-aggregometry and other specific tests.

Materials And Methods: The study included 96 patients suspected of platelet function defects and 26 patients referred to hospital for an evaluation of residual platelet function while on antiplatelet therapy.

Assessment of Platelet Thrombus Formation under Flow Conditions in Adult Patients with COVID-19: An Observational Study.

Background:  Coronavirus disease 2019 (COVID-19) is associated with systemic inflammation, which may dysregulate platelet function. Total Thrombus-Formation Analysis System (T-TAS) is a flow-chamber device that analyses platelet-mediated thrombus formation in capillary channels through the following parameters: (1) the area under the flow-pressure curve (AUC), (2) occlusion start time (OST), time needed to reach OST, and (3) occlusion time (OT), time needed to reach the occlusion pressure.

Methods And Findings:  Sixty-one COVID-19 patients admitted to intensive, subintensive, and low intensive care were prospectively enrolled according to the time of admission: group A (up to 8 days) ( = 18); group B (from 9 to 21 days) ( = 19), and group C ( > 21 days) ( = 24).

Acquired hemophilia A and delta storage pool deficiency in a patient with indolent non-Hodgkin lymphoma.

B-cell lymphoproliferative diseases may be associated with acquired hemostasis disorders, such as acquired hemophilia A (AHA) caused by autoantibodies that neutralize factor VIII activity, and δ-storage pool deficiency, an abnormality of platelet function due to defective dense granules and impaired secretion. We describe the case of a 67-year-old man in whom these two acquired bleeding disorders were concomitantly present as the first clinical manifestation of an indolent non-Hodgkin lymphoma. Immunosuppressive therapy with prednisone was initially started to eradicate anti-FVIII antibodies, subsequently boosted with cyclophosphamide and rituximab, these medications being also chosen to treat the associated indolent lymphoma.

Ferric carboxymaltose for sub-acute and chronic iron deficiency anemia in inherited platelet function defects.

Inherited platelet function defects are characterized by sub-acute and chronic mucocutaneous bleedings leading to iron deficiency anemia (IDA). Oral supplementation is the mainstay of treatment of IDA; however, it can be insufficient to compensate the losses and is often associated with gastrointestinal (GI) side effects. Intravenous (IV) iron is indicated for severe anemia or to overcome GI intolerance.

Novel variant in HPS3 gene in a patient with Hermansky Pudlak syndrome (HPS) type 3.

Unlabelled: Hermansky-Pudlak syndrome (HPS) is a rare autosomal recessive disorder caused by defects in 10 human genes, characterized by oculocutaneous albinism (OCA) and bleeding diathesis associated to platelet δ-storage pool defect (SPD). We report a case of 4-year-old boy from non-consanguineous parents with OCA and negative personal and familiar hemorrhagic history, referred to us for severe bleeding after mild trauma. His platelet function, studied by lumi-aggregometry, showed normal first wave of aggregation in response to exogenous agonists and impaired second wave with defective ATP release.

Acquired platelet dysfunction and overproduction of platelet cyclic AMP in two patients with myeloid malignancies.

The pathophysiology of impaired platelet function in acquired disorders is often poorly understood. We report two unrelated patients with hematologic malignancies associated with acquired severe bleeding diathesis, and complex platelet function abnormalities, including overproduction of the physiological inhibitor cyclic-AMP (cAMP). Patient 1, with mild macrocytic anemia and thrombocytopenia (100 x 10/L), was diagnosed with chronic myelomonocytic leukemia a few months after the onset of her bleeding diathesis and our analysis of platelet function.

Complications of whole-exome sequencing for causal gene discovery in primary platelet secretion defects.

Primary platelet secretion defects constitute a heterogeneous group of functional defects characterized by reduced platelet granule secretion upon stimulation by different agonists. The clinical and laboratory heterogeneity of primary platelet secretion defects warrants a tailored approach. We performed a pilot study in order to develop DNA sequence analysis pipelines for gene discovery and to create a list of candidate causal genes for platelet secretion defects.

Molecular characterization, recombinant protein expression, and mRNA analysis of type 3 von Willebrand disease: Studies of an Italian cohort of 10 patients.

Type 3 von Willebrand disease (VWD3) is characterized by unmeasurable von Willebrand factor (VWF) levels in plasma and platelets and severe but variable hemorrhagic symptoms. To identify and characterize the causal mutations, we screened 10 Italian patients with VWD3 by several techniques including Multiplex Ligation-dependent Probe Amplification to identify large insertions and deletions, High Resolution Melting and PCR coupled with Sanger sequencing. Fourteen different mutations scattered throughout the VWF gene were identified, 10 of which were novel.

Circulating and progenitor endothelial cells are abnormal in patients with different types of von Willebrand disease and correlate with markers of angiogenesis.

von Willebrand disease (VWD) is the most common inherited bleeding disorder and is caused by quantitative or qualitative defects of von Willebrand factor (VWF). VWF, synthesized by endothelium and megakaryocytes (MK), circulates in plasma and is present in subendothelium and platelets. Circulating endothelial cells (CEC) and progenitor endothelial cells (EPC) have been recently proposed as markers of peripheral and bone marrow-derived angiogenesis.

Abnormal VWF modifies megakaryocytopoiesis: studies of platelets and megakaryocyte cultures from patients with von Willebrand disease type 2B.

von Willebrand factor (VWF) is an essential mediator of platelet adhesion to the vessel wall, but little is known about its role in megakaryocytopoiesis. VWF and its platelet receptor, glycoprotein Ibalpha (GPIbalpha), are both expressed during megakaryocyte (MK) maturation. This study was designed to evaluate whether the enhanced VWF-GPIbalpha interactions typical of patients with von Willebrand disease type 2B (VWD2B) modify platelet production.