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Completed

NCT Number: NCT04095715

Anomalies of Dense Platelet Granules

The study aims to know the overall prevalence of granular deficits and their breakdown by type (anomaly of number, content or secretion) in a population of patients with hemorrhagic symptomatology after exclusion of other known causes.

This study consists also to evaluate the association between the presence of a deficit in dense granules and (1) the intensity of the hemorrhagic phenotype (hemorrhagic score) (2) the nature of hemorrhages (post-operative, spontaneous, atypical...)

-Evaluate the association between the type of deficit in dense granules and (1) the intensity of the hemorrhagic phenotype (hemorrhagic score) (2) the nature of hemorrhages (post-operative, spontaneous, atypical...)

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Key information

Age range

2 year and older

Sex eligibility

All sexes

Study type

Observational

Primary location

Hôpital Necker Enfants Malades - AP-HP

Paris, 75015, France

About this study

Patients will be recruited during the exploration visit (v0) or the confirmation/typing visit (v1) according to their follow-up.

  • Exploration visit (v0): inclusion of patients without prior platelet exploration, and study of their dense platelet granules.
  • Confirmation/typing visit (v1): verification of the persistence of anomalies detected in patients with an abnormality identified during v0 (no later than 6 months after v0) and in patients for whom a dense granules anomaly has already been identified during their standard management prior to the start of the study. Completion of complementary examinations to complement the typing of the granular anomaly and molecular analysis for family cases

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Adult or child patient ≥ 2 years
  • Having a hemorrhagic score ISTH > 3 for men, > 5 for women and > 2 for children.
  • With no abnormal coagulation (defined by normal TP and TCK or activity ≥ 50% of FII, FV, FVII, FX, FVIII, FIX, FXI)
  • no deficiency of Willebrand factor (defined by a cofactor activity with Ristoctin (VWF: RCo < 50%))
  • no a known major thrombocytopenia/thrombopathy linked to a deficiency of one of the major platelet receptors
  • Information of the patient and/or his legal representative present

Exclusion criteria

  • Inability or refusal of compliance with research requirements
  • Thrombocytopenia < 100 G/L
  • Treatments interfering with platelet functions within 10 days prior to inclusion
  • Malignant hemopathy

Treatment and study plan

Haemostasis consultation

Other

Haemostasis consultation

Standard management of patients suspected of thrombopathy

Biological

Standard management of patients suspected of thrombopathy

Primary outcomes

  1. Platelet response to different agonists

    Time frame: Baseline (M0)

    Us of some low-dose agonists such as ADP, epinephrine or collagen, which are particularly susceptible to granular defects, on platelet-rich plasma (PRP) prepared from the patient's blood sample to be explored

  2. Platelet response to different agonists

    Time frame: At 6 months

    Use of some low-dose agonists such as ADP, epinephrine or collagen, which are particularly susceptible to granular defects, on platelet-rich plasma (PRP) prepared from the patient's blood sample to be explored

  3. Granular Delta content

    Time frame: Baseline (M0)

    Dosage of platelet serotonin by measuring platelet serotonin by HPLC.

  4. Measurement of ATP

    Time frame: Baseline (M0)

    The measurement is based on the principle of bioluminescence with a two-step transformation reaction of luciferin in the presence of luciferase, this reaction requiring the presence of ATP

  5. Measurement of ATP

    Time frame: At 6 months

    The measurement is based on the principle of bioluminescence with a two-step transformation reaction of luciferin in the presence of luciferase, this reaction requiring the presence of ATP

  6. Measurement of granules opacity

    Time frame: Baseline (M0)

    Delta granules contain calcium, which makes them naturally opaque to electrons and thus allows their direct visualization in electronic microscopy.

  7. Measurement of granules opacity

    Time frame: at 6 months

    Delta granules contain calcium, which makes them naturally opaque to electrons and thus allows their direct visualization in electronic microscopy.

Secondary outcomes

  1. Hemorrhagic risk assessment

    Time frame: Baseline (M0)

    Evaluation using the ISTH score

  2. Typage of delta granules anomalies

    Time frame: At 6 months

    Fib-SEM technic by focussed ion beam scanning which allows a 3D reconstitution of the platelets and thus to visualize any empty granules

  3. Genetic anomalies of delta granules

    Time frame: At 6 months

    Sequencing on a broad set of genes involved in platelet function. Bioinformatic analysis is carried out using BWA-MEM software (Alignment on the genome version HG19)

  4. Prothrombin consumption

    Time frame: Baseline (M0)

    Evaluated by% of residual Thrombin after plasma coagulation

  5. Prothrombin consumption

    Time frame: at 6 months

    Evaluated by% of residual Thrombin after plasma coagulation

Sponsors and collaborators

Lead sponsor

Assistance Publique - Hôpitaux de Paris

Other

Collaborators

  • Assistance Publique Hopitaux De Marseille
  • CENTRE DE REFERENCE DES MALADIES HEMORRAGIQUES CONSTITUTIONNELLES
  • URC-CIC Paris Descartes Necker Cochin

Registry information

Official study title

Diagnosis of Platelet Dense Granules Anomalies in Unexplained Hemorrhagic Syndromes

Acronym: AGRAD

Important dates

Study start
2019
Primary completion
2023
Study completion
2023
First posted
Sep 19, 2019
Registry last updated
Mar 23, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.