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CME Evaluation

Oral Communication Session

Platelet Disorders

Session: Inherited platelet disorders - Functional analysis

OC 55.2 - Diagnosing inherited platelet disorders using immunofluorescence-microscopy on the peripheral blood smear: preliminary results from the first international workshop

Tuesday, June 25, 2024
09:45 – 10:00 ICT
Room: 110 A-C

    Presenting Author(s)

  • Carlo Zaninetti, MD, PhD

    Medical Doctor
    Institut für Transfusionsmedizin, Universitätsmedizin Greifswald, Germany
    Greifswald, Mecklenburg-Vorpommern, Germany

    • Co-Author(s)

  • José Rivera, PhD

    Facultative-Senior investigator
    Servicio de Hematología y Oncología Médica-HU Morales Meseguer-Centro Regional de Hemodonación-CIBERER-ISCIII-CB15/00055, IMIB-Pascual Parrilla, Universidad de Murcia, Murcia, Spain.#Grupo Español de Alteraciones Plaquetarias Congénitas (GEAPC) de la SETH
    MURCIA, Murcia, Spain

  • Loredana Bury

    Scientist
    Department of Medicine and Surgery, Section of Internal and Cardiovascular Medicine, University of Perugia, Perugia, Italy
    Perugia, Umbria, Italy

  • VB

    Valeria Bozzi

    Scientist
    Department of Internal Medicine, University of Pavia, Pavia, Italy
    Pavia, Lombardia, Italy

  • Karina Althaus, MD

    MD
    Center for Clinical Transfusion Medicine, University Hospital Tuebingen
    Tuebingen, Baden-Wurttemberg, Germany

  • SB

    Simon A. Brown

    Medical Doctor
    Department of Haematology, Pathology Queensland, Centre for Children’s Health and Research (CCHR), South Brisbane, Australia.
    Brisbane, Queensland, Australia

  • Dorothée Faille

    Medical Doctor
    Université Paris Cité, INSERM, U1148, F-75018 Paris
    Paris, Ile-de-France, France

  • AS

    Alain Stepanian

    Medical Doctor
    AP-HP, Service d'Hématologie Biologique, Hôpital Lariboisière, Paris Cité University, Paris, France
    Paris, Ile-de-France, France

  • Ana Zamora-Cánovas

    PhD studeny
    Servicio de Hematología y Oncología Médica-HU Morales Meseguer-Centro Regional de Hemodonación-CIBERER-ISCIII-CB15/00055, IMIB-Pascual Parrilla, Universidad de Murcia, Murcia, Spain
    Murcia, Murcia, Spain

  • AN

    Andrew Norman

    Researcher
    Department of Haematology, Pathology Queensland, Centre for Children’s Health and Research (CCHR), South Brisbane, Australia.
    Brisbane, Queensland, Australia

  • CF

    Carmen Freyer

    Scientific assistant
    Institut für Transfusionsmedizin, Universitätsmedizin Greifswald, Germany
    Grei, Mecklenburg-Vorpommern, Germany

  • Tamam Bakchoul, Professor MD

    Medical Director
    Center for Clinical and Experimental Transfusion Medicine, University Hospital of Tuebingen
    Tuebingen, Baden-Wurttemberg, Germany

  • AP

    Alessandro Pecci

    Professor
    Department of Internal Medicine, University of Pavia, Pavia, Italy
    Pavia, Lombardia, Italy

  • PG

    Paola Gresele, MD, PhD

    University of Perugia, Italy

  • TT

    Thomas Thiele

    Professor of Transfusion Medicine
    Institut für Transfusionsmedizin, Universitätsmedizin Greifswald, Germany
    Greifswald, Mecklenburg-Vorpommern, Germany

  • Andreas Greinacher

    Senior Professor
    Institut für Transfusionsmedizin, Universitätsmedizin Greifswald, Germany
    Greifswald, Mecklenburg-Vorpommern, Germany

Background: Diagnosing inherited platelet disorders (IPD) is challenging and benefits from multidisciplinary phenotyping of suspected patients. We have established an immunofluorescence-based method for phenotyping platelets on the blood smear and proposed it as a screening-tool for IPD. The method was validated through comparison with molecular testing for 9 disorders, for which typical changes of platelet structure can be detected. However, an interlaboratory-validation of the method has not been performed.

Aims: To perform an interlaboratory-validation workshop of immunofluorescence microscopy on the blood smear for IPD diagnosis.

Methods: Unstained and unfixed air-dried blood smears prepared in the Greifswald laboratory were shipped by regular mail to each participating Center, where they were fixed and stored at -20°C upon delivery. Subsequently, the slides were stained using a standard panel of 13 mouse and rabbit anti-human primary antibodies against different platelet structures (granules, surface glycoproteins, cytoskeletal markers, CD34), and 2 fluorescence-labelled secondary antibodies. Each Center performed the investigation independently, reported the results according to a defined evaluation-grid and documented the possible obtained diagnosis.

Results: Six European and one Australian Center participated in the workshop. By investigating blood smears from healthy controls, the reproducibility of the staining- and observation method was initially ensured. Subsequently, slides from healthy controls or patients with genetically-confirmed IPD were blindly shipped to each Laboratory, which independently performed their investigation. All (7/7) participant Centers correctly predicted the diagnosis of MYH9-related thrombocytopenia, 6/7 of Bernard-Soulier syndrome, 6/7 of cytoskeletal platelet defect, and 5/7 of delta storage-pool disorder. The workshop is ongoing, final results will be presented at the ISTH meeting.

Conclusion(s): We confirmed the technical reproducibility of immunofluorescence on the blood smear even when performed for the first time by some laboratories. Even in the multicenter workshop setting, the method provides reproducible results. Additional training is expected to further increase sensitivity and specificity.