{
  "abstract": "Background\n\nType 2B von Willebrand disease (VWD) is caused by gain-of-function variants in the A1 domain of von Willebrand factor (VWF), leading to increased platelet binding, loss of high-molecular-weight multimers, and sometimes thrombocytopenia. Conventional diagnosis relies on ristocetin-induced platelet agglutination or molecular testing.Aim\n\nTo evaluate an in-house enzyme-linked immunosorbent assay (ELISA) based on a recombinant glycoprotein Ib wild-type (rGPIb-WT) fragment and ristocetin, as a screening tool to identify first-time referral patients requiring further evaluation for possible type 2B VWD.Materials and methods\n\nPlasma from 131 healthy controls and 31 type 2B patients was analyzed using rGPIb-WT ELISA at ristocetin concentrations of 0.06, 0.09, and 0.12 mg/mL. Optical density ratios of plasma sample to normal pooled plasma were used to generate receiver operating characteristic curves and define screening cut-offs. Plasma from 254 first-time referrals was tested. Positive samples were evaluated for platelet-dependent VWF activity over VWF antigen ratio (VWF:GPIbR/VWF:Ag) and VWF multimers. Candidate patients underwent VWF exon 28 Sanger sequencing.Results\n\nTwenty-six of 254 patients tested positive at least at 1 ristocetin concentration. Sixteen were considered candidates for type 2B VWD evaluation based on a VWF:GPIbR/VWF:Ag ratio <0.7 and/or an abnormal multimeric pattern. Type 2B variants were found in 12 of 16 sequenced patients. The remaining 10 patients showed ultra-large multimers or an increased proportion of high-molecular-weight multimers; 8 of these had a normal VWF:GPIbR/VWF:Ag ratio (>0.7).Discussion\n\nThe rGPIb-WT ELISA positivity may reflect type 2B variants or the presence of larger multimers. Integrated with conventional assays, positivity may guide type 2B-directed evaluation.",
  "abstract_shown": true,
  "affiliations": [
    "Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Angelo Bianchi Bonomi Hemophilia and Thrombosis Center, Milan, Italy.",
    "Università degli Studi di Milano, Department of Pathophysiology and Transplantation, Milan, Italy."
  ],
  "article_type": "research article",
  "arxiv": null,
  "author_total": 8,
  "authors": [
    {
      "affs": [
        0
      ],
      "name": "Maria Teresa Pagliari",
      "orcid": "0000-0003-0778-2271"
    },
    {
      "affs": [
        0
      ],
      "name": "Luciano Baronciani"
    },
    {
      "affs": [
        0
      ],
      "name": "Paola Colpani",
      "orcid": "0000-0003-4180-6011"
    },
    {
      "affs": [
        0
      ],
      "name": "Giovanna Cozzi",
      "orcid": "0000-0002-0267-3773"
    },
    {
      "affs": [
        0
      ],
      "name": "Omid Seidizadeh",
      "orcid": "0000-0002-6630-7879"
    },
    {
      "affs": [
        0
      ],
      "name": "Alessandro Ciavarella"
    },
    {
      "affs": [
        0
      ],
      "name": "Simona Maria Siboni",
      "orcid": "0000-0002-8456-7519"
    },
    {
      "affs": [
        0,
        1
      ],
      "name": "Flora Peyvandi",
      "orcid": "0000-0001-7423-9864"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/eq91rb8wg30vn.bib",
  "cited_by": 0,
  "doi": "10.1016/j.rpth.2026.106971",
  "fulltext_url": "https://europepmc.org/articles/PMC13694992",
  "id": "eq91rb8wg30vn",
  "issns": [
    "2475-0379"
  ],
  "landing_url": "https://europepmc.org/article/MED/42927241",
  "language": "eng",
  "licence": "CC-BY-NC-ND",
  "licence_label": "CC BY-NC-ND",
  "licence_source": "article",
  "licence_url": "https://creativecommons.org/licenses/by-nc-nd/4.0/",
  "metadata_licence": null,
  "native_subjects": [
    [
      "openalex",
      "2720|Platelet Disorders and Treatments"
    ]
  ],
  "openalex": "W7213548800",
  "pdf_url": "https://europepmc.org/articles/PMC13694992?pdf=render",
  "pmcid": "PMC13694992",
  "pmid": "42927241",
  "published": "2026-09-18",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/eq91rb8wg30vn.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:21:18Z",
      "native_id": "MED:42927241",
      "source": "europepmc",
      "url": "https://europepmc.org/article/MED/42927241"
    }
  ],
  "subjects": [
    {
      "field": "medicine",
      "origin": "openalex:2720|Platelet Disorders and Treatments",
      "subfield": "general"
    }
  ],
  "title": "A screening assay for type 2B von Willebrand factor variants using an enzyme-linked immunosorbent assay based on recombinant wild-type glycoprotein Ib and ristocetin.",
  "title_text": "A screening assay for type 2B von Willebrand factor variants using an enzyme-linked immunosorbent assay based on recombinant wild-type glycoprotein Ib and ristocetin.",
  "type": "peer-reviewed",
  "updated_at": "2026-10-30T12:21:18Z",
  "url": "https://research.draconitic.com/paper/eq91rb8wg30vn",
  "venue": "Research and practice in thrombosis and haemostasis",
  "versions": []
}