Okamoto Shuichi, Suzuki Atsuo, Tamura Shogo, Suzuki Nobuaki, Kanematsu Takeshi, Suzuki Naruko, Kawaguchi Yoshino, Katsumi Akira, Hayakawa Fumihiko, Kiyoi Hitoshi, Kojima Tetsuhito, Matsushita Tadashi
Department of Laboratory Medicine, Nagoya University Hospital, Nagoya, Japan.
Division of Cellular and Genetic Sciences, Department of Integrated Health Sciences, Nagoya University Graduate School of Medicine, 1-1-20 Daiko-Minami, Higashi-ku, Nagoya, Aichi, 466-8560, Japan.
Int J Hematol. 2025 Jan;121(1):131-136. doi: 10.1007/s12185-024-03861-6. Epub 2024 Oct 24.
In the diagnosis and treatment of acquired von Willebrand syndrome (AVWS), von Willebrand factor (VWF) antigen levels (VWF:Ag) are helpful for quantifying blood VWF-protein levels. Most clinical laboratories measure VWF:Ag by latex immunoassay (LIA), but underlying diseases of AVWS may influence LIA results. A 60 year-old AVWS patient with immunoglobulin G (IgG) kappa-type monoclonal gammopathy of undetermined significance (MGUS) showed reduced VWF activity but normal levels of VWF:Ag. His VWF multimers were broadly decreased, which represented a large discrepancy with VWF:Ag. To investigate the mechanism of this discrepancy, we measured the patient's plasma VWF:Ag by in-house enzyme-linked immunosorbent assay (ELISA) and LIA. We also purified the IgG fraction from the patient's serum and measured VWF:Ag in VWF-deficient plasma supplemented with this fraction. VWF:Ag measured by in-house ELISA (VWF:Ag) was much lower than that measured by LIA (VWF:Ag), which indicated reduced VWF-protein volume in blood. Indeed, VWF:Ag was detected by LIA in VWF-deficient plasma spiked with a patient-derived IgG fraction. These results suggest that LIA detected a non-specific immunoreaction and overestimated the patient's VWF:Ag. Clinicians should be aware that underlying diseases of AVWS could influence the LIA system, and interpret VWF:Ag cautiously.
在获得性血管性血友病综合征（AVWS）的诊断和治疗中，血管性血友病因子（VWF）抗原水平（VWF:Ag）有助于量化血液中的VWF蛋白水平。大多数临床实验室通过乳胶免疫测定法（LIA）检测VWF:Ag，但AVWS的基础疾病可能会影响LIA结果。一名60岁患有意义未明的免疫球蛋白G（IgG）κ型单克隆丙种球蛋白病（MGUS）的AVWS患者，其VWF活性降低，但VWF:Ag水平正常。他的VWF多聚体广泛减少，这与VWF:Ag存在很大差异。为了研究这种差异的机制，我们通过内部酶联免疫吸附测定法（ELISA）和LIA检测了患者的血浆VWF:Ag。我们还从患者血清中纯化了IgG组分，并在补充了该组分的VWF缺乏血浆中检测VWF:Ag。通过内部ELISA检测的VWF:Ag（VWF:Ag）远低于通过LIA检测的结果（VWF:Ag），这表明血液中VWF蛋白量减少。实际上，在添加了患者来源的IgG组分的VWF缺乏血浆中，LIA检测到了VWF:Ag。这些结果表明，LIA检测到了非特异性免疫反应，并高估了患者的VWF:Ag。临床医生应意识到，AVWS的基础疾病可能会影响LIA系统，并谨慎解读VWF:Ag。
