Optimal Aspergillus fumigatus and Asp f 1 serum IgG cut-offs for the diagnosis of allergic bronchopulmonary aspergillosis

• Hamada Yuto

  Clinical Research Center for Allergy and Rheumatology, National Hospital Organization Sagamihara National Hospital Course of Allergy and Clinical Immunology, Juntendo University Graduate School of Medicine

• Fukutomi Yuma

  Clinical Research Center for Allergy and Rheumatology, National Hospital Organization Sagamihara National Hospital Course of Allergy and Clinical Immunology, Juntendo University Graduate School of Medicine

• Nakatani Eiji

  Division of Statistical Analysis, Research Support Center, Shizuoka General Hospital

• Saito Akemi

  Clinical Research Center for Allergy and Rheumatology, National Hospital Organization Sagamihara National Hospital

• Watai Kentaro

  Clinical Research Center for Allergy and Rheumatology, National Hospital Organization Sagamihara National Hospital

• Kamide Yosuke

  Clinical Research Center for Allergy and Rheumatology, National Hospital Organization Sagamihara National Hospital

• Sekiya Kiyoshi

  Clinical Research Center for Allergy and Rheumatology, National Hospital Organization Sagamihara National Hospital

• Nagai Tadashi

  Central Blood Institute, Japanese Red Cross Society

• Harada Kazuki

  Division of Pulmonary Medicine, Department of Medicine, Tokai University School of Medicine

• Shiraishi Yoshiki

  Division of Pulmonary Medicine, Department of Medicine, Tokai University School of Medicine

• Oguma Tsuyoshi

  Division of Pulmonary Medicine, Department of Medicine, Tokai University School of Medicine

• Asano Koichiro

  Division of Pulmonary Medicine, Department of Medicine, Tokai University School of Medicine

• Taniguchi Masami

  Clinical Research Center for Allergy and Rheumatology, National Hospital Organization Sagamihara National Hospital Course of Allergy and Clinical Immunology, Juntendo University Graduate School of Medicine Center for Immunology and Allergology, Shonan Kamakura General Hospital

Abstract

Background: The presence of IgG antibodies (Abs) to Aspergillus fumigatus (Af) is a crucial diagnostic criterion for allergic bronchopulmonary aspergillosis (ABPA). Although precipitation is traditionally used to document IgG Abs, anti-Af serum IgG levels can also be measured by enzyme immunoassay (EIA). However, there are insufficient data on the optimal cut-offs to assess diagnostic performance of the EIA method. This study aimed to determine cut-off levels of IgG binding crude Af extracts or recombinant Asp f 1 (by ImmunoCAP®) and to compare their efficacy for ABPA diagnosis with Af-precipitating Abs. Methods: The age distribution of levels of IgG to crude extracts of Af (Af-IgG) and recombinant Asp f 1 (Asp f 1-IgG) was established using sera from 694 healthy controls (HC). Receiver operating characteristic analysis for Af-IgG and Asp f 1-IgG levels for the purpose of ABPA diagnosis was performed in 306 Af-sensitized asthma patients (including 49 ABPA), and cut-offs were determined. Results: An age-dependent decline in the levels of Af-IgG was observed in HC. Thus, cut-offs for Af-IgG levels were determined separately by age as 60 mg/L for patients aged <55 years, and 45 mg/L for those aged ≥55 years. For Asp f 1-IgG, 6.6 mg/L was set as the cut-off regardless of age. Although such IgG testing by EIA allowed a sufficiently good diagnostic performance, Af-precipitating Abs had better diagnostic applicability for ABPA. Conclusions: We determined cut-offs for Af-IgG and Asp f 1-IgG measured by EIA, which can be useful in clinical settings where precipitating Abs are unavailable.

Journal

• Allergology International

  Allergology International 70 (1), 74-80, 2021

  Japanese Society of Allergology

Keywords

• Allergic bronchopulmonary aspergillosis
• Asp f 1
• Cut-off
• IgG
• Precipitin

Details

• CRID: 1391412881281336448
• NII Article ID: 130007966764
• DOI: 10.1016/j.alit.2020.07.006
• ISSN: 14401592
• ISSN: 13238930
• Web Site: https://api.elsevier.com/content/article/PII:S132389302030099X?httpAccept=text/xml
• Web Site: https://api.elsevier.com/content/article/PII:S132389302030099X?httpAccept=text/plain
• Web Site: https://search.jamas.or.jp/link/ui/2021283428
• Text Lang: en
• Data Source:
  • JaLC
  • Crossref
  • CiNii Articles
  • KAKEN
• Abstract License Flag: Disallowed