Bingquan Zhu,1,* Junfei Zhu,2,3,* Lingyan Sheng,2 Yake Yao,2 Hua Zhou2 

1Children’s Health Care Department, The Children’s Hospital, Zhejiang University School of Medicine, Hangzhou, 310003, People’s Republic of China; 2Department of Respiratory and Critical Care Medicine, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, 310003, People’s Republic of China; 3Department of Respiratory and Critical Care Medicine, Taizhou Central Hospital, Taizhou, 324110, People’s Republic of China

*These authors contributed equally to this work

Correspondence: Hua Zhou; Yake Yao, Email zhouhua1@zju.edu.cn; dryyk@zju.edu.cn

Background: Aspergillus-specific IgG antibody test is considered to be the most reliable method for diagnosing chronic pulmonary aspergillosis (CPA), while its diagnostic roles in different kinds of CPA are still uncertain and it is a challenge of having a threshold to interpret the IgG levels.
Purpose: This study aimed to evaluate the diagnostic value of the Dynamiker quantitative Aspergillus fumigatus-specific IgG antibody in different types of CPA with the aim of providing a reference for clinical work.
Methods: This prospective study collected the clinical data of patients with suspected CPA admitted to the hospital from January 2020 to December 2022 and divided them into two groups: CPA and non-CPA. The study analyzed clinical characteristics and Aspergillus-specific IgG antibody test’s diagnostic value, and a receiver operating characteristic (ROC) curve was used to evaluate diagnostic efficacy.
Results: We enrolled 54 CPA patients and 132 non-CPA patients. The average admission age of the CPA group was 61.0 (43.8, 70.0) years, and the sex ratio was 32/22 (male/female). The level of Aspergillus fumigatus-specific IgG antibody in the CPA group was significantly higher than the non-CPA group (95.2 (31.3, 213.3) vs 47.5 (34.0, 80.3) AU/mL, p = 0.001). The area under the ROC curve was 0.653 (95% confidence interval [CI]: 0.580– 0.721, p = 0.003). The cutoff with the best diagnostic efficacy was 87 AU/mL, and the sensitivity and specificity were 57.4% and 77.3%, respectively. There was no significant difference in the level of specific IgG antibody among the five CPA types (p = 0.543); however, it was relatively higher in chronic cavitary pulmonary aspergillosis (CCPA).
Conclusion: Aspergillus-specific IgG antibody is valuable diagnostic marker for CPA, while its value in differential diagnosis among different types of CPA is limited.

Keywords: Aspergillus, chronic pulmonary aspergillosis, IgG, subtypes, diagnosis