Prospective study of the serum Aspergillus-specific IgG, IgA and IgM assays for chronic pulmonary aspergillosis diagnosis

Xiuqing Ma,Xiaotian Yu,Lixin Xie,Xin Zhao,David W Denning,Yanqin Li,Chunsun Li,Yang Liu,Kaifei Wang

doi:10.1186/s12879-019-4303-x

Abstract

BackgroundChronic pulmonary aspergillosis (CPA) is an underdiagnosed and misdiagnosed disease and now increasingly recognised. However, the diagnosis of CPA remains challenging. In this study, we aimed to investigate the diagnostic values of serum Aspergillus-specific IgG, IgA and IgM antibodies in patients with CPA.MethodsThe prospective study was performed at Chinese People’s Liberation Army General Hospital in Beijing, from January 2017 to December 2017. Adult patients with lung lesions presented as cavity, nodule, mass, bronchiectasis or severe fibrotic destruction with at least two lobes in CT imaging were enrolled. One hundred healthy persons were also enrolled as additional controls. The serum levels of Aspergillus-specific IgG, IgA and IgM antibodies and galactomannan (GM) levels were measured simultaneously by plate ELISA kit.ResultsA total of 202 patients were enrolled in this study, including 42 CPA patients, 60 non-CPA patients and 100 healthy persons. The most common underlying lung diseases in CPA patients were bronchiectasis (28.6%) and COPD (19.0%). The most common symptoms in the CPA patients were cough (76.2%), sputum (71.4%), and fever (45.2%); chest pain (4.8%) was infrequent. Receiver operating characteristic (ROC) curve analysis revealed that the optimal CPA diagnostic cut-off of Aspergillus-specific IgG, IgA and IgM assays and GM test were 89.3 AU/mL, 8.2 U/mL, 73.3 AU/mL and 0.5μg/L, respectively. The serum levels of Aspergillus-specific IgG and IgA in CPA patients were higher than these in non-CPA patients or healthy persons. The sensitivities and specificities of Aspergillus-specific IgG, IgA, IgM tests and GM test were 78.6 and 94.4%, 64.3 and 89.4%, 50.0 and 53.7% and 71.4 and 58.1%, respectively.ConclusionsThe sensitivity and specificity of serum Aspergillus-specific IgG assay are satisfactory for diagnosing CPA, while the performance of Aspergillus-specific IgA assay is moderate. Aspergillus-specific IgM assay and serum GM test have limited value for CPA diagnosis.Trial registrationNCT03027089. Registered 20 January 2017.

Highlights

Chronic pulmonary aspergillosis (CPA) is an underdiagnosed and misdiagnosed disease and increasingly recognised
Chronic pulmonary aspergillosis (CPA) usually occurs in immunocompetent individuals with pre-existing chronic pulmonary disease, especially those leading to a structural lung damage such as pulmonary tuberculosis (PTB), chronic obstructive pulmonary disease (COPD), and bronchiectasis [1,2,3,4]
There were no statistical differences in C-reactive protein (CRP) concentration, white blood cell (WBC) count, neutrophil percentage, and lymphocyte percentage of peripheral blood between CPA group and non-CPA group, P > 0.05 (Fig. 2)

Summary

Introduction

Chronic pulmonary aspergillosis (CPA) is an underdiagnosed and misdiagnosed disease and increasingly recognised. We aimed to investigate the diagnostic values of serum Aspergillus-specific IgG, IgA and IgM antibodies in patients with CPA. In China, the estimated annual CPA cases after PTB are more than 67,000, but most of the cases are undiagnosed due to lack of efficient diagnostic methods in routine practice [1]. CPA diagnosis requires a combination of characteristic clinical and radiological findings together with demonstration of Aspergillus infection with growth of Aspergillus spp. on culture or the presence of elevated levels of Aspergillus antibody.

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