Abstract
BackgroundChronic pulmonary aspergillosis (CPA) has a high rate of misdiagnosis and has been reported to have an increasing rate of morbidity and mortality. In this article, we assessed the serum Aspergillus-specific IgG and IgM test in the diagnosis of patients with CPA.MethodsA prospective study was conducted from January 2016 to July 2017 in Nanjing Jinling Hospital. Serum samples were collected from CPA patients (178 sera, 82 patients) and from non-aspergillosis patients (125 sera) with community-acquired pneumonia (CAP), active tuberculosis, bronchiectasis or lung tumors. Additionally, we included a control group of healthy patients(50 sera). Aspergillus-specific antibody detection was performed using a Dynamiker ELISA kit, and the results were compared with the value of galactomannan (GM) in bronchoalveolar lavage fluid (BALF).ResultsThe sensitivity and specificity of the Aspergillus-specific IgG antibody in the diagnosis of CPA were 84.1 and 89.6%, respectively. These values were slightly higher compared to those obtained for the sensitivity and specificity using the BALF GM test (79.1 and 84.2%, respectively). However, the sensitivity and specificity of Aspergillus-specific IgM antibody were only 43.9 and 87.2%, respectively. Moreover, the positive rate of IgG in patients with subacute invasive aspergillosis (SAIA) was 87%, compared to the positive rates of IgG in CPA patients sick for 3–6 months (80.0%), 6–9 months (81.8%) and ≥9 months (80.0%). Meanwhile, the positive rate of IgM in SAIA patients was 63%, compared to the positive rate of IgM in CPA patients sick for 3–6 months (46.7%), 6–9 months (0%) and ≥9 months (0%), respectively. Furthermore, serum IgG levels decreased gradually in the majority of CPA patients who showed positive response to antifungal therapy, and IgG levels increased in two CPA patients when their disease worsened.ConclusionA serum Aspergillus-specific IgG test is a valuable tool for the diagnosis of CPA and SAIA, while an Aspergillus-specific IgM test is only modestly specific for the diagnosis of SAIA. Overall, the variation trend of Aspergillus-specific IgG levels may reflect the therapeutic effectiveness in the long-term follow-up of CPA.
Highlights
Chronic pulmonary aspergillosis has been increasingly reported in patients with underlying respiratory disorders, such as chronic obstructive pulmonary disease (COPD), cavitary pulmonary tuberculosis, and bronchiectasis, and in patients given glucocorticoids or immunosuppressants (Garnacho-Montero et al, 2005; Wichmann and Kluge, 2013; Denning et al, 2015; Yan et al, 2016)
Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were calculated to evaluate the diagnostic value of serum aspergillus-specific IgG (As-IgG) and aspergillus-specific IgM (As-IgM) test and Bronchoalveolar Lavage Fluid (BALF) GM test in patients with Chronic pulmonary aspergillosis (CPA)
The GM test based on sputum samples is an exploratory method for the diagnosis of pulmonary Aspergillus infection, there is little evidence documenting its effectiveness in the CPA diagnosis and the clinical application of sputum GM test remains controversial (Kimura et al, 2009; Fayemiwo et al, 2017)
Summary
Chronic pulmonary aspergillosis has been increasingly reported in patients with underlying respiratory disorders, such as COPD, cavitary pulmonary tuberculosis, and bronchiectasis, and in patients given glucocorticoids or immunosuppressants (Garnacho-Montero et al, 2005; Wichmann and Kluge, 2013; Denning et al, 2015; Yan et al, 2016). Because of the relatively intact immune system, these patients often display atypical symptoms coupled with non-standard imaging results, making the early diagnosis difficult. For this reason, many diagnostic methods have been developed to identify fungal infection including biopsy collection or cell culture, detection of the fungal cell wall component, polymerase chain reaction for fungal genes and antibody detection. Previous studies did not address whether As-IgG and As-IgM could be used to monitor the treatment response in patients with CPA. We explored the diagnostic value of As-IgG and As-IgM using the Dynamiker assay using CPA samples and examined the results in the context of treatment response monitoring. We assessed the serum Aspergillus-specific IgG and IgM test in the diagnosis of patients with CPA
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