Agarwal Ritesh, Muthu Valliappan, Sehgal Inderpaul Singh, Prasad Kuruswamy Thurai, Dhooria Sahajal, Singh Mani, Garg Mandeep, Aggarwal Ashutosh N, Rudramurthy Shivaprakash M, Chakrabarti Arunaloke
Department of Pulmonary Medicine, Postgraduate Institute of Medical Education and Research (PGIMER), Chandigarh, India.
Department of Radiodiagnosis, Postgraduate Institute of Medical Education and Research (PGIMER), Chandigarh, India.
Mycoses. 2025 Jul;68(7):e70087. doi: 10.1111/myc.70087.
The diagnostic cut-off values for IgG antibodies against recombinant Aspergillus fumigatus (rAsp) antigens in allergic bronchopulmonary aspergillosis (ABPA) remain unclear.
To derive and validate diagnostic cut-offs for IgG antibodies against rAsp f 1, f 2 and f 4 in ABPA and assess their diagnostic performance in distinguishing ABPA from asthma.
In this case-control study, we prospectively enrolled consecutive subjects with asthma and ABPA. We measured serum IgG levels against rAsp f 1, rAsp f 2 and rAsp f 4 using a fluorescent enzyme immunoassay. Subjects were randomly split into derivation (50%) and validation (50%) cohorts. Cut-offs were derived using receiver operating characteristic (ROC) curves and Youden's index. Additionally, we performed Bayesian latent class analysis (BLCA) using two-component Gaussian mixture models to derive unbiased cut-offs. Diagnostic performance was assessed using sensitivity, specificity and the area under the ROC curve (AUROC).
Of 375 participants, 261 had ABPA and 114 had asthma. ROC-derived AUROC values for rAsp f 1, f 2 and f 4-IgG were 0.63, 0.47 and 0.52, while the cut-off values were 10.1 mgA/L, 10.3 mgA/L and 10.5 mgA/L, respectively. Sensitivity was ≤ 42% for all antigens, while specificity exceeded 89%. BLCA yielded cut-offs of 18.6, 14.9 and 13.7 mgA/L for f 1, f 2 and f 4, respectively, with similarly poor sensitivity and high specificity.
IgG antibodies against rAsp f 1, f 2 and f 4 exhibit high specificity but poor sensitivity in identifying ABPA, limiting their utility as standalone diagnostic markers.
过敏性支气管肺曲霉病（ABPA）中针对重组烟曲霉（rAsp）抗原的IgG抗体诊断临界值仍不明确。
得出并验证ABPA中针对rAsp f1、f2和f4的IgG抗体诊断临界值，并评估其在区分ABPA与哮喘方面的诊断性能。
在这项病例对照研究中，我们前瞻性纳入了连续的哮喘和ABPA患者。我们使用荧光酶免疫测定法测量血清中针对rAsp f1、rAsp f2和rAsp f4的IgG水平。受试者被随机分为推导队列（50%）和验证队列（50%）。使用受试者工作特征（ROC）曲线和尤登指数得出临界值。此外，我们使用双组分高斯混合模型进行贝叶斯潜在类别分析（BLCA）以得出无偏临界值。使用敏感性、特异性和ROC曲线下面积（AUROC）评估诊断性能。
在375名参与者中，261人患有ABPA，114人患有哮喘。rAsp f1、f2和f4-IgG的ROC推导AUROC值分别为0.63、0.47和0.52，而临界值分别为10.1 mgA/L、10.3 mgA/L和10.5 mgA/L。所有抗原的敏感性均≤42%，而特异性超过89%。BLCA得出f1、f2和f4的临界值分别为18.6、14.9和13.7 mgA/L，敏感性同样较差但特异性较高。
针对rAsp f1、f2和f4的IgG抗体在识别ABPA方面表现出高特异性但低敏感性，限制了它们作为独立诊断标志物的效用。
