Oladele Rita O, Otu Akaninyene A, Balogun Oluwaseyi J, Babalola Oladayo M, Nwosu Augustina O, Iyabo Osaigbovo Iriagbonse, Gbajabiamila Titilayo, Irurhe Nicholas K, Fayemiwo Samuel A, Shettima Shuwaram A, Uwaezuoke Nkolika Stella, Edwin Chinagozi Precious, Ayanbeku Toyese Stephen, Okaa Joy U, Elikwu Charles John, Denning David W, Kanki Phyllis J, Ogunsola Folasade T
Department of Medical Microbiology & Parasitology, College of Medicine, University of Lagos, PMB 12003, Lagos, Nigeria.
Department of Internal Medicine, University of Calabar, Calabar, Nigeria.
Ther Adv Infect Dis. 2021 Oct 9;8:20499361211050158. doi: 10.1177/20499361211050158. eCollection 2021 Jan-Dec.
Commercial IgG antibody assays have become pivotal in the current diagnosis of chronic pulmonary aspergillosis (CPA). However, diagnostic cutoffs have been found to vary from manufactures' recommendations in different settings. This study aimed to establish the IgG reference range among Nigerians and determine a diagnostic cutoff for CPA.
Sera from 519 prospectively recruited healthy blood donors and 39 previously confirmed cases of CPA were analysed for IgG levels using the Bordier test kit (Bordier Affinity Products SA, Crissier, Switzerland). Accuracy cutoff profile and receiver operating characteristics (ROC) curve were analysed for both CPA cases and controls using the R-Studio (2020), (Window desktop, version 4.0.2 software with packages "nnet" and "ROCR").
Among healthy blood donors, 141 (27.2%) were aged 16-25 years with median (interquartile range, IQR) of 22 (20-24) years; 304 (58.6%) were aged 26-40 years with median (IQR) of 32 (29-36) years; while 74 (14.2%) were aged 41-60 years with median (IQR) of 46 (44-49.75). Median IgG level in respective age groups were 0.069 (0.009-0.181), 0.044 (0.014-0.202) and 0.056 (0.01-0.265) with no significant difference found in the three age categories ( = 0.69). The overall diagnostic cutoff for the diagnosis of CPA was 0.821 with an accuracy of 97.1% and area under the curve (AUC) = 0.986.
The optimal diagnostic cutoff for diagnosing CPA in Nigerians using the Bordier kit was 0.821 which is lower than the manufacturer's recommended cutoff of 1.0. The determination of this cutoff among Nigerians will significantly enhance accurate identification of CPA and assessment of its true burden in Nigeria.
商业化IgG抗体检测在目前慢性肺曲霉病（CPA）的诊断中起着关键作用。然而，在不同环境下，诊断临界值与制造商的建议有所不同。本研究旨在确定尼日利亚人的IgG参考范围，并确定CPA的诊断临界值。
使用Bordier检测试剂盒（Bordier Affinity Products SA，瑞士克里西耶）对519名前瞻性招募的健康献血者的血清和39例先前确诊的CPA病例的血清进行IgG水平分析。使用R-Studio（2020）（Windows桌面版，4.0.2版本软件，带有“nnet”和“ROCR”包）对CPA病例和对照的准确性临界值分布和受试者工作特征（ROC）曲线进行分析。
在健康献血者中，141人（27.2%）年龄在16 - 25岁，中位数（四分位间距，IQR）为22（20 - 24）岁；304人（58.6%）年龄在26 - 40岁，中位数（IQR）为32（29 - 36）岁；74人（14.2%）年龄在41 - 60岁，中位数（IQR）为46（44 - 49.75）。各年龄组的IgG中位数水平分别为0.069（0.009 - 0.181）、0.044（0.014 - 0.202）和0.056（0.01 - 0.265），三个年龄组之间未发现显著差异（P = 0.69）。CPA诊断的总体临界值为0.821，准确率为97.1%，曲线下面积（AUC） = 0.986。
使用Bordier试剂盒诊断尼日利亚人CPA的最佳临界值为0.821，低于制造商建议的临界值1.0。在尼日利亚人中确定此临界值将显著提高CPA的准确识别及其在尼日利亚真实负担的评估。
