Beijing Tropical Medicine Research Institute, Beijing Friendship Hospital, Capital Medical University, Beijing, China.
Beijing Key Laboratory for Research on Prevention and Treatment of Tropical Diseases, Capital Medical University, Beijing, China.
PLoS Negl Trop Dis. 2019 Apr 24;13(4):e0007318. doi: 10.1371/journal.pntd.0007318. eCollection 2019 Apr.
Leprosy, caused by Mycobacterium leprae, affects over 200,000 people annually worldwide and remains endemic in the ethnically diverse, mountainous and underdeveloped southwestern provinces of China. Delayed diagnosis of leprosy persists in China, thus, additional knowledge to support early diagnosis, especially early diagnosis of paucibacillary (PB) patients, based on the host immune responses induced by specific M. leprae antigens is needed. The current study aimed to investigate leprosy patients and controls in Southwest China by comparing supernatants after stimulation with specific M. leprae antigens in an overnight whole-blood assay (WBA) to determine whether host markers induced by specific M. leprae antigens improve the diagnosis or discrimination of PB patients with leprosy.
METHODOLOGY/PRINCIPAL FINDINGS: Leprosy patients [13 multibacillary (MB) patients and 7 PB patients] and nonleprosy controls [21 healthy household contacts (HHCs), 20 endemic controls (ECs) and 19 tuberculosis (TB) patients] were enrolled in this study. The supernatant levels of ten host markers stimulated by specific M. leprae antigens were evaluated by overnight WBA and multiplex Luminex assays. The diagnostic value in PB patients and ECs and the discriminatory value between PB patients and HHCs or TB patients were evaluated by receiver operator characteristics (ROC) analysis. ML2044-stimulated CXCL8/IL-8 achieved the highest sensitivity of 100%, with a specificity of 73.68%, for PB diagnosis. Compared to single markers, a 3-marker combination model that included ML2044-induced CXCL8/IL-8, CCL4/MIP-1 beta, and IL-6 improved the diagnostic specificity to 94.7% for PB patients. ML2044-stimulated IL-4 and CXCL8/IL-8 achieved the highest sensitivity (85.71% and 100%) and the highest specificity (95.24% and 84.21%) for discriminating PB patients from HHCs and TB patients, respectively.
Our findings suggest that the host markers induced by specific M. leprae antigens in an overnight WBA increase diagnostic and discriminatory value in PB patients with leprosy, with a particularly strong association with interleukin 8.
麻风病由麻风分枝杆菌引起，每年在全球影响超过 20 万人，在中国多民族、多山和欠发达的西南省份仍呈地方性流行。中国麻风病的诊断仍然存在延迟，因此，需要更多的知识来支持早期诊断，特别是基于麻风分枝杆菌特异性抗原诱导的宿主免疫反应，对少菌型（PB）患者进行早期诊断。本研究旨在通过比较 overnight whole-blood assay（WBA）中刺激特异性麻风分枝杆菌抗原后的上清液，来比较西南地区的麻风病患者和对照组，以确定特异性麻风分枝杆菌抗原诱导的宿主标志物是否提高了麻风病 PB 患者的诊断或鉴别能力。
方法/主要发现：本研究纳入了 13 例多菌型（MB）患者、7 例少菌型（PB）患者和非麻风病对照组[21 例健康家庭接触者（HHCs）、20 例地方流行对照（ECs）和 19 例结核病（TB）患者]。通过 overnight WBA 和 multiplex Luminex 检测评估了十种特异性麻风分枝杆菌抗原刺激的宿主标志物的上清液水平。通过 ROC 分析评估了 PB 患者和 ECs 的诊断价值以及 PB 患者与 HHCs 或 TB 患者之间的鉴别价值。ML2044 刺激的 CXCL8/IL-8 对 PB 诊断的敏感性为 100%，特异性为 73.68%，达到最高。与单个标志物相比，包括 ML2044 诱导的 CXCL8/IL-8、CCL4/MIP-1 beta 和 IL-6 的 3 种标志物组合模型提高了 PB 患者的诊断特异性，达到 94.7%。ML2044 刺激的 IL-4 和 CXCL8/IL-8 对 PB 患者与 HHCs 和 TB 患者的鉴别诊断具有最高的敏感性（85.71%和 100%）和特异性（95.24%和 84.21%）。
本研究结果表明， overnight WBA 中特异性麻风分枝杆菌抗原诱导的宿主标志物增加了麻风病 PB 患者的诊断和鉴别价值，与白细胞介素 8 具有特别强的相关性。
