European Public Health Microbiology Training Program (EUPHEM), European Centre for Disease Control and Prevention, Stockholm, Sweden.
WHO Collaborating Centre for Leishmaniasis, National Centre for Microbiology, Instituto de Salud Carlos III, Majadahonda, Spain.
PLoS Negl Trop Dis. 2018 Mar 1;12(3):e0006277. doi: 10.1371/journal.pntd.0006277. eCollection 2018 Mar.
Visceral leishmaniasis (VL), the most severe form of leishmaniasis, is endemic in Europe with Mediterranean countries reporting endemic status alongside a worrying northward spread. Serological diagnosis, including immunochromatographic test based on the recombinant antigen rK39 (rK39-ICT) and a direct agglutination test (DAT) based on the whole parasite antigen, have been validated in regions with high VL burden, such as eastern Africa and the Indian subcontinent. To date, no studies using a large set of patients have performed an assessment of both methods within Europe.
METHODOLOGY/PRINCIPAL FINDINGS: We selected a range of clinical serum samples from patients with confirmed VL (including HIV co-infection), Chagas disease, malaria, other parasitic infections and negative samples (n = 743; years 2009-2015) to test the performance of rK39-ICT rapid test (Kalazar Detect Rapid Test; InBios International, Inc., USA) and DAT (ITM-DAT/VLG; Institute of Tropical Medicine Antwerp, Belgium). An in-house immunofluorescence antibody test (IFAT), was included for comparison. Estimated sensitivities for rK39-ICT and DAT in HIV-negative VL patients were 83.1% [75.1-91.2] and 84.2% [76.3-92.1], respectively. Sensitivity was reduced to 67.3% [52.7-82.0] for rK39 and increased to 91.3% [82.1-100.0] for DAT in HIV/VL co-infected patients. The in-house IFAT was more sensitive in HIV-negative VL patients, 84.2% [76.3-92.1] than in HIV/VL patients, 79.4% [73.3-96.2]. DAT gave 32 false positives in sera from HIV-negative VL suspects, compared to 0 and 2 for rK39 and IFAT, respectively, but correctly detected more HIV/VL patients (42/46) than rK39 (31/46) and IFAT (39/46).
CONCLUSIONS/SIGNIFICANCE: Though rK39-ICT and DAT exhibited acceptable sensitivity and specificity a combination with other tests is required for highly sensitive diagnosis of VL cases in Spain. Important variation in the performance of the tests were seen in patients co-infected with HIV or with other parasitic infections. This study can help inform the choice of serological test to be used when screening or diagnosing VL in a European Mediterranean setting.
内脏利什曼病（VL）是利什曼病中最严重的一种形式，在欧洲流行，地中海国家报告了流行状况，并出现了令人担忧的向北传播。在东非和印度次大陆等 VL 负担较高的地区，已经验证了血清学诊断方法，包括基于重组抗原 rK39（rK39-ICT）的免疫层析检测和基于全寄生虫抗原的直接凝集检测（DAT）。迄今为止，尚无使用大量患者进行评估的研究在欧洲内部进行这两种方法的评估。
方法/主要发现：我们从确诊的 VL（包括 HIV 合并感染）、恰加斯病、疟疾、其他寄生虫感染和阴性样本的患者中选择了一系列临床血清样本（n=743；2009-2015 年），以测试 rK39-ICT 快速检测（Kalazar Detect Rapid Test；InBios International，Inc.，USA）和 DAT（ITM-DAT/VLG；安特卫普热带医学研究所，比利时）的性能。同时还包括内部免疫荧光抗体检测（IFAT）作为比较。在 HIV 阴性 VL 患者中，rK39-ICT 和 DAT 的估计敏感性分别为 83.1%[75.1-91.2]和 84.2%[76.3-92.1]。在 HIV/VL 合并感染患者中，rK39 的敏感性降低至 67.3%[52.7-82.0]，而 DAT 的敏感性增加至 91.3%[82.1-100.0]。在 HIV 阴性 VL 患者中，内部 IFAT 比在 HIV/VL 患者中更敏感，为 84.2%[76.3-92.1]。DAT 在 HIV 阴性 VL 疑似患者的血清中产生 32 例假阳性，而 rK39 和 IFAT 分别为 0 和 2，但比 rK39（31/46）和 IFAT（39/46）更准确地检测到更多的 HIV/VL 患者（42/46）。
结论/意义：尽管 rK39-ICT 和 DAT 表现出可接受的敏感性和特异性，但仍需要与其他检测方法联合使用，以实现对西班牙 VL 病例的高度敏感诊断。在 HIV 感染或其他寄生虫感染合并感染的患者中，检测方法的性能存在重要差异。本研究有助于为在欧洲地中海地区筛查或诊断 VL 时选择血清学检测方法提供信息。
