Department of Animal Biology, School of Life Sciences, University of Hyderabad, Prof. CR Rao Road, Gachibowli, Hyderabad, 500 046, India.
Departments of Biochemistry and Medicine, MOSC Medical College, Kerala, India.
Eur J Clin Microbiol Infect Dis. 2018 Mar;37(3):423-433. doi: 10.1007/s10096-018-3187-9. Epub 2018 Jan 13.
Leptospirosis and dengue are two commonly seen infectious diseases of the tropics. Differential diagnosis of leptospirosis from dengue fever is often difficult due to overlapping clinical symptoms and lack of economically viable and easy-to-perform laboratory tests. The gold standard for diagnosis is the microscopic agglutination test (MAT). In this study, the diagnostic potential of screening for pathogen-specific leptospiral antigens in urine samples is presented as a non-invasive method of disease diagnosis. In a study group of 40 patients, the serum was tested for anti-leptospiral antibodies by MAT and enzyme-linked immunosorbent assay (ELISA). Urine of these patients was screened for leptospiral antigens by ELISA using specific antibodies against LipL32, LipL41, Fla1, HbpA and sphingomyelinase. Group I patients (n = 23) were classified as leptospirosis-positive based on MAT and high titres of circulating IgM-specific anti-leptospiral antibodies. All of these patients excreted all five leptospiral antigens in the urine. The 17 MAT-negative cases included six patients with pyrexia of unknown origin (PUO; Group II) and 11 confirmed dengue patients (Group III). The latter tested negative for both serum anti-leptospiral antibodies and urinary leptospiral antigens. A salient outcome of this study was highlighting the usefulness of screening for urinary leptospiral antigens in disease diagnosis, as their presence confirmed leptospiral aetiology in two PUO patients. Immunoblots of urinary antigens identified well-defined bands corresponding to LipL32, HbpA and sphingomyelinase; the significance of the 42- and 58-kDa sphingomyelinase bands is discussed.
钩端螺旋体病和登革热是两种常见的热带传染病。由于重叠的临床症状和缺乏经济可行且易于执行的实验室检测，钩端螺旋体病与登革热的鉴别诊断常常很困难。诊断的金标准是显微镜凝集试验（MAT）。在本研究中，提出了在尿液样本中筛选病原体特异性钩端螺旋体抗原作为一种非侵入性疾病诊断方法。在一个 40 名患者的研究组中，通过 MAT 和酶联免疫吸附试验（ELISA）检测血清中的抗钩端螺旋体抗体。使用针对 LipL32、LipL41、 Fla1、HbpA 和鞘磷脂酶的特异性抗体，通过 ELISA 筛选这些患者的尿液中的钩端螺旋体抗原。根据 MAT 和循环 IgM 特异性抗钩端螺旋体抗体的高滴度，将组 I 患者（n=23）分类为钩端螺旋体病阳性。所有这些患者的尿液中都排泄了所有五种钩端螺旋体抗原。17 例 MAT 阴性病例包括 6 例不明原因发热（PUO；组 II）和 11 例确诊的登革热患者（组 III）。后者血清抗钩端螺旋体抗体和尿液钩端螺旋体抗原均为阴性。本研究的一个突出结果是强调了筛选尿液钩端螺旋体抗原在疾病诊断中的有用性，因为它们的存在在 2 例 PUO 患者中证实了钩端螺旋体病因。尿抗原免疫印迹鉴定出与 LipL32、HbpA 和鞘磷脂酶相对应的清晰条带；讨论了 42 和 58 kDa 鞘磷脂酶条带的意义。
