Institute of Biochemistry, Molecular Biology and Biotechnology, University of Colombo, Colombo, Sri Lanka.
Department of Bacteriology, Medical Research Institute, Colombo, Sri Lanka.
Int J Infect Dis. 2021 Apr;105:135-140. doi: 10.1016/j.ijid.2021.01.074. Epub 2021 Feb 5.
Leptospirosis is most often diagnosed clinically, and a laboratory test with high diagnostic accuracy is required.
IgM and IgG ELISAs using Leptospira antigens were established and evaluated in relation to the microscopic agglutination test (MAT). Antigen preparation consisted of saprophytic Leptospira biflexa to detect genus-specific antibodies (genus-specific ELISA) and a pool of the five most prevalent Leptospira interrogans serovars in Sri Lanka to detect serovar-specific antibodies (serovar-specific ELISA). IgM and IgG immune responses were studied in severe and mild leptospirosis patients (n = 100 in each group).
The ELISAs showed high repeatability and reproducibility. The serovar-specific IgM-ELISA showed a sensitivity of 80.2% and specificity of 89%; the genus-specific IgM-ELISA showed a sensitivity of 83.3% and specificity of 91%. The serovar- and genus-specific IgG-ELISAs showed sensitivities of 73.3% and 81.7%, respectively, and specificities of 83.3% and 83.3%, respectively. The commercial IgM-ELISA showed a sensitivity of 79.2% and specificity of 93%. The commercial IgG-ELISA showed a sensitivity of 50% and specificity of 96.7%. IgM levels observed in mild and severe leptospirosis patients were significantly higher than in the healthy control group, with mean absorbance values of 0.770, 0.778, and 0.163, respectively. Severe leptospirosis patients had significantly higher mean anti-leptospiral IgG levels compared to both mild leptospirosis patients and healthy control group subjects (0.643, 0.358, and 0.116, respectively; ANOVA, p < 0.001). The presence of anti-leptospiral IgG above an optical density of 0.643 at 1:100 could predict a high risk of severe disease.
The serovar-specific in-house ELISA could be used for the laboratory diagnosis of leptospirosis in endemic settings. The high levels of anti-leptospiral IgG observed suggest its value as a predictor of disease severity.
钩端螺旋体病通常通过临床诊断，因此需要一种具有高诊断准确性的实验室检测方法。
建立了使用钩端螺旋体抗原的 IgM 和 IgG ELISA，并与显微镜凝集试验（MAT）进行了比较。抗原制备包括腐生的双曲钩端螺旋体，以检测属特异性抗体（属特异性 ELISA）和来自斯里兰卡的五种最常见的钩端螺旋体血清型的混合物，以检测血清型特异性抗体（血清型特异性 ELISA）。在重症和轻症钩端螺旋体病患者（每组 100 例）中研究了 IgM 和 IgG 免疫反应。
ELISA 显示出高度的可重复性和重现性。血清型特异性 IgM-ELISA 的敏感性为 80.2%，特异性为 89%；属特异性 IgM-ELISA 的敏感性为 83.3%，特异性为 91%。血清型和属特异性 IgG-ELISA 的敏感性分别为 73.3%和 81.7%，特异性分别为 83.3%和 83.3%。商业 IgM-ELISA 的敏感性为 79.2%，特异性为 93%。商业 IgG-ELISA 的敏感性为 50%，特异性为 96.7%。轻症和重症钩端螺旋体病患者的 IgM 水平明显高于健康对照组，平均吸光度值分别为 0.770、0.778 和 0.163。与轻症钩端螺旋体病患者和健康对照组相比，重症钩端螺旋体病患者的抗钩端螺旋体 IgG 水平明显更高（分别为 0.643、0.358 和 0.116；ANOVA，p<0.001）。在 1:100 时，抗钩端螺旋体 IgG 水平高于 0.643 可能预示着疾病严重程度高的风险。
血清型特异性酶联免疫吸附试验可用于地方性流行地区的钩端螺旋体病的实验室诊断。观察到的高水平抗钩端螺旋体 IgG 表明其作为疾病严重程度预测因子的价值。
