Development of in-house ELISAs as an alternative method for the serodiagnosis of leptospirosis. (April 2021)

• Record Type: Journal Article
• Authors: Niloofa, Roshan; Karunanayake, Lilani; de Silva, H. Janaka; Premawansa, Sunil; Rajapakse, Senaka; Handunnetti, Shiroma
• Is Part Of: International journal of infectious diseases. Volume 105(2021)
• Page Start: 135
• Page End: 140
• Publication Date: 2021-04
• Subjects: Leptospirosis -- IgM and IgG antibodies -- Serodiagnosis -- In-house ELISA; Communicable diseases -- Periodicals; Communicable Diseases -- Periodicals; Communicable diseases; Periodicals; Electronic journals; 616.9
• DOI: 10.1016/j.ijid.2021.01.074
• Languages: English
• ISSNs: 1201-9712

Abstract

Highlights: Confirmatory laboratory diagnosis of leptospirosis is a major challenge. In-house ELISAs were established to detect anti-leptospiral antibodies. Factors responsible for the manifestation of severe leptospirosis forms are unclear. High anti-leptospiral IgG was observed in severe leptospirosis patients compared to mild leptospirosis patients. Anti-leptospiral IgG could be used as a biomarker to predict disease severity. Abstract: Background: Leptospirosis is most often diagnosed clinically, and a laboratory test with high diagnostic accuracy is required. Methods: 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). Results: 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. Conclusion: 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.