Diagnostic efficacy of lsa63 antigen for human leptospirosis.

Background: Timely diagnosis of leptospirosis is essential for early and effective treatment, for there are many differential diagnoses for it.. Leptospiral researchers have an increasing interest in developing new serological methods with recombinant antigens to improve the Leptospirosis diagnosis. Several serological tests have been developed for the proper diagnosis of leptospirosis.

Objectives: To improve the previous works we developed an enzyme linked immunosorbent assay (ELISA) with novel recombinant leptospiral surface adhesion (Lsa63) protein to offer a new test.

Materials And Methods: In an experimental study, Recombinant Lsa63 (rLsa63) was produced in Escherishia coli (E.coli) BL21 (DE3). By using rLsa63, we generated IgM and IgG ELISA. Performance of these tests was compared to microscopic agglutination golden test (MAT). Two hundred twenty human serum samples were obtained from individuals suspicious of leptospirosis who were referred to Guilan Province Central Leptospira Laboratory for definitive diagnosis. The sensitivity, specificity and other statistical indexes of Lsa63-ELISAs were also determined.

Results: Among 220 serum samples, 30% (n = 65) had positive MAT responses, and also 38% (n = 84) and 40.9% (n = 90) showed positive reaction to IgG and IgM rLsa63-ELISA, respectively. The sensitivity, specificity and accuracy were 93.8%, 81.29 % and 85.0 for IgM-Lsa63- ELISA and 83.07, 80, 64 and 81.36 for IgG-Lsa63- ELISA, respectively.

Conclusions: Our results demonstrated that the sensitivity and specificity of Lsa63-ELISAs are promising for the detection of Leptospira serovars.