A study of the technique of western blot for diagnosis of lyme disease caused by Borrelia afzelii in China

Abstract

Objective: To study the technique of Western blot for the diagnosis of Lyme disease caused by Borrelia afzelii in China and to establish the standard criteria by operational procedure.

Methods: FP1, which is the representative strain of B. afzelii in China, was analyzed by SDS-PAGE, electro transfer and immunoblotting assays. The molecular weights of the protein bands of FP1 were analyzed by Gel-Pro analysis software. In a study using 451 serum samples (159 patients with Lyme disease and 292 controls), all observed bands were recorded. The accuracy of the WB as a diagnostic test was established by using the ROC curve and Youden index.

Results: Criteria for a positive diagnosis of Lyme disease were established as at least one band of P83/100, P58, P39, OspB, OspA, P30, P28, OspC, P17, and P14 in the IgG test and at least one band of P83/100, P58, P39, OspA, P30, P28, OspC, P17, and P41 in the IgM test. For IgG criteria, the sensitivity, specificity and Youden index were 69.8%, 98.3%, and 0.681, respectively; for IgM criteria, the sensitivity, specificity and Youden index were 47%, 94.2%, and 0.412, respectively.

Conclusion: Establishment of WB criteria for B. afzelii is important in validating the diagnostic assays for Lyme disease in China.

Keywords: Borrelia afzelii; Diagnostic method; Lyme disease; Western blot.