Comparison between Enzygnost^® Lyme link VlsE/IgG and LIAISON^® Borrelia IgG for the laboratory diagnosis of Lyme disease

Abstract number: 1733_995

Marangoni A., Moroni A., Mondardini V., Accardo S., Cevenini R.

Objectives: We evaluated diagnostic performances of Enzygnost^® Lyme link VlsE/IgG (DADE Behring, Marburg, Germany), in comparison with those obtained by LIAISON^® Borrelia IgG (DiaSorin, Saluggia, Italy).

Methods: In this study a total of 183 human serum specimens were retrospectively studied. Sera were serially collected from 72 Lyme disease patients suffering from EM following a tick bite.

A skin punch biopsy was obtained from each patient when entering the study and cultivated in BSKII medium; the tubes were examined weekly by dark-field microscopy over a period of 45 days.

PCR was performed by using five different sets of primers: FL6-FL7 (amplifying a fragment of the flagellin gene, conserved in all the Borrelia burgdorferi s.l. strains); LD (amplifying a 16S rRNA genomic fragment common to the three genospecies); BB, BG, BA (each one amplifying a species-specific 16S rRNA genomic fragment).

Enzygnost^® Lyme link VlsE/IgG is a quantitative immunoenzymatic method based on a mix of native Borrelia antigens from B. afzelii strain PKo and recombinant VlsE obtained from all the three genospecies pathogenic to humans (B. burgdorferi s.s., B. garinii, B. afzelii).

LIAISON^® Borrelia Screen is a one step sandwich CLIA. Recombinant specific VlsE antigen obtained from the PBi strain of B. garinii is used for coating magnetic particles.

Results obtained by Enzygnost® Lyme link VIsE/IgG and LIAISON® Borrelia IgG, respectively, when the 66 sera obtained at the first presentation were tested.

Results and Conclusion: 66/72 cultures obtained from the biopsies were identified as B. afzelii by PCR; the remaining 6 cultures presented borreliae belonging to more than one genospecies.

Enzygnost^® Lyme link VlsE/IgG was more sensitive than LIAISON^® Borrelia IgG. In particular, considering the 66 sera obtained at first presentation that were available for this study, Enzygnost^® Lyme link VlsE/IgG scored 27 sera as reactive, 10 as border line and the remaining 29 as negative. LIAISON^® Borrelia IgG identified 21 sera as positive, 5 as border line and 40 as negative. No seroconversion was observed by both methods during the follow-up of all the patients found initially negative. Moreover, all the patients initially IgG positive showed a decrease in the serological titre within 3–6 months.