Diagnostic Performance of the Novel BioPlex Lyme Serological Assays in European Patients with Lyme Disease

Evaluation of different standard and modified two-tier testing strategies for the laboratory diagnosis of lyme borreliosis in a European setting

BACKGROUND

Diagnosis of Lyme borreliosis (LB) relies on clinical symptoms and detection of Borrelia-specific antibodies. Guidelines recommend a two-tier testing (TTT) strategy for disseminated LB: serological screening with a sensitive enzyme immunoassay (EIA) and confirmation with a specific immunoblot. Searching for the most sensitive and specific approach, this retrospective study evaluated standard (STTT) and modified (MTTT) strategies using a well-defined study population.

METHODS

Cases included patients with active Lyme neuroborreliosis (LNB; n = 29) or Lyme arthritis (LA; n = 17). Controls comprised patients treated for LNB (n = 36) or LA (n = 8), healthy individuals who were either untreated (n = 75) or treated for LB (n = 15) in the past, and patients with potentially cross-reactive diseases (n = 16). Sera were subjected to three EIAs and two immunoblots. Reactive screening results were confirmed by immunoblot (STTT) or EIA (MTTT). Solitary IgM results in the screening assay and effects of antibiotic treatment on isotype-specific seropositivity rates were also assessed.

RESULTS

Sensitivities of STTT strategies ranged from 90%-97% for LNB and were 100% for LA. MTTT strategies were 100% sensitive. Specificities ranged from 89%-95% for STTT and from 88%-93% for MTTT strategies. Differences between STTT and MTTT strategies were not statistically significant. Solitary IgM reactivity was common among controls. Antibiotic treatment significantly reduced IgM/IgG positivity for LNB patients; for LA patients, a decline was only observed for IgM.

CONCLUSION

In conclusion, MTTT strategies showed a slightly higher sensitivity and similar specificity compared to STTT strategies. Since EIAs are more time- and cost-efficient, MTTT strategies seem more favorable for clinical use. IgG testing enhances specificity with minimal sensitivity loss.

A Step-by-Step Guide to Selecting an Optimal Cut-Off Value Based on the Receiver Operating Characteristic and Youden Index in Methods Designed to Diagnose Lyme Disease

Detection tools designed to diagnose complex diseases such as Lyme Borreliosis require an optimal cutoff point to distinguish the healthy from the diseased. The chapter will provide a practical guide to selecting an optimal cutoff mark by creating the receiver operating characteristic (ROC) in Microsoft Excel. To guide the creation of a ROC graphical plot, we will use example data from an enzyme-linked immunosorbent assay (ELISA) measuring anti-human immunoglobulin G (IgG) against whole-cell Borrelia lysates. Herein, the ROC method will demonstrate that an optical density (OD) value from ELISA with the highest Youden Index (J) is an optimal cutoff value to differentiate positive and negative IgG immune responses in human serum samples.

Diagnostic performance of the ZEUS Borrelia VlsE1/pepC10 assay in European LB patients: a case-control study

This retrospective case-control study assesses the sensitivity, specificity, and area under the curve of the ZEUS Borrelia VlsE1/pepC10 assay in comparison with the C6-ELISA in European patients with Lyme borreliosis, healthy blood donors, and potentially cross-reactive controls. We included a convenience series of 161 sera from patients with physician-confirmed early localized or disseminated Lyme borreliosis (n = 143), 400 sera from healthy blood donors and 44 sera with potentially cross-reactive antibodies, on which we performed the aforementioned serological assays and the recomLine immunoblot. Diagnostic parameters were compared in various single-tier and two-tier algorithms. The specificities of the C6-ELISA and the ZEUS Borrelia VlsE1/pepC10 were comparable in healthy blood donors (e.g., single-tier permissive: C6: 362/400, 90.5% [87.2-93.2]; VlsE1/pepC10: 361/400, 90.3% [86.9-93.0]). The C6-ELISA had an apparently higher sensitivity in EM sera (e.g., both time points combined: C6: 61/76, 80.3% [69.5-88.5]; VlsE1/pepC10: 54/76, 71.1% [59.5-80.9]), but these differences were all not-significant. Interestingly, the VlsE1/pepC10 assay had a significantly higher specificity in sera with potentially cross-reactive antibodies (e.g., single-tier permissive: C6: 34/44, 77.3% [62.2-88.5]; VlsE1/pepC10: 40/44, 90.9% [78.3-97.5]; p = 0.031). While the areas under the curve for both assays were excellent, that of the C6-ELISA exceeded that of the VlsE1/pepC10 (C6: AUC = 0.925; VlsE1/pepC10: AUC = 0.878; p = 0.003). The novel ZEUS Borrelia VlsE1/pepC10 assay has generally comparable diagnostic parameters to the C6-ELISA with potentially improved specificity in cross-reactive sera. Thus, it is a useful tool for the serodiagnosis of Lyme borreliosis in Europe.