Serological Diagnostics of Lyme Borreliosis: Comparison of Universal and Borrelia Species-Specific Tests Based on Whole-Cell and Recombinant Antigens

Seroprevalence of Toxoplasma gondii and Borrelia burgdorferi infections in patients with multiple sclerosis in Poland

Multiple sclerosis (MS) is a chronic, demyelinating disease of the central nervous system that affects mainly young people. It is believed that the autoimmune process observed in the pathogenesis of MS is influenced by a complex interaction between genetic and environmental factors, including infectious agents. The results of this study suggest the protective role of Toxoplasma gondii infections in MS. Interestingly, high Toxoplasma IgM seropositivity in MS patients receiving immunomodulatory drugs (IMDs) was identified. On the other hand, Borrelia infections seem to be positively associated with MS. Although the interpretation of our results is limited by the retrospective nature of the studies, the results strongly indicate that further experimental and clinical studies are needed to explain the role of infectious agents in the development and pathophysiological mechanisms of MS.

In silico epitope prediction of Borrelia burgdorferi sensu lato antigens for the detection of specific antibodies

Despite many years of research, serodiagnosis of Lyme disease still faces many obstacles. Difficulties arise mainly due to the low degree of amino acid sequence conservation of the most immunogenic antigens among B. burgdorferi s.l. genospecies, as well as differences in protein production depending on the environment in which the spirochete is located. Mapping B-cell epitopes located on antigens allows for a better understanding of antibody-pathogen interactions which is essential for the development of new and more effective diagnostic tools. In this study, in silico B-cell epitope mapping was performed to determine the theoretical diagnostic potential of selected B. burgdorferi s.l. proteins (BB0108, BB0126, BB0298, BB0689, BB0323, FliL, PstS, SecD, EF-Tu). Bioinformatics software predicted 35 conserved linear and 31 conformational epitopes with the degree of identity among B. burgdorferi s.l. of at least 85%, which may prove to be useful in the development of a new tool for the diagnosis of Lyme disease.

Utility of Borrelia-specific IgM and IgG antibody titer determinations during a 12-year period - results from a clinical laboratory in Northern Sweden

Interpretation of serological findings in suspected Lyme borreliosis (LB) is challenging and IgM reactivities may have low predictive value. Therefore, if used indiscriminately, there is a risk for incorrect diagnosis of LB. To evaluate the usefulness of IgM titer determination, we performed a study of the prevalence of Borrelia-specific antibodies in serological samples from patients with suspected LB analyzed during the period 2010 - 2021 at the University Hospital of Umeå in Sweden. In total, 19,335 samples had been analyzed for the presence of IgG and IgM antibodies. Overall, there were higher percentages of IgM positive or borderline titers, 1,847 (9.6%) and 905 (4.7%), respectively, than IgG positive or borderline titers, 959 (5.0%) and 406 (2.1%), respectively. Peak number of samples were recorded 2012 - 2013, exceeding 1,800, whereas there were around 1,200 during 2020 - 2021. The peak number of positive IgG and/or positive IgM samples were observed during the period 2015 - 2017 with close to, or above 400, and concomitantly, the proportion of IgG positive samples increased markedly. For IgG positive samples, the increase followed a positive linear time trend (P< 0.001). Peak monthly numbers were observed during August, September, and October. This seasonal increase was significant for the IgG positive group (P< 0.05), but not for the IgM positive/IgG negative group. Repeated samples were obtained from 3,188 individuals and of the initial samples 2,817 were (88%) IgG negative and 2,315 (72%) were IgM negative and of these, 130 (4%) showed IgG seroconversion and 300 (9%) IgM seroconversion. Collectively, the data demonstrate that IgG and/or IgM positive samples represented a minority of all samples, even when repeated sampling had occurred, and IgM positive samples were much more common than IgG positive samples. Thus, the accuracy of the clinical suspicion was low and this will lead to a low predictive value of the analysis, in particular of IgM. These findings question the use of IgM titer determination as a routine analysis.

Cross-Reactive Results in Serological Tests for Borreliosis in Patients with Active Viral Infections

Currently, serological tests for Lyme disease (LD), routinely performed in laboratories following the European Concerted Action on Lyme Borreliosis recommendations as part of two-stage diagnostics, are often difficult to interpret. This concerns both the generation of false positive and negative results, which frequently delay the correct diagnosis and implementation of appropriate treatment. The above problems result from both morphological and antigenic variability characteristics for the life strategy of the spirochete Borrelia burgdorferi sensu lato, a complicated immune response, and imperfections in diagnostic methods. The study aimed to check the reactivity of sera from 69 patients with confirmed infection with Epstein–Barr virus (EBV), cytomegalovirus (CMV) and BK virus (BKV) with Borrelia antigens used in serological tests: indirect immunofluorescence (IIFT), enzyme-linked immunosorbent (ELISA) and immunoblot (IB). In the group of patients infected with EBV, the highest percentage of positive/borderline anti-Borrelia IgM and IgG results was obtained in the following tests: IIFT (51.9% for IgM, 63.0% for IgG), ELISA (22.2% for IgM, 29.6% for IgG) and IB (11.1% for IgM, 7.4% for IgG). In the group of CMV-infected patients, the highest percentage of positive/borderline anti-Borrelia IgM results were obtained in the following tests: IB (23.1%), IIFT (15.4%) and ELISA (7.7%), while in the IgG class in the IIFT (15.4%), IB (11.5%) and ELISA (3.9%) tests. In the group of patients infected with BKV, the highest percentage of positive/borderline anti-Borrelia IgM results was obtained in the following tests: IIFT (25.0%), IB (25.0%) and ELISA (3.9%), and in the IgG class in the tests: IB (50.0%), IIFT (6.2%) and ELISA (6.2%). The native flagellin (p41) and OspC proteins were the most frequently detected Borrelia antigens in all studied groups of patients in both classes of antibodies. Similar to other authors, the study confirmed the fact that serological tests used in the diagnosis of LD have a high potential to generate false positive results in patients with active viral infections, which may be related to cross-reacting antibodies appearing during the most common polyclonal activation of T/B lymphocytes, activated by viral superantigens.

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

Serodiagnosis of Lyme borreliosis (LB) comes with several drawbacks, among which is limited sensitivity in early disease. This study assesses the sensitivity and specificity of the novel BioPlex 2200 Lyme IgG and Lyme IgM assays. It also assesses potential improvements to the assays through receiver-operating characteristic (ROC) analysis. The BioPlex assays were performed on sera of 158 Dutch patients with physician-confirmed LB (both early localized and disseminated), 800 healthy blood donors from the Netherlands, and 90 cross-reactive controls. The BioPlex (Biopl) assays were compared with two commercial enzyme immunoassays (Euroimmun [Eur]/C6-ELISA) and one immunoblot (recomLine). The highest sensitivity in early LB was achieved with the BioPlex assays, which outperformed the Euroimmun and C6-ELISA (Biopl: 81/88, 92.1%; Eur: 64/88, 72.7%; C6: 72/88, 81.8%). Sensitivity of all assays was comparable in patients with disseminated LB. The BioPlex assays were outperformed in terms of specificity (all healthy blood donors, Biopl: 571/800, 71.4%; Eur: 711/800, 88.9%; C6: 727/800, 90.9%), but further analyses showed promising avenues following cutoff optimization. ROC analysis showed that 2/6 antigens of the combined BioPlex IgG and IgM assays had significantly higher areas under the curve (AUCs) than those of the other analyses. Potential modified versions of the assays based on these antigens largely outperformed the Euroimmun and C6-ELISA in EM patients (Biopl: 81/80, 92.1%) while maintaining a comparable or even higher specificity (Biopl: 714/800, 89.3%). The BioPlex 2200 Lyme IgG and Lyme IgM assays are promising tools for the serodiagnosis of early LB, with the potential to be used as a standalone test. Further research is necessary to validate the findings of this discovery cohort.

Evaluation of test characteristics of 2 ELISA tests applied to bulk tank milk and claw-trimming records for herd-level diagnosis of bovine digital dermatitis using latent class analysis

Bovine digital dermatitis (DD) is an infectious claw disease with a negative effect on animal welfare and production. Treponema spp. is the main causative agent, and infected animals produce specific antibodies. Our aim was to estimate sensitivity (Se) and specificity (Sp) of 2 ELISA research tests, Medicago's ELISA test and GD Animal Health's in-house ELISA test, for detection of DD-associated Treponema antibodies in bulk tank milk. We used bulk tank milk samples from 154 Norwegian dairy cattle herds, 96 from an expected high-prevalence region and 58 from a low-prevalence region. Both tests were evaluated separately against herd-level (aggregated) claw-trimming records extracted from the Norwegian Dairy Herd Recording System using latent class models in a Bayesian analysis. Cutoff values were selected using an explorative approach, and both noninformative priors for all parameters and informative β priors for distribution of Se and Sp of claw trimming were explored. The estimated (median) true herd-level prevalence of digital dermatitis varied between 24 and 30% in the high-prevalence region and between 3 and 6% in the low-prevalence region. For Medicago's ELISA test, an Se (95% posterior credible interval) of 0.57 (0.32; 0.94) could be achieved without compromising Sp, and for GD Animal Health's in-house ELISA test, an Se of 0.60 (0.37; 0.92) was achieved. Our study showed that both ELISA tests can detect antibodies against DD-associated Treponema spp. in bulk tank milk. However, neither of the 2 ELISA tests produced satisfactory sensitivity without compromising specificity. Based on these results, inspection at claw trimming in a chute is necessary for surveillance and control of DD at the herd level in Norway, although these ELISA tests of bulk tank milk might be a useful supplement.

Assessing the Need for Multiplex and Multifunctional Tick-Borne Disease Test in Routine Clinical Laboratory Samples from Lyme Disease and Febrile Patients with a History of a Tick Bite

Human polymicrobial infections in tick-borne disease (TBD) patients is an emerging public health theme. However, the requirement for holistic TBD tests in routine clinical laboratories is ambiguous. TICKPLEX® PLUS is a holistic TBD test utilized herein to assess the need for multiplex and multifunctional diagnostic tools in a routine clinical laboratory. The study involved 150 specimens categorized into Lyme disease (LD)-positive (n = 48), LD-negative (n = 30), and febrile patients from whom borrelia serology was requested (n = 72, later "febrile patients") based on reference test results from United Medix, Finland. Reference tests from DiaSorin, Immunetics, and Mikrogen Diagnostik followed the two-tier LD testing system. A comparison between the reference tests and TICKPLEX® PLUS produced 86%, 88%, and 87% positive, negative, and overall agreement, respectively. Additionally, up to 15% of LD and 11% of febrile patients responded to TBD related coinfections and opportunistic microbes. The results demonstrated that one (TICKPLEX® PLUS) test can aid in a LD diagnosis instead of four tests. Moreover, TBD is not limited to just LD, as the specimens produced immune responses to several TBD microbes. Lastly, the study indicated that the screening of febrile patients for TBDs could be a missed opportunity at reducing unreported patient cases.

Evaluation of pathogen specific urinary peptides in tick-borne illnesses

Mass spectrometry enhanced by nanotechnology can achieve previously unattainable sensitivity for characterizing urinary pathogen-derived peptides. We utilized mass spectrometry enhanced by affinity hydrogel particles (analytical sensitivity = 2.5 pg/mL) to study tick pathogen-specific proteins shed in the urine of patients with (1) erythema migrans rash and acute symptoms, (2) post treatment Lyme disease syndrome (PTLDS), and (3) clinical suspicion of tick-borne illnesses (TBI). Targeted pathogens were Borrelia, Babesia, Anaplasma, Rickettsia, Ehrlichia, Bartonella, Francisella, Powassan virus, tick-borne encephalitis virus, and Colorado tick fever virus. Specificity was defined by 100% amino acid sequence identity with tick-borne pathogen proteins, evolutionary taxonomic verification for related pathogens, and no identity with human or other organisms. Using a cut off of two pathogen peptides, 9/10 acute Lyme Borreliosis patients resulted positive, while we identified zero false positive in 250 controls. Two or more pathogen peptides were identified in 40% of samples from PTLDS and TBI patients (categories 2 and 3 above, n = 59/148). Collectively, 279 distinct unique tick-borne pathogen derived peptides were identified. The number of pathogen specific peptides was directly correlated with presence or absence of symptoms reported by patients (ordinal regression pseudo-R2 = 0.392, p = 0.010). Enhanced mass spectrometry is a new tool for studying tick-borne pathogen infections.

Serological diagnostics of Lyme borreliosis: comparison of assays in twelve clinical laboratories in Northern Europe

Lyme borreliosis (LB), caused by spirochetes belonging to the Borrelia burgdorferi sensu lato complex, is the most common tick-borne infection in Europe. Laboratory diagnosis of LB is mainly based on the patients’ medical history, clinical signs and symptoms in combination with detection of Borrelia-specific antibodies where indirect enzyme-linked-immunosorbent assay (ELISA) is the most widely used technique. The objective of the study was to evaluate and compare the diagnostic accuracy (sensitivities and specificities) of serological tests that are currently in use for diagnosis of LB in clinical laboratories in Northern Europe, by use of a large serum panel. The panel consisted of 195 serum samples from well-characterized and classified patients under investigation for clinically suspected LB (n = 59) including patients with Lyme neuroborreliosis, Lyme arthritis, acrodermatitis chronica atrophicans, erythema migrans or other diseases (n = 112). A total of 201 serum samples from healthy blood donors were also included. The panel (396 serum samples altogether) was sent to 12 clinical laboratories (using five different ELISA methods) as blinded for group affiliation and the laboratories were asked to perform serological analysis according to their routine procedure. The results from the study demonstrated high diagnostic concordance between the laboratories using the same diagnostic assay and lower diagnostic concordance between laboratories using different diagnostic assays. For IgG, the results were in general rather homogenous and showed an average sensitivity of 88% (range 85–91%) compared to IgM which showed lower average sensitivity of 59% (range 50–67%) and more heterogeneous results between assays and laboratories.