Evaluation of Modified Two-Tiered Testing Algorithms for Lyme Disease Laboratory Diagnosis Using Well-Characterized Serum Samples

Comparative Evaluation of Commercial Test Kits Cleared for Use in Modified Two-Tiered Testing Algorithms for Serodiagnosis of Lyme Disease

BACKGROUND

Modified 2-tiered testing (MTTT) for Lyme disease utilizes automatable, high throughput immunoassays (AHTIs) in both tiers without involving western immunoblots, offering performance and practical advantages over standard 2-tiered testing (STTT; first-tier AHTI followed by immunoglobulin M (IgM) and immunoglobulin G (IgG) western immunoblots). For MTTT, Centers for Disease Control and Prevention recommends using AHTI test kits that have been cleared by Food and Drug Administration (FDA) specifically for this intended use. We evaluated performance of FDA-cleared MTTT commercial test kits from 3 manufacturers by comparing with STTT results.

METHODS

We performed MTTT (total antibody AHTI with reflex to separate IgM and IgG AHTIs) using test kits from Diasorin, Gold Standard Diagnostics (GSD), and Zeus Scientific on 382 excess serum samples submitted to the clinical laboratory for routine Lyme disease serologic testing in July 2018, measuring agreement between MTTT and STTT using the κ statistic.

RESULTS

Overall agreement with STTT was 0.87 (95% confidence interval [CI], .77-.97) using Diasorin assays (almost perfect agreement), 0.80 (95% CI, .68-.93) using GSD assays (substantial agreement) and 0.79 (95% CI, .68-.90) using Zeus assays (substantial agreement). For detection of IgM reactivity, agreement between MTTT and STTT was 0.70 (.51-.90; substantial), 0.63 (95% CI, .44-.82; substantial) and 0.56 (95% CI, .38-.73; moderate), respectively. For detection of IgG reactivity, MTTT/STTT agreement was 0.73 (95% CI,.58-.88), 0.78 (95% CI, .62-.94), and 0.75 (95% CI, .60-.90), respectively (substantial agreement in all cases).

CONCLUSIONS

MTTT results obtained using commercial test kits from 3 different manufacturers had substantial to almost perfect agreement with STTT results overall and moderate to substantial agreement for IgM and IgG detection independently. Commercial MTTT tests can be used broadly for the diagnosis of Lyme disease.

How Do I Approach the Evaluation and Treatment of Early Lyme Disease?

AbstractThe incidence and geographic spread of Lyme disease are increasing, and more than 476,000 new cases a year are estimated to occur in the United States. Therefore, many clinicians in North America will need to consider how to approach a patient with a concern for Lyme disease. This Curbside Consult addresses common clinical considerations, including discussion of signs of early Lyme disease, available laboratory tests, when to treat and with which antibiotics.

Performance of two modified two-tier algorithms for the serologic diagnosis of Lyme disease

We compared the performance of a new modified two-tier testing (MTTT) platform, the Diasorin Liaison chemiluminescent immunoassay (CLIA), to the Zeus enzyme-linked immunoassay (ELISA) MTTT and to Zeus ELISA/Viramed immunoblot standard two-tier testing (STTT) algorithm. Of 537 samples included in this study, 91 (16.9%) were positive or equivocal by one or more screening tests. Among these 91 samples, only 57 samples were concordant positive by first-tier screening tests, and only 19 of 57 were concordant by the three second-tier methods. For IgM results, positive percent agreement (PPA) was 68.1% for Diasorin versus 89.4% for Zeus compared to immunoblot. By contrast, the PPA for IgG for both Diasorin and Zeus was 100%. Using a 2-out-of-3 consensus reference standard, the PPAs for IgM were 75.6%, 97.8%, and 95.6% for Diasorin, Zeus, and immunoblot, respectively. The difference between Zeus MTTT and Diasorin MTTT for IgM detection was significant (P = 0.0094). PPA for both Diasorin and Zeus MTTT IgG assays was 100% but only 65.9% for immunoblot STTT (P = 0.0005). In total, second-tier positive IgM and/or IgG results were reported for 57 samples by Diasorin MTTT, 63 by Zeus MTTT, and 54 by Viramed STTT. While Diasorin CLIA MTTT had a much more rapid, automated, and efficient workflow, Diasorin MTTT was less sensitive for the detection of IgM than Zeus MTTT and STTT including in 5 early Lyme cases that were IgM negative but IgG positive.

IMPORTANCE

The laboratory diagnosis of Lyme disease relies upon the detection of antibodies to Borrelia species. Standard two tier testing (STTT) methods rely upon immunoblots which have clinical and technical limitations. Modified two-tier testing (MTTT) methods have recently become available and are being widely adopted. There are limited independent data available assessing the performance of MTTT and STTT methods.

Delayed Diagnosis of Locally Acquired Lyme Disease, Central North Carolina, USA

Healthcare providers in North Carolina, USA, have limited experience diagnosing and managing Lyme disease because few cases occur annually statewide. We outline the prolonged diagnostic course for a patient with locally acquired Lyme disease in North Carolina. This case highlights the need for greater awareness and professional education.

Direct Detection of Lyme Borrelia: Recent Advancement and Use of Aptamer Technology

Borrelia burgdorferi sensu lato (B. burgdorferi s.l.), which is predominantly spread by ticks, is the cause of Lyme disease (LD), also known as Lyme borreliosis, one of the zoonotic diseases affecting people. In recent years, LD has become more prevalent worldwide, even in countries with no prior records. Currently, Lyme Borrelia detection is achieved through nucleic acid amplification, antigen detection, microscopy, and in vitro culture. Nevertheless, these methods lack sensitivity in the early phase of the disease and, thus, are unable to confirm active infection. This review briefly discusses the existing direct detection methods of LD. Furthermore, this review also introduces the use of aptamer technology integrated with biosensor platforms to detect the Borrelia antigen. This aptamer technology could be explored using other biosensor platforms targeting whole Borrelia cells or specific molecules to enhance Borrelia detection in the future.

Diagnosis of neuroborreliosis in the context of local seroprevalence: A chart review study and a methodological overview

Background & objectives

In neuroborreliosis (NB) serology might objectively differentiate ongoing from past infection when the intrathecal space is involved. The hierarchy of the parallel serum-CSF (cerebrospinal fluid) methods is seldom discussed and remains elusive in daily practice. We compared the efficacy of certain methods and assessed the prevalence of anti-Borrelia antibodies in the local population.

Methods

We summarized standard two-tier test results in all ELISA-reactive samples of patients with suspected NB (n=152) since 2017 and tested 122 unrelated sera for anti-Borrelia antibodies from central Hungary.

Results

The most common central nervous system symptom was a cranial nerve palsy (27.6% of all subjects). CSF was available in 25 cases. A serum-CSF IgG-matched line immunoassay (LIA) detected intrathecal antibody production correctly in 6 of 8 samples when compared to the ELISA-based antibody-index (AI). Among the 122 random sera the prevalence of specific anti-Borrelia IgG antibodies (on LIA, not including anti-p41) were 6.8% above 30 and 10% above 60 years. Our results enable us to assume the predictive values of serological results according to the pretest probability of neuroborreliosis.

Interpretation & conclusion

Our results suggest that recombinant antigen-based two-tier serology from solely the sera might have sufficient positive predictive value to verify NB in young individuals with characteristic anamnestic data in our region. When parallel serum-CSF testing is warranted, AI should have priority. IgG and albumin concentrations in the both serum and the CSF, the potential time of exposure and the nature and duration of symptoms form the bare minimal set of data for conclusive testing.

Cholesterol Contributes to Risk, Severity, and Machine Learning-Driven Diagnosis of Lyme Disease

BACKGROUND

Lyme disease is the most prevalent vector-borne disease in the US, yet its host factors are poorly understood and diagnostic tests are limited. We evaluated patients in a large health system to uncover cholesterol's role in the susceptibility, severity, and machine learning-based diagnosis of Lyme disease.

METHODS

A longitudinal health system cohort comprised 1 019 175 individuals with electronic health record data and 50 329 with linked genetic data. Associations of blood cholesterol level, cholesterol genetic scores comprising common genetic variants, and burden of rare loss-of-function (LoF) variants in cholesterol metabolism genes with Lyme disease were investigated. A portable machine learning model was constructed and tested to predict Lyme disease using routine lipid and clinical measurements.

RESULTS

There were 3832 cases of Lyme disease. Increasing cholesterol was associated with greater risk of Lyme disease and hypercholesterolemia was more prevalent in Lyme disease cases than in controls. Cholesterol genetic scores and rare LoF variants in CD36 and LDLR were associated with Lyme disease risk. Serological profiling of cases revealed parallel trajectories of rising cholesterol and immunoglobulin levels over the disease course, including marked increases in individuals with LoF variants and high cholesterol genetic scores. The machine learning model predicted Lyme disease solely using routine lipid panel, blood count, and metabolic measurements.

CONCLUSIONS

These results demonstrate the value of large-scale genetic and clinical data to reveal host factors underlying infectious disease biology, risk, and prognosis and the potential for their clinical translation to machine learning diagnostics that do not need specialized assays.

Classical Borrelia Serology Does Not Aid in the Diagnosis of Persistent Symptoms Attributed to Lyme Borreliosis: A Retrospective Cohort Study

OBJECTIVE

The diagnosis of Lyme borreliosis is based on two-tier testing using an ELISA and Western blot. About 5-10% of patients report persistent symptoms of unknown etiology after treatment, resulting in substantial difficulties in further diagnostic workup. This paper presents a study aimed at determining whether serology can differentiate between patients with persistent symptoms attributed to Lyme and other patients with Lyme borreliosis.

METHODS

A retrospective cohort study included 162 samples from four subgroups: patients with persistent symptoms of Lyme (PSL), early Lyme borreliosis with erythema migrans (EM), patients tested in a general practitioner setting (GP), and healthy controls (HC). ELISA, Western blots, and multiplex assays from different manufacturers were used to determine inter-test variations in PSL and to compare reactivity against Borrelia-specific antigens among the groups.

RESULTS

In comparing the IgG and IgM reactivity by Western blot, IgG was more often positive in the PSL group than in the GP group. The individual antigen reactivity was similar between the PSL and EM or GP groups. Inter-test agreement among the manufacturers was variable, and agreement was higher for IgG testing compared to IgM.

CONCLUSIONS

Serological testing is unable to define the subgroup of patients with persistent symptoms attributed to Lyme borreliosis. Additionally, the current two-tier testing protocol shows a large variance among different manufacturers in these patients.

Common Neurologic Features of Lyme Disease That May Present to a Rheumatologist

Lyme disease, caused by Borrelia burgdorferi (Bb) infection, has a broad spectrum of clinical manifestations and severity. Patients with possible Lyme disease may seek out or be referred to rheumatologists. Today, the most common reason to engage a rheumatologist is due to complaints of arthralgia. After skin, neurologic manifestations of Lyme disease are now among the most common. Therefore, it is important for rheumatologists to be aware of clues that suggest neurologic Lyme disease and prompt help from a neurologist experienced with Lyme disease.

Testing Raman spectroscopy as a diagnostic approach for Lyme disease patients

Lyme disease (LD), the leading tick-borne disease in the Northern hemisphere, is caused by spirochetes of several genospecies of the Borreliella burgdorferi sensu lato complex. LD is a multi-systemic and highly debilitating illness that is notoriously challenging to diagnose. The main drawbacks of the two-tiered serology, the only approved diagnostic test in the United States, include poor sensitivity, background seropositivity, and cross-reactivity. Recently, Raman spectroscopy (RS) was examined for its LD diagnostic utility by our earlier proof-of-concept study. The previous investigation analyzed the blood from mice that were infected with 297 and B31 strains of Borreliella burgdorferi sensu stricto (s.s.). The selected strains represented two out of the three major clades of B. burgdorferi s.s. isolates found in the United States. The obtained results were encouraging and prompted us to further investigate the RS diagnostic capacity for LD in this study. The present investigation has analyzed blood of mice infected with European genospecies, Borreliella afzelii or Borreliella garinii, or B. burgdorferi N40, a strain of the third major class of B. burgdorferi s.s. in the United States. Moreover, 90 human serum samples that originated from LD-confirmed, LD-negative, and LD-probable human patients were also analyzed by RS. The overall results demonstrated that blood samples from Borreliella-infected mice were identified with 96% accuracy, 94% sensitivity, and 100% specificity. Furthermore, human blood samples were analyzed with 88% accuracy, 85% sensitivity, and 90% specificity. Together, the current data indicate that RS should be further explored as a potential diagnostic test for LD patients.

Evolution of the vls Antigenic Variability Locus of the Lyme Disease Pathogen and Development of Recombinant Monoclonal Antibodies Targeting Conserved VlsE Epitopes

VlsE (variable major protein-like sequence, expressed) is an outer surface protein of the Lyme disease pathogen (Borreliella species) responsible for its within-host antigenic variation and a key diagnostic biomarker of Lyme disease. However, the high sequence variability of VlsE poses a challenge to the development of consistent VlsE-based diagnostics and therapeutics. In addition, the standard diagnostic protocols detect immunoglobins elicited by the Lyme pathogen, not the presence of the pathogen or its derived antigens. Here, we described the development of recombinant monoclonal antibodies (rMAbs) that bound specifically to conserved epitopes on VlsE. We first quantified amino-acid sequence variability encoded by the vls genes from 13 B. burgdorferi genomes by evolutionary analyses. We showed broad inconsistencies of the sequence phylogeny with the genome phylogeny, indicating rapid gene duplications, losses, and recombination at the vls locus. To identify conserved epitopes, we synthesized peptides representing five long conserved invariant regions (IRs) on VlsE. We tested the antigenicity of these five IR peptides using sera from three mammalian host species including human patients, the natural reservoir white-footed mouse (Peromyscus leucopus), and VlsE-immunized New Zealand rabbits (Oryctolagus cuniculus). The IR4 and IR6 peptides emerged as the most antigenic and reacted strongly with both the human and rabbit sera, while all IR peptides reacted poorly with sera from natural hosts. Four rMAbs binding specifically to the IR4 and IR6 peptides were identified, cloned, and purified. Given their specific recognition of the conserved epitopes on VlsE, these IR-specific rMAbs are potential novel diagnostic and research agents for direct detection of Lyme disease pathogens regardless of strain heterogeneity. IMPORTANCE Current diagnostic protocols of Lyme disease indirectly detect the presence of antibodies produced by the patient upon infection by the bacterial pathogen, not the pathogen itself. These diagnostic tests tend to underestimate early-stage bacterial infections before the patients develop robust immune responses. Further, the indirect tests do not distinguish between active or past infections by the Lyme disease bacteria in a patient sample. Here, we described novel monoclonal antibodies that have the potential to become the basis of direct and definitive diagnostic detection of the Lyme disease pathogen, regardless of its genetic heterogeneity.

Utility of Whole Blood Real-Time PCR Testing for the Diagnosis of Early Lyme Disease

OBJECTIVES

Whole blood real-time polymerase chain reaction (WB-RTPCR) detection of Borrelia burgdorferi is not currently recommended for diagnosing Lyme disease. This study aims to elucidate the utility of WB-RTPCR as a diagnostic aid for early Lyme disease (ELD), defined as either positive PCR or positive immunoglobulin M with negative immunoglobulin G immunoblot.

METHODS

A retrospective analysis was performed on 33,199 blood specimens evaluated concurrently by WB-RTPCR and antibody-capture serology (ACEIA) methods (group A). Fifty-six pairs of specimens from a separate data set were retrospectively identified and analyzed at initial and follow-up time points to monitor for seroconversion (group B). Also, a separate data set of 2,526 specimens concurrently assessed by molecular and modified two-tiered enzyme-linked immunosorbent assay serology methods was analyzed (group C).

RESULTS

Group A yielded 1,379 specimens consistent with ELD when tested by ACEIA and WB-RTPCR. In total, 131 (9.5% of positive results) were identified by WB-RTPCR, with negative serology. Group C identified 358 samples compatible with ELD, with 31 (8.7% of positive results) identified by RTPCR alone.

CONCLUSIONS

When used concurrently with serologic testing, WB-RTPCR testing increases diagnostic sensitivity in cases of ELD.

Diagnostic Testing for Lyme Disease

Standard 2-tier testing (STTT), incorporating a screening enzyme immunoassay (EIA) or an immunofluorescence assay (IFA) that reflexes to IgM and IgG immunoblots, has been the primary diagnostic test for Lyme disease since 1995. In 2019, the Food and Drug Administration approved a modified 2-tier test strategy using 2 EIAs: offering a faster, less expensive, and more sensitive assay compared with STTT. New technologies examine early immune responses to Borrelia burgdorferi have the potential to diagnose Lyme disease in the first weeks of infection when existing serologic testing is not recommended due to low sensitivity.

Lyme neuroborreliosis: known knowns, known unknowns

Lyme borreliosis affects the nervous system in three principal ways-mononuclear cell meningitis, cranial neuropathies and radiculoneuropathies-the last a broad term encompassing painful radiculopathy, unifocal and multifocal peripheral nerve involvement. Diagnostic tools have been significantly refined-including improved peripheral blood and CSF serodiagnostics-and much has been learned about the interactions between the causative pathogen and the nervous system. Despite these advances in our understanding of this disease, a broad range of other disorders continue to be misattributed to nervous system Lyme borreliosis, supported by, at best, limited evidence. These misattributions often reflect limited understanding not only of Lyme neuroborreliosis but also of what constitutes nervous system disease generally. Fortunately, a large body of evidence now exists to clarify many of these issues, establishing a clear basis for diagnosing nervous system involvement in this infection and, based on well performed studies, clarifying which clinical disorders are associated with Lyme neuroborreliosis, which with non-neurologic Lyme borreliosis, and which with neither.

A Comparison of Lyme Serological Testing Platforms with a Panel of Clinically Characterized Samples from Various Stages of Lyme Disease

Background

In 2019, the CDC updated serology testing guidelines for Lyme disease diagnosis to include alternative modified two-tiered testing that replaces the western blots of standard testing with an additional ELISA. Antibody-capture serological assays have also been used as an aid for Lyme diagnosis. A panel of clinically characterized samples from the CDC was tested to compare modified two-tiered testing to the standard two-tiered algorithm and an antibody capture immunoassay.

Methods

A CDC panel of 92 samples comprised a range of samples including early Lyme, Lyme neuroborreliosis, Lyme arthritis, infections by other pathogens, and healthy controls. The panel was tested on a standard two-tiered platform by the CDC, the ZEUS Borrelia Test System for modified two-tiered testing, and a lab-developed antibody-capture serological assay. Sensitivity and specificity results from each assay were compared to determine significance.

Results

The antibody-capture assay demonstrated increased sensitivity but decreased specificity compared to the modified and standard two-tiered platforms. There was no statistical difference found between the modified and standard two-tiered platforms.

Conclusions

Improved sensitivity of antibody-capture when testing early Lyme disease samples is offset by decreased specificity, especially with syphilis-positive samples. Modified two-tiered testing is similar to standard two-tiered methods while also being more scalable and simpler to interpret.

Modified Two-Tiered Testing Enzyme Immunoassay Algorithm for Serologic Diagnosis of Lyme Disease

The modified 2-tier testing algorithm (MTTT) for Lyme disease (LD) has been approved by the US Food and Drug Administration. In this study, we show that the MTTT detected 28% more cases of early infection compared with the standard 2-tier algorithm while retaining high specificity in a region with a high incidence of LD.

Global seroprevalence and sociodemographic characteristics of Borrelia burgdorferi sensu lato in human populations: a systematic review and meta-analysis

Introduction

Borrelia burgdorferi sensu lato (Bb) infection, the most frequent tick-transmitted disease, is distributed worldwide. This study aimed to describe the global seroprevalence and sociodemographic characteristics of Bb in human populations.

Methods

We searched PubMed, Embase, Web of Science and other sources for relevant studies of all study designs through 30 December 2021 with the following keywords: ‘Borrelia burgdorferi sensu lato’ AND ‘infection rate’; and observational studies were included if the results of human Bb antibody seroprevalence surveys were reported, the laboratory serological detection method reported and be published in a peer-reviewed journal. We screened titles/abstracts and full texts of papers and appraised the risk of bias using the Cochrane Collaboration-endorsed Newcastle-Ottawa Quality Assessment Scale. Data were synthesised narratively, stratified by different types of outcomes. We also conducted random effects meta-analysis where we had a minimum of two studies with 95% CIs reported. The study protocol has been registered with PROSPERO (CRD42021261362).

Results

Of 4196 studies, 137 were eligible for full-text screening, and 89 (158 287 individuals) were included in meta-analyses. The reported estimated global Bb seroprevalence was 14.5% (95% CI 12.8% to 16.3%), and the top three regions of Bb seroprevalence were Central Europe (20.7%, 95% CI 13.8% to 28.6%), Eastern Asia (15.9%, 95% CI 6.6% to 28.3%) and Western Europe (13.5%, 95% CI 9.5% to 18.0%). Meta-regression analysis showed that after eliminating confounding risk factors, the methods lacked western blotting (WB) confirmation and increased the risk of false-positive Bb antibody detection compared with the methods using WB confirmation (OR 1.9, 95% CI 1.6 to 2.2). Other factors associated with Bb seropositivity include age ≥50 years (12.6%, 95% CI 8.0% to 18.1%), men (7.8%, 95% CI 4.6% to 11.9%), residence of rural area (8.4%, 95% CI 5.0% to 12.6%) and suffering tick bites (18.8%, 95% CI 10.1% to 29.4%).

Conclusion

The reported estimated global Bb seropositivity is relatively high, with the top three regions as Central Europe, Western Europe and Eastern Asia. Using the WB to confirm Bb serological results could significantly improve the accuracy. More studies are needed to improve the accuracy of global Lyme borreliosis burden estimates.

PROSPERO registration number

CRD42021261362.

Multicenter Clinical Evaluation of Modified Two-Tiered Testing Algorithms for Lyme Disease Using Zeus Scientific Commercial Assays

Modified two-tiered testing (MTTT) algorithms for Lyme disease (LD), which involve the sequential use of orthogonal enzyme immunoassays (EIAs) without immunoblotting, are acceptable alternatives to standard two-tiered testing (STTT; EIA followed by immunoblots) provided the EIAs have been FDA-cleared for this intended use. We evaluated four Zeus Scientific LD EIAs used in two distinct MTTT algorithms for FDA review. MTTT 1 used a VlsE1/pepC10 polyvalent EIA followed by a whole-cell sonicate (WCS) polyvalent EIA. MTTT 2 used the same first-tier EIA followed by separate IgM and IgG WCS EIAs. In a retrospective phase, we compared each MTTT algorithm to STTT using archived samples from LD patients or control subjects. In a prospective phase, we used the same algorithms to analyze consecutive excess samples submitted for routine LD serology to three clinical laboratories. For the retrospective phase, MTTTs 1 and 2 were more sensitive (56% and 74%) than STTT (41%; P ≤ 0.03) among 61 patients with acute erythema migrans (EM). In LD patients with neuroborreliosis, carditis, or arthritis (n = 75), sensitivity was comparable between algorithms (96 to 100%; P = 1.0). Among 190 control subjects without past LD, all algorithms were highly and comparably specific (≥99%, P = 0.48). For the prospective phase, (n = 2,932), positive percent-agreement (PPA), negative percent-agreement (NPA), and overall agreement of MTTT 1 with STTT were 93%, 97.7% and 97.4% (kappa 0.80). MTTT 2 yielded higher PPA (98%) but lower NPA (96.1%) and overall agreement (96.2%, kappa 0.74; all P < 0.05). Compared with STTT, both MTTT algorithms provided increased sensitivity in EM patients, comparable sensitivity in later disease and non-inferior specificity.

Antiphospholipid autoantibodies in Lyme disease arise after scavenging of host phospholipids by Borrelia burgdorferi

A close association with its vertebrate and tick hosts allows Borrelia burgdorferi, the bacterium responsible for Lyme disease, to eliminate many metabolic pathways and instead scavenge key nutrients from the host. A lipid-defined culture medium was developed to demonstrate that exogenous lipids are an essential nutrient of B. burgdorferi, which can accumulate intact phospholipids from its environment to support growth. Antibody responses to host phospholipids were studied in mice and humans using an antiphospholipid ELISA. Several of these environmentally acquired phospholipids including phosphatidylserine and phosphatidic acid, as well as borrelial phosphatidylcholine, are the targets of antibodies that arose early in infection in the mouse model. Patients with acute infections demonstrated antibody responses to the same lipids. The elevation of antiphospholipid antibodies predicted early infection with better sensitivity than did the standardized 2-tier tests currently used in diagnosis. Sera obtained from patients with Lyme disease before and after antibiotic therapy showed declining antiphospholipid titers after treatment. Further study will be required to determine whether these antibodies have utility in early diagnosis of Lyme disease, tracking of the response to therapy, and diagnosis of reinfection, areas in which current standardized tests are inadequate.

Maximum antigen diversification in a lyme bacterial population and evolutionary strategies to overcome pathogen diversity

Natural populations of pathogens and their hosts are engaged in an arms race in which the pathogens diversify to escape host immunity while the hosts evolve novel immunity. This co-evolutionary process poses a fundamental challenge to the development of broadly effective vaccines and diagnostics against a diversifying pathogen. Based on surveys of natural allele frequencies and experimental immunization of mice, we show high antigenic specificities of natural variants of the outer surface protein C (OspC), a dominant antigen of a Lyme Disease-causing bacterium (Borrelia burgdorferi). To overcome the challenge of OspC antigenic diversity to clinical development of preventive measures, we implemented a number of evolution-informed strategies to broaden OspC antigenic reactivity. In particular, the centroid algorithm-a genetic algorithm to generate sequences that minimize amino-acid differences with natural variants-generated synthetic OspC analogs with the greatest promise as diagnostic and vaccine candidates against diverse Lyme pathogen strains co-existing in the Northeast United States. Mechanistically, we propose a model of maximum antigen diversification (MAD) mediated by amino-acid variations distributed across the hypervariable regions on the OspC molecule. Under the MAD hypothesis, evolutionary centroids display broad cross-reactivity by occupying the central void in the antigenic space excavated by diversifying natural variants. In contrast to vaccine designs based on concatenated epitopes, the evolutionary algorithms generate analogs of natural antigens and are automated. The novel centroid algorithm and the evolutionary antigen designs based on consensus and ancestral sequences have broad implications for combating diversifying pathogens driven by pathogen-host co-evolution.

A focused review on Lyme disease diagnostic testing: An update on serology algorithms, current ordering practices, and practical considerations for laboratory implementation of a new testing algorithm

Lyme borreliosis or Lyme disease (LD) is the most prevalent tick-borne illness in the United States. Diagnosing LD can be challenging as symptoms can be nonspecific and the ability of laboratory tests to detect infection varies based on the duration of infection and the methodology used. To date, serology testing is the primary laboratory tool employed to aid in diagnosing LD. Since the mid-1990's, a two-tiered algorithm has been recommended for the optimization of specificity while maintaining high sensitivity. This mini-review aims to provide an overview of LD diagnostic testing in North America, with an emphasis on serologic algorithms, in particular the modified two-tiered testing (MTTT) algorithm, along with a discussion on provider ordering patterns and practical considerations for implementation of MTTT.

A Review of Post-treatment Lyme Disease Syndrome and Chronic Lyme Disease for the Practicing Immunologist

Lyme disease is an infection caused by Borrelia burgdorferi sensu lato, which is transmitted to humans through the bite of an infected Ixodes tick. The majority of patients recover without complications with antibiotic therapy. However, for a minority of patients, accompanying non-specific symptoms can persist for months following completion of therapy. The constellation of symptoms such as fatigue, cognitive dysfunction, and musculoskeletal pain that persist beyond 6 months and are associated with disability have been termed post-treatment Lyme disease syndrome (PTLDS), a subset of a broader term "chronic Lyme disease." Chronic Lyme disease is a broad, vaguely defined term that is used to describe patients with non-specific symptoms that are attributed to a presumed persistent Borrelia burgdorferi infection in patients who may or may not have evidence of either previous or current Lyme disease. The diagnoses of chronic Lyme disease and of PTLDS have become increasingly relevant to the practice of immunologists due to referrals for consultation or for intravenous immunoglobulin (IVIG) treatment. This review aims to explore the relationship between chronic Lyme disease, post-treatment Lyme disease syndrome, and the immune system. Here, we review the current literature on (1) issues in conventional and alternative diagnostic testing for Lyme disease, (2) the hypothesis that B. burgdorferi infection can persist despite appropriate use of recommended antibiotics, (3) current theories regarding B. burgdorferi's role in causing both immune dysregulation and protracted symptoms, and (4) the use of IVIG for the treatment of Lyme disease.

Optimizing use of multi-antibody assays for Lyme disease diagnosis: A bioinformatic approach

Multiple different recombinant and peptide antigens are now available for serodiagnosis of Lyme disease (LD), but optimizing test utilization remains challenging. Since 1995 the Centers for Disease Control and Prevention (CDC) has recommended a 2-tiered serologic approach consisting of a first-tier whole-cell enzyme immunoassay (EIA) for polyvalent antibodies to Borrelia burgdorferi followed by confirmation of positive or equivocal results by IgG and IgM immunoblots [standard 2-tiered (STT) approach]. Newer modified 2-tiered (MTT) approaches employ a second-tier EIA to detect antibodies to B. burgdorferi rather than immunoblotting. We applied modern bioinformatic techniques to a large public database of recombinant and peptide antigen-based immunoassays to improve testing strategy. A retrospective CDC collection of 280 LD samples and 559 controls had been tested using the STT approach as well as kinetic-EIAs for VlsE1-IgG, C6-IgG, VlsE1-IgM, and pepC10-IgM antibodies. When used individually, the cutoff for each kinetic-EIA was set to generate 99% specificity. Utilizing logistic-likelihood regression analysis and receiver operating characteristic (ROC) techniques we determined that VlsE1-IgG, C6-IgG, and pepC10-IgM antibodies each contributed significant diagnostic information; a single-tier diagnostic score (DS) was generated for each sample using a weighted linear combination of antibody levels to these 3 antigens. DS performance was then compared to the STT and to MTT models employing different combinations of kinetic-EIAs. After setting the DS cutoff to match STT specificity (99%), the DS was 22.5% more sensitive than the STT for early-acute-phase disease (95% CI: 11.8% to 32.2%), 16.0% more sensitive for early-convalescent-phase disease (95% CI: 7.2% to 24.7%), and equivalent for detection of disseminated infection. The DS was also significantly more sensitive for early-acute-phase LD than MTT models whose specificity met or exceeded 99%. Prospective validation of this single-tier diagnostic score for Lyme disease will require larger studies using a broader range of potential cross-reacting conditions.

The potential impact of Helicobacter pylori seropositivity on recombinant, antigen-based Lyme serology

We assessed the impact of Helicobacter pylori seropositivity on recombinant antigen-based Lyme serology. We compared the IgG ELISA+LIA (line immunoassay) reactivity of anti-Helicobacter IgG positive and negative samples. The ELISA S/Co values and LIA band numbers were identical. Our results suggest that Helicobacter seropositivity lacks an apparent effect on Lyme disease test reactivity.

Committee Opinion No. 399: Management of Tick Bites and Lyme Disease During Pregnancy

OBJECTIVE

Lyme disease is an emerging infection in Canada caused by the bacterium belonging to the Borrelia burgdorferi sensu lato species complex, which is transmitted via the bite of an infected blacklegged tick. Populations of blacklegged ticks continue to expand and are now established in different regions in Canada. It usually takes more than 24 hours of tick attachment to transfer B. burgdorferi to a human. The diagnosis of early localized Lyme disease is made by clinical assessment, as laboratory tests are not reliable at this stage. Most patients with early localized Lyme disease will present with a skin lesion (i.e., erythema migrans) expanding from the tick bite site and/or non-specific "influenza-like" symptoms (e.g., arthralgia, myalgia, and fever). Signs and symptoms may occur from between 3 and 30 days following the tick bite. The care of pregnant patients with a tick bite or suspected Lyme disease should be managed similarly to non-pregnant adults, including the consideration of antibiotics for prophylaxis and treatment. The primary objective of this committee opinion is to inform practitioners about Lyme disease and provide an approach to managing the care of pregnant women who may have been infected via a blacklegged tick bite.

INTENDED USERS

Health care providers who care for pregnant women or women of reproductive age.

TARGET POPULATION

Women of reproductive age.

EVIDENCE

In November 2018, Medline, EMBASE, PubMed, and CENTRAL databases were searched for 2 main categories: (1) Lyme disease and (2) other tick-borne diseases. Because the main focus was Lyme disease, and considering the limited number of the articles, no further filters were applied for publication time or type of study. For other tick-borne diseases, the results were restricted to a publication date within the last 10 years (2008-2018). The search terms were developed using MeSH terms and keywords including Lyme Disease, Pregnancy, Pregnant Women, Pregnancy Complications, Ehrlichiosis, Anaplasmosis, Rocky Mountain Spotted Fever, Babesiosis, Tularemia, Powassan Virus, Encephalitis Viruses, Tick-Borne, Tick-Borne Diseases, Colorado Tick Fever, Q Fever, Relapsing Fever, and Southern Tick-Associated Rash Illness. All articles on Lyme disease and other tick-borne diseases with a target population of pregnant women were included; other groups and populations were excluded.

VALIDATION METHODS

The content and recommendations of this committee opinion were drafted and agreed upon by the authors. The Board of Directors of the Society of Obstetricians and Gynaecologists of Canada approved the final draft for publication.

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.

Quantitative multiplexed strategies for human Lyme disease serological testing

Lyme disease, which is primarily caused by infection with the bacterium Borrelia burgdorferi in the United States or other Borrelia species internationally, presents an ongoing challenge for diagnostics. Serological testing is the primary means of diagnosis but testing approaches differ widely, with varying degrees of sensitivity and specificity. Moreover, there is currently no reliable test to determine disease resolution following treatment. A distinct challenge in Lyme disease diagnostics is the variable patterns of human immune response to a plurality of antigens presented by Borrelia spp. during the infection. Thus, multiplexed testing approaches that capture these patterns and detect serological response against multiple antigens may be the key to prompt, accurate Lyme disease diagnosis. In this review, current state-of-the-art multiplexed diagnostic approaches are presented and compared with respect to their diagnostic accuracy and their potential for monitoring response to treatment.

Clinical Practice Guidelines by the Infectious Diseases Society of America (IDSA), American Academy of Neurology (AAN), and American College of Rheumatology (ACR): 2020 Guidelines for the Prevention, Diagnosis and Treatment of Lyme Disease

This evidence-based clinical practice guideline for the prevention, diagnosis, and treatment of Lyme disease was developed by a multidisciplinary panel representing the Infectious Diseases Society of America (IDSA), the American Academy of Neurology (AAN), and the American College of Rheumatology (ACR). The scope of this guideline includes prevention of Lyme disease, and the diagnosis and treatment of Lyme disease presenting as erythema migrans, Lyme disease complicated by neurologic, cardiac, and rheumatologic manifestations, Eurasian manifestations of Lyme disease, and Lyme disease complicated by coinfection with other tick-borne pathogens. This guideline does not include comprehensive recommendations for babesiosis and tick-borne rickettsial infections, which are published in separate guidelines. The target audience for this guideline includes primary care physicians and specialists caring for this condition such as infectious diseases specialists, emergency physicians, internists, pediatricians, family physicians, neurologists, rheumatologists, cardiologists and dermatologists in North America.

Laboratory Diagnosis of Lyme Borreliosis

Lyme borreliosis is caused by a growing list of related, yet distinct, spirochetes with complex biology and sophisticated immune evasion mechanisms. It may result in a range of clinical manifestations involving different organ systems, and can lead to persistent sequelae in a subset of cases. The pathogenesis of Lyme borreliosis is incompletely understood, and laboratory diagnosis, the focus of this review, requires considerable understanding to interpret the results correctly. Direct detection of the infectious agent is usually not possible or practical, necessitating a continued reliance on serologic testing. Still, some important advances have been made in the area of diagnostics, and there are many promising ideas for future assay development. This review summarizes the state of the art in laboratory diagnostics for Lyme borreliosis, provides guidance in test selection and interpretation, and highlights future directions.

Serum Epitope Repertoire Analysis Enables Early Detection of Lyme Disease with Improved Sensitivity in an Expandable Multiplex Format

Widely employed diagnostic antibody serology for Lyme disease, known as standard two-tier testing (STTT), exhibits insufficient sensitivity in early Lyme disease, yielding many thousands of false-negative test results each year. Given this problem, we applied serum antibody repertoire analysis (SERA), or next-generation sequencing (NGS)-based serology, to discover IgG and IgM antibody epitope motifs capable of detecting Lyme disease-specific antibodies with high sensitivity and specificity. Iterative motif discovery and bioinformatic analysis of epitope repertoires from subjects with Lyme disease (n = 264) and controls (n = 391) yielded a set of 28 epitope motifs representing 20 distinct IgG antibody epitopes and a set of 38 epitope motifs representing 21 distinct IgM epitopes, which performed equivalently in a large validation cohort of STTT-positive samples. In a second validation set from subjects with clinically defined early Lyme disease (n = 119) and controls (n = 257), the SERA Lyme IgG and IgM assay exhibited significantly improved sensitivity relative to STTT (77% versus 62%; Z-test; P = 0.013) and improved specificity (99% versus 97%). Early Lyme disease subjects exhibited significantly fewer reactive epitopes (Mann-Whitney U test; P < 0.0001) relative to subjects with Lyme arthritis. Thus, SERA Lyme IgG and M panels provided increased accuracy in early Lyme disease in a readily expandable multiplex assay format.

C6 peptide enzyme immunoassay in Lyme borreliosis serology

The cut-off values used in C6 peptide-based enzyme immunoassay (EIA), a widely used test in Lyme borreliosis (LB) serology, have not been thoroughly analysed. The objective of the study was to examine the performance of the C6 EIA, and to determine optimal cut-off values for the test. The analysed data contained results of 1368 serum samples. C6 EIA index values were compared statistically with the immunoblot (IB) test results. The identified cut-off values were further tested in a well-defined LB patient cohort. Cut-off value 1.6 appeared to be optimal when C6 EIA was used as a stand-alone test. When using C6 EIA as the first-tier test, the optimal cut-off values were 0.9 and 2.4 for negative and positive results. When C6 EIA was used as a second-tier test, samples yielding C6 index values ≥3.0 could be considered positive. The identified cut-off values had also a high sensitivity to identify seropositivity among definite LB patients. The identified cut-off values refine the role of C6 EIA in LB serology. Importantly, the use of C6 EIA leads to a reduction in the number of samples that need to be analysed using an IB, thus also reducing the costs. Two alternative workflows for LB serology including the C6 EIA are suggested.

Immune Response to Borrelia: Lessons from Lyme Disease Spirochetes

The mammalian host responds to infection with Borrelia spirochetes through a highly orchestrated immune defense involving innate and adaptive effector functions aimed toward limiting pathogen burdens, minimizing tissue injury, and preventing subsequent reinfection. The evolutionary adaptation of Borrelia spirochetes to their reservoir mammalian hosts may allow for its persistence despite this immune defense. This review summarizes our current understanding of the host immune response to B. burgdorferi sensu lato, the most widely studied Borrelia spp. and etiologic agent of Lyme borreliosis. Pertinent literature will be reviewed with emphasis on in vitro, ex vivo and animal studies that influenced our understanding of both the earliest responses to B. burgdorferi as it enters the mammalian host and those that evolve as spirochetes disseminate and establish infection in multiple tissues. Our focus is on the immune response of inbred mice, the most commonly studied animal model of B. burgdorferi infection and surrogate for one of this pathogen's principle natural reservoir hosts, the white-footed deer mouse. Comparison will be made to the immune responses of humans with Lyme borreliosis. Our goal is to provide an understanding of the dynamics of the mammalian immune response during infection with B. burgdorferi and its relation to the outcomes in reservoir (mouse) and non-reservoir (human) hosts.

Diagnostic parameters of modified two-tier testing in European patients with early Lyme disease

Modified two-tier testing (MTTT) for Lyme borreliosis (i.e. confirmation with an EIA instead of an immunoblot) has been shown to have improved sensitivity compared with standard two-tier testing (STTT) in samples from American patients, without losing specificity. The current study assesses the sensitivity and specificity of various algorithms of MTTT in European patients with erythema migrans (EM) as a model disease for early Lyme borreliosis, and in appropriate controls. Four different immunoassays were used in the first tier, followed by either an immunoblot or the C6-EIA, or were used as standalone single-tier test. These tests were performed on consecutively collected sera of 228 Dutch patients with physician-diagnosed EM in the setting of general practice, 231 controls from the general population, and 50 controls with potentially cross-reactive antibodies. All the variants of MTTT that were studied had significantly higher sensitivity compared with their equivalent STTT, while retaining comparable specificity. Within the MTTT algorithms, classifying equivocal results as positive yielded better diagnostic parameters than classifying equivocal results as negative. The best diagnostic parameters were found using the Enzygnost-2 assay in the first tier, followed by a C6-ELISA in the second tier (sensitivity 77.6%, 95% CI 71.7-82.9; specificity 96.1%, 95% CI 92.7-98.2). This algorithm performed significantly better than the equivalent STTT algorithm in terms of sensitivity (p < 0.001), while maintaining comparable specificity (population controls p = 0.617). Our results show that MTTT can be a useful tool for the serodiagnosis of European patients with early Lyme borreliosis.

Seroprevalence, spatial distribution and risk factors of Borrelia burgdorferi sensu lato in Jordan

Lyme borreliosis has not been studied in Jordan or in much of the Middle East. However, limited research indicates that the tick vector, Ixodes ricinus, exists in the region. This study examined the seroprevalence of B. burgdorferi s.l. in Jordan and potential demographic and zoonotic risk factors for seropositivity. Serum samples of 824 apparently healthy participants from 11 governorates in Jordan were tested for B. burgdorferi s.l. using Enzygnost Lyme link VlsE/IgG enzyme-linked immunosorbent assay. A validated questionnaire was used to collect demographic and animal exposure data. Univariate and multivariate logistic regression were used to identify factors associated with seropositivity. The results showed that 11.7 % (95 % CI, 9.3-14.0 %) of the participants were seropositive for B. burgdorferi s.l.. There was a bimodal age distribution of seroprevalence with higher seroprevalence among individuals <20 and>60 years old. After controlling for governorate of residence, females had 2.77 (95 % CI 1.53-5.00) times greater odds of seropositivity compared to males. Individuals living in the southeastern part of Jordan (Ma'an) had 2.32 (95 % CI, 1.02-5.31) greater odds of seropositivity compared to those living in Amman, the Capital of Jordan, while those living in the northeast had significantly lower odds of seropositivity. This study presents the first evidence of B. burgdorferi s.l. seropositivity in Jordan and suggests several risk factors which were reported in studies conducted elsewhere. This study suggests that Lyme borreliosis should be considered in the differential diagnosis for patients presenting with skin lesions in Jordan.

Lyme Disease Biosensors: A Potential Solution to a Diagnostic Dilemma

Over the past four decades, Lyme disease has remained a virulent and pervasive illness, persisting throughout North America and many other regions of the world. Recent increases in illness in many countries has sparked a renewed interest in improved Lyme diagnostics. While current standards of diagnosis are acceptable for the late stages of the disease, it remains difficult to accurately diagnose early forms of the illness. In addition, current diagnostic methods tend to be relatively expensive and require a large degree of laboratory-based analysis. Biosensors represent the fusion of biological materials with chemical techniques to provide simple, inexpensive alternatives to traditional diagnostic methods. Lyme disease biosensors have the potential to better diagnose early stages of the illness and provide possible patients with an inexpensive, commercially available test. This review examines the current state of Lyme disease biosensing, with a focus on previous biosensor development and essential future considerations.

Lyme neuroborreliosis

PURPOSE OF REVIEW

To review the recent evidence clarifying the symptomatology and diagnosis of nervous system Lyme disease.

RECENT FINDINGS

Two-tier testing combining pairs of ELISAs, using C6 or VlsE assays to replace second tier Western blots, may eliminate confusion about test interpretation. Cerebrospinal fluid (CSF) can be informative in diagnosing central nervous system (CNS) Lyme disease, not peripheral nervous system (PNS) disorders. CSF CXCL13 may provide useful adjunctive information in CNS infection; its specificity remains to be defined. Lyme encephalopathy is not indicative of CNS infection. Post treatment Lyme disease symptoms do not occur in patients who have had definite CNS Lyme infection. Whether post treatment Lyme disease symptom (PTLDS) is an actual entity, or reflects anchoring bias when commonly occurring symptoms arise in patients previously treated for Lyme disease, remains to be determined. Regardless, these symptoms do not reflect CNS infection and do not respond to additional antimicrobial therapy.

SUMMARY

Serologic testing is robust in individuals with a priori likelihood of infection of greater than 2-6 weeks duration. Western blots provide useful confirmation of screening ELISAs, but may be replaced by second ELISAs. CSF testing, including CXCL13, may be informative in CNS Lyme, not PNS, and is generally normal in Lyme encephalopathy. PTLDS does not occur following CNS infection, and may not be a distinct entity.

Performance of a Modified Two-Tiered Testing Enzyme Immunoassay Algorithm for Serologic Diagnosis of Lyme Disease in Nova Scotia

Compared to the standard two-tiered testing (STTT) algorithm for Lyme disease serology using an enzyme immunoassay (EIA) followed by Western blotting, data from the United States suggest that a modified two-tiered testing (MTTT) algorithm employing two EIAs has improved sensitivity to detect early localized Borrelia burgdorferi infections without compromising specificity. From 2011 to 2014, in the Canadian province of Nova Scotia, where Lyme disease is hyperendemic, sera submitted for Lyme disease testing were subjected to a whole-cell EIA, followed by C6 EIA and subsequently IgM and/or IgG immunoblots on sera with EIA-positive or equivocal results. Here, we evaluate the effectiveness of the MTTT algorithm compared to the STTT approach in a Nova Scotian population. Retrospective chart reviews were performed on patients testing positive with the whole-cell and C6 EIAs (i.e., the MTTT algorithm). Patients were classified as having Lyme disease if they had a positive STTT result, a negative STTT result but symptoms consistent with Lyme disease, or evidence of seroconversion on paired specimens. Of the 10,253 specimens tested for Lyme disease serology, 9,806 (95.6%) were negative. Of 447 patients who tested positive, 271 charts were available for review, and 227 were classified as patients with Lyme disease. The MTTT algorithm detected 25% more early infections with a specificity of 99.56% (99.41 to 99.68%) compared to the STTT. These are the first Canadian data to show that serology using a whole-cell sonicate EIA followed by a C6 EIA (MTTT) had improved sensitivity for detecting early B. burgdorferi infection with specificity similar to that of two-tiered testing using Western blots.

Expanding Access to Biospecimens for Lyme Disease Test Development

The laboratory diagnosis of Lyme disease relies upon serologic testing. A standard or modified two-tiered testing algorithm is used to enhance the accuracy of antibody detection. However, this approach suffers from a lack of sensitivity in early Lyme disease. Ongoing efforts to develop more sensitive antibody detection technologies and other diagnostic approaches are dependent upon the availability of quality-assured biospecimens linked to reliable clinical data. In this issue of the Journal of Clinical Microbiology, Horn et al. (E. J. Horn, G. Dempsey, A. M. Schotthoefer, U. L. Prisco, et al., J Clin Microbiol 58:e00032-20, 2020, https://doi.org/10.1128/JCM.00032-20) described the development of the Lyme Disease Biobank. Clinically categorized case patients with early Lyme disease and healthy controls were identified (without laboratory diagnostic testing) from three sites where Lyme disease is endemic. Subjects provided whole blood and urine, which were processed and stored at a central biorepository. Whole blood, serum, and urine aliquots were prepared and are available to investigators developing laboratory diagnostics for Lyme disease. After obtaining samples, extensive laboratory testing was performed, including serologic and nucleic acid amplification testing for B. burgdorferi and other tick-borne pathogens. Direct detection methods yielded few positive results. Relative to the findings for another commonly used biorepository cohort, the results of this testing demonstrated a low seropositive rate, as determined by standard two-tiered testing. Additionally, relatively few subjects demonstrated seroconversion with testing of convalescent-phase samples. This clinical and serologically defined cohort of samples from Lyme disease and control cases from areas of Lyme disease endemicity offers an additional valuable resource for novel test development that includes alternate specimen types.

Modified two-tiered testing algorithm for Lyme disease serology: the Canadian context

BACKGROUND

Lyme disease (LD) is emerging in many parts of central and eastern Canada. Serological testing is most commonly used to support laboratory diagnosis of LD. Standard two-tiered testing (STTT) for LD involves detection of Borrelia burgdorferi antibodies using an enzyme immunoassay (EIA) followed by IgM and/or IgG immunoblots. However, improved sensitivity has been demonstrated using a modified two-tiered testing (MTTT) approach, in which a second EIA instead of the traditional immunoblot is used. This article summarises the evidence supporting the MTTT versus STTT for laboratory diagnosis of LD in Canada.

METHODS

Peer reviewed literature on the sensitivity and specificity of different EIAs were compared by Canadian experts in LD diagnostic for MTTT vs STTT in patients with clinical history of LD residing in LD endemic areas or in samples from the LD serum repository.

RESULTS

The MTTT approach consistently demonstrated improved sensitivity to detect early infections with B. burgdorferi and also maintained high specificity vs STTT.

CONCLUSION

Diagnostic improvements in sensitivity of LD testing without significant loss of specificity have been consistently reported when MTTT is compared with STTT in studies conducted in highly LD endemic regions. Our working group agrees with the recommendation by the United States Centers for Disease Control that serological testing for LD using MTTT is an acceptable alternative to STTT. This recommendation is contingent on development and implementation of comprehensive validation studies on the performance of MTTT vs STTT within the Canadian context, including evaluation of the test performance in areas of low endemicity for LD.

A Fully Automated Multiplex Assay for Diagnosis of Lyme Disease with High Specificity and Improved Early Sensitivity

Lyme borreliosis is a tick-borne disease caused by the Borrelia burgdorferi sensu lato complex. Bio-Rad Laboratories has developed a fully automated multiplex bead-based assay for the detection of IgM and IgG antibodies to B. burgdorferi The BioPlex 2200 Lyme Total assay exhibits an improved rate of seropositivity in patients with early Lyme infection. Asymptomatic subjects from endemic and nonendemic origins demonstrated a seroreactivity rate of approximately 4% that was similar to other commercial assays evaluated in this study. Coupled to this result was the observation that the Lyme Total assay retained a high first-tier specificity of 96% while demonstrating a relatively high sensitivity of 91% among a well-characterized CDC Premarketing Lyme serum panel. The Lyme Total assay also performs well under a modified two-tier algorithm (sensitivity, 84.4 to 88.9%; specificity, 98.4 to 99.5%). Furthermore, the new assay is able to readily detect early Lyme infection in patient samples from outside North America.

Multicenter Evaluation of the C6 Lyme ELISA Kit for the Diagnosis of Lyme Disease

Lyme disease (LD), caused by infection with Borrelia burgdorferi, is the most common tick-borne infection in many regions of Eurasia. Antibody detection is the most frequently used laboratory test, favoring a two-step serodiagnostic algorithm; immunoenzymatic detection of antibodies to C6 has been shown to perform similarly to a standard two-step workflow. The aim of this study was the performance evaluation of the C6 Lyme ELISA kit compared to a standard two-step algorithm in three laboratories located in the northeastern region of Italy which cater to areas with different LD epidemiology. A total of 804 samples were tested, of which 695 gave concordant results between C6 testing and routine workflow (564 negative, 131 positive). Wherever available, clinical presentation and additional laboratory tests were analyzed to solve discrepancies. The C6 based method showed a good concordance with the standard two-step algorithm (Cohen's κ = 0.619), however, the distribution of discrepancies seems to point towards a slightly lower specificity of C6 testing, which is supported by literature and could impact on patient management. The C6 ELISA, therefore, is not an ideal stand-alone test; however, if integrated into a two-step algorithm, it might play a part in achieving a sensitive, specific laboratory diagnosis of LD.

A fluorescent plasmonic biochip assay for multiplex screening of diagnostic serum antibody targets in human Lyme disease

Lyme disease (LD) diagnosis using the current two-tier algorithm is constrained by low sensitivity for early-stage infection and ambiguity in determining treatment response. We recently developed a protein microarray biochip that measures diagnostic serum antibody targets using grating-coupled fluorescent plasmonics (GC-FP) technology. This strategy requires microliters of blood serum to enable multiplexed biomarker screening on a compact surface and generates quantitative results that can be further processed for diagnostic scoring. The GC-FP biochip was used to detect serum antibodies in patients with active and convalescent LD, as well as various negative controls. We hypothesized that the quantitative, high-sensitivity attributes of the GC-FP approach permit: 1) screening of antibody targets predictive for LD status, and 2) development a diagnostic algorithm that is more sensitive, specific, and informative than the standard ELISA and Western blot assays. Notably, our findings led to a diagnostic algorithm that may be more sensitive than the current standard for detecting early LD, while maintaining 100% specificity. We further show that analysis of relative antibody levels to predict disease status, such as in acute and convalescent stages of infection, is possible with a highly sensitive and quantitative platform like GC-FP. The results from this study add to the urgent conversation regarding better diagnostic strategies and more effective treatment for patients affected by tick-borne disease.

Emerging Tick-Borne Diseases

Increases in tick-borne disease prevalence and transmission are important public health issues. Efforts to control these emerging diseases are frustrated by the struggle to control tick populations and to detect and treat infections caused by the pathogens that they transmit. This review covers tick-borne infectious diseases of nonrickettsial bacterial, parasitic, and viral origins. While tick surveillance and tracking inform our understanding of the importance of the spread and ecology of ticks and help identify areas of risk for disease transmission, the vectors are not the focus of this document. Here, we emphasize the most significant pathogens that infect humans as well as the epidemiology, clinical features, diagnosis, and treatment of diseases that they cause. Although detection via molecular or immunological methods has improved, tick-borne diseases continue to remain underdiagnosed, making the scope of the problem difficult to assess. Our current understanding of the incidence of tick-borne diseases is discussed in this review. An awareness of the diseases that can be transmitted by ticks in specific locations is key to detection and selection of appropriate treatment. As tick-transmitted pathogens are discovered and emerge in new geographic regions, our ability to detect, describe, and understand the growing public health threat must also grow to meet the challenge.

Evaluation of Patient IgM and IgG Reactivity Against Multiple Antigens for Improvement of Serodiagnostic Testing for Early Lyme Disease

Serologic testing is the standard for laboratory diagnosis and confirmation of Lyme disease. Serodiagnostic assays to detect antibodies against Borrelia burgdorferi, the agent of Lyme borreliosis, are used for detection of infection. However, serologic testing within the first month of infection is less sensitive as patients' antibody responses continue to develop. Previously, we screened several B. burgdorferi in vivo expressed antigens for candidates that elicit early antibody responses in patients with Stage 1 and 2 Lyme disease. We evaluated patient IgM seroreactivity against 6 antigens and found an increase in sensitivity without compromising specificity when compared to current IgM second-tier immunoblot scoring. In this study, we continued the evaluation using a multi-antigen panel to measure IgM plus IgG seroreactivity in these early Lyme disease patients' serum samples. Using two statistical methods for calculating positivity cutoff values, sensitivity was 70 and 84-87%, for early acute and early convalescent Lyme disease patients, respectively. Specificity was 98-100% for healthy non-endemic control patients, and 96-100% for healthy endemic controls depending on the statistical analysis. We conclude that improved serologic testing for early Lyme disease may be achieved by the addition of multiple borrelial antigens that elicit IgM and IgG antibodies early in infection.

What is the real number of Lyme disease cases in Canada?

BACKGROUND

Lyme disease is emerging in Canada due to expansion of the range of the tick vector Ixodes scapularis from the United States. National surveillance for human Lyme disease cases began in Canada in 2009. Reported numbers of cases increased from 144 cases in 2009 to 2025 in 2017. It has been claimed that few (< 10%) Lyme disease cases are reported associated with i) supposed under-diagnosis resulting from perceived inadequacies of serological testing for Lyme disease, ii) expectation that incidence in Canadian provinces and neighbouring US states should be similar, and iii) analysis of serological responses of dogs to the agent of Lyme disease, Borrelia burgdorferi. We argue that performance of serological testing for Lyme disease is well studied, and variations in test performance at different disease stages are accounted for in clinical diagnosis of Lyme disease, and in surveillance case definitions. Extensive surveillance for tick vectors has taken place in Canada providing a clear picture of the emergence of risk in the Canadian environment. This surveillance shows that the geographic scope of I. scapularis populations and Lyme disease risk is limited but increasing in Canada. The reported incidence of Lyme disease in Canada is consistent with this pattern of environmental risk, and the differences in Lyme disease incidence between US states and neighbouring Canadian provinces are consistent with geographic differences in environmental risk. Data on serological responses in dogs from Canada and the US are consistent with known differences in environmental risk, and in numbers of reported Lyme disease cases, between the US and Canada.

CONCLUSION

The high level of consistency in data from human case and tick surveillance, and data on serological responses in dogs, suggests that a high degree of under-reporting in Canada is unlikely. We speculate that approximately one third of cases are reported in regions of emergence of Lyme disease, although prospective studies are needed to fully quantify under-reporting. In the meantime, surveillance continues to identify and track the ongoing emergence of Lyme disease, and the risk to the public, in Canada.

Epidemiology of Lyme disease among US Veterans in Long Island, New York

In North America, Lyme disease (LD) is caused predominantly by the spirochete Borrelia burgdorferisensu stricto, and is transmitted by blacklegged ticks. Long Island, New York, is highly endemic for the disease. The C6 peptide (C6P) is currently used as a screening test for LD in our institution. Our objective was to examine how screening with C6P concorded with diagnosis of LD at the Veterans Affairs Medical Center, Northport, Long Island. A retrospective chart-review of 2558 C6P tests was performed during the period of 1/1/2010 to 12/31/2016. Patients were categorized by Lyme Disease (LD) or no LD groups. LD group was defined as having an erythema migrans (EM) rash, or ≥ 2 IgM bands or ≥ 5 IgG bands on immunoblot. Out of the 409 patients with positive or equivocal C6P, 181 patients with LD were based on presence of EM, or Western blot IgM and IgG test results; 228 did not have LD. The positive predictive value of C6P was 44.5%. EM was the most common presentation. In the LD group, history of tick bite (P: 0.0001), headache (P: 0.0036), joint swelling (P: 0.0086) and myalgias (P: 0.0005) were more likely to be present. Zip code mapping of our cases mirrored those previously reported in the Suffolk County Department of Health. In our review we encountered a significant number of false positive C6 assays. False positive C6P tests were ordered by primary care physicians (PCP) (37%) followed by neurologists (33%). A history of tick exposure and clinical findings of early Lyme disease such as headaches or joint aches were more likely to denote a true positive C6 peptide test. Rigorous education of physicians about Lyme disease and pitfalls of our available diagnostic tests are needed for their proper utilization.

Evaluation of a Novel Microarray Immunoblot Assay for Detection of IgM- and IgG-Class Antibodies to Borrelia burgdorferi

Diagnostic testing for Lyme disease (LD) remains dependent on detection of antibodies to LD Borrelia using serologic assays, in adherence to the standard two-tiered testing (STTT) algorithm. We present the first analytic evaluation of the automated Borrelia B31 ViraChip IgM and IgG microarray immunoblot (MIB) assays (Viramed Biotech AG, Planegg, Germany) in comparison to two different, semiautomated blot assays for LD, including the Borrelia B31 ViraStripe IgM and IgG line immunoassays (LIAs) (Viramed) and the MarDx Borrelia burgdorferi IgM and IgG Western blot (WB) assays (Trinity Biotech, Carlsbad, CA), using prospectively collected sera (n = 411) and archived, clinically characterized samples (n = 91). We show comparable overall agreement (>84%) of the ViraChip MIB assays against the two aforementioned LD blot methods. The ViraChip MIB assays were also compared to a consensus standard, whereby samples were classified as positive or negative for IgM or IgG to B. burgdorferi if the analyte-matched ViraStripe LIA or MarDx WB assay were positive or negative, respectively. The ViraChip IgM and IgG MIB assays showed >93% positive, negative, and overall agreement versus these consensus criteria. The ViraChip MIB assays were associated with a time savings of 28 min to process one full batch of samples compared to the time required for the ViraStripe LIAs. The ViraChip MIB assays can be programmed and performed on an open-system, automated enzyme-linked immunosorbent assay (ELISA) processor, negating the need for assay-specific equipment and enabling laboratories to consolidate LD testing onto a single platform. We conclude that the ViraChip IgM and IgG MIB assays may be added to the repertoire of supplemental, second-tier blot testing systems for diagnosis of LD.