The C6 Lyme antibody test has low sensitivity for antibody detection in cerebrospinal fluid

Retrospective Evaluation of Various Serological Assays and Multiple Parameters for Optimal Diagnosis of Lyme Neuroborreliosis in a Routine Clinical Setting

Laboratory diagnosis of Lyme neuroborreliosis (LNB) is challenging, and validated diagnostic algorithms are lacking. Therefore, this retrospective cross-sectional study aimed to compare the diagnostic performance of seven commercial antibody assays for LNB diagnosis. Random forest (RF) modeling was conducted to investigate whether the diagnostic performance using the antibody assays could be improved by including several routine cerebrospinal fluid (CSF) parameters (i.e., leukocyte count, total protein, blood-CSF barrier functionality, and intrathecal total antibody synthesis), two-tier serology on serum, the CSF level of the B-cell chemokine (C-X-C motif) ligand 13 (CXCL13), and a Borrelia species PCR on CSF. In total, 156 patients were included who were classified as definite LNB (n = 10), possible LNB (n = 7), or non-LNB patient (n = 139) according to the criteria of the European Federation of Neurological Societies using a consensus strategy for intrathecal Borrelia-specific antibody synthesis. The seven antibody assays showed sensitivities ranging from 47.1% to 100% and specificities ranging from 95.7% to 100%. RF modeling demonstrated that the sensitivities of most antibody assays could be improved by including other parameters to the diagnostic repertoire for diagnosing LNB (range: 94.1% to 100%), although with slightly lower specificities (range: 92.8% to 96.4%). The most important parameters for LNB diagnosis are the detection of intrathecally produced Borrelia-specific antibodies, two-tier serology on serum, CSF-CXCL13, Reibergram classification, and pleocytosis. In conclusion, this study shows that LNB diagnosis is best supported using multiparameter analysis. Furthermore, a collaborative prospective study is proposed to investigate if a standardized diagnostic algorithm can be developed for improved LNB diagnosis. IMPORTANCE The diagnosis of LNB is established by clinical symptoms, pleocytosis, and proof of intrathecal synthesis of Borrelia-specific antibodies. Laboratory diagnosis of LNB is challenging, and validated diagnostic algorithms are lacking. Therefore, this retrospective cross-sectional study aimed to compare the diagnostic performance of seven commercial antibody assays for LNB diagnosis. Multiparameter analysis was conducted to investigate whether the diagnostic performance using the antibody assays could be improved by including several routine (CSF) parameters. The results of this study show that LNB diagnosis is best supported using the detection of intrathecally produced Borrelia-specific antibodies, two-tier serology on serum, CSF-CXCL13, Reibergram classification, and pleocytosis. Furthermore, we propose a collaborative prospective study to investigate the potential role of constructing a diagnostic algorithm using multiparameter analysis for improved LNB diagnosis.

Efficient detection of symptomatic and asymptomatic patient samples for Babesia microti and Borrelia burgdorferi infection by multiplex qPCR

BACKGROUND

Tick-borne infections have been increasing steadily over the years, with co-infections with Borrelia burgdorferi and Babesia microti/divergens emerging as a serious health problem. B. burgdorferi is a spirochetal bacterium that causes Lyme disease while protozoan pathogens belonging to Babesia species are responsible for babesiosis. Currently used serological tests do not always detect acute Lyme disease or babesiosis, and fail to differentiate cured patients from those who get re-infected. This is a major problem for proper diagnosis particularly in regions endemic for tick-borne diseases. Microscopy based evaluation of babesiosis is confirmatory but is labor intensive and insensitive such that many asymptomatic patients remain undetected and donate blood resulting in transfusion transmitted babesiosis.

RESULTS

We conducted multiplex qPCR for simultaneous diagnosis of active Lyme disease and babesiosis in 192 blood samples collected from a region endemic for both diseases. We document qPCR results obtained from testing of each sample three times to detect infection with each pathogen separately or together. Results for Lyme disease by qPCR were also compared with serological tests currently used for Lyme disease when available. Considering at least two out of three test results for consistency, 18.2% of patients tested positive for Lyme disease, 18.7% for co-infection with B. burgdorferi and B. microti and 6.3% showed only babesiosis.

CONCLUSIONS

With an 80% sensitivity for detection of Lyme disease, and ability to detect co-infection with B. microti, multiplex qPCR can be employed for diagnosis of these diseases to start appropriate treatment in a timely manner.

Application of Bayesian decision-making to laboratory testing for Lyme disease and comparison with testing for HIV

In this study, Bayes' theorem was used to determine the probability of a patient having Lyme disease (LD), given a positive test result obtained using commercial test kits in clinically diagnosed patients. In addition, an algorithm was developed to extend the theorem to the two-tier test methodology. Using a disease prevalence of 5%-75% in samples sent for testing by clinicians, evaluated with a C6 peptide enzyme-linked immunosorbent assay (ELISA), the probability of infection given a positive test ranged from 26.4% when the disease was present in 5% of referrals to 95.3% when disease was present in 75%. When applied in the case of a C6 ELISA followed by a Western blot, the algorithm developed for the two-tier test demonstrated an improvement with the probability of disease given a positive test ranging between 67.2% and 96.6%. Using an algorithm to determine false-positive results, the C6 ELISA generated 73.6% false positives with 5% prevalence and 4.7% false positives with 75% prevalence. Corresponding data for a group of test kits used to diagnose HIV generated false-positive rates from 5.4% down to 0.1% indicating that the LD tests produce up to 46 times more false positives. False-negative test results can also influence patient treatment and outcomes. The probability of a false-negative test for LD with a single test for early-stage disease was high at 66.8%, increasing to 74.9% for two-tier testing. With the least sensitive HIV test used in the two-stage test, the false-negative rate was 1.3%, indicating that the LD test generates ~60 times as many false-negative results. For late-stage LD, the two-tier test generated 16.7% false negatives compared with 0.095% false negatives generated by a two-step HIV test, which is over a 170-fold difference. Using clinically representative LD test sensitivities, the two-tier test generated over 500 times more false-negative results than two-stage HIV testing.

Commercial test kits for detection of Lyme borreliosis: a meta-analysis of test accuracy

The clinical diagnosis of Lyme borreliosis can be supported by various test methodologies; test kits are available from many manufacturers. Literature searches were carried out to identify studies that reported characteristics of the test kits. Of 50 searched studies, 18 were included where the tests were commercially available and samples were proven to be positive using serology testing, evidence of an erythema migrans rash, and/or culture. Additional requirements were a test specificity of ≥85% and publication in the last 20 years. The weighted mean sensitivity for all tests and for all samples was 59.5%. Individual study means varied from 30.6% to 86.2%. Sensitivity for each test technology varied from 62.4% for Western blot kits, and 62.3% for enzyme-linked immunosorbent assay tests, to 53.9% for synthetic C6 peptide ELISA tests and 53.7% when the two-tier methodology was used. Test sensitivity increased as dissemination of the pathogen affected different organs; however, the absence of data on the time from infection to serological testing and the lack of standard definitions for “early” and “late” disease prevented analysis of test sensitivity versus time of infection. The lack of standardization of the definitions of disease stage and the possibility of retrospective selection bias prevented clear evaluation of test sensitivity by “stage”. The sensitivity for samples classified as acute disease was 35.4%, with a corresponding sensitivity of 64.5% for samples from patients defined as convalescent. Regression analysis demonstrated an improvement of 4% in test sensitivity over the 20-year study period. The studies did not provide data to indicate the sensitivity of tests used in a clinical setting since the effect of recent use of antibiotics or steroids or other factors affecting antibody response was not factored in. The tests were developed for only specific Borrelia species; sensitivities for other species could not be calculated.

Chronic Lyme; diagnostic and therapeutic challenges

In this review, we aim to discuss the definition, clinical and laboratory features, diagnostics, and management of chronic Lyme. Chronic Lyme is a rare condition caused by long-lasting and ongoing infection with the spirochete Borrelia burgdorferi (Bb). The most common manifestations are progressive encephalitis, myelitis, acrodermatitis chronica atrophicans with or without neuropathy, and arthritis. Chronic Lyme is not considered to present with isolated subjective symptoms. Direct detection of Bb has low yield in most manifestations of chronic Lyme, while almost 100% of the cases are seropositive, that is, have detectable Bb IgG antibodies in serum. Detection of Bb antibodies only with Western blot technique and not with ELISA and detection of Bb IgM antibodies without simultaneous detection of Bb IgG antibodies should be considered as seronegativity in patients with long-lasting symptoms. Patients with chronic Lyme in the nervous system (neuroborreliosis) have, with few exceptions, pleocytosis and production of Bb antibodies in their cerebrospinal fluid. Strict guidelines should be applied in diagnostics of chronic Lyme, and several differential diagnoses, including neurological disease, rheumatologic disease, post-Lyme disease syndrome, chronic fatigue syndrome, and psychiatric disease, should be considered in the diagnostic workup. Antibiotic treatment with administration route and dosages according to current guidelines are recommended. Combination antimicrobial therapy or antibiotic courses longer than 4 weeks are not recommended. Patients who attribute their symptoms to chronic Lyme on doubtful basis should be offered a thorough and systematic diagnostic approach, and an open and respectful dialogue.

High sensitivity and specificity of the C6-peptide ELISA on cerebrospinal fluid in Lyme neuroborreliosis patients

Lyme neuroborreliosis (LNB) is a serious but treatable disease. The diagnosis of LNB poses a challenge to clinicians, and improved tests are needed. The C6-peptide ELISA is frequently used on serum but not on cerebrospinal fluid (CSF). Data on the sensitivity of the C6-peptide ELISA in CSF in patients suffering from LNB have been conflicting. Serum-CSF pairs from 59 LNB patients, 36 Lyme non-neuroborreliosis cases, 69 infectious meningitis/encephalitis controls and 74 neurological controls were tested in a C6-peptide ELISA. With the optimal cut-off of 1.1, the sensitivity of the C6-peptide ELISA for LNB patients in CSF was 95%, and the specificity was 83% in the Lyme non-neuroborreliosis patients, 96% in the infectious controls, and 97% in the neurological controls. These results suggest that the C6-peptide ELISA has a high sensitivity and good specificity for the diagnosis of LNB patients in CSF. The C6-peptide ELISA can be used on CSF in a clinical setting to screen for LNB.

Diagnostic performance of cerebrospinal fluid chemokine CXCL13 and antibodies to the C6-peptide in Lyme neuroborreliosis

OBJECTIVES

The aim of this study was to evaluate the chemokine CXCL13 and C6 antibodies separately and in combination in paired serum/cerebrospinal fluid (CSF) samples in the laboratory diagnosis of Lyme neuroborreliosis (LNB).

METHODS

A large retrospective material with paired serum/CSF samples from 261 patients with clinically suspected LNB was investigated. Patients were divided into three main diagnostic groups based on original results of CSF pleocytosis and intrathecal anti-borrelia antibodies (purified flagellum). Levels of CXCL13, albumin, total IgM and IgG in paired samples and C6 antibodies in CSF were compared across diagnostic groups.

RESULTS

A sensitivity of 99% and a specificity of 96% were achieved for CSF-Serum CXCL13 ratio. CSF-C6 antibodies performed with a sensitivity of 99% and a specificity of 88.0%. A combination of CSF-Serum CXCL13 ratio and CSF-C6 antibodies, evaluated in parallel, revealed a sensitivity of 99% and specificity of 98%.

CONCLUSIONS

This study confirms CSF-CXCL13 as a reliable marker of LNB and suggests improved diagnostic performance especially in children with possible LNB.

Humoral immune responses in patients with Lyme neuroborreliosis

The aim of this study was to analyze and compare the humoral immune responses in serum and cerebrospinal fluid (CSF) for 34 adult patients with clinically evident Lyme neuroborreliosis, 27 patients with clinically suspected Lyme neuroborreliosis, and 32 patients with tick-borne encephalitis. Additionally, we wanted to compare the findings of two methods for the detection of intrathecally synthesized borrelial antibodies: the IDEIA Lyme neuroborreliosis test using flagellar antigen and an approach based on the Liaison indirect chemiluminescence immunoassay using the OspC and VlsE antigens. Borrelial IgM and IgG antibodies were detected by at least one of these methods in the sera of 22/34 (64.7%) and 28/34 (82.4%) patients with clinically evident Lyme neuroborreliosis, respectively, and in the cerebrospinal fluid of 22/34 (64.7%) and 20/34 (58.8%) of these patients, respectively. Intrathecal synthesis of borrelial IgM and/or IgG was found in 19/34 (55.9%) patients: IgM in 17/34 (50%) patients and IgG in 15/34 (44.1%) patients. The relatively low proportion of intrathecal synthesis of borrelial antibodies and the high ratio of IgM positivity could be explained by the short duration of neurological disease as evidenced by reported symptoms (median, 10 days). Assessment of the humoral immune response in the sera and CSF of patients with early Lyme neuroborreliosis confirmed previous findings on the relationship between the duration of illness and the proportion of patients with detectable responses.