Lyme borreliosis in Sweden--diagnostic performance of five commercial Borrelia serology kits using sera from well-defined patient groups

The diagnostic accuracy of serological tests for Lyme borreliosis in Europe: a systematic review and meta-analysis

Background

Interpretation of serological assays in Lyme borreliosis requires an understanding of the clinical indications and the limitations of the currently available tests. We therefore systematically reviewed the accuracy of serological tests for the diagnosis of Lyme borreliosis in Europe.

Methods

We searched EMBASE en MEDLINE and contacted experts. Studies evaluating the diagnostic accuracy of serological assays for Lyme borreliosis in Europe were eligible. Study selection and data-extraction were done by two authors independently. We assessed study quality using the QUADAS-2 checklist. We used a hierarchical summary ROC meta-regression method for the meta-analyses. Potential sources of heterogeneity were test-type, commercial or in-house, Ig-type, antigen type and study quality. These were added as covariates to the model, to assess their effect on test accuracy.

Results

Seventy-eight studies evaluating an Enzyme-Linked ImmunoSorbent assay (ELISA) or an immunoblot assay against a reference standard of clinical criteria were included. None of the studies had low risk of bias for all QUADAS-2 domains. Sensitivity was highly heterogeneous, with summary estimates: erythema migrans 50 % (95 % CI 40 % to 61 %); neuroborreliosis 77 % (95 % CI 67 % to 85 %); acrodermatitis chronica atrophicans 97 % (95 % CI 94 % to 99 %); unspecified Lyme borreliosis 73 % (95 % CI 53 % to 87 %). Specificity was around 95 % in studies with healthy controls, but around 80 % in cross-sectional studies. Two-tiered algorithms or antibody indices did not outperform single test approaches.

Conclusions

The observed heterogeneity and risk of bias complicate the extrapolation of our results to clinical practice. The usefulness of the serological tests for Lyme disease depends on the pre-test probability and subsequent predictive values in the setting where the tests are being used. Future diagnostic accuracy studies should be prospectively planned cross-sectional studies, done in settings where the test will be used in practice.

Lyme disease: point/counterpoint

Lyme disease represents a growing public health threat. The controversial science and politics of Lyme disease have created barriers to reliable diagnosis and effective treatment of this protean illness. Two major clinical hurdles are the absence of a therapeutic end point in treating Borrelia burgdorferi, the spirochetal agent of Lyme disease, and the presence of tickborne coinfections with organisms such as Babesia, Anaplasma, Ehrlichia and Bartonella that may complicate the course of the disease. From a pathophysiologic standpoint, the affinity of Borrelia burgdorferi for multiple cell types and the presence of nonreplicating forms of the Lyme disease spirochete have contributed to persistent infection and failure of simple antibiotic regimens. Newer approaches to the treatment of Lyme disease should take into account its clinical complexity in coinfected patients and the possible need for prolonged combination therapy in patients with persistent symptoms of this potentially debilitating illness. The optimal antibiotic regimen for chronic Lyme disease remains to be determined.

Sensitive multiplex PCR assay to differentiate Lyme spirochetes and emerging pathogens Anaplasma phagocytophilum and Babesia microti

Background

The infection with Borrelia burgdorferi can result in acute to chronic Lyme disease. In addition, coinfection with tick-borne pathogens, Babesia species and Anaplasma phagocytophilum has been increasing in endemic regions of the USA and Europe. The currently used serological diagnostic tests are often difficult to interpret and, moreover, antibodies against the pathogens persist for a long time making it difficult to confirm the cure of the disease. In addition, these tests cannot be used for diagnosis of early disease state before the adaptive immune response is established. Since nucleic acids of the pathogens do not persist after the cure, DNA-based diagnostic tests are becoming highly useful for detecting infectious diseases.

Results

In this study, we describe a real-time multiplex PCR assay to detect the presence of B. burgdorferi, B. microti and A. phagocytophilum simultaneously even when they are present in very low copy numbers. Interestingly, this quantitative PCR technique is also able to differentiate all three major Lyme spirochete species, B. burgdorferi, B. afzelii, and B. garinii by utilizing a post-PCR denaturation profile analysis and a single molecular beacon probe. This could be very useful for diagnosis and discrimination of various Lyme spirochetes in European countries where all three Lyme spirochete species are prevalent. As proof of the principle for patient samples, we detected the presence of low number of Lyme spirochetes spiked in the human blood using our assay. Finally, our multiplex assay can detect all three tick-borne pathogens in a sensitive and specific manner irrespective of the level of each pathogen present in the sample. We anticipate that this novel diagnostic method will be able to simultaneously diagnose early to chronic stages of Lyme disease, babesiosis and anaplasmosis using the patients’ blood samples.

Conclusion

Real-time quantitative PCR using specific primers and molecular beacon probes for the selected amplicon described in this study can detect three tick-borne pathogens simultaneously in an accurate manner.

Diagnostic accuracy and comparison of two assays for Borrelia-specific IgG and IgM antibodies: proposals for statistical evaluation methods, cut-off values and standardization

Two assays (Liaison, Diasorin; IDEIA, Oxoid) for detection of Borrelia-specific antibodies were compared. A case-control design using patients with neuroborreliosis (n = 48), laboratory defined by a positive Borrelia-specific antibody index in the spinal fluid, was available and was intended to represent the serological response of disseminated early Lyme borreliosis in general. Serum samples were obtained from 216 Danish blood donors as controls. By comparing sensitivity and specificity using pre-specified cut-off values, significant differences were found. However, using receiver operating characteristic (ROC) curves to optimize and standardize test interpretation, it was shown that testing with both IDEIA IgG and IgM was comparable to testing with Liaison IgG alone by comparing the area under the curve of the diagnostically relevant 25 % partial ROC curve (P = 0.1). When using the Liaison OspC/VlsE IgM assay, the specificity was decreased without a gain in sensitivity. This study proposes standardizing of reporting by using a control population as the reference and choosing decision thresholds guided by the risk of false-positive results at 2 and 8 %. The sensitivities for IDEIA (IgG and IgM combined) were 85 and 95 % and for the Liaison (VlsE IgG) method were 67 and 96 %, respectively. Methods for test evaluation, test interpretation and statistical testing are presented and discussed. In conclusion, Liaison VlsE IgG alone and IDEIA IgG/IgM combined showed a high and comparable discriminatory ability to distinguish serum samples from patients with neuroborreliosis from blood donor controls. However, cut-off values should be adjusted for a proper comparison.

Clinical, diagnostic and immunological characteristics of patients with possible neuroborreliosis without intrathecal Ig-synthesis against Borrelia antigen in the cerebrospinal fluid

The diagnosis of neuroborreliosis is not always straightforward. Intrathecal immunoglobulin (Ig) synthesis against Borrelia antigen may not be detected, at least early in the disease course. Also other neurological and infectious diagnoses have to be considered. We have studied patients with clinical possible neuroborreliosis without intrathecal Ig synthesis against Borrelia antigen in the cerebrospinal fluid (CSF) (n=17). Diagnosis was based on typical clinical history and at least one of the following findings; mononuclear leucocytosis in the CSF (n=4); typical erythema migrans >5 cm in diameter in relation to debut of symptoms (n=8); prompt clinical response to antibiotic teratment (n=14). Also other possible diagnoses had to be excluded. Seventeen patients first investigated because of suspected neuroborreliosis but later confirmed with other diagnoses were used as controls. All patients had a lumbar puncture. Borrelia specific IFN-γ and IL-4 secretion was investigated in peripheral blood (PBL) and CSF with an ELISPOT assay. Polymerase chain reaction (PCR) was used to reveal any Borrelia antigen in the CSF. Six of 17 patients with possible neuroborreliosis showed high IFN-γ secretion in peripheral blood, otherwise we found no statistically significant differences between the groups. PCR did not reveal any Borrelia antigen in CSF. The diagnosis and treatment of possible but not confirmed neuroborreliosis is a clinical challenge. The clinical response to treatment may be the best option in these cases.

Low risk of developing Borrelia burgdorferi infection in the south-east of Sweden after being bitten by a Borrelia burgdorferi-infected tick

OBJECTIVES

The risk of developing Lyme borreliosis (LB) from Borrelia burgdorferi sensu lato (Bb)-infected ticks in Sweden is largely unknown. In the current study, we investigated the prevalence of Bb in ticks that had bitten humans and the risk of developing LB from Bb-infected ticks.

METHODS

Health questionnaires, blood samples, and ticks were collected from 394 tick-bitten study subjects in the County of Östergötland, Sweden, at the time of the tick bite. Questionnaires and blood samples were also collected 3 months later. Ticks were screened for Bb DNA with PCR, while sera were analyzed for antibodies against Bb using two ELISA assays. Seroconversion, i.e., an at least two-fold increase in anti-Bb antibodies after 3 months, was confirmed using a Strip-Immunoassay.

RESULTS

Seventy-five of 397 ticks collected from the study subjects were determined to be Bb-positive. Sixty-four of the tick-bitten subjects had been bitten by Bb-infected ticks. Four of them showed seroconversion and were therefore considered to have an active Bb infection. None of these four subjects had sought health care due to symptoms, but one reported symptoms.

CONCLUSIONS

Our data suggest that the risk of developing LB after being bitten by a Bb-infected tick is low, and asymptomatic Bb infections appear to be more frequent than symptomatic infections.

Improved laboratory diagnostics of Lyme neuroborreliosis in children by detection of antibodies to new antigens in cerebrospinal fluid

BACKGROUND

Laboratory diagnostics in Lyme neuroborreliosis need improvement. We hereby investigate 4 new recombinant or peptide Borrelia antigens in cerebrospinal fluid in children with neuroborreliosis to evaluate their performance as diagnostic antigens.

METHODS

An enzyme-linked immunosorbent assay was used to detect IgG antibodies to recombinant decorin binding protein A (DbpA), BBK32, outer surface protein C (OspC), and the invariable region 6 peptide (IR6). The recombinant antigens originated from 3 pathogenic subspecies; Borrelia afzelii, Borrelia garinii, and Borrelia burgdorferi sensu stricto. Cerebrospinal fluid and serum from children with clinical features indicative for neuroborreliosis (n = 57) were analyzed. Classification of patients was based on clinical symptoms and laboratory findings. Controls were children with other neurologic diseases (n = 20) and adult patients with no proven infection (n = 16).

RESULTS

Sensitivity for DbpA was 82%, for BBK32 70%, for OspC 58% and for IR6 70%. Specificities were 94%, 100%, 97%, and 97%, respectively. No single antigen was superior. When new antigens were combined in a panel, sensitivity was 80% and specificity 100%. The reference flagella antigen showed a sensitivity of 60% and a specificity of 100%. Over all, the B. garinii related antigens dominated.

CONCLUSIONS

Recombinant DbpA and BBK32 as well as the peptide antigen IR6 perform well in laboratory diagnostics of neuroborreliosis in children. New antigens seem to improve diagnostic performance when compared with the routine flagella antigen. If different antigens are combined in a panel to cover the antigenic diversity, sensitivity improves further and a specificity of 100% can be achieve.

Counterpoint: long-term antibiotic therapy improves persistent symptoms associated with lyme disease

BACKGROUND

Controversy exists regarding the diagnosis and treatment of Lyme disease. Patients with persistent symptoms after standard (2-4-week) antibiotic therapy for this tickborne illness have been denied further antibiotic treatment as a result of the perception that long-term infection with the Lyme spirochete, Borrelia burgdorferi, and associated tickborne pathogens is rare or nonexistent.

METHODS

I review the pathophysiology of B. burgdorferi infection and the peer-reviewed literature on diagnostic Lyme disease testing, standard treatment results, and coinfection with tickborne agents, such as Babesia, Anaplasma, Ehrlichia, and Bartonella species. I also examine uncontrolled and controlled trials of prolonged antibiotic therapy in patients with persistent symptoms of Lyme disease.

RESULTS

The complex "stealth" pathology of B. burgdorferi allows the spirochete to invade diverse tissues, elude the immune response, and establish long-term infection. Commercial testing for Lyme disease is highly specific but relatively insensitive, especially during the later stages of disease. Numerous studies have documented the failure of standard antibiotic therapy in patients with Lyme disease. Previous uncontrolled trials and recent placebo-controlled trials suggest that prolonged antibiotic therapy (duration, >4 weeks) may be beneficial for patients with persistent Lyme disease symptoms. Tickborne coinfections may increase the severity and duration of infection with B. burgdorferi.

CONCLUSIONS

Prolonged antibiotic therapy may be useful and justifiable in patients with persistent symptoms of Lyme disease and coinfection with tickborne agents.

C6 peptide ELISA test in the serodiagnosis of Lyme borreliosis in Sweden

The aim of this study was to evaluate the synthetic C6 peptide test as a first-line test in a two-tiered scheme for Borrelia serology in a clinically well-characterized population of patients with Lyme borreliosis in Kalmar County, Sweden. The study population consisted of a prospective group (n = 200), a control group (n = 255), and a retrospective group (n = 29). The test panel consisted of the Immunetics Quick ELISA C6 Borrelia assay kit (Immunetics, Cambridge, MA, USA), the Virotech Borrelia burgdorferi ELISA (Genzyme Virotech, Rüsselsheim, Germany), and the Liaison Borrelia CLIA (DiaSorin, Saluggia, Vercelli, Italy). Seroprevalence among 200 healthy blood donors was significantly lower in the C6 test (8%) compared to the Virotech ELISA (14%) and the Liaison CLIA (12%). In convalescent sera (2-3 months and 6 months post infection) from 158 patients with erythema migrans, the seropositivity in the C6 test was also significantly lower compared to both the Virotech ELISA and the Liaison CLIA. Serosensitivity in the acute phase of erythema migrans and other clinical manifestations of borreliosis did not differ significantly between the C6 test and the Virotech ELISA or the Liaison CLIA. Overall, a positive C6 test seems to correlate well with acute borreliosis. Cross-reactivity was lower in the C6 test in sera positive for Epstein-Barr virus infection as compared to the Virotech ELISA. This study supports the use of the C6 test as a screening test for borreliosis, in endemic areas.

Lyme disease: the quest for magic bullets

Lyme disease represents a growing public health threat. Recent molecular and genetic studies have confirmed that Borrelia burgdorferi, the spirochetal agent of Lyme disease, is one of the most complex bacteria known to man. Affinity for multiple cell types and the presence of non-replicating forms of B. burgdorferi have contributed to persistent infection and failure of simple antibiotic regimens. The controversial clinical science of Lyme disease has impeded reliable diagnosis and effective treatment of this protean illness. Two major clinical hurdles are the absence of a therapeutic endpoint in treating Lyme disease and the presence of tick-borne coinfections that may complicate the course of the illness. New strategies for the diagnosis, treatment and prevention of Lyme disease are urgently needed.