Evaluation of nine serological tests for diagnosis of Lyme borreliosis

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.

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.

[Role of biological assays in the diagnosis of Lyme borreliosis presentations. What are the techniques and which are currently available?]

The biological diagnosis of Borrelia burgdorferi sensu lato infection is usually made by antibody detection in patient sera. Thus, serological testing (Elisa, immunoblotting) is essential for a biological diagnosis. Specific antibody detection is usually done in serum and CSF of patients suspected of Lyme borreliosis. Laboratories must follow European recommendations to validate these assays in routine practice. Antibody detection lacks sensitivity in the early cutaneous phase of the infection. Therefore, serological testing is not recommended for the diagnosis of erythema migrans. The interpretation of serology must take into account the variability of Elisa sensitivity and specificity and the lack of standardization for Western-blotting in Europe. Besides these indirect diagnosis techniques, there is also direct detection of spirochetes by culture or by in vitro DNA amplification but these require adequate samples. These molecular tests must not be performed routinely, but only for specific clinical situations and in specialized laboratories only.

Identifying diagnostic peptides for lyme disease through epitope discovery

Serum antibodies from patients with Lyme disease (LD) were used to affinity select peptide epitopes from 12 large random peptide libraries in phage display format. The selected peptides were surveyed for reactivity with a panel of positive sera (from LD patients) and negative sera (from subjects without LD), thus identifying 17 peptides with a diagnostically useful binding pattern: reactivity with at least three positive sera and no reactivity with any of the negative sera. The peptides define eight sequence motifs, none of which can be matched convincingly with segments of proteins from Borrelia burgdorferi, the LD pathogen; evidently, then, they are "mimotopes," mimicking natural pathogen epitopes without matching contiguous amino acids of pathogen proteins. Peptides like these could be the basis of a new diagnostic enzyme-linked immunosorbent assay for LD, with sufficient specificity and sensitivity to replace expensive immunoblotting tests that are currently required for definitive serological diagnosis. Moreover, the method used to discover these peptides did not require any knowledge of the pathogen and involved generic procedures that are applicable to almost any infectious disease, including emerging diseases for which no pathogen has yet been identified.

Clinical evaluation of guidelines and two-test approach for lyme disease

OBJECTIVE

The diagnosis of Lyme disease should be based on objective clinical signs and symptoms. In a clinical study, we have evaluated whether the recommended two-step approach for serodiagnosis of Lyme disease is useful in daily clinical practice and can influence clinical decision making.

METHODS

The signs and symptoms of patients with ongoing musculoskeletal complaints, assumed by their referring physician or themselves to be attributable to active or chronic Lyme disease, and of patients diagnosed as having Lyme disease, were evaluated. On the basis of clinical evaluation only, patients were classified into three groups: previous Lyme disease, active Lyme disease and no Lyme disease. Antibodies to Borrelia burgdorferi were determined by means of an enzyme-linked immunosorbent assay (ELISA), followed, when positive, by immunoblotting.

RESULTS

One hundred and three patients (41 males and 62 females, mean age 48.7 yr) participated in the study. Of the 49 patients classified as previous Lyme disease, 25 (51%) had antibodies to B. burgdorferi. All 10 patients with active Lyme disease had positive antibodies and 12 of the 44 patients (27%) classified as no Lyme disease had positive antibodies. No statistically significant differences were found between the percentage of positive immunoblots from patients with previous Lyme disease (72%) and patients with active Lyme disease (100%). In the group of no Lyme disease, five out of 12 patients had a negative immunoblot. Concerning serological testing, immunoblotting could have added additional information. However, immunoblotting did not influence clinical decision making in this group of patients.

CONCLUSION

Immunoblotting did not influence clinical decision making for the 47 patients with antibodies to B. burgdorferi in this study.

A one-step solid phase immunoassay for simultaneous detection of serum IgG and IgM antibodies to Borrelia burgdorferi

A one-step immunoassay for simultaneous detection of serum IgG and IgM antibodies to Borrelia burgdorferi has been developed. The assay is based on C1q, which binds to immune complexes containing IgG and/or IgM antibodies. Micro-beads pre-coated with antibodies to human C1q are mixed with human serum samples and fluorochrome-labelled B. burgdorferi flagellum antigen. In the presence of serum IgG and/or IgM antibodies to B. burgdorferi, fluorochrome-labelled antigen/antibody complexes are formed. These are then bound by serum C1q and are subsequently captured on the anti-C1q-coated beads. The sample is analysed on a flow cytometer and the presence of fluorescent beads is, thus, indicative of a positive test result. In the present study the sensitivity and specificity of the assay are compared to those of the indirect IDEIA B. burgdorferi IgG and the mu-chain capture IDEIA B. burgdorferi IgM ELISAs for separate determination of IgG and IgM. Detection using a flow cytometer can be performed without separation of the beads from the reaction mixture, which means that in practice, the method is carried out as a one-step assay and it is, thus, very suitable for automation. Other advantages of this kind of assay includes an antibody/antigen reaction which occurs in solution and the potential of using the method for the detection of antibodies against several antigens from the same or different infectious agents (multi-parameter screening).

Lyme borreliosis--an overdiagnosed disease?

Ninety-nine patients who were referred to a clinic for infectious diseases on suspicion of Lyme borreliosis and whose major symptoms were fatigue, headache, myalgia and arthralgia were studied retrospectively to find out if there was any difference in symptomatology between patients who were seropositive or seronegative to Borrelia burgdorferi. 64/82 (78%) patients remembered one or more tick bites during previous years and 32/74 (43%) patients had a history of erythema migrans. Fatigue, headache, myalgia and arthralgia occurred in 84%, 72%, 54%, and 63% of the patients, respectively. 62/99 (63%) patients had an elevated IgM and/or IgG antibody titer to B. burgdorferi. There was no difference in frequency of symptoms between seropositive and seronegative individuals. 48/99 (49%) patients were treated with antibiotics, mostly oral doxycycline. Only 50% were improved after treatment. On follow-up 2 to 4 years after the first visit, 40% of the patients had recovered completely, 31% were improved, 24% reported unaltered symptoms and four patients were impaired. There was no difference in symptoms on follow-up between seropositive or seronegative patients. It is concluded that there probably is an overdiagnosis of Lyme borreliosis and that better microbiological methods are needed to confirm active disease.

Antibodies against whole sonicated Borrelia burgdorferi spirochetes, 41-kilodalton flagellin, and P39 protein in patients with PCR- or culture-proven late Lyme borreliosis

The sensitivities and specificities of three enzyme-linked immunosorbent assays (ELISAs) for Borrelia burgdorferi antibodies were compared for 41 patients presenting with symptoms compatible with late Lyme borreliosis (LB) and 37 healthy controls. All subjects were living in southwestern Finland, where LB is endemic. Only patients with culture- or PCR-proven disease were enrolled in the study. The antigens of the ELISAs consisted of sonicated spirochetes, 41-kDa flagellin, and recombinant P39 protein of B. burgdorferi. Fifteen patients had strongly or moderately positive results in the serological assay(s), 19 patients had only weakly positive or borderline antibody levels, and the remaining 7 patients were seronegative by ELISA. The sensitivities of the ELISAs were 78.0% with sonicate antigen, 41.5% with 41-kDa flagellin, and 14.6% with P39 protein. The specificities of the tests were 89.2, 86.5, and 94.6%, respectively. The sonicate antigen ELISA seems to be an effective screening method. These results show that antibodies to B. burgdorferi may be present in low levels or even absent in patients with culture- or PCR-proven late LB. Therefore, in addition to serological testing, the use of PCR and cultivation is recommended in the diagnosis of LB.