Cross-reactivity to Borrelia burgdorferi proteins in serum samples from residents of a tropical country nonendemic for Lyme disease

Antibody Cross-Reactivity in Serodiagnosis of Lyme Disease

Lyme disease is a tick-borne disease caused by spirochetes belonging to the Borrelia burgdorferi sensu lato complex. The disease is characterized by a varied course; therefore, the basis for diagnosis is laboratory methods. Currently, a two-tiered serological test is recommended, using an ELISA as a screening test and a Western blot as a confirmatory test. This approach was introduced due to the relatively high number of false-positive results obtained when using an ELISA alone. However, even this approach has not entirely solved the problem of false-positive results caused by cross-reactive antibodies. Many highly immunogenic B. burgdorferi s.l. proteins are recognized nonspecifically by antibodies directed against other pathogens. This also applies to antigens, such as OspC, BmpA, VlsE, and FlaB, i.e., those commonly used in serodiagnostic assays. Cross-reactions can be caused by both bacterial (relapsing fever Borrelia, Treponema pallidum) and viral (Epstein-Baar virus, Cytomegalovirus) infections. Additionally, a rheumatoid factor has also been shown to nonspecifically recognize B. burgdorferi s.l. proteins, resulting in false-positive results. Therefore, it is necessary to carefully interpret the results of serodiagnostic tests so as to avoid overdiagnosis of Lyme disease, which causes unnecessary implementations of strong antibiotic therapies and delays in the correct diagnosis.

Unexpected failure of Ixodes scapularis nymphs to transmit a North American Borrelia bissettiae strain

Globally, the Borrelia burgdorferi (sensu lato) complex comprises more than 21 species of spirochetes. Although the USA is home to a diverse fauna of Lyme disease group Borrelia species, only two are considered responsible for human clinical disease: Borrelia burgdorferi (sensu stricto) and Borrelia mayonii. However, evidence has implicated additional B. burgdorferi (s.l.) species in human illness elsewhere. While much research has focused on the B. burgdorferi (s.s.)-tick interface, tick vectors for most of the other North American Lyme disease group Borrelia species remain experimentally unconfirmed. In this report we document the ability of Ixodes scapularis to acquire but not transmit a single strain of Borrelia bissettiae, a potential human pathogen, in a murine infection model. Pathogen-free I. scapularis larvae were allowed to feed on mice with disseminated B. burgdorferi (s.s.) or B. bissettiae infections. Molted infected nymphs were then allowed to feed on naïve mice to assess transmission to a susceptible host through spirochete culture and qPCR throughout in ticks collected at various developmental stages (fed larvae and nymphs, molted nymphs, and adults). In this study, similar proportions of I. scapularis larvae acquired B. bissettiae and B. burgdorferi (s.s.) but transstadial passage to the nymphal stage was less effective for B. bissettiae. Furthermore, B. bissettiae-infected nymphs did not transmit B. bissettiae infection to naïve susceptible mice as determined by tissue culture and serology. In the tick, B. bissettiae spirochete levels slightly increased from fed larvae to molted and then fed nymphs, yet the bacteria were absent in molted adults. Moreover, in contrast to B. burgdorferi (s.s.), B. bissettiae failed to exponentially increase in upon completion of feeding in our transmission experiment. In this specific model, I. scapularis was unable to support B. bissettiae throughout its life-cycle, and while live spirochetes were detected in B. bissettiae-infected ticks fed on naïve mice, there was no evidence of murine infection. These data question the vector competence of Ixodes scapularis for B. bissettiae. More importantly, this specific B. bissettiae-I. scapularis model may provide a tool for researchers to delineate details on mechanisms involved in Borrelia-tick compatibility.

Is there a Lyme-like disease in Australia? Summary of the findings to date

Lyme Borreliosis is a common tick-borne disease of the northern hemisphere caused by the spirochaetes of the Borrelia burgdorferi sensu lato (B. burgdorferi s. l.) complex. It results in multi-organ disease with arthritic, cardiac, neurological and dermatological manifestations. In the last twenty-five years there have been over 500 reports of an Australian Lyme-like syndrome in the scientific literature. However, the diagnoses of Lyme Borreliosis made in these cases have been primarily by clinical presentation and laboratory results of tentative reliability and the true cause of these illnesses remains unknown. A number of animals have been introduced to Australia that may act as B. burgdorferi s. l. reservoirs in Lyme-endemic countries, and there are some Australian Ixodes spp. and Haemaphysalis spp. ticks whose geographical distribution matches that of the Australian Lyme-like cases. Four published studies have searched for Borrelia in Australian ticks, with contradicting results. The cause of the potential Lyme-like disease in Australia remains to be defined. The evidence to date as to whether these illnesses are caused by a Borrelia species, another tick borne pathogen or are due to a novel or unrelated aetiology is summarised in this review.

Collection and characterization of samples for establishment of a serum repository for lyme disease diagnostic test development and evaluation

Serological assays and a two-tiered test algorithm are recommended for laboratory confirmation of Lyme disease. In the United States, the sensitivity of two-tiered testing using commercially available serology-based assays is dependent on the stage of infection and ranges from 30% in the early localized disease stage to near 100% in late-stage disease. Other variables, including subjectivity in reading Western blots, compliance with two-tiered recommendations, use of different first- and second-tier test combinations, and use of different test samples, all contribute to variation in two-tiered test performance. The availability and use of sample sets from well-characterized Lyme disease patients and controls are needed to better assess the performance of existing tests and for development of improved assays. To address this need, the Centers for Disease Control and Prevention and the National Institutes of Health prospectively collected sera from patients at all stages of Lyme disease, as well as healthy donors and patients with look-alike diseases. Patients and healthy controls were recruited using strict inclusion and exclusion criteria. Samples from all included patients were retrospectively characterized by two-tiered testing. The results from two-tiered testing corroborated the need for novel and improved diagnostics, particularly for laboratory diagnosis of earlier stages of infection. Furthermore, the two-tiered results provide a baseline with samples from well-characterized patients that can be used in comparing the sensitivity and specificity of novel diagnostics. Panels of sera and accompanying clinical and laboratory testing results are now available to Lyme disease serological test users and researchers developing novel tests.

Coinfections acquired from ixodes ticks

The pathogens that cause Lyme disease (LD), human anaplasmosis, and babesiosis can coexist in Ixodes ticks and cause human coinfections. Although the risk of human coinfection differs by geographic location, the true prevalence of coinfecting pathogens among Ixodes ticks remains largely unknown for the majority of geographic locations. The prevalence of dually infected Ixodes ticks appears highest among ticks from regions of North America and Europe where LD is endemic, with reported prevalences of < or =28%. In North America and Europe, the majority of tick-borne coinfections occur among humans with diagnosed LD. Humans coinfected with LD and babesiosis appear to have more intense, prolonged symptoms than those with LD alone. Coinfected persons can also manifest diverse, influenza-like symptoms, and abnormal laboratory test results are frequently observed. Coinfecting pathogens might alter the efficiency of transmission, cause cooperative or competitive pathogen interactions, and alter disease severity among hosts. No prospective studies to assess the immunologic effects of coinfection among humans have been conducted, but animal models demonstrate that certain coinfections can modulate the immune response. Clinicians should consider the likelihood of coinfection when pursuing laboratory testing or selecting therapy for patients with tick-borne illness.

IgG antibody reactivity toBorrelia burgdorferi sensu strictoantigens in patients with morphea in Colombia

BACKGROUND

Morphea and lichen sclerosus et atrophicus (LSA) are sclerotic skin lesions of unknown etiology involving connective tissue. The hypothesis of a borrelial origin of morphea and LSA is currently controversial.

METHODS

Immunoglobulin G (IgG) immunoblot serologies against Borrelia burgdorferi in patients with morphea and LSA were analyzed and compared with those from healthy donors and patients with syphilis to determine the association with a probable borrelial agent in Colombia.

RESULTS

No significant differences in the number of reactive antigenic bands were found between morphea/LSA patients and syphilis patients or healthy donors. The presence of at least one of the following bands, p28, p39, or p45, was the criterion most able to distinguish morphea/LSA, yielding a specificity of 95% and a sensitivity of 28.6%. Using this criterion as evidence of putative exposure to a causative borrelial agent, sclerotic skin lesions had an odds ratio of 7.60 (95% confidence interval, 1.47-39.23).

CONCLUSIONS

These results could be explained by cross-reactivity; however, the partial shared reactivity of sera from patients with syphilis and morphea/LSA does not rule out the possibility that a new spirochetal agent, unrelated to B. burgdorferi or Treponemas, may be the causative agent of morphea/LSA in Colombia.

Geographical and seasonal correlation of multiple sclerosis to sporadic schizophrenia

BACKGROUND: Clusters by season and locality reveal a striking epidemiological overlap between sporadic schizophrenia and multiple sclerosis (MS). As the birth excesses of those individuals who later in life develop schizophrenia mirror the seasonal distribution of Ixodid ticks, a meta analysis has been performed between all neuropsychiatric birth excesses including MS and the epidemiology of spirochaetal infectious diseases. RESULTS: The prevalence of MS and schizophrenic birth excesses entirely spares the tropical belt where human treponematoses are endemic, whereas in more temperate climates infection rates of Borrelia garinii in ticks collected from seabirds match the global geographic distribution of MS. If the seasonal fluctuations of Lyme borreliosis in Europe are taken into account, the birth excesses of MS and those of schizophrenia are nine months apart, reflecting the activity of Ixodes ricinus at the time of embryonic implantation and birth. In America, this nine months' shift between MS and schizophrenic births is also reflected by the periodicity of Borrelia burgdorferi transmitting Ixodes pacificus ticks along the West Coast and the periodicity of Ixodes scapularis along the East Coast. With respect to Ixodid tick activity, amongst the neuropsychiatric birth excesses only amyotrophic lateral sclerosis (ALS) shows a similar seasonal trend. CONCLUSION: It cannot be excluded at present that maternal infection by Borrelia burgdorferi poses a risk to the unborn. The seasonal and geographical overlap between schizophrenia, MS and neuroborreliosis rather emphasises a causal relation that derives from exposure to a flagellar virulence factor at conception and delivery. It is hoped that the pathogenic correlation of spirochaetal virulence to temperature and heat shock proteins (HSP) might encourage a new direction of research in molecular epidemiology.

Seasonal correlation of sporadic schizophrenia to Ixodes ticks and Lyme borreliosis

BACKGROUND: Being born in winter and spring is considered one of the most robust epidemiological risk factors for schizophrenia. The aetiology and exact timing of this birth excess, however, has remained elusive so far. Since during phylogeny, Borrelia DNA has led to multiple germ-line mutations within the CB1 candidate gene for schizophrenia, a meta analysis has been performed of all papers on schizophrenic birth excesses with no less than 3000 cases each. All published numerical data were then plotted against the seasonal distributions of Ixodes ticks worldwide. RESULTS: In the United States, Europe and Japan the birth excesses of those individuals who later in life develop schizophrenia mirror the seasonal distribution of Ixodes ticks nine months earlier at the time of conception. South of the Wallace Line, which limits the spread of Ixodes ticks and Borrelia burgdorferi into Australia, seasonal trends are less significant, and in Singapore, being non-endemic for Ixodes ticks and Lyme disease, schizophrenic birth excesses are absent. CONCLUSION: At present, it cannot be excluded that prenatal infection by B. burgdorferi is harmful to the implanting human blastocyst. The epidemiological clustering of sporadic schizophrenia by season and locality rather emphasises the risk to the unborn of developing a congenital, yet preventable brain disorder later in life.

Ability of the borreliacidal antibody test to confirm lyme disease in clinical practice

Highly specific borreliacidal antibodies are induced by infection with Borrelia burgdorferi, and a borreliacidal antibody test (BAT) may be an accurate laboratory procedure for confirming Lyme disease in clinical practice. To investigate this, 34 Lyme disease sera and 34 sera from patients with other illnesses who had presented to a primary-care facility located in an area of borreliosis endemicity were tested by the BAT and Western blotting (WB). The BAT was more sensitive (79% versus 65%; P = 0.090), especially in cases in which patients had a single erythema migrans lesion (P = 0.021). In addition, the potentially cross-reactive sera were negative by the BAT but WB yielded three (9%) false-positive results. The results from 104 sera from possible Lyme disease patients demonstrated the clinical usefulness of the more sensitive and specific BAT. The BAT was positive for 40 (38%) sera from patients with Lyme disease-related symptoms and appropriate clinical and epidemiological findings. WB confirmed Lyme disease in 30 (75%) of the 40 BAT-positive patients but failed to detect B. burgdorferi infection in 10 BAT-positive patients. WB was also positive for 11 BAT-negative sera, but six (55%) patients had case histories which suggested that the results were false positives. Collectively, the results confirm that the BAT is a sensitive and highly specific test and suggest that widespread use would increase the accuracy of serodiagnostic confirmation of Lyme disease.

An unusual case of anti-Borrelia burgdorferi immunoglobulin G seroconversion caused by administration of intravenous gammaglobulins

Administration of gammaglobulins to individuals without specific anti-Borrelia burgdorferi antibodies may lead to immunoglobulin G (IgG) conversion as detected by enzyme-linked immunosorbent assay (ELISA). In some cases however, complementary techniques such as Western blot or avidity will be of prime importance in distinguishing the start of an infection from the passive immunization induced by the gammaglobulins. In all cases, the key element before reaching conclusions in relation to any of these investigations remains the confrontation between the clinical context and the biological findings. This is the scenario that has been followed in our observation.

Sensitive and specific serodiagnosis of Lyme disease by enzyme-linked immunosorbent assay with a peptide based on an immunodominant conserved region of Borrelia burgdorferi vlsE

VlsE, the variable surface antigen of Borrelia burgdorferi, contains an immunodominant conserved region named IR(6). In the present study, the diagnostic performance of a peptide enzyme-linked immunosorbent assay (ELISA) based on a 26-mer synthetic peptide (C(6)) with the IR(6) sequence was explored. Sensitivity was assessed with serum samples (n = 210) collected from patients with clinically defined Lyme disease at the acute (early localized or early disseminated disease), convalescent, or late disease phase. The sensitivities for acute-, convalescent-, and late-phase specimens were 74% (29 of 39), 85 to 90% (34 of 40 to 35 of 39), and 100% (59 of 59), respectively. Serum specimens from early neuroborreliosis patients were 95% positive (19 of 20), and those from an additional group of patients with posttreatment Lyme disease syndrome yielded a sensitivity of 62% (8 of 13). To assess the specificity of the peptide ELISA, 77 serum samples from patients with other spirochetal or chronic infections, autoimmune diseases, or neurologic diseases and 99 serum specimens from hospitalized patients in an area where Lyme disease is not endemic were examined. Only two potential false positives from the hospitalized patients were found, and the overall specificity was 99% (174 of 176). Precision, which was assessed with a panel of positive and negative serum specimens arranged in blinded duplicates, was 100%. Four serum samples with very high anti-OspA antibody titers obtained from four monkeys given the OspA vaccine did not react with the C(6) peptide. This simple, sensitive, specific, and precise ELISA may contribute to alleviate some of the remaining problems in Lyme disease serodiagnosis. Because of its synthetic peptide base, it will be inexpensive to manufacture. It also will be applicable to serum specimens from OspA-vaccinated subjects.

Positive IgG Western blot for Borrelia burgdorferi in Colombia

In order to evaluate the presence of specific IgG antibodies to Borrelia burgdorferi in patients with clinical manifestations associated with Lyme borreliosis in Cali, Colombia, 20 serum samples from patients with dermatologic signs, one cerebrospinal fluid (CSF) sample from a patient with chronic neurologic and arthritic manifestations, and twelve serum samples from individuals without clinical signs associated with Lyme borreliosis were analyzed by IgG Western blot. The results were interpreted following the recommendations of the Centers for Diseases Control and Prevention (CDC) for IgG Western blots. Four samples fulfilled the CDC criteria: two serum specimens from patients with morphea (localized scleroderma), the CSF from the patient with neurologic and arthritic manifestations, and one of the controls. Interpretation of positive serology for Lyme disease in non-endemic countries must be cautious. However these results suggest that the putative "Lyme-like" disease may correlate with positivity on Western blots, thus raising the possibility that a spirochete genospecies distinct from B. burgdorferi sensu stricto, or a Borrelia species other than B. burgdorferi sensu lato is the causative agent. Future work will focus on a survey of the local tick and rodent population for evidence of spirochete species that could be incriminated as the etiologic agent.

Serological responses to Ehrlichia equi, Ehrlichia chaffeensis, and Borrelia burgdorferi in patients from New York State

Serological testing at the New York State Department of Health for human granulocytic ehrlichiosis in the residents of Westchester County, N.Y., was performed with specimens from 176 patients by the indirect fluorescent-antibody (IFA) technique with Ehrlichia equi MRK-infected neutrophils. To understand whether human monocytotropic ehrlichiosis also occurs in this northeastern geographic region, specimens were also tested for antibodies to Ehrlichia chaffeensis Arkansas. Screening tests and immunoblots for Lyme disease (Borrelia burgdorferi infection) were also performed. Thirty-two patients had antibodies only to E. equi and 21 patients had antibodies to both E. equi and E. chaffeensis, whereas 12 patients had only E. chaffeensis antibodies by the IFA technique. The remaining patients did not have antibodies to either ehrlichia. Eighteen serum samples from 13 of these patients were coded and sent to the Ehrlichia Research Laboratory (Baltimore, Md.) for repeat analysis by the IFA test and for E. equi and E. chaffeensis immunoblots. Immunoblot analysis for E. equi in samples with positive IFA test results confirmed the results for eight of the nine specimens. Immunoblot analyses for E. chaffeensis were negative for all 18 serum samples. Borrelia-reactive antibodies were found in sera both from patients with granulocytic ehrlichiosis and from patients with monocytotropic ehrlichiosis from New York State. Our results suggest that E. equi antigen is an appropriate substrate for identifying human granulocytic ehrlichiosis. E. chaffeensis antigen lacks appropriate sensitivity to serve as a surrogate substrate for the detection of human granulocytic ehrlichiosis and should be used solely for the diagnosis of human monocytotropic ehrlichiosis. Heat shock proteins may, in some cases, cause cross-reactivity between B. burgdorferi and ehrlichiae.